Another Newbie Question

[mountie1808]

It's quite possible that this topic has been addressed somewhere in the vast confines of the archives. For not having found it, I apologize.

My question is this. How do you set rough cut to mill out the unwanted material and then NOT have the finer cuts cut all the same information again. Let me explain. I'll set a design for a 3/8" rough cut (either step rough or not) and there might be two or three total pass levels. I'll then set the fine ball nose bit and the depth will say that it has to take 3 passes to make the depth. The ballnose will then cut the entire job, 3 times, once on each level, whether it needs to or has already cleaned out that material in either it's own pass or one of the passes of the other bits. Is there a fix or workaround for this??

If not, I don't see where it's very time saving though it does reduce wear on the smaller bits.

I should point out that I am sending only the information specific to that bit to the file to be machined. I'm not sending all the information for the large and small bits in a single file. Speaking of which, is there a way to send the complete job to the router and have it stop and wait to have the bit changed without having to either send seperate files or get a bit changer?

Any tips or suggestions are most welcomed.

Mike

[jseiler]

What software are you using?

A really effective roughing pass is one that doesn't leave more material above the finish pass than your finish bit cutting length. If you can do that, then your cleanup bit can cut in one pass (at least the way I like to do it when I can get away with it). (Sometimes getting an effective roughing pass with a really big bit with deep reliefs is impossible)

In your example, if your 3/8 bit makes its 3 passes and leaves a maximum of 3/16" of material to cut off to finish mostly at transitions and deep wells, than that cleanup pass is easy in one go. If you are finishing with a 1/8" bit with a cutting length of 1/4", no matter what you set the maximum depth at, your bit will never see anything taller (relative to the finished cut) than 3/16". You would just set your maximum depth at full finish depth and have at it. It gets more complicated for really deep reliefs or reliefs with very steep transitions that force you into exceeding the maximum cutting length of your finishing bit.

Sometimes you can define a smaller area to make multiple passes and take care of the rest with one pass.

A pic of your relief would make it easier to answer more specifically.

On the second point, that's been discussed at length in the forum recently. If you've done some programming before, shopbot language is a lot like BASIC.

John