Parts print slightly shrunk in the center
My Robox printers used to print perfectly until around the time of a recent firmware update. Now all my prints are shrunken in the center with a flare out at the top last layer. From the base and 8mm up, there is about 20% shrinkage... then it returns to normal with the uppermost finish layer extending half a mm past.
Any ideas on how to fix this? Never did this before.
The "necking" you mention in the comments is shrinkage. I haven't seen this for along time and I think it is probably related to the ABS you are using. The older ABS we supplied had far more warp than the TitanX we love now.
If it was performing well before but is not now then it is likely the usual culprits:
- Environmental. Keep the door closed for ABS and try to maintain a high temperature inside the box. If the room is cold or draughty it might effect this.
- Moisture in the filament. It is possible that the first few rings of material have absorbed more moisture and are shrinking more with heat from the bed. Are there any popping sounds coming from the nozzles? This would indicate steam bubbles escaping. Ask a new question about drying filament. We have a new industrial dryer at CEL-UK and are having a great time refreshing old filament. It makes a huge difference.
For official support please create a support ticket using this link www.cel-robox.com/support/
Does it do it with say a 20mm test cube. Is it "necking" in one plane only, so say just the X or Y or both all the way around? I too think it is shrinkage, but related to the infill area vs strength. the larger areas of infill can exert more shrinkage on the perimeters. Out of curiosity, if you increased the perimeter shell count does it improve or reduce the infill percentage. If you have only noticed this from a firmware change, you can revert it back to an earlier version, if you want to do a back to back test. I've been told the firmware is normally matched to an AutoMaker release, but you can manipulate this, and BTW my robox_r765.bin file was modded in November 2018. There is a r766 too you can try. 🙂
@bhudson Neither do I 🙂 I've had all flavours but the OP thought it happened from then on, so besides asking questions before to ascertain if there is a mechanical or model issue, and stating first I thought it was shrinkage related, I then suggested a way to revert the firmware back for his peace of mind. I don't use ABS or TitanX anymore.