I thought it was odd that only one side changed as well. I wasn’t sure if anyone else had seen this before. I’ll run it a couple more times at different locations and see if there are any changes.
I finally got around to cutting some more 100mm squares with 50mm squares inside them to work on the dimensional accuracy. I adjusted the belts some, two were a tad loose, and then I cut two out of pine and one out of oak. I also changed the cut speed and cut depth and neither the material or cutting setting affected the results.
Are there any problems with over tightening the belts? Or is it only bad if they are not tight enough?
The first one didn’t get to cutting out the 50mm inside square because I found out that you need to be careful where you position the clamps to hold down the piece because it can get in the way which messes everything up. I didn’t account for how far the Z rails stuck out and they ended up hitting one of the clamps.
this is the results I got (all squares came out at pretty much the same dimensions no matter the location on the cutting surface, the material, or cutting speed and depth)
100mm squares:
- x - axis: 99.45mm
- y - axis: 99.30mm
- x - axis: 49.55mm
- y - axis: 49.40mm
[attachment file=“20190622_184259 2.jpg”]
I would think the 50mm square would have half the error as the 100mm squares but that doesn’t appear to be the case. At least the errors are both changing now and in the same direction by the same amount.
I also double checked my bit diameter and estlcam settings and they all match up with what you state in the directions.
It moves and cuts great and as long as I don’t care if it’s super accurate then everything is wonderful and repeatable.
Any recommendations on what can be done to improve the accuracy or what test I can run to further diagnose it? Can the program be adjusted or maybe something needs to be tightened down? I’d just like to improve it if possible. I’d just like to get in the +/- 0.2 mm if possible.
Yes, you will stall the steppers, or skip steps.
Are you using a finishing pass?
Try cutting an outside 100mm square as you are doing and a 50mm hole in side of it to check what the error does, to outside squares only tells you you have a systematic error (good info) but not what kind.
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Ok, my belts aren’t too tight then.
No, I didn’t use a finishing pass this time. Would that affect the dimensions?
I’ll try doing the 50mm square as a hole next time and see what it does.
Thanks.
You have to use a finishing pass if you care about dimensions at all.
That would be great if it was just loose belts and needing a finishing pass. I didn’t think a finishing pass would affect it but guess I was wrong.
Should I reduce the speed and depth setting for the finishing pass?
Have a look at my milling basics page.
You are “roughing” out the part. This means your tool is under as high a load as you are comfortable with meaning the entire machine is moving and flexing. A Finishing or Spring pass take the last few percent off of the part with extremely minimal load, meaning nothing should be moving or flexing.
I re-ran this again with a finishing pass and then with the 50mm square as a hole.
Below is an image showing the cuts without a fishing pass (left) and then with a finishing pass (center) and then with the center as a hole (right)
[attachment file=“20190625_200536 2.jpg”]
The accuracy increased when adding a finishing pass but the Y dimension on the 50mm square changed from 49.45 when cutting out the outside to 50.20 when cutting it as a hole.
The X dimension is doing pretty good but it appears the Y needs more attention.
Any suggestions on something to adjust or any additional cuts to try? I really just want to improve the Y cuts when cutting out the outside of the cubes.
Do you think the error would continue to grow if I make even larger cuts?
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Larger is to be expected do to runout and such. What is the outer 100mm error vs the inner 50mm error? Did it double or stay the same?
I really so suggest just having some fun for a while and tune it up later, do you really need it within a 1/4 mm right now? Carve some stuff break it in, just doing calibrations is no fun, who knows maybe you are just using the CAM wrong…
Oh, that’s defiantly the plan. I’ve just been running these as I am trying to learn inkscape and estlcam to be able to make some fun parts.
Thought I’d give an update.
I finished learning enough on inkscape to engrave my first sign. It’s not perfect but it showed me what I need to change in estlcam and what I need to pay attention to when carving/engraving.
[attachment file=105484]
I also have been having a hard time finding time to run this because I have three different projects going on (mpcnc running, 3d printing, and restoring an old lathe) and I can only do one at a time because the dust this spews. With this long weekend I decided to make the enclosure for this so I can run it and the 3d printer at the same time. And once I finish the 3d printer enclosure then I can do all the things. It is also nice that I don’t have to wear hearing protection when it runs now.
[attachment file=105485]
[attachment file=105486]
I also wired up the Iot power relay to have it automatically turn the router on and off and I added a Z probe. It took a lot of searching the forum and tinkering but I finally got it to do what I want and it now makes it a lot easier and more accurate if and when I need to do tool changes.
I’m going to try some more engravings/carvings to really get a handle on how to make them well and then I want to try doing 3d engraving. I looked into it a bit on estlcam but I don’t think I will really understand how it works until I actually start cutting some things with it.
What are the blocks covering the ends of the tooth belts?
Very nice work! Love the enclosure - I need to get mine off the sawhorses, now that I know I’m going to keep using the machine.
They’re the alternative of using zip ties I believe (with belt tensioner). There are a few examples available on Thingiverse.
They are These.