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Important Disclaimer: This Is Educational Content, Not Legal or Regulatory Advice.

If your application requires FDA or medical compliance, do not rely on this guide as your sole verification — always confirm with your quality and regulatory teams. FDA compliance for food-contact and medical materials requires verification against specific regulations, grade data sheets, and — for regulated medical devices — FDA submissions or notified body review. This guide explains how acetal fits into common compliance frameworks. Always verify with your material supplier, quality team, and regulatory affairs before using any material in a regulated application.

Section 1 of 5

FDA 21 CFR 177.2470: The Governing Regulation

If your acetal part contacts food during processing, this is the regulation you need to satisfy — and the one your customer's QA team will reference. FDA 21 CFR Part 177 governs indirect food additives — materials that contact food during processing, storage, or packaging but aren't intentionally added to it. Subpart 177.2470 covers polyacetal resins specifically.

What the FDA Regulations Cover

  • 21 CFR 177.2470 permits POM-C (copolymer) resins for food contact; 21 CFR 177.2480 permits POM-H (homopolymer) — separate regulations for each
  • Each specifies base resin purity, allowable additive types, and extractable limits
  • Covers all food types and contact conditions up to 121°C (250°F)
  • Applies to finished parts machined from compliant resin stock
  • Always cite the correct regulation for the grade used: 177.2470 for POM-C, 177.2480 for POM-H

What 21 CFR 177.2470 Does NOT Cover

  • Pigments and colorants — governed separately by 21 CFR 178.3297 (colorants for polymers), not by the base-resin regulation
  • Non-compliant additives (e.g., some lubricants or stabilizers used in non-food grades)
  • Parts that contact food at temperatures above 120°C — POM degrades near its melt point
  • Parts requiring direct human body implantation — different regulatory pathway required
  • Specific lot or batch compliance — requires certificate of conformance from material supplier
Section 2 of 5

Color and Grade Selection for Food/Medical

When you specify acetal color on a food-contact drawing, that choice directly determines whether your part passes or fails a compliance audit. Color is not cosmetic in regulated applications — it determines which grades are compliant.

Color / GradeFDA 21 CFR 177.2470USP Class VI (select)Notes
Natural / white (unfilled POM-H)Compliant — standard gradeAvailable in certified lotsDefault for all food and medical contact applications
Natural / ivory (unfilled POM-C)Compliant — standard gradeAvailable in certified lotsSame compliance as POM-H natural; use POM-C for thick sections
Black (standard carbon black)Not reliably compliantNot typically certifiedStandard black uses non-food-grade carbon black — avoid for food contact
Black (FDA-compliant grade)Compliant if certifiedAvailable (verify)Specifically formulated with FDA-permitted black pigment — requires compliance cert from supplier
PTFE-filled natural (AF grade)Verify with supplierCheck specific gradePTFE filler is generally inert — but verify the specific AF grade meets 21 CFR 177.2470
Glass-filled acetalGenerally not compliantNot typically certifiedGlass fiber grades typically not formulated for food contact; use unfilled for food applications
Colored (blue, red, etc.)Verify each colorantRarely availableRequire colorant-by-colorant compliance per 21 CFR 178.3297 — not practical for most applications
Section 3 of 5

Relevant Standards and Certifications

Multiple standards may apply depending on whether your application is food processing, medical device, or pharmaceutical.

FDA 21 CFR 177.2470 / 177.2480

Food Contact — USA

Governs acetal resins for indirect food contact. 177.2470 covers POM-C (copolymer); 177.2480 covers POM-H (homopolymer). Require supplier compliance certificate citing the correct section for the specific resin grade and lot.

Typical applications: Food processing equipment, beverage dispensing, conveyor components, food packaging machinery

EU Regulation 10/2011

Food Contact — Europe

EU equivalent to FDA 21 CFR for plastic materials in food contact. POM is listed as permitted polymer. Requires overall migration test results and specific migration limits for listed monomers/additives.

Typical applications: Food contact products sold in European markets

USP Class VI

Biocompatibility — Medical

US Pharmacopeia biological testing protocol evaluating systemic, intracutaneous, and implantation toxicity. Acetal grades certified to USP Class VI have passed these in vivo tests. Required for many medical device components contacting bodily fluids or tissues.

