so what causes this?

[printbus]

So to eliminate bounce it wounfs like we need to repl a ce the belts with micro chain...

Not necessarily. The belts are supposedly pretty good at maintaining dimension. They're designed for that. But getting the right tension seems to be tricky, sort of like bed leveling. (lol)

[printbus]

Vacillation of the pressure in the hot end comes to mind as well.

[AbuMaia]

I found it easy to tension the Y belt, I just used a spring clamp to pull the Y motor to the rear, then tightened the motor mount bolts. The X belt was harder to tension, as there's not much room to get a good pull on the X motor. I've been thinking up a redesign of the X belt idler so one can turn a bolt to adjust the X belt tension.

[printbus]

I found it easy to tension the Y belt, I just used a spring clamp to pull the Y motor to the rear, then tightened the motor mount bolts. The X belt was harder to tension, as there's not much room to get a good pull on the X motor. I've been thinking up a redesign of the X belt idler so one can turn a bolt to adjust the X belt tension.

But isn't there a risk that you can get too tight on the belts? That was part of the basis about it being hard to get the right tension - that you want enough but not too much. And again, my belts are now tighter than ever, but I can't say that's made a difference.

Remember that the ringing effect is showing up when the printer has only moved a millimeter or less in the lateral axis. Acceleration and deceleration should have kept the speed for that small of a distance pretty low, at least in the meager bit I understand Marlin move planning. Again - I can understand ringing on major 90 degree corners, but not so easily on cases like shallow recesses for lettering or holes on thin walls.

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My four-sided ringing test print is complete. First, I realized that the case I printed yesterday had small radius rounded corners, so not having ringing there is no surprise. The test object had an identical notch and round hole on all four sides of a cube. Pretty equal ringing on all four sides. I'm not sure pictures will reveal details well, but I may try to take some in the morning.

[beerdart]

For Our Y tension I slotted the bearing end and add two eye bolts through the frame to the bearing attach screw.

[printbus]

For Our Y tension I slotted the bearing end and add two eye bolts through the frame to the bearing attach screw.

Please answer the more important part. How do you know when you've tightened the belt enough? That's really what people want/need to know.

[beerdart]

I dont know the sweet spot but ours is tension-ed so its difficult to force it to the table pushing down in the center of the long loop.

Please answer the more important part. How do you know when you've tightened the belt enough? That's really what people want/need to know.

[MiniMadRyan]

Printbus, you raise a good question. I have always wondered if mine are too tight or not enough, with finding very few actual answers online.

I know that on my y axis, making the belt any tighter starts to warp the rear y bracket, to me that's too tight then. Both my belts are tight, and produce a very low "sprung" noise when plucked, but I always wonder if they could be better!

[printbus]

DanCope - welcome to the board.

As time permits, I've also been running a pile of prints, changing one parameter at a time. I'm not complete, but I've seen some results similar to yours. I dropped xyjerk all the way down to 2. While there was some improvement in the ripple, it certainly didn't make it go away as I expected it to.

One observation on your settngs - you mention lowering Amax X and Amax Y to 500 mm/sec per second. I assume you are referring to what were the MakerFarm default values of 1000 either on the LCD or in DEFAULT_MAX_ACCELERATION? Note that there is another acceleration term Accel on the LCD and DEFAULT_ACCELERATION in configuration.h, which has a MakerFarm default of 500. As I understand it, the acceleration one gets is actually the lowest of either the axis specific acceleration or the global acceleration setting. With Accel set to 500, changing Amax X and Amax Y from 1000 to 500 actually had no effect since Marlin was already using that as the upper limit.

I'm far from being complete in my test prints, but the most effective scheme I've seen so far to eliminate the ripple is to reduce the acceleration (either the axis specific or the global term) down to 200 or below. I don't believe this eliminates the ripple - it may just compress it down to a shorter distance so that it isn't as apparent.

EDIT: Note that I am not suggesting people go lower their acceleration settings to 200 - I'm just sharing what I've observed. Slowing acceleration and lowering jerk can hurt print quality since the nozzle is moving a lot slower through direction changes like corners, leading to softening/blobbing in those areas.

[DanCope]

One observation on your settngs - you mention lowering Amax X and Amax Y to 500 mm/sec per second. I assume you are referring to what were the MakerFarm default values of 1000 either on the LCD or in DEFAULT_MAX_ACCELERATION? Note that there is another acceleration term Accel on the LCD and DEFAULT_ACCELERATION in configuration.h, which has a MakerFarm default of 500. As I understand it, the acceleration one gets is actually the lowest of either the axis specific acceleration or the global acceleration setting. With Accel set to 500, changing Amax X and Amax Y from 1000 to 500 actually had no effect since Marlin was already using that as the upper limit.

Yes sorry I should have clarified, all settings where done through the LCD and defaults were as you described. I thought it odd that Accel was lower than the specific Amax X and Amax Y, but thought I would drop them both anyway. Ignore that setting change then.

Is there a setting to control how the printer decelerates towards an edge? Lowering the Jerk and the Accel are only going to go so far to hide the vibration when I imagine the real cause is when a motor suddenly halts on an axis - surely you would have to lower the overall speed to make it less of a sudden stop?

I would love to know what effect those astrosyn motor dampers would have on this.

I would love to have some of these, but I would be surprised if general motor vibrations were causing this. Unless it's like a resonance thing? Not sure.