Question:
I have a TronXY printer (i3 Clone).  It has a 220x220 mm heated aluminum bed and I print with a Borosilicate glass plate.

I have a slightly longer print (245 mm) I would like to do and I think I could adjust to settings and end stop to stretch the y-dimension travel and I have found a 229x257 mm plate.  This would extend over the edge of the aluminum bed.

Will the thermal conduction and mass of the glass plate be sufficient to still keep the bed warm enough?

Answer:
The aluminum plate is being heated by the heater element although I suspect the element does not encompass the entire area of the aluminum portion. There are going to be cooler spots on the aluminum but not enough to significantly affect the transfer to the glass.
Once you extend the glass, without a corresponding extension to the aluminum and/or heater element, you are ensuring cooler spots. The glass will be surrounded by air, and begin to conduct some of the heat, certainly, but will also radiate a substantial amount.
If you are printing with PLA, you may get away with doing this modification. Very little of the heat from the aluminum will reach the glass.
A quick check shows the thermal conductivity of aluminum to be 205 W/m K compared to borosilicate glass at 1.2 W/m K in the range of temperature used for 3D printing. I did not research the rate of energy dissipation for the same range of temperatures, but if it's not too high (unlikely), it would still take forever for the unheated areas of glass to reach temperature.
Consider your extension to be an unheated bed and print accordingly.


Question:
I'm working with a group at the MIT Launch startup accelerator for high school and I was hoping to do some market research regarding some of the current problems with desktop 3D printers. I was hoping to get some feedback from all your experience with 3D printing and the hours of troubleshooting you've likely encountered.

What workarounds and aftermarket modifications are the most useful? If you could change one thing about your printer what would it be? How do you troubleshoot issues and how long does it take? What would make you more likely to 3d print more often (ie never clogged, didn't have to watch first layer, etc)? In your opinion, what are the biggest issues the desktop 3D printing industry faces? Just share any wishes, thoughts, hopes, dreams, etc about 3D printing

Thank you so much for your time and sharing your experience!

Answer:
First, regarding
"Why do 3D Printers Suck?"
- The answer is
They Don't!
Every tool has its limitations and you need to work withing the limitations of the tool.
Second, there are
A LOT
of different types/technologies, manufacturers, and price points and all of these have specific limitations.
I live in Tigard, OR and both my boys are in High School.  Our High School has a pretty advanced Technologies Department.  We have had a 3D printer for a several years and use it for printing parts for our after school programs (we have three FTC teams, one FRC team, and one (underwater) MATE team).  This last year the school introduced a CAD class and added about 15-20 new Afina printers so that the students can print what they design.
I talked to my sons (they have both used the printers) and they said the only problems they ran into were mistakes they made.  Two examples of that are:
Printing with ABS and having it warp (probably bed temp)
Trying to print a design with too thin a wall
I think there is a BIG opportunity for improvement here.  Having a "Slicing" program that doesn't require tweaking and would warn of likely print problems would help A LOT.  I like the idea of the new
PrusaControl
.  If this idea could be extended further as
Thomas Sanladerer suggested in his video review
I know the Head of Technologies Department (I help mentor several of the after school programs).  He has been responsible for getting printers and I recall he was concerned about more high-level things:
Service, Maintenance and Repair
Fumes (this is a lot of printers in one place with students in the same room)
Network interface and driver compatibility with school computer/network standards.
I believe there is another opportunity here.  If you could provide some sort of a "printer farm" where the students could send their print to the "farm" and then have a highly visible indicator on the selected printer would their name/ID when their print starts.  That way you can get more efficient use of the printers and the space they consume.


Question:
Can anyone help me find/confirm the information needed to setup the CR-10 in the Cura Software

I have following settings from research:

Printer Settings

x =  300 mm

y =  300 mm

z =  400 mm

Build Plate = Rectangular

Machine Center is Zero = Checked

Heated Bed = Checked

G-code Flavor = RepRap (Marlin/Sprinter) -- Uncertain - please help confirm this

Print Head Settings

X min = Unclear where this comes from

Y min = Unclear where this comes from

X max = Unclear where this comes from

Y max = Unclear where this comes from

Gantry Height = Unclear where this is measured from

Number of Extruders = 1

Material Diameter - 1.75 mm

Nozzle size = 0.4 mm

Answer:
GCode flavor
: the firmware your machine uses. Google tells me CR-10 uses Marlin, so you should select that. Volumetric Marlin is not very common.
Print Head Settings
X/Y min/max
define the bounding box of the area your print head takes up. Measure the distance from the centre of the nozzle to the left-most point of the print head and do the same for the right-most, front-most and back-most.
Gantry Height
is the distance from the tip of the nozzle to the lowest point of the gantry, which is the axle on which the print head is mounted.
These print head settings are only used for one-at-a-time printing.


Question:
How do I speed up prints for the Monoprice Select IIIP Plus printer?

The manual shows [Cura] examples of:

Print speed: 50mm/s

Travel Speed: 80mm/s

Bottom Layer Speed: 20mm/s

Infill Speed: 50mm/s

Outer shell speed: 15mm/s

Inner shell speed: 30mm/s

However, this doesn’t line up with their advertisements online of a 150mm/s printing speed.

Are there better settings to use, especially ones which can speed up printing time? Or are there any other measures which I can take in order to reduce printing time in general?

Answer:
In my experience a print speed of 50-70mm/s is ideal. Even if you set the speed to 150mm/s the print head still changes directions often and rarely will have enough time to accelerate from 0->150 before changing direction again.
Some more effective ways of speeding up prints is to adjust
Layer height
Infill percentage (15-25% for regular prints, more if they need to be more sound)
Supports
Number of shells, etc


Question:
I cannot generate the upper part of the solid properly which contain a hole (as in the picture).  The solid part (bottom section) printed well.

What should I change to print the part with hole properly?

Is it a problem with machine or the design?

I am using Hydra 3D printer.

Answer:
It appears that the upper part of your print contains less plastic than the lower. This would mean that as the printer begins to operate in that area, the previously deposited plastic has less time to cool.
The distortions are difficult to see from the distortions of the photograph, but I've experienced similar upper, smaller section failures.
You could consider to print more than one copy of the item on the bed, which will require the nozzle to move away from each layer, allowing more cooling time, or add a throw-away model.
I've also added an ooze shield using Simplify3D to create a single wall around the part, providing the same cooling time concept.
If you try these options and still experience a problem, please consider editing your post with material used (PLA, ABS, PETG, etc) as well as temperatures and speeds used for this print.
Your slicer is not likely the problem, but is often useful information. Printer name is sometimes helpful, but I think it's not critical in this circumstance.
It's also useful to orient the part in the photograph to match that of the print. It's apparent in this case that the top of the print is to the right and bottom is to the left. If that is not correct, please advise in edit.


Question:
I have Ramps 1.4 and would like to get answer on extrusion in Marlin firmware. I have NEMA 17 stepper motor 1.8 deg, set to 1/16 step. Mk7 direct drive.
38 teeth in extruder drive gear. I bought it from this website.

Here are my current settings:

#define DEFAULT_AXIS_STEPS_PER_UNIT   { 80,80, 4000, 180 }
#define DEFAULT_MAX_FEEDRATE          { 500, 500, 3, 45 }
#define DEFAULT_MAX_ACCELERATION      { 9000, 9000, 100, 300 }

I am using ABS 1.75 filament and a 0.4 nozzle.

Answer:
According to the description, the drive gear you have has a
```
10.8mm
```
diameter. This means that (in the ideal case) one full rotation of the drive gear will advance a length of filament equal to its circumference, which is
```
pi x 10.8mm
```
or approximately
```
33.93mm
```
.
Your motor rotates
```
1.8
```
degrees per step, so it takes
```
360 / 1.8 = 200 steps
```
for a full rotation. Since you are using 16x microstepping, this is multiplied to
```
200 x 16 = 3200 steps
```
.
You thus end up with a steps per mm value of
```
3200 / 33.93 = 94.31 steps/mm
```
.
You might need to calibrate this further, for instance by extruding a set length of filament (e.g. 100mm) and measuring how much is actually extruded, and then compensating the steps/mm value to get you closer to the desired 100mm. A simple way to measure this is to put a mark on your filament at 150mm from the extruder, and then (after extruding 100mm) measure how close the mark is to the extruder (which should be 50mm) However, this theoretically computed value should be a good starting point. Note that the speed you do this test at should be close to your normal printing speed, since extruding at a much higher (resp. lower) speed will falsely lead you to believe you are underextruding (resp. overextruding).


Question:
This is my first time building a 3D printer (a "Creality Ender-4").

Everything is going fine except the "extruder kit" part that does not have enough space to attach on the frame.  Should I drill it to have a longer hole so it can be attached to the frame? I just want another set of eyes to look at it to make sure I'm not crazy.

Answer:
According to the description, the drive gear you have has a
```
10.8mm
```
diameter. This means that (in the ideal case) one full rotation of the drive gear will advance a length of filament equal to its circumference, which is
```
pi x 10.8mm
```
or approximately
```
33.93mm
```
.
Your motor rotates
```
1.8
```
degrees per step, so it takes
```
360 / 1.8 = 200 steps
```
for a full rotation. Since you are using 16x microstepping, this is multiplied to
```
200 x 16 = 3200 steps
```
.
You thus end up with a steps per mm value of
```
3200 / 33.93 = 94.31 steps/mm
```
.
You might need to calibrate this further, for instance by extruding a set length of filament (e.g. 100mm) and measuring how much is actually extruded, and then compensating the steps/mm value to get you closer to the desired 100mm. A simple way to measure this is to put a mark on your filament at 150mm from the extruder, and then (after extruding 100mm) measure how close the mark is to the extruder (which should be 50mm) However, this theoretically computed value should be a good starting point. Note that the speed you do this test at should be close to your normal printing speed, since extruding at a much higher (resp. lower) speed will falsely lead you to believe you are underextruding (resp. overextruding).


Question:
I play a berimbau for Capoeira. One of the most fragile (and most expensive) bits is the cabaça, a hollow gourd used as a resonator.

