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Old 04-29-2021, 06:01 PM
William William is offline
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Default Fluctuating Z

Last weekend I cut out a project but my cuts weren't going all the way through even though I had programmed it to cut a few thousands into the spoilboard. My theory is that in this hot weather the humidity had gone down and the spoilboard has shrunk 5 or 10 thousandth.

These are very newbie questions but what's the proper procedure for 1) checking Z 0 before beginning a cut, and 2) what's the process for adjusting of fixing it?

Regarding checking starting accuracy, I'm assuming I put a tool in, jog the spindle to the place I want to check, issue a Z3 command, and then verify the end mill is really 3" above the spoil board.

If it is off do I need to reset my Z0, recalibrate my switch, and measure all the tools again? I suppose I could also increase my depth of cut and go farther through.

This is probably old hat to you all but any guidance on best practices would be appreciated.
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Old 04-29-2021, 07:55 PM
Logan Y Logan Y is offline
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I check my Z before I start running jobs everyday. You can use something like this, https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1, for a pretty precise Z measurement.

The easiest option for me and the one I employ 99% of the time is job my bit down to a piece of paper on the spoilboard. I keep jogging down until the bit just touches the paper and doesn't slide around freely under the bit any longer. I then job down the Z another .005 and zero there. I know paper varies but it gets me close enough to do most work. If I need fine detail I use the first method. You don't have to recalibrate your switch every time you reset your Z. You should only recalibrate your switch after you surface the spoilboard.

Also double check your material thickness with a set of good calipers and use that value in Vectric.
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  #3  
Old 04-29-2021, 08:33 PM
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james mcgrew james mcgrew is online now
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i have a block of aluminum .75 x 3 x 6 true mic'ed.. i will tell bit z2 looks good then z.75 and slide my block under it

worried about a spot on table then move to spot and see if block fits..

an mdf spoil board will swell in humid atmosphere,, when we run cabinets we skin .oo2 before each run and re z after
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Old 04-29-2021, 09:32 PM
boatbuilder2020 boatbuilder2020 is offline
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William,

Was the "depth" inconsistent . . . in other words, were you cutting through in some areas but not in others.

Also, curious to know what material and material thickness you were machining.
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Old 04-30-2021, 04:18 PM
William William is offline
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Quote:
Originally Posted by boatbuilder2020 View Post
William,

Was the "depth" inconsistent . . . in other words, were you cutting through in some areas but not in others.

Also, curious to know what material and material thickness you were machining.
The depth was a little inconsistent but also universally off across the piece. Meaning on the pass I thought would cut through, nothing did. And then as I redid my finish pass with successively lower Z values in the G code, some areas cut through before others but, I think, they were within a few thousands of each other. It did make me wonder if the spoil board is no longer consistently parallel to the gantry.

I'm cutting 3/4 baltic birch which measured out to be .72 in.
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