Measuring Z depth incorrectly

So, I think my smart clamp is not so smart. I typically get an extra 0.05" of depth on my carves, I noticed it particularly using the inlay generator app on 0.125" plastic for a “Happy St Patricks Day” cloverleaf token for my kindergarten son. I set the depth of cut to 50% for the fill-cut (so 0.0625) and on most of the piece, it was almost all the way through the plastic (to the extent that the center of the ‘a’ is being held on by a whisker of plastic at the bottom.

It also means the first plunge into the workpiece is significantly over-stressing the bit, so I’d like to sort it out. Is there any sort of offset you can apply to the “measured” value ? Is there a hardware fix ?

I think it’s always been like this, btw - it’s just the up until now I’ve mostly been cutting 100% cuts, and although it meant I had to have an extra-thick wasteboard to absorb the extra cut, the stress of the first cut hadn’t occurred to me until just recently…

Cheers
Simon

No-one ?

I have found that the issue is directly related to the little switch that is contained in the “Smart Clamp” going bad. As it gets worse, it takes more force to actuate, to the point where the carriage on my machine was bending by up to a quarter of an inch before it would trigger. A new switch will solve your issue. Easy, straightforward replacement if you have a miniature Philips screwdriver. However, you have to get the part from Inventables support, you can’t stock up replacements for when the next goes bad. I wish they would have them in the main store, but the don’t.

Simon,

Were you able to resolve this issue? I’m struggling with the same problem. I setup a test piece and it’s consistently cutting about .03" over.

-CJ

@CjHainley Is the first pass too deep? Try easing up on the clamp pressure with the “Smart” clamp.
You might want to try this as well.

Not really.

They did try to do something with the machine config I think - they asked for my serial number and I think the machine phones home (or at least your browser does) with information when you use it.

That worked for a few cuts, but then we were back to square one. Overall I’ve used the Carvy less and less as time goes by.

It’s definitely a Smart Clamp issue. I ran series of blocks stepped down by .01" and the initial cut was too deep, along with all the others as well. The quick fix was to put a 1/32" gage wire underneath the Smart Clamp and it was more or less accurate.

The Carvey is part of a maker space that we have here on campus, and the guy in charge said that he changed the smart clamp a bit ago… I’m not sure how recently that was. Looks like we might need a new one.

-CJ

I have been having the same problem since I first started using the Carvey I thought it was me that was doing something wrong but then everyone has had the same problem. So what is the fix? Put a piece of metal under the clamp to fake it out to think the material is thicker than it actually is so it doesn’t cut all the way through. I am not sure how I can tell how much it is off by but I will fiddle around with it. Also what about the issue of the initial plunge depth? I guess I could do the cut right on the edge of the material so I could measure how deep the first cut goes. Could that contribute to excessive bit wear and out and out obliteration? Any other advice or shared experiences are very welcome. Thanks, Amy

@AmyKraemer Can you try the step test I linked to above (and below)? Also, don’t think of the “smart” clamp as a clamp that needs pressure…ease up on that pressure.

Thank you Neil, I will give it a try and post my results. The smart clamp is confusing. When we first started using the machine I assumed that because it was called a “smart” clamp it measured the thickness of the material in the clamp, but then when my colleague cut all the way through to the waste board, I thought that maybe it was just a clamp. And being a clamp I figured that it needed to be tight like most clamps when you are trying to hold something in place. Live and learn and thanks for helping figure it out.
Amy

That’s the intent. Although precise, the Carvey isn’t a powerful machine. If that cut depth is off by a small amount, and your feed is aggressive, you’ll lose position.

Hi Neil,

I’m having similar issue here, got a consistent 0.7mm error.

Tried everything like loosen the smart clamp, different wood, different dirll bits, now thinking to change it from $102 .

Any advise?

Hi @Tff,
Can you try that step test I included a few posts up?

Can you describe, in detail, what you’re seeing?

Hi Neil,

Will test it later today.

What I have done is print it on different MDF from 0.5mm all the way to 5mm with 1/8 and 1/16 drill bit.

Also have tried to reduce the depth per step down to 0.5mm and 0.3mm .

Pretty much I have a constant error of 0.7-1mm extra depth cut.

Will come back later today or tomorrow with your StepTest.

Thanks for helping !!!

Hi Neil,

Thanks for helping, I did a test with your “step test 4”

The result i got is first one is 1.36mm , then 1.05 on top , then 1.07 and inner circle is 1.07.

any ideas?

The first is probably error in the smart clamp. The others seem like you do have a consistent issue. Do you have any play in the Z axis? Can you push the spindle up or down?

Hi Neil,

I did try to put a small 0.5mm spacer on the smart clamp, which have improved the result a little bit.( before the error was 0.8mm for initial touch instead of 0.4mm)

I can push the spindle up and down a very tiny bit , not sure if that is how it suppose to be.

I am not too concern about the others small error but am more concern about the initial touch as the error is much higher.

Do you think the smart clamp need to be replace or is there anyway I could change the parameter setting like changing the step/mm ? ( did saw someone change the X-crave $102, but not sure if Carvey can do the same)

Thanks again for helping.

The Carvey shouldn’t really need that calibration because it uses a screw drive. You might have something loose, but it’s not trivial to take that Z apart.
The initial plunge issue with the smart clamp won’t change if you adjust the $102 settings.
When did you get the Carvey?

It has been there for quite many years.

Is there anyway I could adjust it ?