I’m running a large number of children’s toys for my business. They’re made in Cherry and involve a 2d pocket and a 2d contour. I’m trying to get both of these operations done with one tool in order to minimize touch-time. I’m currently using a compression endmill but I’m having a large amount of “fuzz” on the top edges of the pockets. I know that a down-cut spiral bit is ideal for pockets, but would it be a bad choice to also use the down-cut bit for the 2d contour? Would chip clearing with the down-cut bit be a problem? Let me know if you have any advice for a tool that could handle both.
A compression endmill should give you a clean top and bottom to the workpiece, if it’s plunged far enough into the piece to have the downcut portion at the top face (normally about 6mm).
How old is your bit? What are the chances that it’s been used enough to be blunt?
I don’t think my pockets are deep enough to receive that benefit. They are only .13in deep. The bit defiantly isn’t dull. Its a carbide spektra bit that’s about 2 months old. Probably only used for about 6-8 hours.
So, if your cut isn’t going deep enough to engage the downcut part of the spiral then you’re effectively using an upcut bit at that point.
Although it’s a tool change I’d suggest a low helix downcutter, there’s loads of them around, I have some of the Yonico and they’re surprisingly good for the price.
A bitsetter might speed things up for you, although since I started putting my Z=0 at the spoilboard or jig face it’s very quick to swap out the bit and re-zero Z only with the bitzero.
I know I could easily fix this issue with a single tool change for each job. The issue is I’m running 4 of these operations each day, as well as operating my laser cutter, doing hand sanding and gluing, packaging etc… Any way I can cut down on touch time is preferred. Is it a really bad idea to do a 2d contour path with a down-cut spiral bit?
Not sure about bad idea, this seems to be a question of optimising your cost & time for a finish quality.
Is there space for you to make up a jig to put more than one workpiece on the Shapeoko at a time? That way you could run more than one of each stage.
The compression cutters tend to be a little more expensive, but you’re trading your time doing other work here against that small increase in tool cost.
In terms of finish though, the compression cutters are intended to be used at full depth (or rather deep enough to engage the downcut) so that you get the benefit of the downcut for the top surface.
Is your rough finish in the shallow pocket affecting the quality of the finished piece or just costing you extra time in cleanup work?
I might try the contour path in two stages: the first just outside the desired finished cut; and finish with a light pass (0.25-0.50mm). This will take more machine time, but reduce your touch time. How deep is the contour cut? I’ve been cutting cherry with a Yonico 3 flute 6.35mm square end mill and 6mm slots to start a pocket are noisy, but not a problem if the finishing cuts are narrower (1.0mm in my case).
I was picturing a bullnose, for being able to pocket with a flat bottom & use the radiused corners for 3D contouring, but I don’t actually know if the software can calculate complex contouring toolpaths with cutters shaped like anything but a ball endmill.
Doesn’t really help with your frayed edge problem though. The only thing beyond tool choice for that may be to adhere (via clamps, or even adhesive) a sacrificial layer of material on top of your finished surface & cut through it. Whether thin plywood or a heavy tape, cutting through your finished surface while it’s firmly secured, like the meat in a sandwich, is time consuming & burns up a lot more material, but gets it done. In composites, that’s essential much of the time we have to cut or drill into a finished surface.
Unfortunately, that geometry of endmill is not supported in Carbide Create — I’ve been experimenting with using OpenSCAD to model toolpaths for unsupported endmills and it’s been working pretty well — hopefully I’ll have a file and matching cut to show off later this evening.
