Skipping steps?

At least in estlcam, you can adjust the settings for the finishing pass to have at least your full depth (in the bit settings). In the toolpath, you set your finishing tool and the amount of material to leave (Ryan suggested 0.5mm for something soft). Estlcam will cut the roughing pass 0.5mm away from the final dimension, and use your main DOC and multiple passes. But then it will come back around with the bit down at the final dimension.

I don’t remember any other settings you need to change.

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Just click on the setting for that tool you are using and you will see a more detailed settings window open. Leave the regular settings as is and adjust your finish setting to have a full depth Z, you can usually leave all the other settings the same.

In the actual tool path window just select the correct finishing tool, and stock to leave.

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Thanks guys! Is there a reason why not do the first cuts in full depth then? I mean, if it could cut 18mm deep for the finishing pas it might do it for the rough cut too. Or would this put to much force on it as there’s no “guide channel” just yet?

And what distance would you suggest for harder material? More or less than 0.5mm?

Yes! The first cuts involve the whole width of the tool. The finishing pass is just a fraction of the to width.

Think of the cut as volume removrd per second. A full pass of the tool removes (for example) 3.175mm width by (again example) 3.5mm depth by 10mm per second. That is 111.125mm^3 per second. That puts a certain load against the motors and tool mount. Also evacuatig the chips from the tool is hard because it can only go above and behind the tool path.

Now say you are running a finishing pass, 13mm deep, removing .5mm material. At the same speed that’s 65mm^3 per second, obviously less load, but you also run it slower, say half speed which halves the load again. This lets everything be more accurate.

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Thank you for confirming it with numbers. That makes sense.
My key take away is that I should set the feed for a finishing pass lower too, right?

While we are discussing this, yesterday I did my first trochoildal full doc.
What is your opinion on doing a full cut using trochoildal for roughing, then a cleaning pass. Would this make sense? I imagine this could speed up jobs enormously (if it works).

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No, I usually go higher. The load is tiny. Compared. Pay super close attention to how much debris comes out to get an idea of how much it is cutting.

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Trichodial is usually much much slower than a normal cut. Unless you are cutting metal, trichodial is extremely slow. If it is faster than your wood cuts you have lots of room left to speed up.

You might want to start looking at cutting calculators if you need to see some actual numbers, it can get pretty complicated though.

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Depends on results. I run my finishing passes at 75% speed, but also at a bit more load, to make sure I am smoothing the finish. At the typical loads (more like 0.15mm) I would go faster, but I find with that finishing pass sometimes the rough pass has already cut as far. If I want a smoother finish, I increase the load to a larger cut and slow it down. When I just need accurate dimensions, I use the 5% tool diameter and speed it up to ~125% speed.

Edit: this is what works for me. YMMV

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alright!
The feedback is clear to me, I need to experiment more :smiley:
up until today I was playing on the safe side as I have no experience operating a CNC, so “I am just doing things”.

I actually have been looking at calculators, but got lost in the bigger scheme :stuck_out_tongue: