What are the key properties of Delrin (Acetal)?

Delrin combines outstanding dimensional stability and wear resistance with low friction for smooth motion components, and it machines easily with crisp edges and smooth surfaces. Natural Delrin 150 stock has a tensile strength at yield of 76 MPa, a flexural modulus of 2900 MPa and a dynamic coefficient of friction of 0.20 against steel, the basis for gears, bushings, fixtures and other parts that slide or turn.

Can Delrin (Acetal) be 3D printed?

Forge Labs machines Delrin from extruded acetal rod and plate rather than 3D printing it. Parts up to 1000 × 600 × 500 mm are held to ±0.050 mm typical and ship in 5-7 business days, with deburring, polishing and threading available. If you need a 3D printed part for wear or snap-fit features, SLS Nylon PA12 is the closest alternative.

What are the common applications of Delrin (Acetal)?

Delrin is used across automation, industrial equipment, consumer products and medical equipment for precision gears and motion components, wear-resistant bushings and pulleys, soft jaws and protective fixtures, fluid handling manifolds and valve bodies, and non-implant fixtures and mechanism parts.

What are the advantages of using Delrin (Acetal)?

Delrin offers low friction and wear resistance without lubrication and machines easily with crisp edges and smooth surfaces. Its fatigue resistance suits repetitive motion parts, with a flexural fatigue endurance limit of 32 MPa at a million cycles in Delrin's moulded-resin tests. It absorbs only 0.25% water in 24 hours, so machined parts stay dimensionally stable, and natural stock is listed by its supplier for food contact and drinking-water components.

Are there any limitations to Delrin (Acetal)?

Delrin is not recommended for long-term use above 85 °C, although it handles intermittent exposure to 149 °C. Chlorine at 3 to 5 ppm and above, strong acids, strong bases and oxidizing agents attack it, and Delrin does not recommend it outside pH 4 to 9. Large-diameter rod and thick plate can have a low-density centre, so critical features are best kept away from the core of large sections. It is rated UL 94 HB rather than flame retardant.

What temperatures can Delrin (Acetal) handle?

Natural Delrin 150 stock is rated for 85 °C long-term service under UL 746B and 149 °C for intermittent exposure. It deflects at 125 °C under a 1.8 MPa load and melts at 175 °C, and Delrin reports extremely high fatigue resistance from −40 to 82 °C.

Is Delrin (Acetal) food safe?

Natural Delrin 150 rod and plate is listed by its stock supplier to FDA 21 CFR 177.2480 for food contact and to NSF/ANSI 51 and 61 for food equipment and drinking-water system components. The listings cover natural stock; black and coloured stock need their own supplier documentation, so ask us for the stock documentation for your application.

CNC Machining Delrin (Acetal) For Low-Friction Gears, Bushings and Wear Parts

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CNC Machining

Tight Tolerances

CNC machining material

Delrin (Acetal) overview

Delrin acetal is a hard, low-friction plastic, CNC machined into gears, bushings, rollers and fixtures that need to slide or turn smoothly. Parts run quietly without grease, wear slowly, stand up to repetitive motion and keep their size in damp or oily conditions. It machines cleanly, with crisp edges and smooth surfaces, and holds tight tolerances. Natural stock is listed by its supplier for food contact and drinking-water components, which suits valve parts and food-processing equipment.

How Delrin (Acetal) is manufactured

Delrin is manufactured by CNC machining, cutting each part from extruded acetal rod or plate rather than building it in layers. It is a stable material that cuts very well, so gear teeth, bores, threads and sliding faces come off the machine clean and tight tolerances are easier to hold. Acetal is sensitive to heat at or above 121 °C while it is cut, so machining keeps the cut cool to protect the finish and dimensions of every part.

Machining envelope: 1000 × 600 × 500 mm
Lead time: 5-7 business days
Tolerance: ±0.050 mm typical

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Industry applications

Industry applications for Delrin (Acetal)

Delrin acetal is trusted for automation, industrial equipment and consumer products programs that need outstanding dimensional stability and wear resistance where uptime matters. It combines low friction for smooth motion components with excellent fatigue resistance for repetitive motion parts, so gears, bushings, rollers and fixtures run without lubrication, and it machines easily with crisp edges and smooth surfaces.

