I’m basically new to CNC (busted two bits by accidentally plunging them into the workpiece), and I’ve got a rather complicated model of a jewelry box that has a lot of area to clear (50 x 80 x 10 mm) The box is constructed of 3 layers ad a lid, so that I can do it 3-axis (with some flipping of pieces.
There is also an angled “insert” holder piece of wood with carving on the angled side, and a “mold” which is cut to allow the (angled) front face of the holder to be carved.
The insert has a “frame” around it to make it easier to slice it down to size after doing the dragon carving. The reason for the big pillar at the back is that I tried cutting the insert today, and it only carved down to a depth of (I think) the default "target depth” of 2mm. It says the target depth should be less than the flute length, which obviously isn’t long enough for the to carve the entire depth (which is 1-1.5 mm for each piece). But since I’m only going to be taking off 0.5-1 mm of material at any one time, and the entire area is going to be cleared before it starts the next layer, does that apply?
Is clearing a volume like that even doable? The corners of the box are rounded (see photos), so will probably have to be milled with the carving bit (inefficient and damn slow, but…), or ball nose. The box is three layers that are each 10 mm high to match the maximum depth, which I plan to then glue together and then sand off the inevitable “not-quite-line-up-places”. (Rule one of woodworking: nothing is ever square. CNC’ing should be different, but… my guess is a big NO!)
Doing this with a 3 mm flat end mill is not really optimal, but… it’s what I have :(. I suppose I could get a 1/4 inch the end mill here and 1/4’’ ER11 collet - would that really save any real time though? The diameter is bigger, but that might increase the chip load. Or should I just cut most of it with a non-CNC router? Although I’d have to build a probably rather finicky jig to hold something so relatively small (5x8 cm) in place.
For the insert/mold combination, I guess I could do the entire insert and dragon carving in one operation, instead of cutting the blank and mold, then using the mold to hold the blank at an angle for the carving. But can’t figure out how to get SCAD to take an extruded SVG (the engraved carving) and “extrude it again straight up”, to make it doable with 3-axis (otherwise the engraving just goes to the angled face itself, and isn’t accessible to the bit).
The STL files for everything are here:
https://drive.google.com/drive/folders/1S293fuRSPdUHEo9NpENXcFSeysRQU-Pm?usp=sharing
And here are the pictures of the pieces:
- Box Bottom
- Box Middle
- Box Top
- Box Lid Top 1
4.5 Box Lid Top 2 - Box Lid Underside
- Insert with “frame”
6.5 Insert with Carving on angled surface - Insert Plate
- Insert Mold
Thanks,
Jim