I'm not very familiar with the qualities of the resin used for 3d printing. If I were to take this to our local Maker Lab and have them scan and print a copy, how likely is it that it would work? My fear is that the plastic would be too sound deadening.

If you want a less exotic parallel, imagine the body of a guitar. That's a resonating chamber.

Answer:
I'll take a stab here, but my gut instinct is to say that a printed part will not sound the same as your original gourd resonator.
I believe the acoustics rely on the hardness, shape, and size of the material. In which case, a gourd is a hard and often thin material (after gutting it). Typical 3D printing materials will have a minimum thickness which may get in the way of achieving the same shape of the gourd resonator and plastics are typically going to be softer in hardness than your gourd.
So, in short, I think if your try to replicate the resonator with 3D printing it will not sound the same. That may not be a bad thing, depending on what you're looking for.
Also, who's to say the resonator has to be shaped like that? 3D printers allow us to manufacture parts that have historically been impossible to make and many instruments that we use today were designed hundreds of years ago with far less advanced tools available. I say its worth trying a replica of the gourd and then exploring other shapes to print that may affect the tonality of your instrument.


Question:
I am extending the bed of my TronXY X3 FDM RepRap printer.

I am extending the bed from 220 mm x 220 mm to 220 mm x 300 mm.  For now, I will keep the existing bed and add and aluminum sheet on top.  That leaves 40mm on front and back of the original bed.

Right now I only plan on running PLA; but, I do plan on heating the bed.

How thick does the aluminum sheet need to be?

Answer:
Main factors that control the process of the print bed selection are
weight: too thick plate increases inertial force, limiting maximum acceleration/jerk (decreased print speed)
stiffness: too thin plate will warp when heated or bend during calibration (decreased print quality/printer reliability)
For table sizes around 400x400mm I would think of 4mm plate, but it still can warp if heated unevenly.
Sometimes it makes sense to use a sandwich-type table: lower level is MDF, cork panel for heat insulation and thin (1.5-2mm) aluminum heated bed on top.


Question:
I have a mesh of a bowl that has the perfect shape of half a sphere. I want to easily convert it to the containing sphere solid and a box solid that will be subtracted from it.

Googling mesh to solid shows that in various tools such as 3ds Max, Fusion, etc., manual approximation of where the sphere might go is created manually by visually comparing to the mesh or the cross section when creating the solid but I am looking for the minimum enclosing sphere and box to be generated/calculated by the software.

Source file format is of course not an issue, it can be any known mesh file.

Answer:
The calculations for your objective could be considered simple geometry, although the results in terms of formulae are a bit more complex than simple, but not by much.
According to
Quora
, the foundation for this goal is that the cube's eight vertices will be coincidental to the sphere's surface. If one desires to print a 3D object with this form, such an object may fail the requirement of being manifold, but may not, depending on the floating point operations of the software being used.
I found a simplistic formula which provides the radius of the sphere given the length of the side of the cube.
```
```
$fn = 90;
edge = 10;
cube([edge, edge, edge], center = true);
sphere_radius = sqrt((3 * pow((edge/2), 2)));
sphere(sphere_radius);
```
```
The above code is done in
OpenSCAD
, resulting in this image with the sphere made transparent for clarity:
Translated into general English, it appears that one can take the edge length, divided by 2, then take the square of that result and triple it. Take the square root of that value and it becomes the radius of the sphere.
The above answer is courtesy of
Math Forum
and is represented verbatim as such:
```
```
____________________________
  D = \| (L/2)^2 + (L/2)^2 + (L/2)^2
```
```
The letter D in this case appears to be slightly misrepresented as diameter when it should be referred to as radius.
As part of this fun exercise, I also subtracted the cube from the sphere, slicing it in half for visibility, resulting in this image:


Question: I am curious about the algorithm/principles behind the estimates that the slicing softwares provide. Is there a standard technique behind this and how accurate is it ?

Answer:
Generally speaking, the typical algorithm takes into account the slicer's speed settings for specific features of the build, such as infill, perimeters, top/bottom layers, etc. The distance traveled by the nozzle at a specific speed for each feature is also part of the equations involved. There are some rather vague portions of the nozzle movement based on acceleration and other factors which makes the calculations less accurate.
How accurate is it?
Not too accurate. My experience with three different slicers is that it's never been within better than ten percent. I believe the various combinations of features of a build are not going to be identical from one model to the next, preventing even a ballpark figure to be created from previous builds.


Question:
On my Mac I've got two versions of Cura installed, in /Applications/Cura250 and /Applications/Cura262.

How can I copy my printer and profile settings from Cura 2.5 to Cura 2.6?

Answer:
Generally speaking, the typical algorithm takes into account the slicer's speed settings for specific features of the build, such as infill, perimeters, top/bottom layers, etc. The distance traveled by the nozzle at a specific speed for each feature is also part of the equations involved. There are some rather vague portions of the nozzle movement based on acceleration and other factors which makes the calculations less accurate.
How accurate is it?
Not too accurate. My experience with three different slicers is that it's never been within better than ten percent. I believe the various combinations of features of a build are not going to be identical from one model to the next, preventing even a ballpark figure to be created from previous builds.


Question:
Carbon 3d made a 100x faster printer which has a simple and cheap mechanism using a Teflon layer. It appears to have a 20mn in RnD Costs and $7000 mass market production cost.

The only access method for one is a USD$ 161,250 yearly subscription.

Their printer is not available in shapeways... Is there something wrong with  Carbon 3D so that it does not view consumers as a direct market, and has no market news on it's website?

How can they spend 222 million in investment money and not have a 3d printer in shapeways or public access?

Answer:
I will take the question seriously, and consider reasons why Carbon 3D might choose to offer their technology through a yearly subscription, rather than building a product accessible to the consumer market.  These reasons are speculation and do not reflect any specific knowledge about Carbon 3D, the details of their technology, or anything unique about their corporate mission.
1) The mission of a company, especially in the beginning while competition makes it possible, to make as much money as possible.  If the technology is unique and brings good value to a large enough set of interested customers, it can easily consume the full attention of a company to service those customers.  The price those companies pay for access may be higher than others would pay because their derived value is higher.
2) If a technology is new, and perhaps still somewhat immature, there may be very high support efforts and cost required.  Through this time, the learning curve does it's job, the technology improves and matures, and the costs go down.
3) If the technology is immature, and perhaps is evolving quickly, it could be to the advantage of a supplier to only offer the technology on a service rather than capital acquisition basis.  It simplifies replacing components.
4) If the technology is immature, selling the service may be easier than selling the hardware.  It simplifies the acquisition process, and makes it easier for customer's to expand their usage since the supplier's capital is used to finance the machines instead of the customer's.
5) Even with a mature, proven technology, it can be advantageous to maintain a higher price point.  The game is optimizing the profit on volume times price.  The point they operate at is influenced by their perception of the market.
6) In the early adopter phase, it is critical that the customer experience be stellar.  They may be limited in how rapidly they can scale in some critical dimension -- consumables supply chain, manufacturing capacity, trained installation technicians, local service offices, or many other limits.  Anything going wrong makes for a bad customer experience.
It doesn't surprise me that they aren't going after the consumer market at this time.
But, I'm not in the CEO's office, and I don't see where his pain comes from.  My purpose here is only to propose some plausible reasons why the company has not launched a consumer facing product.


Question:
I was looking for some advice on which 3D printers are good for someone who is just getting into 3D printing?

I have been looking at the Anet A8 on ebay but not sure if they are any good or not.

Regards

Answer: A budget would make answering your question alot easier. Do you have any experience with cad/cam software? What are you wanting to do with it? There are many inexpensive 3d printers but your skill level in mechanics/machinery, electronics, programming etc will also help others choose a good option for you. For example, plug and play units are usually more expensive than build your own models. But if you don't have the skill to assemble it the savings wasn't worth it


Question:
I'm interested in printing small machine parts (gears, linkages, structural components) so I'm looking for accuracy and mechanical strength over speed and volume.

I'm also somewhat concerned about harmful emissions so would like a solution with some sort of filtration, whether it's built into the machine or something added. I'm thinking I will run the machine in an unventilated garage, which is quite warm and humid during the summer in Texas.

My price range is \$1500-\$2000 USD. I've looked at several options but I didn't really come across any scenarios like I've described and would like some advice from the experts before committing.

Anyone in a similar boat have any suggestions?

Answer:
Your environmental conditions will preclude finding a machine suitable for your purposes in the budget specified.
Humidity is a problem with many material types, especially nylon, but also with PLA and ABS, the more common filaments used in 3D printing.
You can likely reject PLA for your mechanical needs, as it is brittle and weak compared to ABS. PLA releases virtually no gases of concern, while some find ABS fumes to be offensive and dangerous.
The humidity issue is forefront in your search. You may have to construct within the garage a chamber in which you would operate a portable or window air conditioner unit, to keep the humidity in check. If you can assign a different budget to such a construction, that will leave your printer funding intact and better able to address your goal.
Selective Laser Sintering using nylon powder, also susceptible to humidity, which is sintered by a laser, hence the name, making very detailed and strong parts. The process is also self-supporting, allowing for fairly intricate parts. Once the machine is calibrated, the part accuracy can be quite good. Unfortunately, SLS machines are also out of the budget range you've noted.
You can use an external service to print the parts you design, at least at first, to get a better indication of how the various materials will work for you. Start with PLA, then move to ABS for a set of test parts, and even perhaps have some printed using SLS.
If you find, for example, that ABS will be strong enough, you might find an affordable 3D printer which will generate parts on your budget and timeline. For printing ABS, the warmer temperatures are to your advantage, but the humidity has to be properly addressed in any home/shop/garage installation.


Question:
My printer stopped printing during a few prints, and i found that the extruder had stopped heating, and the motors had stopped running. I checked the code, and nothing was wrong. My 5A fuse though, was extremely hot. I wanted to verify whether it was my fuse that had turned bad or there was some kind of short in my circuitry.
With the power switched on, none of my appliances drew any current. However, the RAMPS board drew about 0.16 amps.
Is that normal?
If that is normal, does it mean that my fuse needs replacement? Because none of my loads seemed to draw unnecessary current.
Thanks in advance.

