Part Alignment ERROR

So, I’ve been trying to mill some parts out of aluminum for some time now. I Start my process on one side, everything looks perfect. I flip it over to remove the left over stock and finish the bottom side and things don’t align. My chamfers and other features are off by at least 0.01" every time. I’ve double checked my probe and its within 0.0005" of runout, the machine travel compensation is almost 0.0005"-0.001 of deviation on the X, Y and Z axis.

I will greatly appreciate any efforts in trying to solve this issue

Can you post some pictures of what you’re seeing? Is it consistently off in one direction? The probe hasn’t been 100% accurate in my machine, but I just used it to align a part last night that came out nearly perfect.

Are you re-probing after stock removal? I generally re-probe after I remove the hat, as stock isnt very accurate.

Yes I do re-probe once I flip the stock and re-probe again once the waste stock is removed

Sure. The alignment is in a different direction each time especially if you home after probing. I noticed that it tends to shift everything about 0.013" sometimes

Do you have an edge finder? Could try that and possibly narrow down if the problem is with the probe or elsewhere.

The only thing I have to find edges is the touch probe Langmuir supplied and the dial indicator.

This is the edge finder I’ve been using, which I’ve had for years.

It is so inexpensive, I should probably order a spare. The version without the point I one end is a few dollars cheaper:

The major draw back vs. a digital touch probe is that a wobbler can’t be used to set Z.

Thanks! I was thinking of just purchasing a Haimer and not use the probe MR-1 supplied. Something I noticed with the touch probe is when I opened it up, there were only 2 of the 3 screws holding the board in place and those two screws seemed like they were just started and not even tightened down which seems ridiculous for a device that is used for accuracy.

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Those three screws on the bottom are intended to be snug only. Tightening those excessively will compromise its accuracy. A properly assembled touch probe will repeat within .0005 every time. We have don’t many repeatability tests.


I wasn’t talking about the silver screws on the outside of the probe. The screws inside the probe (small black ones appears to be about the size of an M2.5) were lose so the board was able to wiggle around and the probe would never centre again. Now, yes you’re correct the silver screws on the outside bottom are just snug and not tight.

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I had the same issue of black screws being loose and the entire circuit board moving around with the probe. In addition the probe tip base had very badly machined bearings that would cause very hard move of the tip. I got a replacement probe from Langmuir that works better.

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The mechanical Haimer is pretty large, I dont think it would work super great with our Z limits. Unless theyve come out with a tiny one I haven’t seen.

yeah they’re about 6 inches in length sadly

Has anyone ever tried something like this?

It would have to be done manually and it can only be used with conductive materials which is fine for me.

Its a Precision Easy-View Electronic Edge Finder

I have never used one but I can see the attraction for finding the Z offset.

I saw a YouTube video many years ago with a demo showing that mechanical wobblers should always find the spindles true axis of rotation, even if the collet isn’t running concentric.

Of course, the same issue should apply to any electriconic touch probe. Which is why they need to have a calibration mechanism and be constructed to tight tolerances.

Just a thought, did you double check your vice tram?

yes and its perfect

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If you set wpc off the rear vice jaw corner and align the part off that point for both ops so you don’t have to probe the second op I’d be curious if it’s still happening. I almost always try to set my plane to the back left corner of the part when I’m programming for that ability.

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