Vref for stepper motor...?

Please advice me how to find a vref for this stepper motor

What are you using to drive them? They’re 6 wire steppers.
https://datasheetspdf.com/pdf-file/1047045/NMB/17PM-K402V/1

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ok thanks Barry, with A4988

The data sheet for the motor should give you a maximum amperage for the motor (looks like .8 amps if I’m reading the linked sheet correctly), then you tune the driver’s vRef to keep the driver at (or just below) that amperage. There are a number of suppliers of clone A4988 drivers, and some use different “sensing” resistors on their boards. This makes the target reading for a given vRef vary. This article got me on the right track by helping identify the resistors on my drivers. I actually had different resistor values on drivers bought at the same time from the same supplier, so I strongly suggest checking them all.

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FYI: V1 recommends a minimum of 50oz.in steppers. If I’ve done my conversion right, your steppers are 47.6oz.in. As a point of reference, the steppers that V1 sells are 76oz.in. These steppers will likely still work, but you should have lower expectations with respect to feeds and depth of cut.

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ok thanks,

planning to cut spruce veneer with 1mm cut height

Depending on your use, at 1mm cut height you might want to consider a diode laser rather than a router/spindle for your cutting. You end up with burned edges, but your “kerf” will be substantially smaller.

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Thanks Robert,

I will cut cut 3D shape anyhow to spruce plywood.

Some high density foam as well. I am fine with CAM tuning, mpcnc building is the thing which is slowing me now…