Answer:
As @Mikhail Z commented, it does sound like the fuse may be bad.
The first thing to do is put an ohmmeter across the fuse (with power off!) -- if you get high resistance the fuse is definitely bad. However, if you get low resistance that does not prove the fuse is good -- see @Tom's comments below re. polyfuses in particular, and how to disconnect from the rest of the circuit.
If you don't get lucky testing a fuse in-line, remove it and put the ohmmeter on it in isolation. Whether good or bad, it's good to put in a fuse-holder or socket, so you never have to de-solder the fuse again.
Some boards use auto-resetting fuses or circuit breakers, which might have more complicated ways of failing (you can always replace the part to be sure). I personally avoid auto-resetting for anything that supplies heaters; if there's a problem I want to intervene rather than letting it try again endlessly.
Since the heaters and the motors are both down, it's a good bet it's the fuse or something very early (that is, "near" the power supply). If it were a single motor or single heater, then the output control (typically a solid-state relay, or perhaps the logic controlling it) would be a better bet. Though unlikely, it's possible for two or more such controls to fail at once, so don't rule that out
completely
.
Let us know what you discover.


Question:
I made a tea bowl, but it leaked when making it in PLA...

What are the key points to keep in mind when designing and printing an object that is intended to hold water using an FDM printer?

Answer:
When designing the object, you should make sure your object is completely enclosed (obviously). When printing, try increasing the print temperature so that the layers stick to each other well. The most important thing is the print temperature, because if the layers don't adhere to each other well, you will get a leak. The wall thickness of the object can be thin, as long as it isn't so thin that it has too little strength to hold anything.
Some tips:
Printing in vase mode can save loads of time, otherwise the printer wastes time doing each layer separately.
Your nozzle should be 0.4 mm and up, otherwise the print will take forever.


Question:
I have a generic printer with no support documentation.

How do I determine what firmware is in use so that I can research how to make the print run?

Answer:
Send
```
M115
```
to the printer. This command is
Request the Firmware Version and Capabilities of the current microcontroller.
Response example:
ok PROTOCOL_VERSION:0.1 FIRMWARE_NAME:FiveD FIRMWARE_URL:http%3A//reprap.org MACHINE_TYPE:Mendel EXTRUDER_COUNT:1
For more info see here,
RepRapWiki- G-code - M115: Get Firmware Version and Capabilities
.
Of course, this isn't guaranteed to tell the truth, just whatever your generic clone firmware had in its source code.


Question:
I'm getting this printing where it's not laying the plastic down very well. What could be causing this? I've printed with these settings before, and it turned out just fine. If you need any other info to properly diagnose this, let me know.

I'm using a Robo3D R1+

[

Answer:
I´ve seen this in my Prusa due two parameters that may vary your results depending on climate if your printer has not a temperature chamber or having a mechanical issue too.
Lack of extrusion is due a cold filament which it can't reach the melting temperature due a fast extrusion feed; I mean in normal conditions we can print @70 mm/s with 195 °C but on wet or colder days is not possible so I need to slow down the speed (feed rate) with 10 % less than normal to get @60 mm/s or less until get a good flow with out modifying the G-code. If I try to print faster on normal conditions I will get the same lack of material due 195 °C is a low temperature (this is an example).
If I set the temperature 200 °C or 210 °C I will get a better flow and also print faster than @80 mm/s (not affected too much on climate on 100 % feed rate).
For first layer I´m using an speed of 40 mm/s to allow a good adhesion and Z height 90 % of layer height (0.22 typically or 0.18).
Mechanical side: The extruder is not feeding all the filament due a missing pression on the traction gear (filament slip).


Question:
I have make a little test with 4 dots aligned with A tower, B and C tower. Distance W and S are the same in the stl but not in the print. I have tried diferent values of diagonal root but S always is smaller than W, and all S are equal (more or less 38.20mm) and all W are equal (more or less 40.80). I expect that W and S will be 40mm. How can fix this problem?

Update:

Here is the stl I use: https://www.dropbox.com/s/2vwjbo387cmk5qa/DeltaCalibration%20v15.stl?dl=0

Update:
I have replaced the steper motor in tower B but same result.

Answer:
Well, you have two main issues:
1.-
Your calculation for stepping is a little wrong, for example your firmware indicates 2315.84 when you need 2321.70 (REMEMBER this is an example and is not accurate), So you will see a diference about 2.0mm along your printing. If your printing is bigger more diference you will get.
2.-
Misalignment, your printer is not angled correctly to 90° and also Z axe if has the same condition. with this uncalibrated parameter are you going to have pisa towers on every tall part.
For delta Printers this not apply
3.-
Tension. Your belts are a little weak; avoid weak tension band to eliminate something called backslash, of course this is for screw parts but is the same efect and even bigger. Also you will get an accurate dimension of the parts.


Question:
I have a Alunar M508 machine that I am trying to get new firmware on. The firmware that was loaded on the machine wasn't very good. The x axis was mirrored and the home point was way off. I was looking into Marlin to put on the machine, but don't have any experience on what to edit in the code to make it work for this machine.

Does anyone have any experience with this machine? Uploading new firmware that works or editing the code to make it work for this machine. I appreciate any help!

Here is a link to the firmware I am currently using. I'm on MacOS Sierra 10.12.5 using the 1.6.8 Arduino IDE.

Answer:
disclaimer
: I am the maintainer of the firmware that
you linked
.
The firmware will not improve your print quality. well, it may to some extent, but for the most part, it wont.
There is fine tuning involved that may be set for MY printer, but the values may need to be changed for you. Not to mention the physical tuning that I have done with my printer. Software is not the place to initially look for print quality improvements.
Some examples:
I printed anti-wobble caps for the Z-axis rods. Which improved the print drastically for me. As the print got higher, the quality got worse.
I printed Z-stop improvements, so I could fine tune the Z-stop.
I printed X & Y belt tensioners. Loose belts cause skipped steps which causes poor quality prints.


Question:
Is there anything special for printing TPU material e.g extruder or temperature?

It's my first time printing TPU material, so if you have any photos, it would be great if you can share them.

Answer:
Elastomers do much better on direct-drive heads (pulled to the head by the motor) than on Bowden designs (where the material is pushed to the head by a motor). This is because the flexible TPU or TPE can bend in the guide tube, causing lag during advance/retract changes, and sometimes even bind up during delivery.
Look for equipment which explicitly states that it is compatible with, and designed for, flexible filaments.


Question: I am new to Fusion 360 and I think I'm going straight to something complicated. Is there a way to make a nose cone for a model rocket? What tools would one you to accomplish this?

Answer:
If you have a specific shape in mind and can create a sketch to represent that shape, you are halfway to your goal.
The concept is simple. Create a single line sketch that would represent the desired curve, starting from, in this example, the nose of the cone and traveling to the base. Create only one-half of the nose cone curve and maintain a "standard" axis reference, say, using the Y-axis as the rotation point.
The process is called
revolve. Fusion 360
supports this action directly.
```
```
In the Sculpt workspace, choose Create Revolve.
Select the profile to revolve.
In the Revolve dialog:
    Click Axis and then select the axis to revolve around.
    Choose Full or Angle to specify whether the revolution is full or to a specific angle.
    For Direction choose One Side, Two Side or Symmetrical.
    For Symmetry, choose None or Circular.
```
```
The above text is taken directly from the link. The specific web site also includes a Flash video of the steps involved.
If thickness is required for your creation, consider to draw the sketch from the nose to the base, then use Offset or hand sketch in a parallel line that returns to the nose. Ensure the base segment is joined and that the nose segments are open and are aligned to the Y-axis.
As the sketch is revolved, the nose sections will "close" while the base creates the closure necessary to make a solid that is hollow within and open at the bottom.
Use The Google or your preferred search engine with the terms "Fusion 360 Revolve" to find many tutorials and videos with the same information presented in various ways.


Question:
I'm having a Prusa i3 derivative printer with a capacitive sensor for the z-axis. It switches a tiny bit before the nozzle hits the print bed and hence needs a z-offset to be configured.

In Slic3r I have configured the z-offset to -0.1 on the General page of the Printer Settings, but currently I'm evaluating Cura and can't find such a setting. Slic3r seems to apply this setting directly to the generated z-values in the g-code, so it does not use a short version at the beginning of the g-code. My current (except of the auto-bed-leveling part default) g-code:

G28 ;Home
G29 ; auto-bed-leveling
G1 Z15.0 F6000 ;Move the platform down 15mm
G92 E0
G1 F200 E3
G92 E0

Is there a way to configure Cura, e.g. using the Start Gcode options, to apply the z-offset?

Answer:
You can trick the printer into applying an offset using the
```
G92
```
command:
```
```
G0 Z0

G92 Z0.1
```
```
First, we move the nozzle to
```
Z=0
```
. Next, through the
```
G92
```
command, we tell the printer to, from now on, treat the current position as
```
Z=0.1
```
. This effectively applies an offset of
```
-0.1
```
to the Z-axis, since if we now executed
```
G0 Z0
```
again, the nozzle would move down
```
0.1mm
```
.
Note that this needs to be done after homing and leveling to be effective.
Of course, you don't necessarily need to move the nozzle to
```
Z=0
```
for this to work. You could also just insert
```
G92 Z15.1
```
after
```
G0 Z15
```
to get the same effect.


Question: I want to draw kossel delta corner in fusion 360 for 2040 aluminium extrusion like on picture below, but cant find a way to actualy start, I draw 3 side polygon and 20x40mm rectangle but cant go from there, so do you have any suggestion?

Answer:
I attempted to create your drawing but discovered that an important set of parameters is missing. You have to have either the intersection point of the legs (73.34) from each side or the angle between the legs (73.34) and the base (106.41) to create construction lines. Once you have either of those items, you can construct the remainder of the design using offsets, radii, etc.
More accurately, one other missing item that would be required to complete this design is the placement of the holes at the top (12) relative to some other feature of the design.
Having taken on the challenge of your drawing, I've found that it is necessary to surrender. The angles or the intersection point are critical and without them, no solution comes to my alleged mind.
I have also discovered one additional datum missing. The distance of the bottom truss and the thickness of this truss would be required to provide a more certain solution.
One the flip side, I've found
alpha-tech3d.com
which appears to include similar parts, rotated 180° with what appears to have all of the necessary data.


