External Perimeter Resonance Issues - stretching/scratching marks on outer shell
I'm trying to figure out my best quality & speed settings for external perimeters to make the outer shell of the print.
I've tuned extrusion, flow rate, temperature, cooling, etc. and am getting very good results as far as the tops and bottoms of things go, so now I'm onto Resonance, Pressure Advance, etc.
I'm following the https://www.klipper3d.org/Resonance_Compensation.html guide, so Input Shaper and PA are off.
Attached is my latest tuning tower, and a recent best surface finish print
Settings:
Enclosed V-Core3.1 - 500 | 48V 5160s, Carbon Fiber Gantry, latest toolboard & beacon
This tuning tower is running from 500 mm/s2 to 6500 mm/s2 accel
External Perimeter: 100mm/s
Normal Perimeters: 500mm/s
Max Flow Rate: 24 mm3/s throttles back the high perimeter speed most of the time.
ASA 250/110C fan at 40%
I typically print with external perimeter speed at 3k accel and 180mm/s but that and anything higher on this tuning tower is horribly ugly with these stretch marks/striated gaps.
I understand this test is usually about ringing and resonance frequencies, but that's not my main concern right now.
My questions:
1. Is there a term or name for this other diagonal distortion/scratching texture I'm seeing at higher accelerations?
2. How am I supposed to address this? Do I just have to accept this test at face value and print external perimeters at 100mm/s at 500mm/s2 accel (the bottom of the tuning tower) or even slower?
3. Is there some critical setting/parameter I could be overlooking?
For how clean & fast I've been able to get the infill & top surfacing these numbers seem unusually slow to produce a very high quality & visually consistent outer shell, but my perspective is limited.
4 Replies
The striations do appear to a lesser extent on most of my test prints - various external perimeter accel from 3k, 5k, 10k, and 20k. I haven’t found settings that produce a super clean shell like something I might get off of my A1 Mini (which I understand prints dramatically slower)
Here's all sides of another hexagon at 60mm/s @ 1k for both inner and outer perimeters
I have this same issue. Any luck figuring it out?
Ive had similar problems with my first 3d printer, but I don't know if it is the same problem. I think it might be fixable with pressure advance and resonance comp. My guess is as your print turns the corner the print head wiggles a bit (as resonance comp tries to fix) and the extra filament pressure in the nozzle from the deacceleration trickles out and squishes out and gets caught on the wave of the resonance(not sure if that explanation made sense, im thinking like the same principle that causes the tree branches when you have filament stringing, but in this case it is all contained in the walls of your print. I would try tightening your print head to make sure nothing is loose, tuning pressure advance and then resonance.