Calibration Test Procedure

I used a dial indicator set a measured distance with a 6" mic standard.
Set the x zero, measured the distance and fed the x to 6", adjusted the $100 until it zeroed out time after time. Did the same on Y.
For z I used a 2’ dial and it was bang on over the whole 2".

I am thankful for you posting the how as it went well.

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Thanks for the feedback, I’m glad it worked out for you!

I debated whether to add an average column, but I ended up running out of room without going to ridiculously small margins or super-small boxes for data (or multiple sheets). As for the quality, I figure that’s more of a personal definition. It would have been hard to describe multiple levels of finish quality without bringing in a bunch of instruments or tools that not everyone may have.

I probably didn’t need so many circles and squares, but it gave me a chance to add multiple depths for more Z data points. I’ve also noticed that unless my machine is perfectly dialed in, small errors in small circles tend to be a lot more obvious than in larger ones.

I’m always working on the next version in my head, so let me know if you come up with any more comments or suggestions!

Great idea, and well done! Do you have a picture of how you set up the dial indicator for X and Y?

Yes I do.

I used a .250 smooth rod to make it easy. Worked well.

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I use a DeWalt 611and a .125 bit.

How would I use this in vcarve desktop.?

Don’t know but think outside the box. I do not have one so I cannot advise.

I’m not sure how you’d use it in V-Carve, since I designed it for use in Easel. If you find a way, let me know and I can add the instructions as another step or in the next version.

@RobertA_Rieke

From what I can read about it (I don’t use Easel - and this is another reason for me not to) you can only export G-code files from Easel. I could not find a way to export the design to any other format. Basically, if you use Easel for designing then you’re locked in.

In the end, it’s basically a bunch of circles, squares, and a triangle. I didn’t put any relative spacing between objects, so with the given dimensions on the PDF it could probably be re-created easily enough in a different program.

Would you be willing to help me interpret the outcome? I’m going to remeasure the carving today since I think I had measured wrong the first time. I’m unsure what to do in order to make adjustments anyway!

I’ll try my best, and others will be able to help too. Here’s a quick summary though:

  1. If all your squares are the wrong size in X and/or Y, you either have lost steps or you need to calibrate the axis. If they’re all off by the same percentage, it’s probably a calibration issue.
  2. If your depths are off by a small amount, you probably just need to calibrate the Z axis.
  3. If your circles are somewhat oval, that indicates you’re losing steps. The way to figure out which axis is losing steps is to compare the direction it was cutting (clockwise or counterclockwise) to the long axis of the oval. For example, if it was cutting clockwise and the longest measurements are at the 1 and 7 o’clock positions, that says you lost steps on your Y axis (because it traveled too far on the X before the Y started to move).

I’ve got a video explaining how I calibrate my machine in this thread: X-Carve Maintenance/Troubleshooting Videos - Add Your Own!

There is a great explanation and procedure for fixing lost steps in this thread: [Guide] Offset cutting, Lost steps, Positioning errors, etc

I’ll review the links you gave and go from there. I’m just not certain how to interpret the results, have to start somewhere!

These are the results, I typed them up in Google Sheets

Hi Robert,

Thank you very much for writing this Calibration Test Procedure. It is easy to follow and very informative.

I have question a about the z-axis. I executed the calibration pattern project. X and Y axis look ok. But the Z axis shows a constant offset of about +0.012in across all depths (ie. it is overshooting by about 0.012 +/- 0.003 for depth). My understanding is that changing the z steps per mm setting would fix a constant percentage discrepancy (e.g, say +.03in at .100in depth, +0.06in at +.200in depth, +0.09in at .300in depth, etc.) But how do you correct a constant offset per depth? (e.g., +.03in at .100in depth, +0.03in at +.200in depth, +0.03in at .300in depth, etc.).

Note: I am using a Z-probe to zero the z-axis.

Thank you for sharing!

Juan Carlos

Steps/mm would probably not cause a constant offset. It’d be an ever growing/decreasing offset the more steps that are performed.

Remeasure your probe and verify your probing sequence is accurately adjust for probe thickness.

Hi Justin,

Yes! That is my mental model also about the constant offset: it is not solved by adjusting the steps/mm parameter. But is there a way to “calibrate” the Z-probe? I just followed the steps from Easel. The program guides you every time you click on Carve and want to home the position of the bit in the Z using the probe and the XY manually. However, I am not aware of any steps/guide to “calibrate” the z-probe thickness, etc… Is there one? (sorry, I am pretty new at this stuff)

Thanks!

Juan Carlos

You need a caliper and you measure the thickness of your probe block. Then, when running Easel’s machine setup, and you get to the Probe screen, you click on the “Advanced” part and enter in your calipered probe thickness in the appropriate field. This will set your probe thickness properly and should eliminate your 0.012 offset.

Hi Justin,

I found the setting! Thank you! :grinning:

DSC02520DSC02522DSC02521

Love your calibration pattern still have to do the measurements, but the cuts look good.

Thanks Robert it’s folks like you that make learning new stuff enjoyable.

Very much appreciated Robert!

Not sure why Inventables never made anything like this, but sure glad you did!

Can’t wait to use it. Thank you for all of your hard work on this.

Very nice Phil. Thanks also for the mobile and computer links. :+1:

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