Typical applications: Medical devices, fluid handling components, diagnostic equipment housings

ISO 10993

Biocompatibility — Medical Devices

International standard series for biological evaluation of medical devices. More comprehensive than USP Class VI. Specific tests depend on device classification and intended use (duration and type of body contact). Acetal can be evaluated under ISO 10993 with appropriate testing program.

Typical applications: Regulated medical devices requiring 510(k) or CE mark

FDA-Grade Acetal Parts — Natural Color, Verified Grade

MakerStage machines natural-color acetal (POM-H and POM-C) for food processing and medical device applications. Upload your CAD file and specify your compliance requirements — free DFM review on every order.

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Section 4 of 5

Sterilization Compatibility

If your acetal part requires sterilization, choosing the wrong method will warp precision features and scrap the part. Sterilization method selection is critical — the wrong method destroys precision acetal parts.

Sterilization MethodTemperatureAcetal CompatibilityNotes
Steam autoclave (121°C, 15 psi)121°C (250°F)⚠ Limited cycles onlyExceeds continuous service temp (90–100°C). Some POM-C grades survive limited cycles, but creep and dimensional change occur — not suitable for tight-tolerance parts
Steam autoclave (134°C)134°C (273°F)✗ Not compatibleSevere degradation — POM melts and deforms; use PEEK for autoclavable parts
Ethylene oxide (EtO)37–60°C✓ CompatibleStandard sterilization for acetal medical components; no dimensional impact at these temperatures
Radiation (gamma, e-beam)Room temperature⚠ With cautionHigh-dose gamma (> 25 kGy) can cause chain scission and embrittlement in POM; verify with specific dose and grade
Chemical disinfection (IPA, glutaraldehyde)Room temperature✓ Compatible (most)Verify against acetal chemical resistance chart — avoid bleach and strong oxidizers
Dry heat sterilization (160°C)160°C✗ Not compatibleFar above POM service temperature; severe degradation
UV disinfectionRoom temperature✓ CompatibleUV does not affect material properties at room temperature; ensures surface disinfection only
Section 5 of 5

Design Rules for Food and Medical Acetal Parts

Your part geometry matters as much as your material choice — blind holes, sharp corners, and poor drainage create contamination traps that fail sanitary inspections. Physical design affects cleanability and contamination risk as much as material selection.

Cleanability Design

  • No blind bores or blind pockets where food particles can accumulate
  • Minimum radii 1/16 in. (1.6 mm) on all internal corners — no sharp internal corners
  • Avoid horizontal facing flat surfaces that collect standing water
  • Drainage: ensure all surfaces drain fully; avoid pools at joints
  • Avoid threaded blind holes in food zones — threading is a contamination trap

Surface Finish

  • Food contact surfaces: Ra 32–63 µin (0.8–1.6 µm) as-machined
  • Smoother finishes (Ra < 32 µin (< 0.8 µm)) do not provide additional safety benefit and increase cost
  • No painted, coated, or plated surfaces in food contact zones — coatings can chip
  • Engrave part number / lot traceability on non-food-contact surface only
  • Anodize and conversion coatings not applicable to acetal

Material Specification

  • Drawing callout: "Acetal Homopolymer (POM-H) per ASTM D6100, natural color, FDA 21 CFR 177.2480 compliant" (D6100 covers finished extruded / compression-molded shapes; reserve D6778 for raw resin classifications)
  • Request material compliance certificate (CoC) from machine shop supplier
  • Request heat/lot traceability if required by your QMS
  • Specify "Natural color only" explicitly — prevent accidental substitution with colored or filled grade

Assembly and Fasteners

  • Fasteners in food zones: 316L stainless steel only
  • Thread-locking compounds (Loctite, etc.) in food zones: FDA-grade formulations only
  • No aluminum fasteners — aluminum corrodes and can contaminate food streams
  • Brass bushings or inserts: not for food contact zones — copper content not FDA-listed

Procurement Checklist: What to Request from Your Supplier

If you're sourcing FDA-grade acetal parts, include these line items on your PO or RFQ to avoid compliance gaps at incoming inspection.