Question:
I recently switched to a RAMPS 1.4 on an Arduino Mega 2560.
Ever since I have extruder temperature swings a couple of minutes into the print, but it looks like a problem reading the temp rather than actual fluctuations in the temperature (as can be seen in the attached pic).
Also, I've noticed that the MOSFET is getting really hot when I heat the heated bed.

What is the problem and how can I fix it?

Answer:
For the really hot mosfet I would say it might be a good idea to get one of those external mosfet module boards. It just seems like a good idea to me, to not have the huge current of the bed-heater flowing through the ramps board. And for the thermistor wires, do you have them twisted together? If not, try tightly twisting the pair (of + & -) together to ensure there is no interference from other signals. Careful not to put stress on where the wires are attached to the actual thermistor-head. Honestly, all of your wiring should be in twisted-pair configuration.
https://en.m.wikipedia.org/wiki/Twisted_pair


Question: So I've seen some very good design software, but almost all of it is very expensive. I'm just wondering if there's a good cheap design software out there.

Answer: Try Fusion 360. It's free for educators, students, enthusiasts and start-ups. It's not 100% intuitive, but once you learn the basics, it probably has all the facilities that you will ever need for mechanical design.


Question:
How can I center a model at the middle of the printing area of the printer when creating a g-code with CuraEngine.

Are there any parameters I can add to ultimaker2.def.json to achieve this?
Thanks.

Answer:
If this is over the commandline tool "CuraEngine", then you will have to read the sourcecode. According to the
Author
, 'Nope. Only documentation there is in the code, readme and my head.' (cringe!).
If you're talking of the GUI program, then right click and click "Center". But this requires GUI usage. Not so nice if you want to automate using curaengine as your slicer.


Question: So I started using Cura a few weeks ago, and when I print it goes to 204 Celsius instead of 200. It doesn't really affect my print quality but I just want to know if there's a fix for it. My printer is a Da Vinci Jr 1.0.

Answer:
That's called PID overshoot. All control loops have varying types of outliers like this. Sometimes, you can't overshoot, sometimes you cant undershoot. But it's a remnant of the math.
The solution here, is to
PID Tune
. Once you get an established Kp Ki and Kd constants, then you can either save it to eeprom or you can recompile your firmware with this change.
It's pretty common, especially if you have different hotends without known profiles. PID tuning also works on heated beds as well. But usually those use what's called
Bang-bang
.


Question:
I am re-writing this question because, well, it needs to be updated.

I have the Anet A6, but in a general sense of things, what kind of threads can I produce before it no longer works?

Answer:
This depends on the nozzle diameter, the layer thickness, and the material.
I've made very good M8 and acceptable M6 threads (nut and bolt) at 0.2mm layers with a 0.5mm nozzle, out of ABS, and also out of PETG.


Question:
Is there any software/methods to automatically splice objects into multiple pieces sort of like a jig saw puzzle so that I can combine them together and bypass the build plate size limit?

As an example I have this 2D image that I want to print out but my printers size limit is roughly the size of the blue "squares." It's pretty tedious and time consuming to do this manually. Also, any tips on getting seamless lines or proper alignment when gluing these pieces together are appreciated.

Answer:
From what I understand, you're trying to partition your object into smaller pieces with the hopes of putting them back together in a manner similar to a Jigsaw puzzle.
There are two options that I know of to do this, which requires using OpenSCAD:
The
PuzzleCut
library - This allows you to disassemble your object into a multiple pieces that can be assembled together in a jigsaw puzzle type manner
The
PinCut
library - This allows you to disassemble your objects into multiple pieces that than be reassembled using the pins and corresponding holes on the pieces.


Question:
I have a 3D printer that I built using CD-ROM drives. It's all set and ready to go but when I generate .stl or .obj files my G-code sender program cannot load it. I have found that Slic3r will export the .stl into G-code but it has the option of changing the G-code flavour, or firmware.

My machine is running from an Arduino Uno with Grbl v0.8.

So the question is, which firmware setting would be appropriate for my machine that would require the least amount of editing before I can print?

Answer:
From what I understand, you're trying to partition your object into smaller pieces with the hopes of putting them back together in a manner similar to a Jigsaw puzzle.
There are two options that I know of to do this, which requires using OpenSCAD:
The
PuzzleCut
library - This allows you to disassemble your object into a multiple pieces that can be assembled together in a jigsaw puzzle type manner
The
PinCut
library - This allows you to disassemble your objects into multiple pieces that than be reassembled using the pins and corresponding holes on the pieces.


Question:
I am writing some G-code for my DIY 3D printer. From what I understand, G4 is dwell and its expressed in milliseconds. So my extruder takes about 30 seconds to heat up. Do I just type

G04 30000

Answer:
You are correct about needing to specify the dwell value in milliseconds. However, the RepRap Wiki indicates that you need to use the
```
Pn
```
argument, and not just an unadorned number as the argument to the command. To adapt the Wiki's own example, you will need to use:
```
```
G4 P30000
```
```
This should cause the firmware to dwell (pause) for 30 seconds.
RepRap Wiki: G4: Dwell


Question: On the reprap wiki it says using Znnn it sets a new axis position.  But then it says "No physical motion will occur". What would the line G92 E0 be used for?

Answer:
The
```
G92
```
command is used to set the start position (origin) of one of more axes (including the current extruder) to any arbitrary value. The command
```
G92 E0
```
is often used to perform retraction and nozzle priming. For example, the following commands are often used in start-gcode sequences (prologues) to prime the current extruder by extruding a small amount of filament:
```
```
G92 E0     ; Reset the extruder's origin
G1 F200 E3 ; Extrude 3 millimetres of filament
G92 E0     ; Reset the extruder's origin
```
```
RepRap Wiki: G92: Set Position


Question: I planning on getting a resin 3d printer kit, and I don't want to take any risks building it myself.  Where, or who, could I hire a professional capable of constructing a 3D printer kit? They don't necessarily have to specialize in constructing 3d printers, I just need someone qualified with the mechanical and technical skills for the job.

Answer:
If you have a makerspace in your area, you'll likely find individuals with reasonable mechanical skills suitable for simple kit assembly. Most kits are engineered to be reasonable assembly, not rocket surgery. Makers are by nature capable of construction, often from raw materials, and kits are typically not particularly challenging comparatively speaking.
Resin 3D printers are also simple in construction, as the component count is less than that of an FDM printer, or quite close in count. SLA designs involve laser modules, mirrors and alignment, while DLP designs involve light projection and light masking. Both designs involve vats and movement mechanics.
Even if you do not have a makerspace local to you, consider to contact one that might be nearer than farther away, as those spaces may have leads for you to locate a suitable victim/candidate.
Our local library makerspace often farms out contacts to me or other makers with the necessary skills to meet a patron's requirements.


Question:
Materials used in space need to not outgas significantly

An answer to this question: Would 3d-printed objects outgas in vacuum?

referred to the NASA outgassing database which showed that ABS, PET, and PLA filaments are all fairly low outgassing and suitable for space application.

What I'm wondering is whether there are any 3D-printable plastics that are both suitable for space and also self-lubricating.   Nylon is the obvious printable self-lubricating material, but I believe that it outgasses too much (I don't think NASA has tested nylon filament, at least I can't find it in the database).

My primary interest is in hobbyist-grade, FDM printers but if there are materials that can be commercially 3D printed, that is also of interest.

Any ideas?

Answer:
If you have a makerspace in your area, you'll likely find individuals with reasonable mechanical skills suitable for simple kit assembly. Most kits are engineered to be reasonable assembly, not rocket surgery. Makers are by nature capable of construction, often from raw materials, and kits are typically not particularly challenging comparatively speaking.
Resin 3D printers are also simple in construction, as the component count is less than that of an FDM printer, or quite close in count. SLA designs involve laser modules, mirrors and alignment, while DLP designs involve light projection and light masking. Both designs involve vats and movement mechanics.
Even if you do not have a makerspace local to you, consider to contact one that might be nearer than farther away, as those spaces may have leads for you to locate a suitable victim/candidate.
Our local library makerspace often farms out contacts to me or other makers with the necessary skills to meet a patron's requirements.


Question:
Disclaimer: I am not a professional 3D printer, so I'm not really familiar with how 3D printing works.

I was thinking about trying to make a real life model of the atomic orbitals, to clearly see how the orbitals are really shaped. I thought about trying to 3D print a block, made up of colored transparent "ink", in such a way that the darkness of the color at a point in the block should be proportional to the ψ2 value (probability of the electron cloud). This would print a block in which high density areas are darker than light intensity areas.

My question is, would it be possible to design an algorithm to print a specific darkness of ink at a specific location based on the computed value of ψ2, which is obtained by solving Schrödinger's Equation. Also, would it be possible to have this fullfilled at a reasonable price to be afforded by a regular customer, such as an engineering employee?

Answer:
problem definition
I'm not quite sure if it's really question for this group. Looks like the problem itself is more for programming or physics group. Having requested calculations (electron cloud shape) resolved, there will be something to print but...
printing probability cloud
at first, please take a look for example
here
it's a review of 3d printing technologies. i think you should have clear picture if your idea is feasible or not.
IMO it's not with todays technologies. in general (and deadly simlified) we have 3 main printing technics
out of solid (or semi-solid) filaments - can be colorful and semi-transparent but it's not homogenous in terms of your needs
out of solid powders - can be colorful but it cannot be transparent
out of liquids - can be really transparent and color but unfortunately not colorful
i'd say rendering but not printing is what you really need


Question:
I've seen several Q&As on recycling and reusing plastic from failed prints, but what have you done with the last few meters of filament?  I've been keeping the ends of PLA (or sections I needed to cut) to maybe use for friction welding pieces together, but I only need so much for that.  I've considered just shoving the last bit in the tube and using a new roll to push it through (so long as retractions aren't necessary).