From rapid prototyping to production runs, teams rely on Delrin to maintain tight tolerances, because it keeps its dimensions in environments containing moisture, lubricants and solvents.

Beyond motion hardware, natural Delrin stock serves food-processing and water equipment, and as an electrical insulator it suits insulating parts in electrical assemblies.

Machining from stock needs no moulds or minimum order quantities, so a Delrin part can be ordered as a single piece or in repeat production batches. A machined Delrin part performs close to a moulded one, so it can serve as a bridge part while the permanent production route is still being finalized.

All industries

Robotics & Automation
Gears, Bushings & Pulleys
Gears, bushings and pulleys that run quietly without lubrication and stand up to repetitive motion.
Automotive & Assembly
Soft Jaws, Nests & Line-Side Fixtures
Soft jaws and fixtures that hold finished parts without marking them and stay true through repeated loading.
Water & Process Equipment
Valve Components, Manifolds & Fittings
Valve parts, manifolds and fittings in natural stock listed for food contact and drinking-water components.
Medical Devices
Device Fixtures, Handles & Mechanism Parts
Fixtures, handles and mechanism parts for device and lab equipment with low wear and spring recovery.
Consumer Products
Mechanisms, Prototypes & Bridge Parts
Gears, cams and latches for prototypes and pilot builds, tested for feel, wear and noise before tooling.

Lathe turning a ring groove on a cylindrical metal part held in a three-jaw chuck

Robotics & Automation

Gears, Bushings & Pulleys

Robotics and automation teams machine Delrin into gears, bushings, pulleys and cams for actuators and conveyors. Its low friction against steel lets these parts run quietly without external lubrication, and its fatigue resistance suits repetitive motion: it carries 32 MPa in flexure for a million cycles.

Spur, helical and worm gears
Bushings and bearing cages
Pulleys, rollers and cams

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Metal valve body held in machined vise jaws, with a finished seal face, a threaded port and an O-ring beside it

Automotive & Assembly

Soft Jaws, Nests & Line-Side Fixtures

Production and assembly lines use machined Delrin for soft jaws, nests, locating fixtures and protective pads that hold finished parts without marking them. Its surface hardness keeps machined slots and locating faces true through repeated loading, low friction lets parts slide in and out cleanly, and it resists the oils, hydraulic fluids and cleaning solvents used around the line. A Delrin fixture weighs roughly half as much as the same geometry in aluminium, which eases manual changeovers and leaves more payload for robot-mounted tooling.

Soft jaws and vise inserts
Assembly nests and locating fixtures
Protective pads and guides

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Machined metal plate with an O-ring groove, threaded ports, a quick-connect fitting and a handle

Water & Process Equipment

Valve Components, Manifolds & Fittings

Water, food and process equipment makers machine Delrin into valve bodies and components, manifolds, fittings, spacers and conveyor parts. Natural Delrin 150 stock complies with FDA 21 CFR 177.2480 for food contact and is listed to NSF/ANSI 51 and 61 for food equipment and drinking-water components. Its low friction lets valve stems, spools and conveyor wear strips run without added grease. Chlorine attacks acetal at 3 to 5 ppm and above, so continuously chlorinated lines call for another material.

Valve bodies and fittings
Manifolds and spacers
Food and bottling conveyor parts

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Touch probe measuring a machined bore on a metal manifold on a granite inspection table

Medical Devices

Device Fixtures, Handles & Mechanism Parts

Medical device and laboratory teams machine Delrin for assembly and test fixtures, instrument handles and non-implant mechanism parts such as clamps, triggers and connectors, where low wear, low friction and spring recovery matter. Acetal withstands 100 fifteen-minute steam autoclave cycles at 121 °C. Delrin 150 is an extrusion grade, not one of Delrin's medical grades, so it serves fixtures and equipment outside the patient-contact path.

