I’ve been loving my new Taz 5 and I jumped straight to PET+ becuase I wanted a new filament and the low warp was too appealing. I’ve had a few issues here and there so I figured I would share some things I learned.
1. Lay down some glue first!
This is where everything went wrong at first. The PEI bed and PET plastics have a tendency to bond, my first print got destroyed when trying to take it off the bed and the PEI surface got scratched up. Using glue causes the PET to stick to the glue and actually come off the bed. I use Elmers Purple but Lulzbot recommends UHU.
2. Don’t let your bed completely cool off
This contributed to my first print sticking as well, for PET+ I use this in my ending gcode:
M140 S45 ; Set bed temp to 45 for part removal
3. Make sure your Z endstop is set properly.
With PEI the “squish” isn’t really good and will also make it harder to remove prints.
4. Follow all manufacturer specs.
For MadeSolid and Simplify3D this includes changing the flow rate to .96, setting the correct nozzle diameter, extruder width (I use manual @ .5 because it fits in to 1 nicely), density (1.38), and speed (30-60 mm/s). I use 30mm/s for outline and 60mm/s for infill.
5. Ditch the brim!
Even at extreme angles PET+ has little to no warp. If you followed step 3 and remove the brim then your first layer will be the same width as the rest of your print with no sanding!
6. Play with the temps
So far I find the hbp @ 60 and extruder @ 260 for the first layer and 245-250 for the rest work for me. PET+ colors can react differently to temperature though, so ymmv.
7. Turn your fan down/off
The manufacturer recommends turning your fan off but I find that running the fan around 20% helps. The lower your temperature the less fan you should use. PET+ cools very fast and you will experience layer adhesion problems if your temps are too low and/or your air flow is too high.
8. Set your bottom/top layers to ~1.2mm
My bottom layers are usually half this, but I’ve found that sometimes .6mm-.8mm for top layer sometimes just isn’t enough.
9. Replace your start gcode with this
This will extrude an anchor to clean the extruder head and prime the nozzle for a clean start. Note that repeated extruding in the same spot for each print may degraded the PEI surface in that one spot, especially if you remove the anchor improperly.
G28 ; home all axes G1 Z0.5 F1200 ; lift G1 X280 Y5 Z2 F5000 ; move to wait position in right corner G1 Z0.4 ; position nozzle G1 E25 F300 ; purge nozzle M400 ; wait for purge to complete G1 X200 F1200 ; slow wipe G1 Z0.5 F1200 ; lift
There’s probably more, I’ll update this as I remember and if other users contribute.