PCTG - A better PETG
Like most, I started 3D printing with PLA, quickly ran into it's limitations with functional prints and moved to PETG. Not having an enclosed chamber at the time (first an Ender 3 then a Mk4) I wanted to advance into better filaments but had limited choices. The various CF filaments like PC-CF were available, expensive and came in a variety of colors as long as it was black.
I started using PETG for functional telescope parts: brackets, cases etc but it didn't really survive being banged up. So I was looking for an alternative that didn't require a heated chamber. One of the YouTubers recommended PCTG as a "better PETG" so I picked up a roll of Spectrum PCTG.
PCTG is PETG with: better impact resistance and toughness, chemical resistance, improved print surfaces and clarity, much lower moisture absorption, identical print difficulty and basically the same thermal characteristics. It's not as UV resistant as ASA but it's much easier to print and doesn't require an enclosed heated chamber.
Downsides are it's not as widely available as PETG, doesn't come in as many colors (although that is getting better) and is slightly more expensive. After doing some research, the four major vendors: Spectrum, Fiberlogy, 3DJake, 3D-Fuel all use Eastman Tritan copolyester (or a direct equivalent) as the base resin. Eastman sells it to filament converters who then extrude, spool, QC, brand, and sell it under their own names. PrusaSlicer has built-in profiles for 3D-Fuel and Spectrum which are basically interchangeable with each other and Fiberlogy/3DJake.
I now use 3D-Fuel PCTG exclusively over PETG except for one very specific color: Prusa Orange.
Here are my calibrated settings:
- Nozzle Temp: 245C
- Bed Temp: 80C
- Fan: 10-40%, 70% bridge (taken from PrusaSlicer Spectrum PTCG profile)
- Chamber: 0 minimal, 40 nominal (although this can be 0 as well)
- Extrusion Multiplier: 0.96 for PTCG-CF and 1.0 for PTCG
- Pressure Advance (0.4mm Diamondback): 0.053
- Shrinkage: 0.2%