Making a parametric pencil case (box)

To see a 3D preview of the box w/o installing OpenSCAD see:

Start by downloading the OpenSCAD file:

If need be, install OpenSCAD from:

Launch OpenSCAD and load the file, and set the parameters:

Then toggle off the 3D view and enable generating the DXF:

and Render the file:

so that it may be exported to a DXF or SVG:

Design into 3D_ Box with Lid - Pencil Case

which loads into Carbide Create as expected:


In Carbide Create, set the stock area to match the bounds of a single set of parts:

Then create a Layer for each thickness or tool type used in the design, group the matching parts, move them to the appropriate layer and align the group to the Stock Area:

Adjust the Stock Area to match the actual stock which will be used for cutting:

and arrange parts to efficiently use the stock:

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Select the part outlines and offset to the outside by the diameter of the endmill plus 10%:

Clean up where appropriate:

and duplicate the geometry which is affected by the rabbets so that the rabbets can be punched out:

Then select the outer geometry and set up a Pocket toolpath to the rabbet depth:

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Select the geometry for the box joints and copy-paste it in place:

Then Boolean subtract the joint geometry from the part outlines:

Recreate, or copy-paste in-place the surrounding geometry:

select it and the joint-part geometry and define a pocket from rabbet depth down to the joinery depth:

If the endmill used to cut out the joinery is not small enough to cut out the dogbones, it will be necessary to define geometry to make this cut — select the geometry in question:

If need be, clean it up to remove any extraneous dogbones:

(repeat as needed for all copies)

Offset to the outside by the size of the dogbones (should be the small endmill diameter plus 10%):

then node edit to limit the geometry to where the cutting actually needs to be cut:

and duplicate the original geometry and punch it out of the offset shape:

and simplify the geometry to make the cutting more efficient:

Repeat to then apply a toolpath w/ an inside contour:

To cut the parts out, we need geometry at the top/bottom of each part — the sides and the bottom of the front are easily done:

While working around the detailing of the tops of the front and back requires a bit of judicious offsetting:

and then node editing:

then assign a pocket toolpath which starts at the bottom of the joint depth pocket and cuts through:

For the blind miter, rather than using a V carving, it is most expedient to use a no-offset contour toolpath applied to open geometry which precisely describes where the cut is needed, so draw in such geometry:

along the edges of the joints:

Which previews as:

The size of this box is such that the lid and the bottom can be on the same piece of stock:

Select the part geometries and offset by endmill diameter plus 10%:

Select the geometry which will need to not be cut away, and the offset geometry, and assign a toolpath to cut as deeply as is necessary to ensure that the parts will fit into the rabbets:

Then select the offset geometry and the part geometry for the bottom and lid and assign toolpaths from that depth down to the top of the tabs:

and then select each outer part geometry and assign an outside contour toolpath which cuts from the top of the tabs down to the bottom of the stock:

and add tabs:

In addition to cutting to size, and cutting the rabbets for the bottom, there are three additional features which are wanted for the lid:

  • an advanced V carving as a relief on the underside for opening the box
  • a relief cut along the side edges of the lid, either a V carving, or w/ a roundover bit to make closing easier, and to match the radius of the endmill used to cut out the front/back
  • a relief cut along the back edge of the lid w/ a roundover bit which is sized to allow the box to open

For the roundover reliefs, draw in geometry offset by the radius of the tip:

and assign toolpaths which cut as deeply as is needed for the desired roundover:

and for the opening notch, draw in suitable geometry:

and assign an Advanced V carving toolpath to the desired depth:

Arrange toolpath groups to match the desired cutting order:

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Files are at:

Design into 3D_ Pencil Case bottom and lid.c2d (742.6 KB)
Design into 3D_ Pencil Case front back and sides.c2d (921.3 KB)

Cutting (w/ a bit of adjustment reflected in the files above) went well:

separating the parts, cleaning up the edges, and drilling for hinges, glue-up and assembly will have to wait the morrow.