This is especially a concern for more exotic filaments where friction welding isn't useful and the price is higher for that 1m section (something like Copperfill).

Note: I have a Bowden extruder.  I imagine this is less of an issue with DD extruders.

Answer:
Weld the fragment to the beginning of a new spool and use it that
way.
Most are made from metal
so they aren't that easy to make
at home.  Here is another
answer
that lists other methods to
weld filament including using heat shrink tubing.
As you mentioned, you can use it for friction welding.
Use it for pin/studs/rivets/hinges in prints.
Throw it away.  1.75mm * 1Kg is about 330m of filament, 3mm * 1Kg is
about 110m of filament.  The leftover isn't worth much when you
consider how much is on a spool.


Question: I am working on g code for my homebrew 3d printer and i have found the line G1 -2.000 F2400.000. From what i understand there should be an axis before the number and x and y shouldnt have negative. I am using grbl which is for cnc milling but and i have been deleting this line with no problems but i am wondering what it does because i will be upgrading to a "real" 3d printer asap

Answer:
G1 indicates a movement and -2.000 the distance, F2400.000 the feed rate mm/min, normally the
(-)
values are for retraction on extrusion
E
, for example:
G0 X12 (move to 12mm on the X axis)
G0 F1500 (Set the feedrate to 1500mm/minute)
G1 X90.6 Y13.8 E22.4 (Move to 90.6mm on the X axis and 13.8mm on the Y axis while extruding 22.4mm of material)
```
```
1. G1 F1500
2. G1 X50 Y25.3 E22.4
```
```
In the above example, we set the feedrate to 1500mm/minute on line 1, then move to 50mm on the X axis and 25.3mm on the Y axis while extruding 22.4mm of filament between the two points.
```
```
1. G1 F1500
2. G1 X50 Y25.3 E22.4 F3000
```
```
However, in the above example, we set a
feedrate of 1500 mm/minute
on
line 1
, then do the move described above
accelerating to a feedrate of 3000 mm/minute
as it does so. The extrusion will accelerate along with the X and Y movement, so everything stays synchronized.
So, in your case if some axis is not defined the feed rate applies to all motors.
(part of this content is from reprap-wiki)
You will see negative numbers if your starting point is on the center of the bed just like rectangular coordinates.
```
```
G1 X-50.318 Y8.849 E11.70313
G1 X-52.606 Y3.087 E12.26689
G1 X-53.240 Y1.297 E12.43953
G1 X-54.398 Y-2.097 E12.76562
G1 X-54.683 Y-2.995 E12.85132
```
```


Question:
I have .stl for the 3d printing. And I want to analysis wall thickness of this model before printing. I have no idea about any tools. Can I create any console or wpf app for calculating wall thickness and cost of the printing.
Please help me.

Answer:
If your talking about a hollow object, such as a cube with a hollow center. The wall thickness is determined by the model.
If your talking about a solid object, the wall thickness is determined by your nozzle diameter multiplied by your # of walls. This is all adjusted by your splicing software. If you have a nozzle of 0.5mm and you print at 3 perimeters, your wall should be 1.5mm. If you want the wall to be 2mm, then you will adjust your perimeters to 4. Everything within those walls will be whatever you choose for infill.
I work with ASP.NET, Windows Forms, and Console Apps myself. I'm sure you can find libraries capable of taking 3D models but I don't think it would matter because the printed thickness is determined by your splicing settings.
Also for cost of printing, I recommend just using Cura which you just have to plug in some cost information about the filament and it will tell you estimated cost, mm of filament usage, and time.


Question:
We need a 3D printer, that can print with plastic suitable for medical applications. We have about $5000 for the printer. What printers can we choose? I am not a specialist in 3D printing, so please answer in detail.

We need to print breathing tubes with cuffs. The tubes should be flexible, but rigid enough in order not to collapse. The cuff material should be thin and collapsible, but very strong. Breathing tubes are inserted through the mouth and stay in contact with mucous membrane for many hours.

Answer:
I am not an expert but I think you will find that because 3D printers use a layer by layer construction method, and the boundary between the layers creates grooves along the surface or leaves a rough texture on the surface. That the textured surface left by 3D printer construction would trap microbes and make 3D printed objects not suitable for medical applications where you need the product to be sterile.
It might be possible to treat the printed object or post process it. By vapor smoothing or painting/coating, but I doing think this would work for flexible materials.
If you are considering 3D printing because of the ability to customize the design, then I would suggest considering combining 3D printing with molding or casting. You could then use a cheap 3D printer to create the mold and use a flexible resin to create the object you want.
I have heard of SLA 3D printing being used to create molds for casting fake teeth. There 3D printing is used to create a custom shape and the print is used to make a mold and the final product is cast using the mold to get the quality and finish needed.
And I have head of FDM printing being used in used in remote areas to print clamps for umbilical cords. But I believe this was because not no other option was available.


Question:
If I have a 3D cylindrical extrusion (in Onshape), how can I scoop, carve, or indent a concave/parabolic curve in one of the ends?

The yellow surface is the target.

Here is the basic shape I'm trying to bore out (like a satellite dish, parabolic antenna, or even a contact lens.. You get the idea).

Answer:
As is typical with many CAD type programs, a feature in Onshape known as revolve may be your solution. As you have a clear formula for the cross-section, half of the work is complete.
You would generate a sketch representing the curve, then use the Revolve feature with the axis oriented to vertical. According to the
Onshape video
, you can generate a solid or a surface from the options that appear when selecting that feature.
As you can see in the images above, the axis selected in the tutorial video is horizontal. Other features of revolve are covered in the video. Your post suggests it will also be necessary to perform a subtraction action on the assembly in order to get the scoop/concave result.


Question:
I'm trying to print a large piece with polycarbonate but it keeps warping, I'm using a Taz 5 printer and setting 290 C in the extruder and 145 C in the heating bed.

Other setting I have are:

printing speed: 20 mm/s

layer height: 2.5mm

infil: 20%

brim: 15mm

Can anyone tell me any tips or suggestions to avoid warping?

Answer:
I would take a look
here
and
here
.
Literally the first two results of Google.
To summarize what they say,
You need good bed adhesion to keep the first layer from warping near the edges like you will get normally with ABS or PC(Polycarbonate). Some use hairspray or gluestick. I manage myself with buildtak surface. I would stay away from blue painters tape. Your looking for something very sticky. This of course makes it a nightmare to get the part off the bed but well worth the trouble if it keeps your print on the bed and flat.
Make sure the part receives adequate heat. Like someone wrote in the comments, a enclosure works best to keep the temperature of the entire print warm instead of just the few layers closest to the bed.
More perimeter layers works very well by providing more structural strength to try and combat the warping. I've stumbled upon this solution when I had trouble with ABS.
Lastly, first layer is always the most important part of any print. You want to make sure it is as level as possible and a good tip is to raise your bed just so slightly than usual so the first layer is jammed hard against the bed. This provides better surface area. Just be careful not to clog your printhead cause if you constrict the flow out of the nozzle too much, you'll might end up with plastic trying to flow upwards or maybe grind the filament with the extruder gear.


Question:
I know you should, like an infant, never leave your printer without surveillance.

But sometimes we all do, trusting our double thermistors and heat runaway configurations. But electronics fry and who says there is no danger even after the print job has finished and it's cooling down, still hooked up?

I have searched but smoke/fire detectors come in a wide range of varieties:

They can be battery powered or hardwired, they detect different things: carbon monoxide, heat, smoke..., they thus also have different detectors like photoelectric sensors, ionization sensors or both. We also print with different materials...

So what's the best safeguard for my 2 year old (CoreXY ^^)?

Answer:
There’s no huge difference between both. The printing settings like temperature and printing speed are practically the same. But the PLA+ have a much better surface quality and it’s slightly more bright than normal PLA. Another difference is that the PLA+ it's more effective in bridges than PLA.
If you want to the comparison between PLA and PLA+ go right here,
PLA vs PLA+ (short review)
. This post is an awesome experiment with both materials.


Question:
I recently backed a 3D printer on Kickstarter, and I would like to 3D print parts for high-temperature applications. So I have two questions;

What's the highest temperature polycarbonate can be safely heated to without warping or releasing toxins?

If there's a filament with better temp-resistance I can print could you tell me? (If you know the highest temperature it could reach safely, that would be helpful too.)

My 3D printer will have a heated bed up to 100°C, and an extruder temp of up to 250°C.

Answer:
Polycarbonate is
heat-resistant up to ~120C
. Above this temperature it will gradually become flexible and may irreversibly bend. It will not generate any toxic fumes all the way up to ignition temperature (630C), because
it's fumes are not considered harmful
. Note though, that with your temperature limit you may not be able to print with polycarbonate, or only do so at a very low speed.
According to the
sheets of commercially available printable plastics
, PC has the highest printing temperature and heat resistance among them, seconded by nylon. This refers to the FDM printers only. SLS printers may be able to use other materials, even metals like aluminum or titanium, so if you really wish to get temperature-resistant prints, you may look for workshops that have SLS printers and ask them.


Question: I have seen some photos of aluminum based Prusa i3 printers, and I like to know the numbers and the specs of the profiles? Also I want to know Is the first pic strong enough for reliable printer or I must use the second(respect to profiles I mean).

Answer:
They are 2020 (20mm x 20mm) T-slot extrusions. They should not be confused with V-slot extrusions, which are similar to T-slot, but have a 45-degree slot profile to accommodate V-slot wheels.
If you are contemplating a new build, I would recommend using V-slot. Note that T-slot and V-slot come in a number of sizes (in multiples of 20mm). A 2040 profile is 20mm x 40mm, and will have two slots on the wider sides. Other sizes are available, such as 2060, 2080, 4040, and even C-shaped profiles.
You may want to use 2040 profiles for greater rigidity, especially if you are contemplating a large build volume.
Note that there are imperial as well as metric T-slot profiles. RepRap uses metric profiles.
ReRap Wiki: T-slot
OpenBuilds: V-slot


Question:
I’m trying to have this bracket printed, but I don’t know what settings I should use.

