I have read all the comments again and I think, you are milling using the spiral side of the mill (because you use a router table). If the milling blade cuts, it may pull the stock deeper in to the mill because the stock is not fixated and will flex. That will give a less good finish.
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Machining UHMW polyethylene question
- Thread starter dml66
- Start date
Here's a picture of the setup, if I'm doing something incorrectly, I can fix that.
Please note, I only set these on the machine for the purpose of taking a picture.
The piece of aluminum flat stock clamped to the back of the router table serves as a guide; the bearing guide of the spiral bit is not used in this case.
I have manually milled a piece of 35 mm diameter POM (not UHMPE) that was turned in the lathe using a CCGT060204 insert at 0.05 mm/rev. The finish (left side of the ring) is top but not shiny.
The milling tools is a DCGT060202 insert in a 20 mm single flute end mill, 0.1 mm cutting depth.
First test, fast manual feed about 240 mm/min, 0.24 mm/rev
Second test, slow manual feed at about 80 mm/min 0.08 mm/rev.
The third test at 120 mm/min, 0.05 m/rev, a UHMPE bar:
- milling using the same DCGT070202 20 mm tool, the milled strip on the right, finish is good, not shiny, comparable to POM
- milling using a the spiral side of 12 mm end mill convention milling , first half of the left strip. It has the same marks as your test, finish is less
- milling using a the spiral side of 12 mm end mill climb milling, second half of the left strip. Finish is not good
The milling tools is a DCGT060202 insert in a 20 mm single flute end mill, 0.1 mm cutting depth.
First test, fast manual feed about 240 mm/min, 0.24 mm/rev
Second test, slow manual feed at about 80 mm/min 0.08 mm/rev.
The third test at 120 mm/min, 0.05 m/rev, a UHMPE bar:
- milling using the same DCGT070202 20 mm tool, the milled strip on the right, finish is good, not shiny, comparable to POM
- milling using a the spiral side of 12 mm end mill convention milling , first half of the left strip. It has the same marks as your test, finish is less
- milling using a the spiral side of 12 mm end mill climb milling, second half of the left strip. Finish is not good