PETG flat vs satin/semi-gloss top layer finish
Happy Holidays all!
Over the last month or two I've re-sliced various objects for printing using the generic preset among others. Since overriding previous files and their settings, the prints end up with a flat top finish using PETG vs the satin/semi-gloss top layer I've always had previously. I have not found a way to control the finish. This is happening with filaments I've used for a while. Any ideas would be appreciated. Recent software updates? Firmware related? Obscure print setting?
Prior to these recent results, everything I've printed (1,000s of objects) I never saw a flat finish. Now that I'm seeing some, some objects might benefit from this finish while others a satin/semi-gloss finish would be preferred. Knowing how to manage the top layer finish should be an obvious setting, correct?
RE: PETG flat vs satin/semi-gloss top layer finish
It's the increased print speed. The faster it prints the duller the finish tends to get because the plastic is not spending as much time getting heated in the nozzle. I see this as a sign of nearing underextrusion, which can be bad.
The fix in most cases is pretty simple, raise your nozzle temperature. I find that 240-250 is good for the IS profiles depending on your filament supplier. I've found that Polymaker needs 250, while Hatchbox is good at 240.
If that doesn't solve it I recommend lowering your volumetric flow rate in the filament profile. Essentially this will limit maximum print speeds based on the required flow.