I designed and printed a set of feet for a wooden garden bench.
I have attached the .3mf file and photos.
Printed in Elegoo Rapid PETG which I have used for the last 16 mths without issue after I dialled it in on the P2S.
As you can see the first print on the left showed artifacts on the outer face.
The second print in the middle showed artifacts on the outer and inner face
The third print showed no artifacts atall…
The outer face was aligned to the left of the X axis so basically 90 degrees to the image shown.
Each was a separate print and the bed was cleared after each one.
Can anyone suggest a reason for this changing from bad to good over 3 prints.
I changed nothing as they were just feet for a garden bench out of site having a bad finish didn’t matter, its just the change that I don’t understand..
BENCH_FEET_PETG.3mf (266.6 KB)
You have a pretty severe under extrusion problem.
It’s interesting that the bases of all three were good, the issues don’t appear until further up the print, and even the best one still is showing pretty inconsistent quality.
Are you in a hot weather area, and is there a chance conditions were just warm enough that you were getting a hint of heat creep happening and that was impacting flow consistency, and by the third print either the room was cooler or perhapd you had the door open?
I will also say 0.6 nozzle and 0.3 layer height is capable of pushing extrusion to the limit, so is there a chance you tuned the filament just a little bit too far - to the point of unreliability?
Something like a speed test might be helpful:
Thank you for your reply, I think you have made good and relevant points, I have printed with this filament successfully at 0.3mm layer height 0.6mm nozzle before, hence my surprise at the odd quality.
I did the max flow and got approximately 26 mm/s so went for 23 mm/s to stay within limit.
I am open to any suggestions on adjustments or your insights into this Under Extrusion issue that you may have? 
I don’t disagree with the idea to derate slightly, but I suspect your test to 26 isn’t prolonged enough to really show if that is a stable value or not.
I’d pick a flow test shape, scale it extra tall, set your rate to 23 and see if it remains stable through the whole print.
Or try reprinting with flow rate at 20.
Make sure your hotend fan is clean and spinning freely, too.
Ok, sounds like a plan,
I will print the 4th one at 20 mm/s tomorrow and show you the results.
Thanks again for your help and advice.
