Jan 18

After milling the first parts I got hold of a piece of very nice plastic called POM, this turned out to be perfect! It mills three times as fast as aluminum and the mills stay perfectly sharp. It’s a hard plastic so the forces that can be applied to the part are high, I would definitively advice you to use this material.

For aluminum type 5083 the milling speed is typical 100mm/min for a 6mm endmill using a 1.5mm depth per pass and 2mm stepover. For POM this can be 200mm/min for a 6mm endmill using 3.0mm depth per pass and 2mm stepover. In a single pass 2 times the amount of material is removed with 2 times the speed.

Jan 18

The first milling attempts used aluminum, I received a lot of scarp material from one of my customers and found that one piece was milling just fine but another piece was not. It turns out there are various types of aluminum, the best type for milling is 5083 in which case HSS Co8 grade non-coated end-mills are ball nose mills can be used. I don’t use any cooling liquid since it results in a wet mess, as a result the mills wear down and you need to replace them if the cuts results in burrs or if you hear a continuous squeaking notice during the milling process.

Types of aluminum