Cutting Marine HDPE

Advice on cutting marine-grade high-density polyethylene (HDPE). June 17, 2009

I just acquired some King Starboard to cut. Iíve never cut it before as I mostly cut melamines. Does anyone have any tips on feeds, speeds and a bit to use?

Forum Responses
(CNC Forum)
From contributor J:
Have you considered contacting King Starboard?

From the original questioner:
It turns out the sheets are not King Starboard but a product called Boatboard by Laminations. It seems similar to Starboard. I will be talking to them later but would like to hear from anyone who has cut this type of material.

From contributor S:
I have had a chance to cut King Starboard several times and found that a 1/4" spiral "O" upcut bit works great. I have used 16000 rpm on the spindle and depending on the depth of cut I adjust my cut speed. Watch the chip load and chip size to gauge your speed. You should enjoy cutting this material.

From contributor B:
We cut King Starboard all the time as it is used in the boating industry. The material is 1/2 inch thick. Remove the plastic coating before cutting (it wraps around the tool and sounds like a chopper coming in for landing). I use a 3/8 High Helix down-shear in two passes 18,000 rpm and 240 IPM feed. The chips are very small and curl. It cuts very nicely, doesn't get hot, and has a nice finish. Be sure to ramp in with a downshear so the material does not pack and clog the bit.

From the original questioner:
Well I cut some before I read the previous post. I did not remove the plastic coating and it wrapped around the tool and pulled a small part and broke a bit. Other than that it cut nicely. I used a 3/8" compression and cut in three passes on 3/4" material. I will go to a 1/2" compression and try that with a little slower feed to get a better finish on the edge. These are the bits I have available and I will see how it works. I do have downshears but no upshears in the shop.

From contributor J:
I cut sea board almost every day. The 3/4 inch white is the toughest. I use a 1/2" 2 flute down shear at 18000 RPM; 900 IPM however if for some reason a two or three flute duel compression bit ends up trying to cut it. It does not work out. The half white and gray I use the 1/2" 2 flute duel compression, 18000 RPM at 1300 IPM (the same set up for 1/2" plywood).