Metals and plastics we machine every week
More than fifty grades in regular rotation, from 6061 aluminum for anodized housings to 17-4PH for a pump shaft and PEEK for an insulator. Mill certificates, RoHS and REACH declarations on request, and customer-specified grades sourced to your standard.
Metals
Grades we keep in rotation. If yours is not listed — Inconel, Monel, 15-5PH, AZ91 — ask; specialty stock is quoted daily.
| Family | Grades | Why specify it | Watch-outs |
|---|---|---|---|
| Aluminum | 6061-T6, 6063, 7075-T6, 5052, 2024 | Fast to machine, light, anodizes beautifully | 7075 and 2024 are strong but less corrosion-resistant; 6061 welds and finishes best |
| Carbon and alloy steel | 1045, 4140, 42CrMo, 40Cr, S355 | Strength and fatigue resistance at low cost | Rusts immediately — plan a finish or oil protection |
| Stainless steel | 303, 304, 316L, 416, 420, 430, 17-4PH | Corrosion resistance, food and medical contact, cleanability | 304 work-hardens if the cutter rubs; 303 machines best but welds poorly |
| Titanium | Grade 1, Grade 2, Grade 5 (Ti-6Al-4V), Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-2Mo | Strength-to-weight and corrosion where both matter | Slow cutting, high tool wear, and heat at the cut must be controlled |
| Copper alloys | C110 copper, C360 brass, bronze, beryllium copper, nickel-copper | Electrical and thermal conductivity, RF shielding, non-sparking | Gummy and abrasive on tools; beryllium copper needs dust control |
Engineering plastics
Plastic parts are lighter, cheaper to iterate and often good enough structurally — the trick is picking the one that survives your environment.
| Material | Strength of the choice | Typical parts |
|---|---|---|
| POM (acetal) | Dimensionally stable, low friction, machines cleanly | Wear pads, rollers, bushings, jigs |
| PEEK / PEKK | High temperature, chemical resistance, low outgassing | Semiconductor parts, insulators, medical instruments |
| PA (nylon) 6 / 66 | Tough and impact-resistant, absorbs moisture | Gears, covers, brackets, cable guides |
| PC | Transparent and very impact-resistant | Lenses, guards, housings, light pipes |
| ABS | Cheap, easy to finish, good for validation builds | Prototype housings, covers, fixtures |
| PMMA (acrylic) | Optical clarity, polishes well, brittle | Windows, light guides, display parts |
| PTFE | Chemically inert, very low friction, creeps under load | Seals, liners, insulators |
| PPS, PET, PE, PU, UHMWPE | Chemical resistance, wear, food contact or impact | Pump parts, wear strips, food-handling components |
Choosing between them
Start with the environment, not the datasheet. A part that lives outdoors in a coastal climate is a different answer from the identical part inside a climate-controlled cabinet — 6061 with Type II anodizing versus 316L, or 303 versus 17-4PH after heat treatment. Then load: if the part is stiffness-critical, aluminum sections win on weight and steel on absolute strength; if it is wear-critical, hardness and a wear surface matter more than bulk strength. Then tolerance: plastics move with temperature and moisture, so holding ±0.005 mm in POM over a 200 mm length is a different promise from the same tolerance in steel. Then cost: material is often the smallest line on a machined-part quote — the routing, the tolerance and the finish usually decide the price.
Certificates, compliance and customer grades
Material arrives with the supplier’s mill certificate and the grade, heat number and condition are checked against it before the stock is released to a job. On request we supply the certificate with the shipment, plus RoHS and REACH declarations where the part is going into the EU or North America. Customer-specified or certified material — including grades we do not hold — is sourced against your specification, and we will tell you when the lead time is governed by the mill rather than by our machines.
What material choice does to the price
Two identical geometries can differ by a factor of three. Titanium cuts five to ten times slower than aluminum and eats tooling; stainless work-hardens and needs different feeds; PEEK machines cleanly but the stock itself is expensive. When a program is cost-sensitive we quote the geometry against two or three materials so the trade-off between performance, finish and piece price is visible before the design is frozen.