Engineering Plastics (POM, PEEK, PMMA, PA)
CNC machined and laser-cut plastic parts: acetal, PEEK, acrylic, nylon, PTFE and HDPE for MENA workshops and OEMs
Engineering plastics replace metal where you need low weight, no corrosion, electrical insulation or a self-lubricating surface. CutLinq supplies CNC milled and turned parts in POM (acetal), PEEK, PA6 (nylon), PTFE and HDPE, and laser-cut or CNC-routed sheet parts in PMMA (acrylic) and polycarbonate. Suppliers in Egypt, the UAE and Saudi Arabia machine from stock rod and plate, and you receive a binding quote within 12 hours of uploading a STEP or DXF file.
This page compares the common grades by strength, service temperature and machinability, gives the tolerances plastics can realistically hold, and lists the design rules that matter in a region where a parked enclosure can reach 70 °C.
Grade comparison
POM-C (acetal copolymer) is the workhorse: stiff, dimensionally stable, machines like brass and is the first choice for gears, bushes, guides and jigs. PA6 (nylon) is tougher and more wear-resistant but absorbs up to 3% water, which swells parts by 0.5 to 1% in coastal humidity. PEEK keeps its strength to 250 °C and resists most chemicals, at roughly 20 to 40 times the material cost of POM. PTFE has the lowest friction and widest chemical resistance but creeps under load and cannot hold tight tolerances. PMMA (cast acrylic) is used for transparent covers, machine guards and signage; polycarbonate where impact resistance matters. HDPE and PP are cheap, food-safe and weldable but soft.
| Material | Tensile strength | Max continuous service temp | Water absorption (24 h) | Relative cost (POM = 1) |
|---|---|---|---|---|
| POM-C (acetal) | 65 to 70 MPa | 100 °C | 0.2% | 1 |
| PA6 (nylon) | 70 to 80 MPa | 90 to 100 °C | 1.5 to 3% | 0.9 |
| PA6 cast, oil-filled | 75 MPa | 100 °C | 1% | 1.5 |
| PEEK | 95 to 100 MPa | 250 °C | 0.1% | 20 to 40 |
| PTFE | 25 to 35 MPa | 260 °C | under 0.01% | 3 to 4 |
| PMMA cast (acrylic) | 70 to 75 MPa | 70 to 80 °C | 0.3% | 0.6 |
| Polycarbonate | 60 to 65 MPa | 115 to 120 °C | 0.2% | 1.2 |
| HDPE | 25 to 30 MPa | 80 °C | under 0.01% | 0.4 |
Machining and cutting processes
POM, PA, PEEK and PTFE are milled and turned on the same CNC machines as aluminium, with sharp polished tools, high spindle speeds and air or mist cooling. Plate and rod stock runs from 5 to 100 mm thick for POM and PA and from 6 to 50 mm for PEEK; larger blanks are possible but expensive. PMMA up to 25 mm cuts with a CO2 laser giving a polished edge; fiber lasers cannot cut clear acrylic. Polycarbonate must be CNC-routed or sawn, since laser cutting chars and yellows it. HDPE and PP are routed and can be hot-gas or extrusion welded into tanks and trays.
| Process | Materials | Thickness or size | Edge or surface |
|---|---|---|---|
| CNC milling | POM, PA, PEEK, PTFE, HDPE | Plate 5 to 100 mm | Ra 1.6 to 3.2 µm |
| CNC turning | POM, PA, PEEK, PTFE | Rod 10 to 300 mm dia | Ra 0.8 to 1.6 µm |
| CO2 laser cutting | PMMA cast and extruded | 2 to 25 mm | Flame-polished edge |
| CNC routing | PC, PMMA, HDPE, PP | 2 to 30 mm | Milled edge, can be polished |
| Plastic welding | HDPE, PP, PVC | 3 to 20 mm | Tank and tray fabrication |
Tolerances and stability
Plastics move. Thermal expansion of POM is about 110 µm per metre per °C, roughly five times steel, so a 300 mm POM guide grows 1 mm between a 20 °C workshop and a 50 °C Riyadh summer floor. Machined tolerance of ±0.05 mm is achievable on small features in POM and PEEK if the part is measured at 20 °C and 50% humidity, but ±0.1 to ±0.2 mm is the sensible default. Nylon should be specified at ±0.2 mm or wider unless it is conditioned before machining. PTFE holds ±0.2 mm at best. Thin walls below 1.5 mm and long unsupported bars distort during machining; leave stock and rough, rest, then finish.
