Engineering plastics: nylon, polycarbonate, acetal and offcuts

This table helps you identify what you have. It is not design advice. Keep the grade information from your supplier with the offcuts.

Nylon is a family, not one material. Keep PA6 and PA66 apart where you know which is which. Hold on to the grade code from the bar, sheet or delivery paperwork.

Do not mix glass-filled or lubricated nylon with plain nylon. A trade name can cover several different formulas, so give the supplier grade.

Solid offcuts, regrind and turnings are packed differently, so say which form you have. For nylon 6 recycling or nylon 66 recycling, the supplier's specification sheet is the most useful thing you can send. Do not guess a nylon recycling number for an unlabelled bag. Set it aside and check your purchase records.

Polycarbonate offcuts come from clear sheet, coloured stock and machined shapes. Protective film, coatings and fittings change what can be recycled, so tell us if they are still on.

Clear sheet is not always polycarbonate. Acrylic looks similar but is a different plastic, and we do not take it. Check your purchase records if you are unsure.

For polycarbonate recycling, keep offcuts clean, dry and apart from other plastics. New offcuts and old guards removed from machines should be kept separate. The polycarbonate recycling code names a broad family, not a specific grade.

Acetal, also called POM, comes in several grades. Do not bag it with nylon just because they are used for similar parts.

UHMWPE and PTFE also need their own labels. Do not put them in a mixed white-plastic bag because they look alike.

Acetal, UHMWPE and PTFE offcuts are not collected at present. Keep them out of nylon and polycarbonate bags so the bags we take stay clean.

If a batch has plastics you cannot identify, say so. Do not try burn or solvent tests to work it out.

Glass, carbon, mineral fillers and other additives change the plastic. Keep filled and unfilled grades in separate, labelled bags. Ensinger's compounds information shows how many variations exist beyond the basic plastic name.

Metal inserts, fasteners and bonded layers also matter. Ask before you send parts with them attached. Do not cut or grind parts apart just to make them look like clean offcuts. A photo of the whole part and its specification is more useful than a bag of pieces with no label.

The easiest time to keep grades apart is when the stock reaches the machine. Label the offcut bin with the plastic and grade for the current job. Empty or swap the bin before a different plastic goes on.

Keep floor sweepings out of clean bins, because they pick up metal, other plastics and dirt. Have a separate bin for anything you cannot identify.

Do not rely on one experienced worker recognising every plastic by feel. Labels and job sheets make the system work when that person is away.

Tell us about any coolant or oil. Turnings can look dry and still carry oil. Do not wash residues into stormwater or drains.

Store clean offcuts under cover and away from spills. A bag left under a leaking roof is no longer clean and dry.

Use clean, sound bulk bags or pallets, as agreed when you book. Label each plastic and grade. Stop sharp or long pieces poking through the bag.

Do not overfill a bag just because there is room. Tell the collector the weight, what the bag sits on and how it can be lifted. Say whether a forklift and driver will be on site, and describe the route to the truck. Track how quickly offcuts build up so collections can be planned before bags start blocking work areas.

Household recycling bins are not for engineering offcuts. A council bin that takes bottles does not take machined nylon, acetal or PTFE.

HDPE, PP, ABS, PET regrind and PVC offcuts are looked at case by case. They are not the focus of the main nylon and polycarbonate service. Keep polystyrene, flexible foam, acrylic, soft film and dirty mixed plastics out of engineering offcut bags.