Delrin / Acetal in Flint, MI

Karl Gillihan

⚪ DELRIN / ACETAL

Delrin and Acetal Machining in Flint, MI

If a Flint shop needs a plastic part that has to be dimensionally precise, slick, and stiff, the conversation usually starts with Delrin. Acetal is the workhorse engineering plastic for gears, bearings, and wear components across the region's automotive and equipment supply base, machining like a dream and holding tolerances metal-tight. This page sorts out Delrin versus generic acetal, the homopolymer and copolymer split, and how local buyers source it.

ISO 9001IATF 16949

Delrin, Acetal, and Why the Names Matter

Buyers often use Delrin and acetal interchangeably, but the relationship is worth getting straight before you spec a part. Acetal is the generic name for the polymer polyoxymethylene, POM. Delrin is DuPont's brand name for their acetal homopolymer specifically. So all Delrin is acetal, but not all acetal is Delrin, and a meaningful chemistry difference separates Delrin homopolymer from the acetal copolymer made by other suppliers. For most Flint machining work, the practical distinctions are stiffness, surface quality, and a specific defect called centerline porosity. Homopolymer Delrin is slightly stiffer and stronger and has a harder, more wear-resistant surface, which is why it is favored for high-load gears and bearings. Copolymer acetal trades a little of that mechanical edge for better resistance to hot water and aggressive chemicals and, importantly, for the absence of centerline porosity, the small voids that can form down the core of homopolymer extruded rod. When a part is machined from the center of a large-diameter rod, that porosity can show up as a cosmetic or sealing problem, which steers some applications toward copolymer.

01

Grade Selection for Local Applications

Delrin 150 is the standard general-purpose homopolymer grade and the default for the region's precision machined parts: gears, cams, bushings, rollers, wear strips, and fixtures. It offers the high stiffness, low friction, good fatigue resistance, and excellent machinability that make acetal the go-to engineering plastic, and it holds tight tolerances because it has low moisture absorption and good dimensional stability compared with nylon. For a Flint shop turning a precision bushing or milling a gear, Delrin 150 is a reliable starting point. Acetal homopolymer, the Delrin family, leads where maximum mechanical performance and surface hardness matter, high-load gears and bearings that see continuous wear. Acetal copolymer is the choice when the part contacts hot water, steam, or aggressive chemicals, or when centerline porosity would compromise a sealing surface or a part machined from the core of large stock. Copolymer also tends to be a bit more forgiving in wide temperature swings. For most automotive and equipment wear parts the difference is minor, but knowing which way to lean, homopolymer for mechanical and wear performance, copolymer for chemical and porosity concerns, is what separates a good spec from a guess.

02

Machining and Procurement in Flint

Acetal is one of the most machinable plastics available, which is exactly why Flint's CNC base likes it. It cuts cleanly with sharp tools, produces well-formed chips, and holds fine tolerances and good surface finishes without drama, making it ideal for high-volume turned and milled parts. The main things a shop watches are heat, since acetal can melt and gum if a tool dwells, and dimensional movement, because the material has a relatively high coefficient of thermal expansion and parts should be measured at a stable temperature. Stress relief on tight-tolerance parts and machining away from the porous core on homopolymer rod are standard precautions. For procurement, acetal comes as extruded rod, plate, and tube in natural, usually white, and black, with black often preferred where UV exposure or appearance matters. The buy comes down to grade, homopolymer or copolymer, dimensions, and color. Because acetal is moderately priced and widely stocked through plastics distributors serving mid-Michigan, lead times are short and small quantities are easy. For automotive programs, confirm whether the part needs a specific grade callout or certification. ManufacturingBase can connect Flint buyers with acetal distributors and the precision machine shops that run it daily.

03

Acetal Versus Nylon for Wear Parts

A common decision in Flint shops is acetal versus nylon for a bushing, gear, or wear part, and the answer hinges on a few properties. Acetal wins on dimensional stability and machinability: it absorbs very little moisture, so it holds tolerance in humid or wet environments where nylon swells and loses precision, and it machines more cleanly. It also has lower friction and better fatigue resistance, which is why precision gears and bearings so often land on acetal. Nylon pulls ahead where impact toughness and abrasion resistance matter more than tight tolerance, and it tolerates higher temperatures in some grades. The rule of thumb local shops follow: if the part must stay dimensionally precise, run with low friction, and resist fatigue, choose acetal, usually Delrin homopolymer. If it must absorb impact and shrug off abrasion and a little dimensional movement is acceptable, nylon may be better. For the bulk of automotive and equipment precision wear parts in the region, acetal is the more frequent choice, which is why Delrin 150 is a staple on the shelf.

