Acetal (Delrin) CNC Machining
Acetals are high strength thermoplastics known by the brands Delrin, Tecaform and Sustarin. Compared to other more versatile plastics, it has excellent mechanical properties and temperature resistance. Easy processing and good dimensional stability. The combination of these characteristics makes Delrin’s CNC machining ideal for high-precision mechanical parts such as gears and bearings. Accessories can be found in consumer electronics such as printers and televisions.
Acetal CNC Machining
Delrin is the DuPont brand name for homopolyacetal. It has better mechanical properties and significantly improved impact endurance than acetal copolymers. In addition to its outstanding mechanical properties, CNC processing of acetals provides excellent dimensional stability, making them ideal for high-precision parts.
Acetal At a Glance
| Application | Acetal is ideal for high-precision mechanical parts such as bearings, bushings, gears, and valve components |
| Advantages | Good fatigue resistance, low friction, good overall toughness, moisture resistant |
| Disadvantages | Centerline porosity |
| Lead Time | Lead time is generally a minimum of 3 days. However, this can increase depending on availability or if the parts are to be internationally manufactured. |
| Price | $$ |
| Tolerances | Machining tolerances of 0.010” (0.25 mm) are achievable. |
| Wall Thickness | A minimum wall thickness of 0.03” (0.8 mm) is achievable. This can vary depending on the ratio of wall thickness to planar dimension. |
Delrin 150
The Delrin 150 is the highest mechanical strength in the DuPont Delrin family. Due to its high impact toughness and low friction characteristics, the Delrin 150’s CNC machining is suitable for gears, door parts and bearings. It is lighter and cheaper than metal parts, bridging the gap between plastic and metal in many ways. Delrin 150 can withstand a wider range of loads than other plastics.
Delrin 150 Properties
| Tensile Strength, Yield (MPa) | Elongation at Break (%) | Hardness (Rockwell M) | Heat Deflection Temperature (°C) at 0.46 MPa | Melting Point (°C) |
|---|---|---|---|---|
| 73-76 | 25-45 | 94 | 160-169 | 175-178 |
Delrin 100 (AF)
Delrin 100 is a mixture formed by injecting polytetrafluoroethylene (Teflon) fibers into Delrin to enhance the wear resistance of the material and reduce the coefficient of friction. This makes the material particularly suitable for applications that require low wear or friction, such as bearings. Teflon fibers also help to improve the strength, toughness and dimensional stability of the material.
Delrin 100 (AF) Properties
| Tensile Strength, Yield (MPa) | Elongation at Break (%) | Hardness (Rockwell M) | Heat Deflection Temperature (°C) at 0.46 MPa | Melting Point (°C) |
|---|---|---|---|---|
| 53-56 | 10-19 | 77 | 160-169 | 175-178 |
Finishes
As with most plastic parts,Delrin parts can only accept a few types of surface treatments. Here are some options for improving the surface finish of Delrin components:
Direct machining: Good surface finish can be produced from CNC machine tools. Findtop manufacturers achieve this using sharp HSS(high speed steel) tools with appropriately high front and stress angles.
Findtop uses specialized polishing processes including polishing sand, lubricants and polishing tools to achieve a neatly polished surface.
Cost-saving Design Tips
As with most plastic parts,Delrin parts can only accept a few types of surface treatments. Here are some options for improving the surface finish of Delrin components:
Direct machining: Good surface finish can be produced from CNC machine tools. Findtop manufacturers achieve this using sharp HSS(high speed steel) tools with appropriately high front and stress angles.