1. Machining Plastics Joe Latchaw Carl Caldwell Doug French

2. Why? For small production volumes Prototype production Shapes impossible by injection molding Create certain features more precisely Threads Lower stresses

3. Why? (cont.) For long holes Unacceptable injection molding aspects Parting line, ejection marks, flash, draft Large or thick section parts Short lead time Secondary operations on injection molded parts

4. Common Machining Processes Drilling Sawing Milling Turning

5. Common Machining Processes (cont.) Routing Waterjet cutting Laser cutting

6. Tooling Requirements Sharp Highly positive

7. Other capabilities Micro parts Annealing Polishing While being machined Flame Vapor Mechanical buffing

8. Applications Any applications Medical Electrical Aerospace Fiber optics

9. Common Materials Acetal Acrylic ABS Nylon PEEK

10. Common Materials (cont.) Polycarbonate Polyethylene Polypropylene PVC

11. Plastics Machining Shop Metal machining contaminants Material knowledge Material discount Plastic based equipment Higher quality Lower cost

12. Advantages Smaller quantities Less tooling problems & delays No common effects of injection molding Lower nitial cost CNC benefits

13. Advantages (cont.) Lower stresses Consistent properties Tighter tolerances Thicker parts

14. Disadvantages Longer cycle times Higher part cost Waste Thermal Expansion Dissipate heat slower