Secondary Operations on Plastic Lumber
The force that is applied to the cutting edge of the tool generates friction resulting in a build-up of heat in the tool and the work piece. HDPE dissipates heat slowly (low thermal conductivity) therefore it is important to quickly remove as much heat as possible. Sharp and coarse cutting blades with a generous gullet will remove hot chips fast without clogging. For vertical mills and routers, two-fluted cutters are better than multi-fluted cutters because of the larger gullet. The same is true for horizontal milling machines – coarse tooth cutters are a better choice. Feed rates can be as high as the part and the setup can safely stand. Shavings resulting from milling operations should be curled without much dust, and spindle speeds should be adjusted accordingly. It is advisable to grind or stone radii on all cutting edge corners to achieve a good finish. Also, it is good practice to rough out parts first and then, when the part returns to ambient temperature, apply light cuts to finish the part to specs. Cycle times can be reduced by cooling the cutting tool with a mist applicator or a compressed air nozzle.
Drilling Plastic Lumber
For drilling operations, “Peck” drilling gives the best results because the interrupted feed will break up the shavings and assist in clearing the hole. It is good practice to rough out parts first and then when the part returns to ambient temperature, apply light cuts to finish the part to specs. Cycle times can be reduced by cooling the cutting tool with a mist applicator or a compressed air nozzle.
Flood cooling is usually not recommended since HDPE is lighter than the coolant and will make a difficult to-clean-up mess.
Cutting Plastic Lumber
To cut MAXiTUF© Plastic lumber any available metal or wood cutting tool can be used. Six teeth per inch and less work better than finer toothed blades. A coarse tooth cutter has larger gullet areas for chips and therefore will not clog up as quickly.