The project details say 50% for infill, but is there a reason why I wouldn’t get 100% for making it sturdier?  I imagine the developer used 50% because he used his own printer and wanted to preserve more material.  The 3D printer service I’m using doesn’t charge more for 100%.

But I’m more concerned about the material I should select.  Should I select PLA or ABS?  The developer didn’t specify this.

Answer:
For such a small item and the small load it will carry, even 50 percent is substantial. Keep in mind that one hundred percent infill is not necessarily stronger. If you need to know why, consider a 'net search for "why not use 100% infill" for more detailed information. The primary foundation for not using 100% infill is that the stress is better distributed over the structure of a non-100% part, while the completely filled part has more intra-layer stress failure. Another link suggests that there's a possibility of increased warping with full infill.
Because the load is small, it matters very little if you select PLA over ABS. PLA is more brittle compared to ABS and will crack or fracture or break under loads that might otherwise cause the same part in ABS to bend.
If you need yet more strength, select PETG or nylon, although I suspect either one would be more expensive from a service.
If you select ABS, you can use acetone smoothing later to make a shiny surface, but that's cosmetic, not structural.


Question: I have been working at converting game files into 3d files that can be printed, but many of the models have very thin or walls. I was wondering if there was a way to increase the thickness of the walls using meshmixer or meshlab.

Answer:
Only today, I learned of a solution for this sort of objective, but it uses Fusion 360 rather than Meshmixer  or Meshlab. As your question does not include that program, I'll toss the Meshmixer method.
This image is of the model prior to modification:
When you load your STL file into MM, use Edit, Generate Face Groups. This will cause the surfaces to change color. Click Accept.
With face groups created:
If you can be assured of all one surface, use Select, then double click on the interior. This should turn the entire interior red. If you discover unselected surfaces, simply click on those surfaces until all is completed. If you select a surface in error, use Shift-Click to clear that one surface.
Once selected, the select menu gives you a new edit menu.
Use Edit, Offset for yet another menu. As you make changes in the menu settings, you'll see the results on the model. Ideally, you won't have an overly complex model with too many facets/triangles, as it can really bog a machine down.
This particular model has a nearly uniform interior. Double clicking on the inside surface caused the full cylinder (not the bottom) to be selected (turning red).
Low accuracy offset, with surfaces still selected:
For smoothest results, keep the accuracy high. Any protruberance in the interior will give very strange results.
High accuracy results, surfaces selected:
Experiment with the settings, aim for the best result and click accept. As long as you don't export the model over your original, all experimentation is a learning experience and not a destructive one.


Question:
I am writing my own slicer and wonder if there is a mathematical proof that proves that the intersection of the slicing plane with the STL file will only produce closed-loop polygons for every given slicing plane?

Thanks!

Answer: You can't prove that because it isn't true. An STL file is just a collection of triangles. There is no guarantee that an intersection with the slicing plane will consist of closed-loop polygons. To be suitable for 3D printing an STL file should represent one or more closed, disjoint polyhedra (which would yield closed-loop polygons) but this is not always the case. Many slicers have heuristics to try and "fix" bad STL files on a best-effort basis. Especially considering the possibility of rounding errors, it is important to at least detect polygons that are almost (but not quite) closed and connect their endpoints together.


Question:
I upgraded from Cura 2.7 to 3.1.0 and I'm getting horrible under extrusion, I'm sure this is the software because I rolled back to 2.7 and everything is working fine again.

My printing is a Robo3D R1+ using the "custom FDM printer" profile.

Is there any new setting or a setting that isn't migrated properly that causes this?

Answer: Some users have reported upgrades to Cura changing the filament size to the default 2.85 mm. If you are using 1.75 mm filament (which most printers do), you will get extreme under-extrusion.


Question: I just bought new TEVO Tarantula and tried to print xyz cube. I found that my cube's layer was shifted as showed in picture. How can I fix this ?

Answer:
From an electrical standpoint, a two-phase stepper motors (what most 3D printers use) works the same backwards and forwards, the phase just reverses.  If you are stalling on only one direction, I would look to see if you have a mechanical bind in that direction.  Generally a wiring issue will cause the motor to either not run at all or to run in the wrong direction.
A few things you can check:
Decouple the motors from their mechanical load and confirm that they all run correctly when they aren't driving a load.  If you can't do that, disconnect them all then connect a spare motor to each cable one-at-a-time.
Turn each of the axis with your hand and make sure it turns smoothly throughout the entire range in both directions.  Note: Some times a binding issue is acceleration related - a loose frame or coupling can cause this.
Monitor the supply voltage to make sure that one of the motors is not pulling the supply down causing all the others to stall.


Question: I have a prusa 13 that's shipping in the mail, and I intend to make good use of it, one also own a da vinci jr. and the one time it got so clogged that the extruder itself was filled with pla, with that said I replace the extruder, for the da vinci, but besides that, as for my a prusa, what should I do if the extruder, not the nozzle gets clogged that badly?

Answer:
From an electrical standpoint, a two-phase stepper motors (what most 3D printers use) works the same backwards and forwards, the phase just reverses.  If you are stalling on only one direction, I would look to see if you have a mechanical bind in that direction.  Generally a wiring issue will cause the motor to either not run at all or to run in the wrong direction.
A few things you can check:
Decouple the motors from their mechanical load and confirm that they all run correctly when they aren't driving a load.  If you can't do that, disconnect them all then connect a spare motor to each cable one-at-a-time.
Turn each of the axis with your hand and make sure it turns smoothly throughout the entire range in both directions.  Note: Some times a binding issue is acceleration related - a loose frame or coupling can cause this.
Monitor the supply voltage to make sure that one of the motors is not pulling the supply down causing all the others to stall.


Question:
I added a custom boot screen to marlin by adding _Bootscreen.h to the project root folder and it works fine. The problem is that the custom screen shows quickly and disappear then the marlin boot screen is then displayed for a longer time.
I want to remove the marlin boot screen.

I dug around in the source code and found a void lcd_bootscreen function in the   ultralcd_impl_HD44780.h header. This seems to be the function that is loading the marlin's boot screen due to the comments in the code. I added return; to the first line of code in this function but the marlin's boot screen is still loading.

How can I remove the marlin boot screen. How can make my custom boot screen wait for more time?

The marlin version is 1.1.8.

Answer:
So after some search:
You can't (at least should not) remove the marlin bootscreen according to this issue
SHOW_CUSTOM_BOOTSCREEN hides Marlin logo
, quote:
We wanted an additional logo - not a replacement of the Marlin logo.
According to the
code here
there's a constant CUSTOM_BOOTSCREEN_TIMEOUT taking the default value of 2500 which is 2.5 seconds but you can redefine it in your _Boostrap.h file.
This constant is only available for DOGM lcd screens which is chosen by the code here in
ultralcd.cpp
and whitout more details on your machine it's hard to tell from
Conditionals_LCD.h
which will be used.


Question:
The bottom of my prints warp/curve upwards, most often at the corners. This is a very slight curve, only about 1-2 mm.

I print with a raft all the time.

I don't have a heated bed.

I print with PLA at 199 °C (390 °F) with a print speed of approximately 40 mm/s

I have a Sindoh 3DWOX DP201.

What slicer settings might be the cause of this phenomena?
Or could it be 3D printer settings?

Answer:
If you have a heat bed, heat it up accordingly (for example for PLA 50 °C first layers, 40 °C then can be a good starting point).
If the first layer isn't close enough, then warping can happen (Happened to me when moving from 0.3 mm layers to 0.1 mm).
If you are under extruding / have dirt in the system (the heat chamber) so that extrusion is uneven it can make warps.
And as always, you can try to print slower, it helps not always but often.
Please also do tell what temperatures (heat bed & nozzle) you are using and what material.


Question:
I created my model in onshape then exported it to stl file then imported it to simplify 3d to convert to gcode.

However my model didn't go any in fill, it just continue to print layer after layer in the same fasion as the 1st layer.

Correct me if am wrong infill is used so that the middle of your model isn't completely solid hence saving on filament.

Is there something special I need to do in onshape or simplify 3d for it to use infill? To me it looked like it was just filling it up with pla

Answer:
The infill portion of your model is configured during the Simplify3D process. After loading your STL file into S3D, edit the process and examine the Infill tab and Infill slider. You'll see a percentage indicator, as well as an extruder selection (left or right, if you have two) to be used for the infill. There are other options within the configuration that would have little to no effect on the problem you are experiencing.
Once you have checked and corrected the settings as needed, used the prepare-to-print option and press the play button for a preview to see the infill being printed before you send it to the printer.
100% infill is impractical, and one can create strong models with as low as 20% infill.
Infill is used to save filament, as you suggest, but it is also used to provide support for top layers on areas that are not vertical. Sometimes, one would use a higher infill figure to provide for smoother top surfaces although increasing the layer count for top/bottom can accomplish that.
Check your top/bottom layer figure in the layers tab to ensure you have a reasonable figure. Three or four layers are good for cosmetic reasons, more if you need additional strength. Anything higher or absurdly high would cause some of the trouble you describe.


Question:
After a long time tweaking my new 3D printer I solved all the unexpected errors and I can print succesful pieces but I am facing a "problem", they are over sized, I found this problem trying to print a Raspberry Pi Case and an smartphone case, the printed pieces are bigger than the objects.

Here some related information

Printer: Geeetech Prusa i3 Pro B

Firmware: My GitHub (Marlin)

Software: Repetier Host with Slic3r

Does somebody know how could I solve it?
Thank you very much

Answer:
You have to know:
distance between belt teeth (usually 2mm)
number of teeth on pulley
motor step angle 1.8 deg?
microstepping count, probably 16?
Then you can enter all these numbers info the calculator here:
https://www.prusaprinters.org/calculator/


Question:
I have a Monoprice Select Mini v2 and it came with a 256 MB SD card. I have a bunch of 16 GB cards. I have made sure that the new SD card has a FAT32 filesystem. I copy the gcode file onto this card and when I put it in the printer, it can't find any files!

And yes, the file is at the root level of the filesystem and it uses the proper naming convention. The file works on the old card.

Since the old card still works, this isn't an emergency, but I want to have a backup and I don't have any other cards that small.

