Bevelled Edge with Square (Mitered) Internal Corners

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Brad.At.CNC
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Bevelled Edge with Square (Mitered) Internal Corners

Post by Brad.At.CNC »

SquaredMitered Internal Corners.png
I would like to be able to use the sample closed vector pictured to:
  • Run a V-Bit (90° inclusive) around the part to create a 45° bevel. The External AND Internal corners should be squared/mitered. The bevel should be within the closed vector.
  • Then run a straight bit (1/4") around (Comp OUTSIDE) to cut the part to size.
Goal.png
(I fudged things to get the image above.)

When I run the V-Bit along (ON) the closed vectors, all items on the CORNERS TAB of the "Profile" operation are greyed/disabled. No way to to square/miter/sharpen the internal corners. (It would be nice to be able to square/miter/sharpen the EXTERNAL/INTERNAL/ALL corners when following ON any vector.)

When I run the V-Bit compensated to the OUTSIDE, the CORNERS TAB is ENABLED, but the ALLOWANCE FOR CUTOUT TOOL is LOCKED to the same value as the CUT-DEPTH. There is no way to change this value!! Is this a *bug*? (I would think that we should be able to manually modify the ALLOWANCE FOR CUTOUT TOOL - like setting it to 0 to shift the operation inwards.) Note: The standard ALLOWANCE parameter is disabled when the SHARP INTERNAL CORNERS is checked.

With the current tools, how would you do something like this? (Preferably without having to create additional geometry. :wink: )

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dealguy11
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by dealguy11 »

Additional geometry will be necessary, at least the way I always do it.

You need to offset the profile inwards by the depth of the bevel - so if you're making the bevel 1/4" deep, then offset inward by 1/4". Make sure you have Create Sharp Offset Corners checked. Use that vector, not the outside vector, for your bevel toolpath, and set the profile to cut outside the vector. On the "Corners" tab you will now be able to check both inside and outside sharp corners. They are always grayed out when you're cutting on the vector because it's ambiguous to Aspire what is an inside or outside corner.

Doing this will put the point of the v-tool on the cutout vector for the bevel. Then use the outside vector to cut out.

I view the "Allowance for cutout tool" number to be informational and don't try to change it. If you used something other than a 90-degree bit, it would have a different number, which is the amount you need to do the offset.
Last edited by dealguy11 on Wed Feb 05, 2020 5:38 pm, edited 1 time in total.
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TReischl
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by TReischl »

Use a V Carve toolpath? Offset the vector both in and out, then vcarve between those vectors.

Maybe I am missing something here? I am thinking he wants sharp internal corners?
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by dealguy11 »

My approach will give sharp inside corners without a v-carve toolpath
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by dealguy11 »

See Example
Attachments
Bevel Example.crv3d
(33.5 KiB) Downloaded 51 times
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dealguy11
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by dealguy11 »

The advantage of this approach over a v-carve approach is that a v-carve will run around the vector twice, so that it can sharpen the outside of the outside corners. This approach only runs around the vector once, so it's 1/2 the cutting time.
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by SteveNelson46 »

I offset the line inward by the thickness of the material and used a moulding toolpath.
Attachments
Beveled edge.jpg
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by 4DThinker »

Start with a profile pass ON the line using a V-bit.
Add a short vector in each inside corner that runs from the top of the bevel to the corner. Use the fluting toolpath with the same V-bit to sharpen the inside corners.
Inside miter bevel corners 4D.jpg
Example attached. Aspire 9.519
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Inside miter bevel corners 4D.crv3d
(33.5 KiB) Downloaded 31 times

Brad.At.CNC
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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by Brad.At.CNC »

DealGuy11,

Thank you. This is what I have done in the past as well.

I had been asked by a former ArtCAM user if there was a way to do it with only the original outline without the need to add the offset vector path to follow. But alas... This will have to do.

It would be "nice" :wink: to be able to use the original outline, define the PROFILE operation with the SHARPEN INTERNAL CORNERS and then use the (currently disabled) ALLOWANCE OFFSET in the "Machine Vectors..." section with a negative value to move it in the required amount - but we work with what we have. No biggie.

The other suggestions are appreciated, but DealGuy11's is the simplest and most straightforward.

Thanks all.

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Re: Bevelled Edge with Square (Mitered) Internal Corners

Post by TReischl »

Mr DealGuy:

I had not tried that before! So, like any good neanderthal I go with what I know. I like your method, a lot. Thanks for the enlightenment.

Now, if there was a way to get rid of radii on the straight inside corners. . . . gonna need a flux capacitor in my puter for that I think.
"If you see a good fight, get in it." Dr. Vernon Jones

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