Frequently Asked Questions

Acetal is the generic name for the polymer polyoxymethylene, or POM, while Delrin is DuPont's brand name for their acetal homopolymer specifically. So all Delrin is acetal, but not all acetal is Delrin, and the distinction carries a real chemistry difference. Delrin is a homopolymer, while many other acetal products are copolymers. Homopolymer Delrin is slightly stiffer and stronger with a harder, more wear-resistant surface, which favors high-load gears and bearings. Copolymer acetal gives up a little mechanical performance for better resistance to hot water and aggressive chemicals and, importantly, avoids centerline porosity, the small voids that can form down the core of homopolymer extruded rod and cause problems on parts machined from the center of large stock. For most Flint machining work the two are interchangeable, but when maximum stiffness and surface hardness matter, choose homopolymer Delrin, and when chemical resistance or freedom from core porosity matters, choose copolymer acetal.

Delrin 150 is the standard general-purpose acetal homopolymer grade and the default material for a wide range of precision machined parts in Flint's automotive and equipment supply base. It is used for gears, cams, bushings, bearings, rollers, wear strips, and machined fixtures, anywhere a part needs to be stiff, low friction, fatigue resistant, and dimensionally precise. Its appeal comes from a strong combination of properties: high stiffness, a low coefficient of friction that lets it run as a bearing without lubrication, good fatigue resistance for parts that cycle, low moisture absorption for dimensional stability, and excellent machinability that lets shops hold tight tolerances and clean surface finishes. For a shop turning a precision bushing or milling a gear, Delrin 150 is a dependable starting point. When the application involves hot water, steam, aggressive chemicals, or a sealing surface machined from the core of large rod, an acetal copolymer is usually the better choice instead.

The choice between acetal and nylon depends on which properties the part needs most. Acetal, usually Delrin homopolymer, is the better pick when dimensional precision and low friction matter, because it absorbs very little moisture and holds tolerance even in humid or wet conditions, where nylon swells and loses precision. Acetal also has lower friction and better fatigue resistance, which is why precision gears and bearings so often use it, and it machines more cleanly. Nylon pulls ahead when impact toughness and abrasion resistance are the priority, and some nylon grades tolerate higher temperatures. The practical rule Flint shops use: if the part must stay dimensionally stable, run with low friction, and resist fatigue, choose acetal; if it must absorb impact and shrug off abrasion and some dimensional movement is acceptable, lean toward nylon. For most precision automotive and equipment wear parts in the region, acetal is the more common answer, which is why Delrin 150 is a shelf staple.

Centerline porosity is a string of small voids that can form down the central axis of extruded acetal homopolymer rod as it cools, because the core solidifies last and can pull apart slightly. It is essentially a casting-style defect specific to the way homopolymer extrudes. It matters when a part is machined from the center of a large-diameter rod and the finished surface either needs to seal, such as a piston or valve component, or needs to look defect-free cosmetically. In those cases the exposed porosity can leak or appear as visible pinholes. The two common fixes are to machine the part from rod sized so the finished surfaces avoid the porous core, or to switch to acetal copolymer, which does not exhibit centerline porosity. For most solid machined parts like gears and bushings the porosity is buried in the body and irrelevant, but for sealing or cosmetic surfaces it is worth flagging to your Flint machine shop up front so they can plan stock and grade accordingly.

Yes. Acetal is moderately priced and widely stocked through plastics distributors serving the mid-Michigan and Flint market, so small quantities and short runs are easy and lead times are short. The material comes as extruded rod, plate, and tube in natural, usually white, and black, with black often chosen where appearance or UV exposure matters. Acetal is also one of the most machinable engineering plastics, cutting cleanly with sharp tools and holding tight tolerances and fine finishes, so the region's CNC shops run it routinely for prototype and production quantities alike. When you request a quote, specify whether you need homopolymer Delrin or acetal copolymer, the dimensions and color, and any tolerance or surface requirements, plus a grade or certification callout if the part feeds an automotive program. ManufacturingBase can connect you with acetal distributors and the precision machine shops in Genesee County that turn and mill Delrin daily, for both one-off parts and ongoing production.

Last updated: July 2026

Find Delrin / Acetal Manufacturers in Flint, MI

Search verified Flint shops that work in Delrin / Acetal.

Search Manufacturers →Get Your Shop Listed (Free)

No logins. No email gates. Just results.