galacticroot
02-23-2006, 10:28 PM
I'm building a CNC impact engraver for engraving anodized aluminum, plastic, and maybe some other materials. The idea is a cross between the handheld vibratory engravers and a dot-matrix printer. It works like a dot matrix printer, except it produces small pits in the material instead of applying ink.
The travel will be about 30x20" depending on the slides I find. Either way, it is larger than any other cnc impact engraver I'm aware of.
Anyways, I'm trying to decide on the drive system. The machine looks like a typical gantry cutter. My idea is to use a toothed belt drive to move the gantry and cross axis. The gantry would have a belt on each side to keep it perpindicular to the slides. The belts are what dot-matrix printers use, and it seems to work well to get the required resolution, but I am wondering about using ball screws instead.
The resolution would be in the 200-400DPI range, so the tolerance would ideally be around 0.0025". Realistically, as long as it too far from that, it should produce nice engravings. I would be engraving equipment faceplates, computer cases, etc... so it doesn't have to be perfect since it will be viewed from a few feet away.
Would ball screws be worth the extra cost for this, or would the belts work well? I'd like the machine to be under 800$ (which it would be with belts), but its more important that it work. Another option is to make the gantry ride on a rack and pinion.
I might be able to add a linear encoder later if high precision is required (as is also used in some printers).
Any thoughts?
The travel will be about 30x20" depending on the slides I find. Either way, it is larger than any other cnc impact engraver I'm aware of.
Anyways, I'm trying to decide on the drive system. The machine looks like a typical gantry cutter. My idea is to use a toothed belt drive to move the gantry and cross axis. The gantry would have a belt on each side to keep it perpindicular to the slides. The belts are what dot-matrix printers use, and it seems to work well to get the required resolution, but I am wondering about using ball screws instead.
The resolution would be in the 200-400DPI range, so the tolerance would ideally be around 0.0025". Realistically, as long as it too far from that, it should produce nice engravings. I would be engraving equipment faceplates, computer cases, etc... so it doesn't have to be perfect since it will be viewed from a few feet away.
Would ball screws be worth the extra cost for this, or would the belts work well? I'd like the machine to be under 800$ (which it would be with belts), but its more important that it work. Another option is to make the gantry ride on a rack and pinion.
I might be able to add a linear encoder later if high precision is required (as is also used in some printers).
Any thoughts?