Nylon 6/6 CNC machining produces tough, wear-resistant parts at a low material cost, as long as the design and the shop account for one property: nylon absorbs water. Nylon 6/6 is an extruded polyamide with good strength, fatigue resistance and abrasion resistance, and it is a common choice for gears, rollers, bushings and wear parts. Wexmar machines extruded nylon 6/6, cast nylon 6, and molybdenum disulfide, oil and glass-filled grades on CNC lathes, Swiss-type machines and horizontal machining centers at our shop in Canastota, New York.
Machinability of nylon
Nylon, like other plastics, is not rated on the AISI 1212 steel scale. It cuts freely, but it is softer and more elastic than acetal, so it tends to push away from the tool and spring back. The real limits are heat, stress, clamping and dimensional stability. Nylon 6/6 can absorb roughly 2 to 3 percent moisture at typical room humidity and more when fully saturated, and it grows as it does. A part machined dry and measured in a humid plant can read differently a week later.
Tolerances and surface finish
For machined nylon parts, plus or minus 0.002 in. is typical on small turned diameters, and plus or minus 0.003 to 0.005 in. on larger features, depending on section size and the service environment. Tolerances tighter than the material can hold in use are discussed at the quote stage. A 63 Ra finish is typical, and 32 Ra is achievable on turned surfaces with sharp tooling. Filled grades generally finish slightly rougher than unfilled nylon.
Tooling, moisture and chip control
- Condition the stock. Material is kept at shop conditions before machining. For critical parts we agree with the customer on whether dimensions apply dry as molded or at equilibrium moisture.
- Sharp, high-rake tools. Nylon smears and melts under a dull edge. Polished carbide with generous clearance cuts cleanly and limits heat.
- Coolant. Air blast or water-soluble coolant controls heat. Nylon fed too slowly rubs and builds heat; fed too fast it tears.
- Stringy chips. Nylon throws long, tough ribbons on the lathe. Chip breakers and programmed feed interruptions keep them off the part and chuck.
- Burrs. Nylon burrs are tough and flexible and do not break off cleanly. Programmed chamfers and sharp finishing tools reduce hand trimming.
- Clamping. Soft jaws and moderate pressure avoid out-of-round bores after unclamping.
Stress relief and finishing
Large or thick nylon parts benefit from stress-relieved stock, and cast nylon is often preferred for large sections because it has lower internal stress than extruded shapes. Annealing and moisture conditioning, when a drawing specifies them, are performed through qualified outside processors. Most nylon parts ship as machined, with no coating or plating.
Common nylon 6/6 parts
- Spur gears, sprockets and sheaves (lathes with live tooling, horizontal mills)
- Rollers, idlers and wheels for conveyors and material handling (CNC lathes)
- Wear pads, slides and guides for equipment (horizontal machining centers)
- Bushings, spacers and washers (Swiss-type, parts to 32 mm diameter, and lathes)
- Electrical insulators and terminal blocks (horizontal mills)
Round nylon parts run on our CNC turning lathes, and plate parts such as wear pads and insulators run on horizontal machining centers with pallet changers. See the machine list for equipment details.
Cost index vs 6061 aluminum
| Material | Approx. machinability (1212 = 100) | Cost index vs 6061 | Notes |
|---|---|---|---|
| 6061-T6 aluminum | ~180 | 1.0 | Baseline |
| Nylon 6/6 | Not rated; cuts freely | 1.0 | Tough, absorbs moisture |
| Delrin / acetal | Not rated; cuts freely | 1.0 | More stable in humidity |
| UHMW | Not rated; cuts freely | 1.1 | Higher abrasion resistance, less rigid |
| 1018 steel (CD) | ~78 | 1.1 | Metal alternative for gears |
| Polycarbonate | Not rated; cuts freely | 1.3 | Clear, impact resistant |
These values are typical and illustrative for a comparable part; actual quotes depend on geometry, quantity, tolerances and mill pricing. Where tighter dimensional stability is required, Delrin and acetal machining is often the better fit.
Applications and industries
Nylon machining services support packaging and conveying equipment builders, power transmission and bearing OEMs, agricultural and food processing machinery, electrical equipment makers and general industrial maintenance. Parts are made from prototype quantities through production, and ship nationwide from Central New York.
Getting a quote
To price nylon 6/6 or cast nylon parts, upload a drawing for an instant estimate or call (315) 400-2654. A human estimator confirms every quote, including the grade and whether any fillers are required.