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I'm using an Eagle plugin to make G-Code commands called pcb-to-gcode, for those who don't know what eagle is, its a program to design circuit boards.

In the program, of course are able to set your tool diameter and cutting depth, but it does not take into account the angle of the bit, so it can take off more material than you want.

What calculation can I use to find the width of the bit at a certain depth?

In my case the bit diameter is 0.1mm, and the angle is 30°, and I'm cutting 0.127mm.

Thanks

Edit: I found another forum post, so maybe someone could double check my math.

He basically starts with saying "Assuming the bit ends in a point, A is the angle, and D is the depth, do this."

W = tan(A/2)*D*2

Then he says "Since bit tips have a width, we do this"

W = tan(A/2)*D*2 + Tw

But then he says "In your case (the OP) for 60° do this"

W = 1.1547*D + Tw

But tan(60/2) is 0.577.... not 1.1547?

I tried it anyways, and for my case I got 0.134..., so is this right?

tan(30/2) * 0.127 + 0.1?

In the program, of course are able to set your tool diameter and cutting depth, but it does not take into account the angle of the bit, so it can take off more material than you want.

What calculation can I use to find the width of the bit at a certain depth?

In my case the bit diameter is 0.1mm, and the angle is 30°, and I'm cutting 0.127mm.

Thanks

Edit: I found another forum post, so maybe someone could double check my math.

He basically starts with saying "Assuming the bit ends in a point, A is the angle, and D is the depth, do this."

W = tan(A/2)*D*2

Then he says "Since bit tips have a width, we do this"

W = tan(A/2)*D*2 + Tw

But then he says "In your case (the OP) for 60° do this"

W = 1.1547*D + Tw

But tan(60/2) is 0.577.... not 1.1547?

I tried it anyways, and for my case I got 0.134..., so is this right?

tan(30/2) * 0.127 + 0.1?

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