Delrin Grades — 100, 150, 500, 507, 570 & 100AF Compared

Delrin (POM-H acetal homopolymer) is sold in a structured grade series based on molecular weight class and filler content. Each grade optimizes a different engineering trade-off: Delrin 150 is the extrusion workhorse for stock-shape rod and sheet; Delrin 100 maximizes impact toughness; Delrin 500 is the general-purpose injection molding standard; Delrin 507 adds internal lubrication; Delrin 570 brings glass-fiber reinforcement; and Delrin 100AF incorporates PTFE fiber for maximum tribological performance. This guide covers all grades with selection logic and key property data.

At a glance:

Delrin 150: dominant stock-shape grade — high MW, optimized for extrusion, best surface finish
Delrin 100: highest MW; maximum toughness; used where impact or ductility is critical
Delrin 500: general-purpose; most used injection molding grade; widely available in stock shapes
Delrin 507: internally lubricated; lower CoF, extended wear life for sliding/bearing use
Delrin 570: 20% glass-fiber reinforced; ~14,000 psi tensile; creep-resistant structural use
Delrin 100AF: PTFE/aramid fiber-filled; best-in-class CoF and wear life for bearing applications
Delrin 150SA / 500SA: FDA 21 CFR 177.2480 compliant natural grades

The Delrin Grade System

Delrin's grade numbering reflects the melt flow / molecular weight class:

Lower numbers (100) = higher molecular weight, higher viscosity, slower processing, better toughness
Higher numbers (500, 900) = lower molecular weight, lower viscosity, faster injection molding cycle, somewhat lower toughness

The letter suffix indicates modification: AF = aramid/PTFE fiber, SA = FDA-compliant (sans additifs non-approuvés in the original French DuPont designation), 07 = internal lubricant.

Grade-by-Grade Comparison

Delrin 150 — The Extrusion Grade

Delrin 150 is the grade most engineers encounter in stock shapes (rod, sheet, tube). DuPont engineered it specifically for extrusion: medium-high molecular weight provides the melt viscosity needed for smooth, uniform extrusion into large cross-sections, while still offering excellent post-machining surface finish and dimensional stability.

Key search keyword: "delrin 150" (US search volume ~300/month) — engineers searching this term are almost always looking for stock-shape material, either purchasing or qualifying against a print callout.

Why Machinists Prefer Delrin 150

Delrin 150 produces shorter, cleaner chips than Delrin 100 (which, at higher molecular weight, can produce longer, stringier chips in some cutting geometries). The result is better chip evacuation in drilling and internal threading operations, and fewer re-cut chip marks on finished surfaces. Surface finish on a freshly turned Delrin 150 part at 600 SFM is typically Ra 16–32 µin without any additional finishing operations.

Delrin 150SA

Delrin 150SA is the FDA-compliant version of Delrin 150. "SA" indicates the grade uses only FDA 21 CFR-listed additives and colorants. Delrin 150SA meets 21 CFR 177.2480 for repeated-use food-contact service. It is natural (white) color. For full FDA compliance details, see Delrin FDA food-grade compliance.

Delrin 100 — Maximum Toughness Grade

Delrin 100 has the highest molecular weight of the standard Delrin series. This translates to significantly higher elongation at break (40–75% vs. 25–40% for Delrin 500) and notched Izod impact of ~2.0 ft·lb/in vs. ~1.2 for Delrin 500.

Search keyword: "delrin 100" (~70/month US volume) — typically engineers qualifying a tougher grade than the default 500 for impact-sensitive applications.

When to Use Delrin 100

Parts subject to shock loads or impact (tool bodies, latches, catch mechanisms)
Snap-fit designs where repeated snap-in/out cycling is a design requirement
Large-diameter rod stock where core toughness matters more than surface finish throughput
Applications where ductile fracture mode is preferred over brittle fracture (safety components)

Delrin 100 Processing Trade-offs

Higher molecular weight means higher melt viscosity. In injection molding, Delrin 100 requires longer fill times and higher injection pressures than Delrin 500, limiting its use in thin-wall or complex-geometry molds. In stock shapes (extrusion), this is less of a limitation — extrusion equipment handles the higher viscosity better than injection molds.

