CamBam - Tutorial : 2.5D Profile

This example is based on the efforts of my friend Terry (aka MrBean).
Thanks Terry for the source files as well as CamBam beta testing.

We are going to start by loading a HTD pulley profile DXF file into CamBam.

For DXF drawings of various HTD and other pulleys, visit and follow the links to their e-store and 3D CAD model downloads.  When prompted for format, select Autocad 2D .DXF.
These drawings contain much uneeded information such as side, elevation and isometric views.
With a few edits, these drawings can be used as is, but for simplicity I delete any unneeded objects and layers.

As with many DXF files, there is insufficient or ambiguous information in the above example to get the drawing units correct, so the first thing to do is to change the drawing units to Metric.  Select the root of the file tree on the left (where it says 12t-htd.dxf), then in the object properties on the lower left, change the Scale = 1.

ALT + double click will zoom the drawing to fit the view window.

This profile is made up of a number of spline segments, so the next thing to do is convert them to polylines and join them together.

Select all splines making up the outside of the pulley by dragging the selection rectangle around these parts. Deselect any unneeded geometry like the inner and outer circles.  Alternatively, use CTRL+A to select all geometry.

From the Edit menu, select PolyLines -> Convert to PolyLines.
Wait for the operation to complete, then select PolyLines -> Join PolyLines.

If this has worked, you should now be able to select the outside of the pulley by a single click.

With the outside of the pulley selected, chose the CAM -> 2.5D Profile menu option.  This will add a new machining operation to the file tree and display the properties of the profile operation in the property window.

Set the following property values.

TargetDepth = -5
DepthIncrement = 0.5
CutterDiameter = 2
CutWidth = 2.2
StepOver = 0.25

NOTE: At the moment, CamBam only generates metric gcode from metric drawings and imperial gcode from Imperial drawings. This behaviour will be made more flexible in the next releases.

Right click the machining operation in the file tree and select Generate Toolpath.  You should now see the toolpaths around the geometry. Rotate the view using ALT+drag to inspect the toolpaths.

Now for the hole. Select the inner hole and again select the CAM -> 2.5D Profile menu option.  Set the target depth and other properties to match the first profileoperation.  Change the InsideOutside property to Inside. Again, right click the machine operation in the file tree and Generate Toolpath.

Right click the machining node and select Create GCode file.

That's it! You may need to edit the GCode file to suit your machine first.