Hi.
What’s the best way or method do you use to level the workpiece?
I’m having some difficulties to engrave an acrylic because in some places the bit is engraving deep enough and in other it is just not touching the material. To my eyes, the acrylic is leveled and the ShapeOko base is also leveled. I’ve used a bubble level too, but I guess that I might be doing something wrong.
Are you having this kind of issues?
I was playing a while with PCB leveling and measuring the Z distance while making touching probes, and then doing some math, but in this case, the acrylic is not conductive so I can’t use that method.
Well… if anyone would like to share experiences about this, I’ll appreciate it.
Thanks! (and sorry if my english is not too well)
PD: I’ve tested -0.25 to -0.40 for engraving, knowing that 0 is where the acrylic starts.
(Units in millimeters)
A bubble level is way too inaccurate.
Is the acrylic flat or is it bending due to pressure.
You could build
that would be a nice project and benefit you in the future.
What about manually using a dial gauge?
You’re not really leveling the bed, you’re making every point be the same distance from the cutting tool.
With acrylic engraving you’re only removing a tiny amount of material, and with angled bits the deeper you go the wider the cut. Most of my engraving has been with fixed size tags - I got a good deal on a large quantity of identical sized sample tags - so I took a plastic cutting board, fastened it to the table, and routed a pocket that fit the tag and held it in place. The pocket gave a flat surface that was a consistent depth, and if you mount it in the same place every time you use it it’ll be flat and “level” so you’ll have a consistent cut depth. I did some light sanding on the bottom to remove the ridges, and for the second engraving put in a finger sized notch so I could get the part out when I was done.
If your parts aren’t the same size you can make the pocket bigger and use two edges to get the right alignment, plus double sided tape or some other hold down method to keep it in place. I’ve experimented with engraving PCBs doing this.
Good Luck!
Kirk
One way is to mill a surface like MDF, then use that surface as the base for your work. Since it was milled in the machine you know every part of it will be the same distance to the tool. For example http://www.jcopro.net/2011/10/11/milling-your-cnc-router-to-make-it-flat/