1/16" cutter in HDPE

[cr2]

I need to cut 1/8" deep grooves in HDPE with a 1/16" end mill. Can I cut the full depth in one pass? What speed? Thanks.

[dana_swift]

Charlie..

When I start working with a material I use the bit radius as a guide for my pass depth. Later when I have learned that the material clears chips easily I get more aggressive, but not till then.

The question of "Can I cut the full depth in one pass?" Of course you can, right up until the bit breaks.

CNC involves a lot of factors of chip size, bit strength, material density, etc. Your bits will be different than mine most likely.

Set your cut feed rate from the RPM, chip size and number of flutes in the cutter. The depth of cut is determined by the material density and torque available from the router/spindle at that RPM. The bit strength is a limiting factor also. Small diameter bits cannot handle the torque and cutting pressures without bending.

Bending generates internal heat in the bit. Heat reduces the life of the bit, sometimes drastically.

To go full depth you can reduce your feed rate, but then the chips get so small that the bit has no way to dissipate heat. Reduce bit life again..

An experiment or two will tell you the story. If you cut for a minute or so and then the bit breaks.. its caused by heat from flexing.

If you can cut for 8 hours without breaking the bit at a depth, its able to handle the load. Try deeper. When the bits start breaking and possibly ruining the job, cut shallower.

D

[gundog]

I wouldn't and I cut a lot of HDPE If you try make sure and blow air to get the chips out. I cut a lot of profiles with a 1/8" bit single flute spiral up cut and I go .250" deep but I think that is maxing it out. I am not sure you will get away with it in that smaller bit but you might make sure you have 2 bits just in case.

Mike