Unigraphics CAM - Boundary Machining

Today I would like to share the boundary machining methodology I tried recently. In one of my recent project on Aluminum machining, I have nested four parts. My intention was to create four different parts from a single stock. It includes the rough cavity cut and finish fixed contour cut.

I have used #8 counter sunk screw to hold the part and used a 1/8" dowel pin to avoid rotation of part. 1/8" Ball nose cutter was used for entire machining.

I normally prefer to use a single cutter for complete machining which eliminates the need of "Z" point reset.

Instead of machining the unnecessary stock material, I have created a rough boundary against each part which is slightly greater than the tool diameter. I wanted to separate the remaining stock in block form itself instead of machining it into chips.

I have taken care to use the transfer plane as clearance plane instead of previous plane at each level of cut. Well, it all worked well except for one problem. There was a chunk of island remained after the boundary cut which was separated from parts. I have not cleared the bottom surface of material so that this island can fall down.

Hence, it remained inside the pocket hindering the tool movement in successive cuts. Luckily I was watching the machine that time, slowed down the cutting speed and carefully removed the island. It was almost breaking the cutter.

So, here is the lesson I learnt. It is a very good practice to do the boundary machining with clearance plane transfer (don't forget this to avoid cutter fouling with in process work piece). You have to make sure the solid scrap material will fall down automatically after its separation from the blank stock.

This method can save up to 30 to 40% of overall machining time.


Jythra Engineering Services
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