Squish!
Printing the first layer can be frustrating for the do-it-all hobbyist since everything always changes
Materials prefer different heights
This is not based upon the material such as PLA vs PETG or ASA, but might be more individual to the specific color of each material from a given brand and how well that color wants to stick to the build surface being used.
When the best possible reliability and quality are desired, we need to calibrate each printer for each new material
- Print a test part
- Warp - Long & thin to check for warping and adhesion issues
- Tolerance - ensures filament thickness averages are being met!
- Warp - Long & thin to check for warping and adhesion issues
- Start with less Squish for a new material
- If there are ANY adhesion issues with a print line that just has the top flattened, squish a little more
- Starting with too much squish can cause some materials to become permanently bonded to some build surfaces
- In my experience, this can make repeat prints difficult, prior to removal ;)
- Big changes are OK at the beginning
- If there is an adhesion issue with the first "lightly flattened" test, I tighten the squish significantly
- This is often too much but should FIX adhesion issues and maybe cause other issues
- Too much squish can cause smearing and stringing among other issues
- If we STILL have adhesion issues, its time to go back to the cleaners and maybe adhesives for troublesome materials
- This is often too much but should FIX adhesion issues and maybe cause other issues
- If there is an adhesion issue with the first "lightly flattened" test, I tighten the squish significantly
No PETG on PEI / PEX?
Some claim PETG should not be printed on PEI or PEX build plates without adhesive separation layers, and I believe they say it for liability reasons.
Many PETG filaments have a higher coefficient of adhesion at ~85c when compared to ABS or ASA at ~100c with the same nozzle/bed offset, but raising the nozzle height can alter this significantly. Raising the nozzle to a point of just flattening the top of the print line, seems to allow the same material to stick to the same sheet and pop off nicely after cool down like PLA in most cases.
No Silver Bullets!?!
Unfortunately this is a trial and ERROR process that requires failing regularly.
The information here is provided in hopes that we will learn to question "normal" and look outside the box!