Circular Interpolation Milling in HDPE - Tormach CNC

Tormach on the web @ http://www.tormach.com

Overview:
This video reviews cutting a 3" diameter hole into 2" High Density Polyethylene with a ½" 2 flute high speed steel cutter.

Material: 2" High Density Polyethylene
Cutters: ½" HSS 2 flute End Mill
Speed: 2500 RPM
Feed: 20 IPM
Machine: Tormach PCNC 1100

Background:
Milling is described as climb milling or conventional milling. Convention milling is when the cutting edge enters the material at the finish surface and exits on the uncut surface. Climb milling has the cutter entering the old surface and exiting at the finish surface. Climb milling provides longer tool life and better surface finish, but requires a precise machine tool with no backlash.

Fixtures & Tooling:
The work piece was clamped to the machine table using parallels between the table and the material so the cutter would not hit the table when it went thru the part. The tool used was a standard ½" 2 flute high speed steel cutter.

Motion Planning:
We started out with a 10" step per minute plunge into the HDPE. This is not the optimized tool path, indicated by the swarf build-up on the tool. If we would have used a peck drilling technique, we would have chips instead of swarf and this would result in a cleaner cut. At the end of the cut, we spiral out at an 80% cut, meaning 80% of the ½" tool diameter or 0.4". This technique is called climb milling.

Cutting Process & Results:
High Density Polyethylene is a very easy material to cut. Even without an optimized tool path, the cut was smooth and quiet. We cut the HDPE at 20" per minute. To prevent recutting, heating, and a poor finish the operator used a vacuum to pick-up chips.
http://www.tormach.com/MfgDatabase/AN20109_CircularInterpolationMilling.pdf


Keywords:
HDPE, High Density Polyethylene, HSS end mill, 2 flute end mill, climb milling, peck drilling.

Category:

Science & Technology

Tags:

• Tormach
• CNC
• milling
• machine
• techniques
• HDPE
• High
• Density
• Polyethylene
• HSS
• end
• mill
• flute
• climb
• peck
• drilling

[SupermaxCNC]

@mdocod

Cant go faster on a Tormach, stepper motors on the axis limit the feed rate.

[mdocod]

check out usplastics for plastic stock... I would suggest a faster feed rate in that stuff to get the ship weight up so it clears from the tool from centrifugal force a little better.

[PixelPi]

Where's a cheap source for HDPE plate?