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CNC Router Losing Z Height During Carve
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I checked it out, and I didn't realize we're using a threaded rod rather than a lead screw.


I've actually got a 75*75cm workbee that I'm not using right now - there's a small amount of electronic work to do, but I've got all the components and just haven't had the time.


If there's appetite, I'm happy to have it available for the makerspace to use. I majorly oversized the motors for it so that it could be expanded - we could always use a few pieces of extrusion and a couple of longer lead screws to make it much larger.


Either way, it's got enough rigidity and power that it could be easily used for non-ferrous metals and PCB work.

Hi there Torsten,


Not off hand no. As far as I know the repairs have been working but the offer is definitely appreciated. Maybe give it a test and see if an upgrade would be useful?


I'd been thinking of putting a workshop on with that machine at some point in the future...

Hey, I'm a new member and this thread is a bit old... but I have built a few CNC routers and my have some of the correct couplers. Do we happen to know the ID required for the lead screw and the stepper?

Great work and ingenuity fabricating that coupling out of what you could find!


A nice attempt on the 3d printed coupling by who did that, would have worked with some clamp bolts. There's a trick to doing these where you just download a suitable one from McMaster Carr and tweak for printing.


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Quick update:

I pulled apart the z axis to have a look at things. As I suspected, there was no indexing on the 3D printed coupling, and as such, you could turn the stepper without moving the z axis screw.

I fabricated a new coupling with what I found here. Took me 4 hours of messing around, but it seems to work well. It's a direct connection, so hopefully that works effectively. It's also not perfectly concentric, so there's a slight wobble in the mount as it moves, but the machine doesn't seem to mind.

It's carving well now, without issue.


Oh, and I also replaced the wood shims.

Hi, Grant. Yeah I thought of that, but I have a mark on the shims and it's not moving. I'm wondering if there's some shim stock in the fab shop to properly secure it. But it doesn't appear to be moving.

I've been doing a lot of searching online and a lot of people have had a stepper that begins to miss steps so they've replaced their stepper motor and it seems to fix the problem. I'm tempted to swap it out, since we have an abundance of them, but the coupling that's in place looks to be 3D printed, and perhaps friction fit? I can't see any indexing on the shaft. It's a weird setup securing the stepper, with the wood riser screwed and glued attachment that I'll eventually fix, but just trying to get through the carve I have to complete today (Friday).

Hi Jeff. I haven't used the machine myself for a while. I did notice that the router is not the original one and looks like it has wedges to hold it in place. Is it possible the router is slipping? Is it possible that you might be accidentally bumping the router up when you set the Z height and having it settle back down over time?

Just thinking of some troubleshooting steps

Hello!


I'm a new member this month, and I've been actively using the CNC Router. However, it has not been without it's challenges.


What I'm consistently running into is that over the course of a carve, I am losing Z Height.


I am using Easel to export my G-code, as I have an X-carve myself (1000mm square). It works well for the most part, but over the 5 or 6 carves that I've done, I'll lose about 3-4mm of height every hour. I don't have this issue with my own machine, just this one. I've been navigating through this issue by pausing the machine occasionally and resetting my 0.0 on the Z, then resuming on the last line of code that I was on. It doesn't make for nice, consistent depths, but it has been working in a pinch.


I'm hoping that there's someone experienced enough with the build of this machine to help me troubleshoot the issues so that I have less to stress about while carving.


Thanks, all.


Jeff

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