PETG Fine Tuning 3D printing
3d-print Filament

Back to fine tuning PrimaSelect PETG

So the last couple of weeks I have been trying to print the PrimaSelect PETG filament. I have printed all kind of parts of various shapes and sizes. I have also experienced all kinds of problems, tried 3 different surfaces which Includes PEI, BuildTak and LokBuild. I have adjusted the nozzle height countless times. I have changed Filament Flowrates, adjusted layer heights, changed Filament temperature, adjusted heat bed temperature and so on…

But still I does not work as I expect.

Some Problem I have encountered.

  1. Bad bed adhesion
  2. Cracking
  3. Warping or Curling
  4. Bad Infill (Weak part)
  5. Bad layer adhesion.

 

So with this problems I have not yet be able to print the first part for the Valify Robot Lawnmower. Making me quite frustrated. I want to advance in this project and not stuck in trying to get the the PrimaSelect PETG to work. If it had not been because I had already bought 8.8 kilos of this filament, I had already switched to another brand or used ASA instead. I have already wasted around 2.2kg of this filament and yet have not been able to print a great part.

So here we go, Once again I am giving this the PrimaSelect PETG a chance, I will once again try to find the sweet spot for this filament. Reading around the internet is always a great tool for troubleshooting, You can find all kinds of different problems and how to fix it, BUT, sometimes this is also a cause of confusion. When there are so many answers to a problem, you start seeing all kind of suggestions which actually goes against each other. Making it impossible to know which one fix is the best one for my specific case. All Printer have different setups and all filaments brands are also different, making the answer a bit more complicated.

 

So, In a past blog I actually printed a full sized model of the first part for the lawnmower. It started of great. No liftings in the corners, layer looked nice. etc.. But with 7hours left on the 44hours print I started too see cracking in the outer shell. I let the print continue because it was so close to finishing, and I wanted to feel and see the part in real life. The model “looked” alright, but the cracking effected the structure strength of the model, making it way to weak too actually use. But it was not a completely waste, I spotted I potential problem with the mount mount installations. I had made it to tight, making it very hard to get in and install the motor mounts. The model have now been adjusted, with a hatch to the motors. If it had not been that I would share the model with anyone who wants it. Then I had built the motor mounts directly into the model. But People are going to use different sizes and types of motors, so to only modify the motor mount is a minor task.

3d printing lawnmower hatch
Motor hatch, a fix for mounting the motor mounts.

Anyways. To solve the cracking I was forced to go up in the filament temperature, creating a better bond between each layer and probably a much stronger model. So in the last model was printed with a temperature of 225C, and the filament is rated at MAX 235C. So in attempt to solve the cracking I started at 240C. setting the Heat bed at 85C. I also installed a blower fan that starts at layer 2 @90%.

The settings for this Test 1

  • Filament temperature 240C
  • Heat bed 85C
  • Flowrate 105%
  • Top / Bottom fill 97%
  • First layer speed 15mm/s
  • Default speed at 35mm/s
  • Fan Covers ON
  • Blower fan at 90% @layer 2

Here is the result:

3D printing calibration test
3D printing PETG
3D printing calibration test
3D printing PETG
3D printing calibration test
3D printing PETG

Summary:

  • A very strong structure strength, I can’t brake it. (I prioritize strength before beauty)
  • First layer not very nice
  • Bed adhesion to great. Almost impossible to remove
  • No sign of Warping or Curling
  • Layers are very strong bonded
  • Top Layer looks nice and smooth
  • A lot of nozzle oozing and stringing in the first 2 layers, the print manage to resolve a white nice print anyways.

To improve to next test

  • Lower the bed adhesion (I will try printing 80C.)
  • Nozzle oozing, I will try a lower flow rate at the top /bottom infill to see if I can reduce the Oozing.

