Making inlays using geometry

Since Carbide Create doesn’t have explicit support for doing inlays (software which does includes Vectric Vcarve and possibly F-Engrave) one has to calculate out the toolpaths for this manually. Considerations include:

• endmill geometry
• glue line / thickness — suggestion here is to glue together a stack of 6 popsicle sticks, then after it dries, measure the difference between the glued stack and 6 which are not so fastened — that thickness difference divided by 5 is a typical glue line for the glue / clamping technique used
• inlay thickness
• part geometry

Some cases can be quite simple: — a flat inlay of a part which doesn’t have any corners which the endmill won’t fit into is simply a matter of cutting out the part, then cutting a matching (possibly mirrored) pocket which is deeper and larger around the perimeter by the glue line (if using hide glue, this may be negligible).

A more complex situation is a V inlay of a material of one thickness into a material of greater thickness — this will require that one:

• measure the material (plus anticipated glue line)
• calculate the offset necessary to cut the part to the desired size
• calculate the inset needed to cut the perimeter of the pocket as a V carve
• calculate the inset needed to cut the bottom of the pocket

Let us consider the following case:

• 60 degree V bit (Carbide 3D #302)
• 0.316" thick material
• 0.004" thick glue line
• 0.5" thick stock material to inlay into

For simplicity, we’ll use a 1" circle.

One can either draw up the geometry, or calculate it. To calculate some useful references include:

To draw, one begins by making a 1" circle:

Draw a triangle to represent the angle of the endmill, and a rectangle to represent the width to which we will wish to cut (which is also the depth since a 60 degree endmill is an equilateral triangle):

Then do a Boolean intersect of the two shapes.

To cut the pocket you will need to inset by the desired thickness to cut a V carve to that depth along the perimeter, and by half that so that you can clear the bottom of the pocket:

Select the inner and outer circles and assign a V carve toolpath:

Select the middle circle and assign a pocket toolpath at the desired depth to clear the pocket:

The two pockets will preview as:

Inlay-vcarve-pocket.c2d (85.3 KB)