  1. 1Material certificate of conformance (CoC) citing the applicable FDA regulation — 21 CFR 177.2470 for POM-C or 21 CFR 177.2480 for POM-H — for the specific resin lot used
  2. 2Material test report (MTR) or mill cert with resin grade, lot number, and manufacturer
  3. 3Specify "Natural color (white/ivory) acetal only" on the PO — prevent substitution with pigmented grades
  4. 4If USP Class VI is required: request copy of biocompatibility test report from resin manufacturer (not the machine shop)
  5. 5Drawing callout: "Acetal Homopolymer (POM-H) per ASTM D6100, natural color, FDA 21 CFR 177.2480 compliant"
  6. 6Lot traceability requirement: supplier must record which resin lot was used for each production run
  7. 7If black acetal is required: request supplier-specific FDA compliance letter for the exact black grade — do not assume compliance

Further Reading

Common Questions

Frequently Asked Questions

Is acetal (Delrin / POM) food safe?
Natural (white/ivory) acetal is compliant for food contact: copolymer (POM-C) under FDA 21 CFR 177.2470, and homopolymer (POM-H) under FDA 21 CFR 177.2480. These regulations cover polyoxymethylene resins in contact with food. The key qualification: only natural-color grades are reliably FDA-compliant. Black and colored acetal grades use pigments and additives that may not be compliant — always verify the specific grade with the material supplier and request a compliance certificate for regulated applications.
What FDA regulation covers acetal for food contact?
Two FDA regulations apply: 21 CFR 177.2470 covers POM-C (copolymer) and 21 CFR 177.2480 covers POM-H (homopolymer). Each permits the respective acetal resin for food contact applications subject to specified extractable limits — the maximum amount of substances the resin can release into food under test conditions. Both regulations require the resin to meet specified purity standards and not impart substances to food above permitted thresholds. Natural acetal rod and plate stock from major producers (Celanese Delrin for POM-H, BASF Ultraform for POM-C) is typically produced to comply with the applicable standard.
Can acetal be autoclaved for medical sterilization?
Not recommended for precision parts. Standard acetal (POM) has a continuous service temperature of 90–100°C, and autoclave conditions (121–134°C) exceed this threshold. Some POM-C copolymer grades can survive limited autoclave cycles at 121°C without catastrophic failure, but dimensional creep and tolerance loss occur — unacceptable for tight-tolerance CNC parts. For parts requiring repeated autoclave sterilization, PEEK is the standard alternative. Acetal can be sterilized with ethylene oxide (EtO) at temperatures below 60°C, or with cold chemical disinfectants, without dimensional compromise.
What does USP Class VI mean for acetal?
USP Class VI (United States Pharmacopeia Biological Test Class VI) is a biocompatibility testing standard that evaluates materials for systemic injection, intracutaneous injection, and implantation toxicity. Acetal grades tested and certified to USP Class VI have passed these biological safety tests. USP Class VI acetal is required for medical devices that contact bodily fluids. Not all acetal grades are tested — verify the specific grade has a USP Class VI certificate from the manufacturer.
Is black acetal food safe?
Not reliably. Black acetal typically uses carbon black pigment, which must comply separately under 21 CFR 178.3297 (colorants for polymers) — the base-resin regulations (177.2470 for POM-C, 177.2480 for POM-H) do not cover pigments. Some black acetal grades are formulated with FDA-compliant black pigments — but this must be verified with a specific compliance letter from the material supplier. For any food-contact application, natural (white/ivory) acetal is the safe default unless a specific FDA-compliant black grade certificate is in hand.

Related Resources

Acetal / POM Guide
Complete material guide with all properties
Acetal vs. PEEK
When PEEK is needed for autoclave sterilization
CNC Machining Acetal
Speeds, feeds, and cleanability design rules

FDA-Grade Acetal Parts with Material Traceability

CNC machining in natural-color acetal (POM-H, POM-C) for food processing and medical device applications. Material certificates available. Free DFM review on every order.

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