3d block machining and "full send" with finishing bit?

I created a 3d image, and used the block machining option in estlcam.
This is my first “real” 3d project, so I opted to use some project/laminated pine. For the most part it all worked ok, but I have some questions about the gcode it produced.

The roughing pass was done with a 1/4" 2 flute upcut bit. All the cuts made by Estlcam were nice and conservative. The finishing pass was with a 1/8" 0 flute upcut but. Some of the cuts were ridiculous, and I’m surprised the bit didn’t break off. It ran a full length slot at full depth (1/4" deep) – one pass! On the exterior edge of the object it would move to a spot, do a full depth insertion and then move along anywhere between a 1/2" and 3/4", then retract. Obviously these cuts are not particulary straight – the whole machine torqued over a bit.

I just “finished” the top side, in the next day or two I’ll be able to do the back side. I’m curious to see how it turns out, but I’m not really holding my breath.

Any thoughts on how to make the finishing pass a little less aggressive?

You could try to change the tool settings, like maximum stepover, Z stepdown, etc.

Yeah, that was the first thing I checked… I use this bit In Estlcam) for 2d carves on a regular basis.
I’m a little baffled.

As a SainSmart machine user I learned to slow the feed rate way down when the bit was doing a lot of deep sideways movement.

But I don’t understand why it would decide to do a full depth slot. It’s a “finishing pass”…

Is your roughing bit too wide to fit into the slot so it all has to be done by the finishing bit?
Can you use a smaller roughing bit? Or decrease the roughing allowance? Or widen the slot so the roughing bit can fit?

I think in 3d mode EstlCAM ignores some settings, it just does full depth parallel toolpaths for finishing, you’re supposed to clear enough material with the roughing pass…

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Ok. That makes sense to me. It did part of the outside carve with the 1/4" bit. But not the whole thing. So if the outside margin was too narrow for the roughing bit, it would not attempt it. And the finishing pass would assume that it’s just taking the final skim off so it would be fine with the full depth pass.
I’ll look into that. Thanks!

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