Answer:
The maximum size is 32 GB, however using microSD has a little disadvantage:
The microSD adapter and Micro memory are wrong assembled and the chip are unable to be read.
Solution: stick with a tape adhesive to keep Micro memory and SD adapter well aligned
The SD adapter can't be read on the 3D printer
Solution: Add an extra tape adhesive over the SD adapter just like sticker, to make tight the assembly inside the reader.
Clean the contacts of the SD adapter, normally has the same issue like nintendo cartridge.
I´m planning to get a bunch of SD cards instead microSD's, none of SD 8 GB and 16 GB are failing due wrong contact assembly.


Question:
I am still at calibration stage and need some info from the PCB. I connected the USB and ran Repetier. The PCB wants to talk at a higher baud rate than my serial port says it can do. I tried setting the serial port to its highest setting 125k and reduced the PCB baud in Repetier setting to 125k. No joy. PC port reverts to 9600 every time I check it. Thoughts?

PC running Windows 7 Home Premium 32bit.

Answer:
Are you sure that the A8 connects to a PC using a serial port? I don't know of any 3D printers that do that. Typically, 3D printers connect to PCs using a USB connection, and there will be a type-B USB socket on the printer.
However, there will be a USB bridge chip on the printer's controller board that connects the microcontroller to the USB socket. This bridge chip does have a serial port that is used to communicate with the microcontroller. Typically, these serial ports operate at 115,200 bits per second (115.2 kbps), although this may vary. Some USB bridge chips are capable of operating at 250kbps.
Often, the software running on the PC needs to know what speed the serial port on the bridge chip runs at, in order to send data at a suitable rate. Of course, the USB connection is capable of handling data at a much higher rate, but the microcontrollers used in many 3D printers are not capable of handling such speeds.
Note that the USB bridge chip on the printer may appear as a virtual COM port on a PC.


Question:
I'm relatively new in the field of 3D printing and design. By now I've created and printed some technical objects with TinkerCAD, but now I've a task, which I don't know how to solve.

I have the following model as STL-file:

Now I want to "adjust" the arms of the model, as shown in the picture. I want the arms to hang besides the body.

I know that I could cut and rotate the arms and then merge them again with TinkerCAD but the outcome dosn't look good and the workflow feels wrong.

So what is the right tool/way to get this task done?

*Disclaimer: I'm not Denis Almaral, but he released this model unter CC license. So I kept his name on the image to credit him, as requested via CC.

Answer:
Basically there's no good easy way to do this.
At this point you only have the mesh - a list of triangles - the 3D model you have does not contain the concept of joints or moving parts so it can't regenerate the shoulder after the rotation.
The original author may or may not have the ability to do this, depending on his workflow and software.
If all you have is the STL your only choice is to rotate the arm and then rebuild the shoulder from scratch and manually fix anything that doesn't look good


Question:
Here is my understanding of Coasting: Coasting stops extruding early in a move so that the string itself will finish the layer.

Here is my understanding of Combing: Combing reduces the need to retract during travel moves by making sure that the nozzle oozes where you want it to on the way to the next point.

I'm curious as to what types of prints these are good for, and also what types of prints these would be bad for.

So for instance, Coasting is good for prints that have a high propensity to exhibit stringing, but what types of prints would I want coasting to be deselected for?

Similarly for combing, although I know neither the pros nor cons other than it reduces the number of retractions (decreases wear on extruder?)

In short, basically I'm looking for the pros and cons of both of these settings. Also if my understanding of the settings themselves is incorrect please let me know. Any advice would be much appreciated.

Answer:
If anything, combing and coasting allow to
mitigate problems that are printer and filament specific
, rather than dependent on particular STL models.
Combing helps
- as you imply in your question -
with materials prone to oozing
(e.g. PETG)
Coasting is particularly good for printers with a bowden extruders and low jerk/retraction speeds
.  This is because in bowden extruders there is a lot of filament compressed between the teeth of the extruder servo and the nozzle, and that pressure doesn't instantly disappears when the printer stop "pushing" (i.e.: turning the extruder servo).
I believe there are
firmware implementations where coasting is also used when approaching sharp corners
.  This is to mitigate the problem of "blobs" forming there.  The mechanics of this are similar to those explained above: the pressure within the extruder cannot be instantly relieved and coasting accounts for that.  The only difference being that - because of the micro-scale of the problem - even non-bowden printers are prone to corner blobs.
In my experience (I look forward to other answers to "compare notes") there are
very few reasons not to use combing
.  The only risk with it is that it increases the risk of the nozzle crashing into the print and destroying it.  It sound dramatic, but it is in practice it requires everything to work against you: a big blob on the previous layer, the nozzle passing exactly there, poor bed adhesion... for me that has proved problematic only when printing miniatures with a 0.2 mm nozzle and 0.05 mm layer height (on a cheap printer).
There is of course a
(usually very small)
time penalty in combing
, as it typically requires the nozzle to travel longer paths.
In my experience (again: YMMV, I look forward to more answers!)
the limitations of coasting are related to the way it is implemented
.  For example, a given coasting setting may work great for getting rid of oozing, but will create under-extrusion in other parts of the print, as the calculations performed within the firmware may be spot-on for linear motion but inaccurate for corners, or vice-versa.
I believe this is the reason while some popular slicers (like cura) have this setting hidden under "experimental".


Question:
So I am trying to get the XSD-Schema from this object. When I open the File I just get something like this code (snippet):

¸†2¡Q·2ºyƒeCã2ï…w ïÀ|¼ðAøä[0Ÿ |>‚|ó‘å2²ºFƒ¼Æò1ùàåcj@Þ`ùÐ¸Ì{áÈ;0/|¾
 ùÌ'Ÿ„ Á|d½¬¬¯Õ ¯±|l¾…Œo@Þ`ùÐ¸Ì{áÈ;0/|¾ùÌ'Ÿ„ Á|d½œ¬¯Ó ¯±|h\æŒo@Þ`ù¸|
 ßBs¦5–Œ~ôè»£(™c´“Ç£[yp1:æ'Ã‰c4Jó Uâ˜ÍÇ<h—8^'Ð¯É

What is this? How can I convert it back? I need to edit the structure manually.

Thank you in advance.

Answer:
Seems to be your are trying to edit a file with the wrong file editor.
If you have Microsoft® Windows® 8.1, you can print directly using the 3MF format included. Simply set the print options in the 3D Print PropertyManager and print to the 3D printer. A preview of the print bed and the model's location within the print bed lets you modify settings before committing to a 3D print job.
To access the 3D print dialog box and specify print options, click File > 3DPrint.  The print dialog box that is available depends on your installed 3D print driver.
If you need to get the STL you may need to use a file conversion,
here
is a youtube tutorial to makeprintable


Question:
I am looking for a plastic which is transparent to radio waves.  I want to place my transmitter in a cylinder. That cylinder would be placed in a big RC plane  ( whose body is made up of cardboard). I want the plane to be both telemetry, and RC controlled.  That cylinder should allow the signals,  should be strong and light.

So which material would you suggest and is that material easy to do 3d print?

Answer:
For the kind of application you are looking for, transparency to radio signal shouldn't really be an issue, so you are more or less free to choose whatever suits your taste better.
Looking at the 3d printed drone community, the 3 most common materials I see being used there are:
impact-resistent PLA
PETG
ABS
This order also match their "ease of use", with PLA being very easy to print even without heated bed, behaving well with glues in the assembly and being easy to paint on.  The impact resistance of "though PLA" still doesn't match that of - say - ABS, but is typically considered "good enough" for anything but the propellers.
PETG is tougher. Print relatively easy (stringing and oozing being the typical problems) but it is known to be somewhat difficult to glue and paint.  It is also quite dense, so - dimensions being the same - it will weight more than PLA.
Finally, ABS is a classic.  It is strong, durable, easy to finish (with acetone) but it is the most finicky material to print with, requiring an enclosure and proper ventilation (the fumes being toxic).


Question:
I am using python 3.6 with pySerial library to connect to the Hyrel System 30M 3D Printer. I am able to read the data from the device but unable to write any commands to it

Here is the code:

    ser = serial.Serial()
    ser.port = 'COM4'
    ser.baudrate = 38400
    out = ser.readline()
    ser.write(b'M106 T14 S30\n') %This is the command to turn on the fan at 30% power

Can somebody suggest me how to write commands to printer through python

Answer:
If the one in your question is your
complete
code, a possibility is that your computer is just buffering the output for the serial port, withholding it in memory.  Try to add
```
```
ser.flush()
```
```
after your last line.  This command will... well...
flush
anything into the buffer through the actual connection.


Question:
This is what is happening to my motor. Any suggestions would help.
1. I have tried adjusting the trimpot.
2. Rewire the connector to match the one on the motherboard.
3. Anything else I found on the internet.

Answer:
If the one in your question is your
complete
code, a possibility is that your computer is just buffering the output for the serial port, withholding it in memory.  Try to add
```
```
ser.flush()
```
```
after your last line.  This command will... well...
flush
anything into the buffer through the actual connection.


Question:
I would like to ask this in more of a general sense than anything, just for people to make note.

I am printing out things for people and some files have some edges hanging out the side. I always worry, since it is printing in mid air, that it would screw up the print. But I was able to go, maybe 1mm(I am not to good with metric when it comes to guessing). My question is, how far at 90* from a wall can a printer pull off before it is necessary to have support? This would help me when slicing up files.

Answer:
It is typical for a 3D printer to be able to manage one-half the width of the nozzle for unsupported layer printing. This frequently calculates out to a realistic 45° from the start point.
If you are getting 1 mm extension from a 0.4 mm nozzle you are doing well. It's possible that the layers are not strongly bonded at the point of extension from the vertical wall, but are then strengthened by the layers printed above, if they do not extend excessively.
If your part is designed well, the extension will be distributed gradually over more than one layer, allowing that 1 mm extension over 2.5-3 layers without impacting the appearance of the model in an excessive manner.
The above does not apply to bridges, as it involves a different dynamic for the printer/slicer software.


