Moulding Toolpath

[markbachman]

I want to do a profile cut the shape of Indiana and then follow up with a moulding toolpath for 0.25 radius on the edge.
The problem I have is that it wants to place the moulding toolpath outside of my vector but I need it on the inside the vector.
What am I doing wrong?

[4DThinker]

Use the offset tool and your perimeter line to make a line inside the perimeter. The offset value should be the width of your profile. Then use the offset line rather than the perimeter line as the guide line to extrude the profile around.

[markbachman]

Use the offset tool and your perimeter line to make a line inside the perimeter. The offset value should be the width of your profile. Then use the offset line rather than the perimeter line as the guide line to extrude the profile around.

I tried that but the sharp curves did not work out and the out edge of moulding cut did not match the profile.
I found out that you cannot place a moulding toolpath inside a closed vector. I tricked it and clipped the vector in on of the straight area so it was open just slightly then I was able to get the moulding toolpath on the inside.

[ken whiklo]

I am new at this so not sure I should be adding my comments. I setup two box type vectors, one inside the other. I designed a moulding toolpath to cut a one inch by one inch round over from the inside vector to the outside one. Then cut the whole thing out on the outside vector. If this describes your situation what I found was that changing the direction of the moulding vector allowed me to make this cut successfully. The only problem I have yet to solve is the cutout, using a 1/2" bit did not follow the one inch radius of the outside vector. It cut wide in the radius area. This does not seem right to me.

[dealguy11]

1. The moulding toolpath always cuts to the outside of a closed vector. As you discovered, you can trick it into cutting on the inside of an open vector, but may have problems at the open section. If you're going to do that, best to leave the break in a straight or gently curving part of the vector, as there can be problems at corners.
2. Ken - Not sure exactly what you're seeing, but it's likely it's because the moulding toolpath stops cutting when the center of the bit gets to the end of the profile vector. Any radius bit is going to leave a little cup at that point. The normal way of dealing with this is to put a little foot at the bottom of the profile to force the ballnose bit down the profile. The longer you make it, up to the radius of the bit, the farther down the curve the bit will go. When it gets to the radius it is at the bottom of the curve.

First 2 pictures show what I'm imagining you're seeing, and second 2 show the cure.

[markbachman]

Use the offset tool and your perimeter line to make a line inside the perimeter. The offset value should be the width of your profile. Then use the offset line rather than the perimeter line as the guide line to extrude the profile around.

First image is the result of trying the inside offset as the drive rail.
Second image is from clipping the outer vector and then I can get profile on inside of drive rail.
Third image shows the little gap in profile that I can blend in with sanding.

[highpockets]

I just made the map .5" smaller than the final then used the Moulding Toolpath with a .25" radius profile.

[NormanAlbert]

Why not use a pointy end round over bit on the profile at the appropriate depth? Then do a profile cut with the em. Norm

[ken whiklo]

Here is a picture. Even before I put the tabs in it still cut wide on the corners.

[dealguy11]

Can you post the file? Something does look odd there but would need to see the vectors to understand it.

[dealguy11]

Should have noticed this last night. It doesn't look like you checked "Create Sharp Corners" when you created the moulding toolpath. That's why the corners are rounded off.

[ken whiklo]

Sorry I didn't explain this completely. I want the corners to be rounded. This is a block that is rounded on all sides and all corners. So I use a .25 ball nose to machine a one inch by one inch round sweep profile. Then I use a 1/2" end mill to profile a cut out. So it is the end mill that does not cut close at the corners. If I adjust the vector inward then it cuts the straight edges too much. The current result is not too bad since I used to make these by sanding all the edges round, a very imprecise method. At least here most of that work is done. However is this the best I can do?

[dealguy11]

OK, I think I understand the issue. Try this as a workaround. Rather that offsetting the outside cutout vector with the rounded corners inward by an inch, make a rectangle the appropriate size for the rail vector used in the moulding toolpath, like this:

You can get to the same place by making a large rectangle for the profile, offsetting inward by 1", then filleting the corners on the large rectangle to get the rounded version.

This should give you this:

If you put the little "foot" on the sweep vector as described above, you can greatly reduce the amount of sanding required.

[dealguy11]

Another alternative is to buy one of these IF your machine can swing it:

https://www.magnate.net/ProductDetails. ... tCode=3927

Be aware that it will cut about 1/4" deeper than the radius, and that you'll have to offset the profile vector outward by 1/4" for the flat on the bottom.

EDIT: Just looked up your machine and the bit is too big to be safely used on it.

[ken whiklo]

Sorry but I was unable to duplicate what you had. Could you post the file. I could not get the outside vector to cut inside. My original set up is like your drawing only with both rectangles with rounded corners. I cut on the inside vector outward and used the outside vector to cut the piece out.