Hi
Brent113, I have now tried to loosen all the scews again. When i run the machine with all screws loose i do not get the problem. But once i fasten the 4 screws to tighten the base plate, the problem come back. (All the screws on the linear modules for the y-axis are still loose)
I also turned the machine off, manually pushed the axis to the end, started the machine and drove the axis to the middle before i tightened the 4screws on the base plate. Still same problem.
Try also to loosen the screws of your linearmodules, please!
There was a topic about a bad base plate one or two months ago
All the screws on the linear Y-axis modules are loose, but still same problem
Hmm, well I guess back to the original plan of waiting for support
Well poo, me too.
I see it and hear it in calibration and high speed manual transits. Seems more a sideways twisting motion to me. like a nut is binding and skipping maybe. Also had to remove endcaps on Zs to release a stuck limit switch. (Toolhead would only move down…) Noticed a 4 or 5mm difference in the shaft height sticking out the top… Either length or assembly is significantly off or at least different on the two units I’ve opened…
Has anyone moved linears around to see if they can move the bump?
Hi all,
My name is Xabier, and I also have the same problem. After a week and a half using my Snapmaker 2.0 (A350) and some ruined laser cuts, I have noticed this bump in the Y-Axis.
In the next image you can see the effect of this bump, which makes the machine useless as I have to cut large pieces of plywood with more than 1 pass. This bump displaces the bed, so further passes don’t go through the same place.
Each time happens in a different position of the linear module. I haven’t yet tried anything like loosening the screws or changing the y-modules by the z ones. I believe that the machine is correctly assembled. Tomorrow I will try to document when is happening in order to try to identify a patron.
I have to say that this is really annoying.
Any help would be much appreciated,
Kind regards,
Xabier
Just received mine today and I’m having the same issue. Any resolution to this yet?
Same, as in it doesn’t bump when the screws on the y linear modules to the base are loose and the bed is removed? If so, double check your assembly, and submit a support ticket 
So if it doesn’t do it while the screws are loose, is that an assembly issue?
Screws are loose and problem goes away.
That seems to be the current theory some other people here have come up with, but maybe not.
It could be the base plate isn’t square? Or maybe the module has a curve in it?
No one has gotten a real answer from support, other than they are shipping new linear modules?
I might be mis-remembering.
I just ran about a half hour of the laser module engraving a greyscale picture with the screws loose with no bumping, skipping, or jumping. The screws started to fall out, so I thought I should tighten them down. I tightened the linear modules to the base plate first as the instructions say, I did this while pushing them to the back end of the base plate. Then I tightened the printing/skeleton plate to the linear modules via the four M4-8 screws per module. Restarted my engraving and I haven’t heard it jump yet. So it seems that there is an issue with base plate alignment more than anything, but I’m not technical support.
So this seems to have resolved my issue.
Just as I go back out there, I hear it jumping again, so I guess this didn’t resolve my issue. Looks like I need to open a ticket.
Hi all again, let me share what I have done this morning.
First of all, I have loaded in the workspace a G-Code consisting in a 10x300mm rectangle (along Y-axis) centred in the bed.
I have done all the following steps with Luban software from my computer, not with the pad:
I don’t have a clue about what has happened. I haven’t done anything else from what I have described. I keep “running boundaries” and no bumps are hear at all.
I am going to try to cut a large piece with 4 passes. I will keep you informed if anything new happens.
Regards,
Xabier
I ended up swapping two of the linear modules, the skipping y-module for a z-module. I started my etching again and it has been running all night with no issues and actually looks great. No skipping or runoff at all. I’m going to try and cut something today. I’ll still want the module replaced as there is definitely something going on with it.
I haven’t been able to find any patron in this Bump.
Most times happens, sometimes not. I don’t know if it comes from software or hardware. It looks like it always happens in pairs, like if something is clamped, and then released.
Next, are some of the G-Codes I have been trying (only pressing “Run boundary”, not actually cutting them). Red dots indicate when the bumps happened. First and second only differ in the “optimise” option when generating the code. Third one is equal to the first but rotated 180º: no bumps at all happened here (and I tried many many times). Fourth and fifth are just the same codes but taken to the upper left corner of the working area. In the fourth one, sometimes there was no bump, but most times yes (like 7 times out of 10). In the fourth one, after 2 “Run boundaries” without a bump, I moved the head 1mm in -X and +Y and the bump came again. In the fifth it always happened.
No idea what it is going on, but this a really estrange and annoying issue.
Some ideas:
Hi again,
Sorry for the long delay in posts here, life has gotten in the way for the last week. I did receive some feedback from Edwin at support who suspected that my issue was caused by speed differences between the two Y-axis modules. He had be disassemble the plate off the modules and then run through some movement tests to ensure that both modules were moving at the same speed/distance. All appeared correct with these tests. However, when running the tests, I noticed that my left module has a noticeable higher resistance to movement than the right. It also seems to make more noise than the right when moving and holding position.
Since it had been several days since I submitted my photos and video of the tests to support and I hadn’t heard anything back, I reassembled everything a couple nights ago, being very careful not to induce any twist in the Y-axis base plate when tightening the screws. I ran some movement tests while I was tightening the screws (tighten the screws 1/8 turn, then power on the system, move the Y-axis repeatedly, power the system off, repeat). I also made sure that the Y-axis was nominally level on my workbench with a higher precision torpedo level. So far, I have been able to run a few calibrations, including a 5x5 calibration, without any binding. I have also noticed that the system is quieter when moving than before.
Perhaps this issue on my particular unit is being caused by the combination of a marginal left module and some binding induced when the Y-axis base plate was tightened, which then causes the left module to miss steps on occasion, causing the “bump” and grinding?
I have the same issue and is in contact with support.
So far it seems my 2 Y-axis linear modules travel different lengths. When commanding 340mm with the touchscreen one module moves 0,9mm longer than the other. This leads to a bump when one decides to halt and wait for the other(when bed is bolted on).
Don’t know yet how this will be solved.
@General_Tux @danieln This is a good step forward in finding a solution, thanks for sharing.
I wonder if the solution will involve adjusting the eccentric nuts that tension the carriage against the rails…
Confirmed, at least in my case, the problem comes from different Y-module working speeds.
I have set up the following rudimentary way of measuring this difference:
And this is what happens after moving the Y-module 330mm in the -Y direction:
If moving it back to the first position, both marks match up again.
Now the tricky question, how we fix this?
That’s brilliant, nice test jig!
Really interesting find that it matches up when you go back. That sort of eliminates skipped steps as a result of a mechanical issue, because those would not be made up since these modules are open loop control.
Is this issue limited to the Y axes? I have so many questions, so many things that could be tried. Swap which Y splitter is being used? Try one module at a time directly to the controller with no splitter and see if they both go the same distance? Swap another module into there? Try swapping the Z and Y cables at the controller and see if the problem stays with the Y axes or does it move to the Z axes?
Clever thinking!
Not sure: How much tolerance is there in the lead screws? It almost looks like one lead screw has a slight difference in its slope as compared to the other.
Potential quick fix: Remove the X-axis module and try if a combination of one of the Y-axis modules and the X-axis module yields consitent results. Then use the deviating module as X-axis module.
Still, I’d contact Snapmaker support, since in the end it’s a production error IMHO.
