Odd mechanic skipping/bouncing/hitting
I originally thought my nozzle was running into printing because of over extruding. After fine tuning my extrusions, it kept happening, but only in certain parts of prints. I could hear it hitting something but couldn't see anything. After trying many things, I eventually tried the print without any filament at all. And it made the exact same sounds in the exact same spots.
So I tried moving/rotating the print. It did the same thing in different spots. Eventually, I narrowed it down to when it is going back and forth within 10 to 20mm. It starts small and gets worse the longer the infill stays in that 10-20mm range. Eventually, it will cause skipping.
Here's a video showing smooth motion in the same area when going long distance, but when it starts solid infill it starts jerking like it's hitting something.
https://www.youtube.com/watch?v=q9PTMPjv-t8
I have NO idea what's going on. This is SO weird.
11 Replies
extended-salmon•10mo ago
That looked/sounded to me link the x-gantry Are your belts properly tensioned?
adverse-sapphire•10mo ago
I believe so. I'll generate a few graphs and post them here.
adverse-sapphire•10mo ago
They look ok to me. The Y resonance has a extra hump that I can't explain, but they look ok. The only thing that really baffles me about them is that the x and y resonances are so close to each other. I'd expect x to be higher than that.
stormy-gold•10mo ago
Are you sure that you've assembled the Idler stacks correctly? Looks like the lower belt is working itself off of the middle of idler stack in the back, running on the rim on the idler stack and snapping back...
You know, running like this:
stormy-gold•10mo ago
stormy-gold•10mo ago
instead of like this
stormy-gold•10mo ago
stormy-gold•10mo ago
at 0:46 you can see the belt moving sideways:
stormy-gold•10mo ago
adverse-sapphire•10mo ago
I thought I did but I will verify. Thank you!
As I was verifying that I assembled the idler stacks correctly, that involved removing the belt. For fun, I jiggled the print head back and forth and it would bind going diagonally or front to back but not side to side.
In the end I replaced a Y rail and it's running smooth now. I can't explain it. The rail FEELS smooth off the machine, but replacing it made all the things better. Or maybe I screwed it into a better spot or more aligned.... I don't know.
Bottom line: She's printing well now. Thanks for all the help!
yappiest-sapphire•10mo ago
I've been having a similar problem on the top belt but not as nad. I can see extra wear on the top of the belt from it rubbing upwards. Without the belt everything runs smooth and the printer is quiet during prints. I printed my parts out of ASA but has anyone with more hours on their VC3 had problems with them deforming in an enclosure causing missalignment?