Can the X-Carve handle tolerances of .002"? (Emboss plates)

I am trying to find an affordable router / CNC machine that can make emboss plates. We make graphical overlays and some have buttons. The emboss plates we currently order cost quite a bit and it would be nice to make them in house.

  • maintain tolerances within +/- .001.
  • work on magnesium? Although I’m interested to see if an aluminum plate will work I believe it may not have the durability that an emboss plate needs to have. We are embossing polycarbonate.
  • there is a male and a female plate so the male plate needs to have the vast majority of material removed except for the button of course.
  • the diameter of the parts will range from 4 inches to 2 feat.

As I type this I’m pretty sure the x-carve would have a hard time handling these tolerances. But has anybody had experience with an affordable type of machine that could handle it?

Not reliably. The weakest link in most routers in this price range is the Z-axis. Upgrades are available like a cnc4newbie linear Z which gives you much better repeatability, but even then you’re somewhere in the neighborhood of 0.002-0.01" accuracy. At least, that’s what I’ve been able to achieve. These machines are not really designed for that kind of tolerance. You’re probably going to need to look into a proper CNC mill like a Tormach 440.

LARGE
AFFORDABLE
PRECISE

Pick any 2. Can’t have all three.

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Thank you Pyrex and xfredericox, this confirms my suspicion. I appreciate the help!

And thank you for the machine suggestion Pyrex!

What do you pick for affordable and precise? 3d printer? The pick 2 of 3 is a great exercise!

Is that tolerance really required?
I am not saying the Xcarve is the right tool for the job but chasing this accuracy and precision will make the cost go way up. You will also need a veeeery stiff and rigid machine, high quality spindle with no runout to even support a precision of this level. You may also need controller software with backlash/tool deflection and wear compensation etc.

Mechanically though:
SFU1605 (16mm diam.) or 2005 (20mm diam.) ball screws coupled with the typical 1.8deg/step stepper = full step resolution = 5mm/200steps = 0.025mm (a shade less than a thou)
Same screw coupled to a servo with 2-4000step/rev give you much finer resolution.

Wouldn’t suggest something I haven’t tried myself. But obviously the smaller the span, the more rigid and accurate the machine. It also greatly depends on what you consider affordable :wink:

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If you add a screw drive to a X-Carve wouldn’t that increase the accuracy?

Yes, by a factor of about 3 IIRC. (25mm/rev vs 8mm/rev)
Torque is also greater as less travel per revolution = effectively gearing it down.

Max rapids also drop by a similar factor

Thank you Haldor. Yes the customer specs demand that tolerance. The equipment to which the overlays are adhered to are in the $5000+ price point. And they are BIG on quality and consistency.

Like I said, normally we send out for these plates and we pay at least $2,500 a pair because of the amount of effort it takes to make them. But I’m still learning about this whole process and so I thought I would start investigating from the bottom and find a decent machine that can do the work.

wow that’s expensive…

They’re trying to pay off the machines it costs to make them, hehehe.