- POM, PEEK: ±0.05 mm achievable, ±0.1 mm standard
- PA6: ±0.2 mm standard, allow for 0.5 to 1% swell in humid coastal air
- PTFE, HDPE: ±0.2 to ±0.3 mm
- PMMA laser cut: ±0.2 mm, edge taper about 0.1 mm per 10 mm thickness
- Flatness on plates: 0.5 mm per 300 mm unless stress-relieved
Heat, UV and dust in MENA
Choose materials for the real temperature, not the room temperature. A black POM part in a Sharjah rooftop enclosure will reach 80 °C and soften; use PEEK, PPS or glass-filled PA for anything in direct sun. Standard PMMA and polycarbonate yellow within 2 to 3 years of Gulf UV unless a UV-stabilised grade is chosen. Sand abrasion scratches clear covers, so specify hard-coated polycarbonate for outdoor displays. Dust does not harm plastics, but electrostatic charge on POM and PMMA attracts it; antistatic grades exist for electronics jigs.
What to send with your file
State the material and grade (for example POM-C natural, PA6 cast black, PEEK natural, PMMA cast clear 8 mm), whether food or medical contact applies (FDA or EU 10/2011 grades are available at a premium), the operating temperature, and which dimensions are critical. Include threads only where needed: a tapped M6 thread in POM needs 1.5 times the diameter of engagement, and threaded metal inserts are better for repeated assembly. Sheet parts should be sent as DXF, machined parts as STEP.
Design tips
- Keep wall thickness at or above 2 mm in POM and 3 mm in HDPE; thinner walls warp during machining.
- Use internal corner radii of at least 1 mm and ideally 3 mm; plastics are notch-sensitive and crack at sharp corners.
- Add 0.2 to 0.3 mm clearance on POM sliding fits and 0.5 mm on nylon fits to allow for heat and moisture growth.
- Specify threaded brass inserts for any hole assembled more than 10 times; direct tapped threads in POM wear.
- Design PMMA parts with holes at least 2 times the material thickness from the edge to avoid cracking.
- Select a UV-stabilised or hard-coated grade for any transparent part exposed to sun in the Gulf.
- For gears and bushes in 40 °C+ ambient, specify PEEK or PA6 cast instead of standard POM.
Applications
| Industry | Example parts | Typical material |
|---|---|---|
| Packaging machinery | Guides, star wheels, change parts | POM-C, PA6 cast |
| Food and beverage | Cutting boards, scrapers, conveyor wear strips | HDPE food grade, UHMW-PE |
| Electrical | Insulators, terminal blocks, bushings | POM, PA6 GF30, PEEK |
| Medical and lab | Fixtures, trays, housings | PEEK, PMMA, POM |
| Signage and retail | Displays, light diffusers, covers | PMMA cast, polycarbonate |
| Oil and gas | Seals, valve seats, wear rings | PTFE, PEEK |
| Automotive aftermarket | Bushes, spacers, prototypes | PA6, POM |
Pricing and lead time
Three factors set the price: material grade (PEEK blanks alone can cost more than a finished POM part), machining time driven by the amount of stock removed and the tolerance class, and the blank size, because plastics are bought as plate and rod and a part 5 mm larger may need the next stock size. Batches of 20 to 100 pieces cut unit cost by 30 to 50% compared with one-offs. Laser-cut acrylic parts ship in 2 to 4 working days; machined POM and PA parts in 4 to 8 working days; PEEK and PTFE parts in 6 to 12 working days depending on stock availability in the region.
Frequently asked questions
No. Laser cutting polycarbonate leaves a burnt, yellow edge and releases fumes. We CNC-route polycarbonate instead, which gives a clean edge at ±0.2 mm. Acrylic (PMMA) is laser cut with a polished edge.
Upload your STEP or DXF file, select the plastic grade, and receive a binding quote within 12 hours.