Basic Information:
Most plastics can be machined using high speed cutting tools but it is essential that only correctly sharpened equipment is used.  Plastics have a poor thermal conductivity;  therefore it is essential for good heat dissipation.  Localized overheating during machining is to be avoided as the material can degrade.  If large amounts of material are to be removed it may be essential to re-annel the material after rough machining.  Plastics also have a very high thermal expansion and some have high moisture absorption (nylon) which must be considered.

1. Turning
A guide for tool geometry is enclosed but for a high quality finish a smoothing tool (Figure 1) should be used.  To reduce burrs during parting off see (Figure 2) for parting tool.

2. Drilling
Twist drills are generally used, having smooth spiral grooves which should have a twist angle of 12 to 16 degrees.  Special attention to properly sharpened drills is essential as compressive stress can cause solid material to split (Figure 3 & 4). This is particually evident with large diameter Nylon.

3. Milling
For plane surfaces, face milling is more acceptable than peripheral.  For profile and peripheral the tool should have more than two cutters to reduce vibration.

4. Sawing
Good sharpened saw blades with a large tooth offset is essential as this will reduce friction which causes unnecessary heat generation.

5. Thread Cutting
Thread Chasers, particularly twin toothed are recommended as they reduce burr formation but die nuts are not advised.  A small machining allowance is necessary when using tap drills.

All our advice either oral or written is purely to help and as such is offered without obligation, we cannot assume any liability for any mistakes or damage which may occur as a result or during machining.