Nesting of parts while machining using CAM

While working on a recent CAM project using CAD model, we found few interesting techniques. In the first job, we requested the operator to use a 1/4" Ball nose cutter of 1" long. We were expecting there could be some tool flexing because for the first cavity profile cut. But he used almost 1 1/2" long cutter. Finally, once the machining is done there is a clear cut draft left on the part which is almost 3 degrees. Also, there was not enough overpass of ball nose at the bottom of the part leaving a radius there. It was not too bad other than doing some manual cleanup of the part after machining.

In our second batch of CAM, we nested four parts as shown on image from two separate CAD models. So, we have to make a single pre-machining block to make two separate parts of quantity two each. Also, we tried to machine only up to 4 mm around the part using 1/4" cutter. This saved us almost 50% of machining time as we eliminated machining unneeded stock. Also, we ensured the cutter overhang is only 22mm just more than nose overpass. This didn't cause any tool flex and squeak.

Another interesting thing is after doing the rough cut with 1/4" cutter, we lost the datums where we set original zero. So, for finish cut we have not changed X and Y coordinates. But, asked the operator to reset Z with respect part top surface which was intentionally left unmachined before. This helped us in quickly running the finish cut using 1/8" cutter without much time on reference point set.

Jythra Engineering Services

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