Unlike 3D printing, machining applies substantial lateral loads on parts: clamps, vises, and other workholding methods are crucial — and ingenuity is key. This “two-setup” job was able to be done in one setup by moving clamps midway through the cutting operation.
We start off by importing and orienting the part prior to creating the CAM operations – this is where we choose what cutting tools (drills, end mills, etc) to use.
Excess Material Tips
In volume production the material for this job would be waterjet cut to avoid unnecessary machining, but that’s not practical for one-off jobs. You could still rough-cut some excess material away with a bandsaw, but for this job, I chose to machine it away.
Use larger, roughing cutters to rapidly remove material, then clean up with higher quality “finish” end mills.
Use CAM simulation to evaluate the job prior to running on machine! (6:00 minutes into video).
Sacrificial Layer Tips
At 8:45 into the video, we have moved on from the programming and are now working with our raw materials. I want to clamp the material directly to the mill, but need to use a “sacrificial sub plate” to ensure the machine does not cut into the machine table. At 10:10 we use a small benchtop sheer to cut some aluminum to make this plate.
Aluminum and plastic can all make great, inexpensive sacrificial sub plates. Wood can work as well but some woods will expand with moisture (e.g. flood coolant), so factor that in as applicable.
Aluminum extrusions often have bow in them – keep this in mind when you decide which side faces up, how the part is clamped, and where you set you “Z” axis “zero” point (a.k.a. height offset). At 16:00, we discus clamping and cut strategy, then at 19:45 we are making chips! We swap the clamps at 28:30 – this lets us complete the whole part without having to reindicate our “zero” which helps ensure perfect tolerances. Then some final part cleanup before shipping off to customer.