Delrin 500 — General-Purpose Grade

Delrin 500 is the baseline commercial grade: the "vanilla" Delrin that appears on data sheets and serves as the reference for most published property values. It is the most widely produced and least expensive standard Delrin grade.

Stock-Shape Availability

Delrin 500 is available in rod, sheet, and tube — though Delrin 150 is preferred for extrusion-critical forms. In machined-parts applications where toughness is not a differentiating factor, Delrin 500 is interchangeable with Delrin 150 in terms of mechanical output.

Delrin 500SA

The FDA-compliant analog of Delrin 500, meeting 21 CFR 177.2480. Used wherever FDA compliance is needed and Delrin 150SA stock is unavailable or the part is injection-molded from pellets rather than machined from stock.

Delrin 507 — Internally Lubricated Grade

Delrin 507 incorporates an internal lubricant system (the specific lubricant is proprietary to DuPont/manufacturer) that lowers the surface coefficient of friction and reduces wear rate in sliding applications — without requiring external oil or grease supply.

Typical coefficient of friction: 0.10–0.20 vs. steel (vs. 0.20–0.35 for unlubricated Delrin 500)

Applications

Sliding drawer mechanisms and guide rails in furniture and office equipment
Gear trains where lubrication access is impractical (sealed enclosures)
Cam followers and wear pads in low-to-moderate PV applications
Worm gear components where tooth sliding velocity creates frictional heating

Trade-offs vs. Standard Delrin

Tensile strength is slightly reduced vs. Delrin 500 (~9,500 psi vs. 10,000 psi) due to the lubricant phase acting as a minor discontinuity. Bonding and adhesive joining are more difficult due to lubricant migration to the surface — if bonding is required in the application, evaluate alternative joining methods or switch to standard Delrin.

Delrin 570 — Glass-Fiber Reinforced Grade

Delrin 570 incorporates approximately 20% glass fiber by weight, raising tensile strength to ~14,000 psi and tensile modulus to ~800,000 psi. Creep resistance at elevated temperatures improves substantially compared to unfilled grades.

Applications for Delrin 570

Structural brackets and frames where unfilled Delrin would creep under sustained load
Pump housings and valve bodies where dimensional stability at elevated temperature is required
High-load bearing surfaces (the glass fiber increases PV limit compared to unfilled)
Automotive brackets and underhood components where temperature cycles above Delrin 500's HDT

Machining Delrin 570

Glass fiber is abrasive. Machining Delrin 570 dulls carbide tooling significantly faster than unfilled grades. Use PCD (polycrystalline diamond) inserts for high-volume turning; maintain higher tool-change frequency with standard carbide. Feed rates should be moderate to prevent glass-fiber delamination at machined surfaces. Detailed parameters in the Delrin machining guide.

Delrin 100AF — PTFE/Aramid Fiber Tribological Grade

Delrin 100AF is the highest-performance tribological grade in the Delrin family. "AF" refers to the aramid/PTFE fiber blend that is compounded into the base resin. The PTFE fiber deposits a thin transfer film on the counterface, dramatically reducing adhesive wear. The aramid fiber reinforces the composite structure.

Tribological Properties of Delrin 100AF

When to Specify Delrin 100AF

High-duty bearing and bushing applications where unfilled Delrin exceeds its PV limit
Thrust washers, flanged bushings, and thrust plates in mechanical assemblies
Conveyor rollers and idler wheels in dry-running service
Snap-fit components that require both good tribological performance and ductile failure mode

Delrin 100AF is not FDA-compliant in standard formulations and is not typically available in white/natural color.

Grade Selection Decision Tree

FDA food-contact required? → Delrin 150SA or 500SA (natural color only)
Maximum bearing/wear performance? → Delrin 100AF
Maximum structural stiffness and creep resistance? → Delrin 570
Need low friction without extreme wear duty? → Delrin 507
Maximum toughness / impact resistance? → Delrin 100
Best surface finish for precision machining from stock? → Delrin 150
General-purpose injection molding? → Delrin 500
Price-sensitive, no special requirements? → Delrin 500 or Delrin 150

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