Assembly and test fixtures
Instrument handles and triggers
Clamps and connectors

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Thread being tapped by hand into a small metal block held in a bench vise

Consumer Products

Mechanisms, Prototypes & Bridge Parts

Product design teams machine Delrin for gears, cams, latches, hinges and sliding mechanisms in appliances, office equipment and other consumer products, using functional prototypes and pilot builds to test a mechanism for feel, wear and noise before tooling is cut. Because each part is cut from stock, a design change between iterations is a new program rather than a new mould.

Gears, cams and latches
Hinges and sliding mechanisms
Bridge production parts

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Performance data

Technical performance for Delrin (Acetal)

Values for natural Delrin 150: stock-shape datasheets for rod and plate, and Delrin Design Guide moulded-resin data where noted, tested to the standard listed with each property.

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Mechanical performance

Mechanical properties

Delrin delivers dependable strength, stiffness and toughness, and its balanced mechanical profile handles demanding load conditions without turning brittle in critical parts. It suits precision gears and motion components, soft jaws and protective fixtures, and wear-resistant bushings that need long-term durability under repetitive stress.

The flexural fatigue endurance limit is the stress acetal carries for a million load cycles, the basis for sizing gear teeth, snap features and springs. Compressive strength at small and large strain, with deformation under a sustained load, helps size bushings and wear pads. Rows marked moulded resin are Delrin's injection-moulded test-bar values, which Delrin publishes for comparing grades. Unnotched bars do not break while notched values are far lower, so generous radii at corners and tooth roots keep the full toughness of the material in machined parts.

PropertyValue

Tensile Strength at YieldASTM D638: 76 MPa
Tensile Modulus (moulded resin)ASTM D638: 2800 MPa
Elongation at BreakASTM D638: 25 %
Flexural StrengthASTM D790: 97 MPa
Flexural ModulusASTM D790: 2900 MPa
Compressive Strength at 1% StrainASTM D695: 18 MPa
Compressive Strength at 10% StrainASTM D695: 107 MPa
Compressive ModulusASTM D695: 2240 MPa
Shear StrengthASTM D732: 68 MPa
Deformation under Load (moulded resin, 13.8 MPa, 50 °C)ASTM D621: 0.5 %
Poisson's Ratio (moulded resin): 0.35
Flexural Fatigue Endurance Limit (moulded resin, 10⁶ cycles, 23 °C, 50% RH)ASTM D671: 32 MPa
Izod Impact Strength, Notched (23 °C)ASTM D256: 107 J/m
Izod Impact Strength, Unnotched (moulded resin, 23 °C)ASTM D256: No break
Rockwell Hardness MASTM D785: 94
Rockwell Hardness RASTM D785: 120
Shore Hardness DASTM D2240: 84

Material makeup

Physical properties

Consistent density and surface quality keep critical features in tolerance and downstream finishing predictable. Delrin absorbs little water even at saturation, so machined parts hold their dimensions in humid or wet service and assemblies fit without secondary rework.

Friction and wear factor come from unlubricated thrust-washer tests against steel. Use them to compare acetal with other bearing materials for bushings, slides and gears; lubrication, speed and load change the results.

PropertyValue

DensityASTM D792: 1.41 g/cm³
Water Absorption (24 h, 23 °C)ASTM D570: 0.25 %
Water Absorption (moulded resin, equilibrium, 23 °C, 50% RH)ASTM D570: 0.22 %
Water Absorption (saturation, 23 °C)ASTM D570: 0.90 %
Dynamic Coefficient of Friction (vs. steel, 40 psi, 50 ft/min)ASTM D3702: 0.20
Wear Factor (40 psi, 50 ft/min)ASTM D3702: 55 ×10⁻¹⁰ in³·min/ft·lb·hr

Heat performance

Thermal properties

Delrin reports extremely high fatigue resistance from −40 to 82 °C, so gears and snap features in automation and consumer products keep working across that range. Heat deflection shows the short-term limit under load and should not be used to judge maximum use temperature; size parts from the long-term service rating and use the intermittent rating for short excursions.

Acetal expands several times more than steel or aluminium, and expansion rises with temperature, so check clearances and press fits against metal mating parts at operating temperature.