 

Test print 2: I simple model to test bridging, warping and structure strength (bending). You Find the it here

  • Filament temperature 240C
  • Heat bed 80C
  • Flowrate 98%
  • Top / Bottom fill 97%
  • First layer speed 15mm/s
  • Default speed at 35mm/s
  • Fan Covers ON
  • Blower fan at 20% @layer 2

Here is the result:

3D printing test calibration
3D printing test calibration
3D printing test calibration top layer
3D printing test calibration top layer
3D printing test calibrations side
3D printing test calibrations side

Summary:

  • A very strong structure strength, Breakable in the middle. (I prioritize strength before beauty)
  • First layer OK.
  • Bed adhesion OK. Hard to tell when such small surface.
  • No sign of Warping or Curling
  • Layers are very strong bonded but ugly us hell.
  • Top Layer looks nice and smooth
  • less nozzle oozing and stringing in the first 2 layers.
  • Bridging works, but they are very ugly. Bridging distance is 10mm and 15mm.

To improve to next test

  • Lower the bed adhesion (I will try printing 80C first layer and then drop it to 70C.)
  • Nozzle oozing, I will try a lower flow rate at the top /bottom infill to see if I can reduce the Oozing.

 

Test print 3: a bigger surface to check first layer and bed adhesion. Also easier to see signs of warping.
I also need to improve the layers looks (It can’t look too ugly). So something in between the first and the second test.

  • Filament temperature 240C
  • Heat bed 80C (First 2 layer, then 70C)
  • Flowrate 98%
  • Top / Bottom fill 97%
  • First layer speed 15mm/s
  • Default speed at 35mm/s
  • Fan Covers ON
  • Blower fan at 40% @layer 2

Here is the result:

3D printing calibration test 3
3D printing calibration test 3
3D printing calibration test 3
3D printing calibration test 3
3D printing calibration test 3
3D printing calibration test 3 bottom layer

Summary:

  • A very strong structure strength, NOT Breakable and also a bit flexible.
  • First layer OK.
  • Bed adhesion VERY strong.
  • No sign of Warping or Curling
  • Layers are very strong bonded and the look are OK.
  • Top Layer looks nice and smooth
  • less nozzle oozing and stringing in the first 2 layers.

 

Test print 4: a actual part for the robot partly printed. to check first layer and bed adhesion. Also easier to see signs of warping.

  • Filament temperature 240C
  • Heat bed 80C (First 2 layer, then 70C)
  • Flowrate 98%
  • Top / Bottom fill 95%
  • First layer speed 15mm/s
  • Default speed at 35mm/s
  • Fan Covers ON
  • Blower fan at 40% @layer 2
  • Infill 10%
  • 3 shells
  • Brim 10 strings.

Here is the result:

3D printing Buildtak PETG
3D printing Buildtak PETG
3D printing First layer PETG
3D printing First layer PETG
3D printing Top layer PETG
3D printing Top layer PETG
3D printing Side PETG
3D printing Side PETG

Summary:

  • A very strong structure strength, NOT Breakable and also a bit flexible.
  • First layer OK.
  • Bed adhesion Almost too strong. (First Layer a bit destroyed when trying to remove the part)
  • No sign of Warping or Curling
  • Layers are very strong bonded and the look are OK.
  • Top Layer looks OK (Some minor colar changes at the top)
  • minor nozzle oozing and stringing in the first 2 layers.

 

I am pretty pleased with this print. The overall quality is good. The strength is very good with only 10% infill. Layers looks very nice and smooth and they seems to be bonded very hard together. The brim actually was sticking to hard to the print causing the a minor defect on the first layer when trying to remove the part from the BuildTak. Maybe I will try to print without brim,  because of the great bed adhesion and drop the temperature to 75C on the Heat Bed.

So in summary of the calibration, I think this is as good as it gets with my basic knowledge of 3D printing. I started With 3D printing only 2 months ago and still have a lot to learn. But hey, that is one of the parts I enjoy, to learn. So tonight I will mount a new spool of the PrimaSelect PETG and try to actually print the part again. Worth knowing is that i modified the part now, so the consumption is estimated to around 420grams (going down from almost 800grams on the unmodified part with supports etc.) As I wrote earlier I prioritize structure strength before minor defects. I need a solid part thats going to last and have the strength needed to build a robot with good stability.

If you have any suggestions on any settings to fine tune, just drop me a comment below.

Cheers.

raess

Chief Technology Officer with a demonstrated history of working in the internet industry. Skilled in Business Planning, Computer-Aided Design (CAD), Quality Process Development, and SolidWorks. Strong business development professional with a Higher Education Diploma with specialization in Mechanical Engineering focused in Product development from Blekinge Institute of Technology.

http://valify.se

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