Question:
I am printing some minion chess pieces for my teacher at school and on every model I have found something called "ghosting", or at least I heard that is what it is called. For example there is a strap on the model for the pants. And going left and right there is very shallow "straps" or something happening.

I am interested to know what causes this to happen and how to fix it. It is not super bad, but would be nice to fix.

Answer:
Ghosting is an artefact in the print due to the vibrations in the printer that are induced by rapid changes of direction
.  It is important not to confuse them with inherent vibrations in the printer due for example to the belts being loose or the bearings not being in perfect order.
The good news is that it is relatively easy to tell them apart:
ghosting
(also known as "ringing" or "ripples" or "waves" or a number of other names...)
is always downstream of a change of direction, and fades rapidly
.
Inherent vibrations - on the other hand - tend to be consistently present when printing along a given direction, and do not fade.
Mechanically, ghosting works like this:
The moving part is travelling along - for example - the x-axis, when suddenly the direction of movement becomes the y-axis.
At that moment, the stepper motor of the x-axis stop rotating, but the
momentum
of the moving part stretches the belt even so slightly past the intended stop point.
At this moment the belt becomes like a rubber bend / spring, absorbs the kinetic energy of the moving mass and releases it by "throwing" it past the intended stop point in the other direction.
This keeps on repeating a number of times, but at each pass, some of the energy is dissipated, and the moving mass moves less end less away from the ideal stopping point.
While all of the above is happening, the object has also begun to move along the y-axis, so the extruded plastic looks "weavey" along the y-axis.
Understanding how this process works, makes it possible to understan why the three main factors affecting ghosting are:
The
amount of mass
being moved
The
speed, acceleration and jerk
settings
The
elasticity of the mechanical components
Namely,
mass and speed are important because their product is the momentum
.  That in turn means that diminishing either one of the two will reduce the amount of "overshooting" past the stopping point.
Elasticity of the mechanical components is important as
the more flex/stretch the part can take for a given amount of force, the more overshooting
a given momentum will result in.
Finally,
acceleration and jerk are important because
- simplifying things a bit -
the faster the change of direction happens, the less time the system has to adjust
without vibrating.
So, concretely... what can you do to fix/reduce ghosting?  Three things, of course! :)
Reduce the mass being moved
.  Depending on the geometry of your printer, the mass being moved could be the bed+print, the printing head, or an entire gantry.  These are normally considerations done when designing the printer itself, and engineers normally mitigate problems by using lighter materials (plastic over metal, aluminium or carbon fiber over steel, etc...), or adopting different designs (like using a Bowden extruder instead of a direct one, to save the weight of the stepper motor).
Reduce speed, acceleration and/or jerk
.  Speed is normally the safest bet, as - besides your prints taking longer - there is really no penalty for it.  Acceleration and jerk - on the other hand - can cause overestrusion at sharp corners.
Reduce the elasticity of the system
.  This is commonly achieved by tightening the belts and eventually switching to more rigid rods / tracks / rails.
A couple of resources that may come in handy for you to understand and solve the problem better:
A
really nice article
with illustrations (two of which I "stole" for this post)
A
test model
specifically designed to highlight any possible ringing problem with the printer.
A
video
showing lots of different test prints done with various settings (very useful to understand how changing the above parameters affects the print).


Question:
Anet A8 with Cura. First time use. The extrusion temperature is set at 190 °C for PLA but the temperature never quite gets that hot, e.g. 189.2 °C. So the printer never prints.

The bed temperature is fine.

Any suggestions on how to fix?

Answer:
Two common problems to look out for in this situation:
Make sure that your
part fan
(the fan that is supposed to cool the filament you just extruded, and that does not start spinning until the print starts) do
not
blow air on the hot end of your extruder.
Make sure that your
hot end is well insulated
.  If available for your printer, silicone sleeves are the best:
otherwise the most common, universal and low-cost solution are cotton pads:


Question:
I saw an extruder mod on Amazon "EAONE 2 Pcs PTFE Teflon Tube (2 Meters) with 4 Pcs PC4-M6 Fittings for 3D Printer 1.75mm Filament (2.0mm ID/4.0mm OD)"
Anybody know how this is fitted?  Is it simply tapping the feed hole on the top?

Answer:
Is
this
what you are referring to?
If yes, the cold end of the extruder is nomally already tapped and you simply have to screw the new fitting in it.  The PTFE tube itself needs just to be fed through the hole in the fitting
until it cannot go any further
.
Failing to do so will most likely result in a clog and/or leaking.
It is a self-locking mechanism, in order to release the tube you have to press
down
the plastic flange on top of the fitting while pulling
up
the PTFE tube.


Question: I had been printing with ABS and took the advice to alter the fan so I can see the filament when I am loading it into the cold end. It was tricky but doable. I am now trying with PLA and getting it to line up with the whole is a nightmare. Can the driving cog and guide wheel be moved? A couple of mm would stop the driving cog pushing the filament off line.

Answer:
I was having the same issue as you and know what you are talking about and there is a file that you should print that will help you (I have printed this).
While the file says for the Anet A6, I think the extrude are the same on the Anet A8. It goes under the gear and bearing and guides the filament to the hole. Should work well for you.
Other things that you can do is straighten out the filament. That is what I do, it helps that much more. You can also cut the end at a angle to sharpen the end with a pencil sharpener, also helps find the hole.
So try the file, I think it will help you would.
File -->
https://www.thingiverse.com/thing:2242903


Question:
I have a homemade 3D printer running on ramps 1.4
When i start a new print and the hotend reaches melting point of PLA, the PLA start coming out of the hotend.

This goes on for as long as the temperature is kept above melting point, without moving the extrusion gear.

The extruder is a bowden type.

Hotend is a J-head.

I am currently using simplify if that makes any difference regarding configuration.

Any ideas what to do to prevent this from happening?

Answer:
Does it really go on for more than a minute or so?  You can't get filament from nowhere, so if the feed gear isn't moving, sooner or later all the material in the reservoir inside the nozzle & hotend will be melted and gone.  Leakage like this is normal, and probably a lot more noticeable if you have a larger diameter nozzle.
I would recommend checking to see if your gcode includes a large retraction at the end of the print.  That would reduce the pressure and the amount of material left inside the hotend.


Question:
I'd like to attach a piece I printed out of PLA to a small titanium rod. I've previously used Superglue (cyanoacrylate) to glue PLA pieces to each other with great success, but the problem is that if you don't apply it perfectly cleanly, it leaves very noticeable stains on the PLA.

Can anyone recommend a good glue for this application that won't leave stains like that?

Answer:
I've been a fan of epoxies for unusual adhesion problems. I found on
Amazon a product with titanium
in the name, but there's a caution regarding polypropylene plastics.
PLA is not of that family of plastic, which gives it a good chance of success. Epoxy is typically more viscous than cyanoacrylates, giving you a bit more control of the application, but also creating the need for care with "ooze-out."
The big glue company, Gorilla, also makes an
epoxy
that includes plastic and metal in the adhesion listing.
As PLA is somewhat sensitive to heat, one would consider that fast-cure epoxies generate more heat than slow-cure epoxy, but the amounts you'll be using are not likely to create enough for concern.


Question: I read that the best way of removing ABS was to let the temperature at the hot end to drop to around 190deg c then a sharp pull. This worked really well. I am trying to print with PLA but no matter what temperature I drop the hot end to I get left with a length of PLA in the feeder tube. OK I can heat the hot end and poke the excess down with a wire but that is a pain. I think the technique is right but the temperature is wrong. Any help great fully appreciated.

Answer:
One resource you can use is called the
nylon cleaning method
. It works by setting nylon filament temperatures, pushing nylon filament into the nozzle until only nylon is extruding, then cooling the hot end to a specific temperature. The page linked suggests a hard yank, but I disagree. Brutality is not a recommended action for 3D printers, in my opinion. When I use the NCM and the hot end reaches the correct cooler temperature, I use pliers and lever them against a suitable surface. The lever action is slower, yet the mechanical advantage is increased, making removal easier.
Some 3D printer users disagree with the expense of nylon, which is, on the surface, excessive. I've found that I am able to see light through the hot-end after using this method, however, so I find the expense justified by a completely clean filament path.
The above linked page also includes the modification of this method for use with the same type of filament to be cleaned, in your case PLA.
Consider that you should be able to use ABS to pull PLA from the nozzle. Heat the nozzle to the lower end of your ABS filament temperature and push or extrude until you get the ABS color. Allow the hot end to cool to the low end of PLA temperatures and reverse the extruder/pull out the filament.
If you use contrasting color filament (for example, white PLA, black ABS) you should be able to see the ABS collecting the other color as you remove it. Eventually, you would have no contrasting color, indicating that the previous filament has been removed.


Question: Some filaments suggest "reducing cross-sectional area" of the print. Is this referring to the vertical plane or horizontal plane? In other words, if I were to print a rectangular prism, would I want the long side of it printed in the vertical direction or parallel to the print bed?

Answer:
One resource you can use is called the
nylon cleaning method
. It works by setting nylon filament temperatures, pushing nylon filament into the nozzle until only nylon is extruding, then cooling the hot end to a specific temperature. The page linked suggests a hard yank, but I disagree. Brutality is not a recommended action for 3D printers, in my opinion. When I use the NCM and the hot end reaches the correct cooler temperature, I use pliers and lever them against a suitable surface. The lever action is slower, yet the mechanical advantage is increased, making removal easier.
Some 3D printer users disagree with the expense of nylon, which is, on the surface, excessive. I've found that I am able to see light through the hot-end after using this method, however, so I find the expense justified by a completely clean filament path.
The above linked page also includes the modification of this method for use with the same type of filament to be cleaned, in your case PLA.
Consider that you should be able to use ABS to pull PLA from the nozzle. Heat the nozzle to the lower end of your ABS filament temperature and push or extrude until you get the ABS color. Allow the hot end to cool to the low end of PLA temperatures and reverse the extruder/pull out the filament.
If you use contrasting color filament (for example, white PLA, black ABS) you should be able to see the ABS collecting the other color as you remove it. Eventually, you would have no contrasting color, indicating that the previous filament has been removed.