PropertyValue

Melting PointASTM D2117: 175 °C
HDT @ 0.45 MPaASTM D648: 169 °C
HDT @ 1.8 MPaASTM D648: 125 °C
Service Temperature, Long TermUL 746B: 85 °C
Service Temperature, Intermittent: 149 °C
Coefficient of Linear Thermal ExpansionASTM D696: 122 ×10⁻⁶/K
Thermal Conductivity (moulded resin): 0.4 W/m·K
Specific Heat (−18 to 100 °C): 1.47 kJ/kg·K

Functional performance

Electrical properties

Delrin is an electrical insulator with high resistivity and good dielectric strength, and natural acetal does not carbon track under an arc. It suits insulating parts, connector bodies and electrical housings in integrated electrical systems.

Delrin reports that moisture has minimal effect on its electrical properties, and its low dissipation factor means low dielectric losses at power and radio frequencies, which helps in signal-sensitive use.

PropertyValue

Volume ResistivityASTM D257: > 10¹⁵ Ω·cm
Dielectric Strength (short time)ASTM D149: 19.7 kV/mm
Dielectric Constant (23 °C, 60 Hz)ASTM D150: 3.7
Dissipation Factor (23 °C, 60 Hz)ASTM D150: 0.005
Arc Resistance (moulded resin, 3.1 mm, no tracking)ASTM D495: 220 s

Compatibility data

Chemical properties

Delrin resists alcohols, aldehydes, esters, ethers, fuels, lubricants, hydraulic fluids and many weak acids and bases, and keeps over 90% of its tensile strength after exposure to almost all solvents. The table shows the change in unstressed bars after long immersion, with the temperature and duration listed with each chemical and a range where Delrin tested several commercial products. Bars held bent in toluene, acetone, motor oil or brake fluid for a week showed no stress cracking.

Acetal is not suitable for strong acids, strong bases or oxidizing agents, and Delrin does not recommend it outside pH 4 to 9. Chlorine attacks it at 3 to 5 ppm and above, so keep it out of continuously chlorinated water. Confirm chemical ratings with application-specific testing before production release.

ChemicalStrength changeWeight change

Acetone (23 °C, 365 days): Strength change−5%; Weight change+4.9%
Ethanol (23 °C, 365 days): Strength change−5%; Weight change+2.2%
Methanol (60 °C, 275 days): Strength change−10%; Weight change−2.3%
Ethyl acetate (23 °C, 365 days): Strength change−7%; Weight change+2.7%
Toluene (23 °C, 365 days): Strength change−7%; Weight change+2.6%
Hexane (60 °C, 275 days): Strength change−4%; Weight change+0.7%
Kerosene (60 °C, 275 days): Strength change0%; Weight change0%
Gasolines, 7 grades (23 °C, 820 days): Strength change−4 to −9%; Weight change+0.7 to 1.6%
Motor oil 10W-30 (70 °C, 365 days): Strength change+3%; Weight change−0.2%
Brake fluids, 2 products (70 °C, 310 days): Strength change−6 to −23%; Weight change+0.9 to 1.6%
Sodium chloride 10% (70 °C, 365 days): Strength change−15%; Weight change−0.6%
Calcium chloride 5% (23 °C, 365 days): Strength change0%; Weight change−0.2%
Acetic acid 5% (23 °C, 365 days): Strength change0%; Weight change+0.8%
Hydrogen peroxide 50% (23 °C, 365 days): Strength change−2%; Weight change−0.1%
Hydrochloric acid 10% (23 °C, 90 days): Strength changeUnsatisfactory; Weight changeUnsatisfactory
Sulfuric acid 30% (23 °C, 182 days): Strength changeUnsatisfactory; Weight changeUnsatisfactory
Sodium hydroxide 10% (23 °C, 365 days): Strength changeUnsatisfactory; Weight changeUnsatisfactory
Bleach, 5% hypochlorite (23 °C, 30 days): Strength changeUnsatisfactory; Weight changeUnsatisfactory

Compliance

Compliance profile

Each status comes from the stock supplier's datasheet for natural Delrin 150 rod and plate, so food-equipment and drinking-water reviews can start from supplier listings. The listings cover natural stock; ask us for the supplier documentation for black or coloured stock.

Delrin rates every acetal composition UL 94 HB, so it is not flame retardant. Delrin sells dedicated medical grades for parts with body contact; Delrin 150, an extrusion grade, is not one of them.

StandardStatus

FDA 21 CFR 177.2480 (Food contact)Listed for natural Delrin 150 shapes; compliance refers to the resin the shapes are extruded from. Black and coloured stock need their own supplier documentation: Stock supplier listing
NSF/ANSI 51 and 61Food equipment (51) and drinking-water system components (61), listed for natural Delrin 150 shapes. Delrin advises against continuous exposure to chlorine at 3 to 5 ppm and above: Stock supplier listing
ASTM D6100 S-POM0111 / ASTM D6778 POM0111Extruded acetal homopolymer rod and plate specification that natural Delrin 150 shapes are supplied to: Stock specification
UL 94 flammabilityDelrin rates every composition HB; acetal is not flame retardant: HB

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Resources

Datasheets and design resources

Datasheets, design guidance and supplier documentation for Delrin (Acetal).

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Access the most recent datasheet and supporting documentation maintained by our engineering team.

Delrin (Acetal) datasheet

Design guidelines

Tolerance, wall thickness and finishing guidance for machined parts.

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Five-axis CNC machining centre with its enclosure door open and a part on the rotary table

Advanced Manufacturing

Built with Precision CNC Machining Technology

Delrin is manufactured using advanced CNC machining technology, keeping the full properties of the extruded stock and holding dimensional accuracy.

Production capacity: Large work envelope for machining multiple parts or assemblies efficiently
Quality control: In-process monitoring and batch traceability for consistent part quality and material properties
Colours & finishes: Natural white or black stock; deburring, polishing and threading

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Frequently Asked Questions

Frequently asked questions about Delrin (Acetal)

Can't find the answer you're looking for? Reach out to our customer support team.

: Delrin combines outstanding dimensional stability and wear resistance with low friction for smooth motion components, and it machines easily with crisp edges and smooth surfaces. Natural Delrin 150 stock has a tensile strength at yield of 76 MPa, a flexural modulus of 2900 MPa and a dynamic coefficient of friction of 0.20 against steel, the basis for gears, bushings, fixtures and other parts that slide or turn.
: Forge Labs machines Delrin from extruded acetal rod and plate rather than 3D printing it. Parts up to 1000 × 600 × 500 mm are held to ±0.050 mm typical and ship in 5-7 business days, with deburring, polishing and threading available. If you need a 3D printed part for wear or snap-fit features, SLS Nylon PA12 is the closest alternative.
: Delrin is used across automation, industrial equipment, consumer products and medical equipment for precision gears and motion components, wear-resistant bushings and pulleys, soft jaws and protective fixtures, fluid handling manifolds and valve bodies, and non-implant fixtures and mechanism parts.
: Delrin offers low friction and wear resistance without lubrication and machines easily with crisp edges and smooth surfaces. Its fatigue resistance suits repetitive motion parts, with a flexural fatigue endurance limit of 32 MPa at a million cycles in Delrin's moulded-resin tests. It absorbs only 0.25% water in 24 hours, so machined parts stay dimensionally stable, and natural stock is listed by its supplier for food contact and drinking-water components.
: Delrin is not recommended for long-term use above 85 °C, although it handles intermittent exposure to 149 °C. Chlorine at 3 to 5 ppm and above, strong acids, strong bases and oxidizing agents attack it, and Delrin does not recommend it outside pH 4 to 9. Large-diameter rod and thick plate can have a low-density centre, so critical features are best kept away from the core of large sections. It is rated UL 94 HB rather than flame retardant.
: Natural Delrin 150 stock is rated for 85 °C long-term service under UL 746B and 149 °C for intermittent exposure. It deflects at 125 °C under a 1.8 MPa load and melts at 175 °C, and Delrin reports extremely high fatigue resistance from −40 to 82 °C.
: Natural Delrin 150 rod and plate is listed by its stock supplier to FDA 21 CFR 177.2480 for food contact and to NSF/ANSI 51 and 61 for food equipment and drinking-water system components. The listings cover natural stock; black and coloured stock need their own supplier documentation, so ask us for the stock documentation for your application.

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