Our Polyoxymethylene POM Injection Molding Services

Elevate your high-performance production with Yigu Technology’s premium Polyoxymethylene (POM) Injection Molding services—where precision meets durability. Leveraging our injection molding expertise, advanced machinery, and custom tooling, we deliver POM parts that excel in low friction, high stiffness, and dimensional stability—perfect for automotive, industrial, electronics, and consumer applications demanding reliable, long-lasting components.​

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What Is Polyoxymethylene (POM) Injection Molding?

Polyoxymethylene (POM), commonly known as acetal resin, is a high-performance engineering thermoplastic renowned for its exceptional mechanical properties and low friction. Derived from formaldehyde monomers (either homopolymers or copolymers), POM’s linear molecular structure gives it a unique combination of strength, stiffness, and wear resistance that mimics metal. Injection molding is a manufacturing process that melts POM pellets, injects the molten material into a custom mold cavity, cools it to solidify, and ejects the finished part. Together, POM injection molding produces robust, precision-engineered components ideal for moving parts, gears, and other applications where low friction and dimensional consistency are critical.​

Key Definitions & Core Concepts​

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Material Properties of POM​

POM’s unique properties set it apart as a top choice for engineering applications, often replacing metal (e.g., brass, steel) to reduce weight and cost:​

• High Strength: Tensile strength of 60–70 MPa (POM homopolymer: 70 MPa; copolymer: 60 MPa)—stronger than ABS (40 MPa) and comparable to some metals.​

• Low Friction: Coefficient of friction (0.15–0.30) similar to Teflon but with higher wear resistance—ideal for parts that slide or rotate.​

• High Stiffness: Flexural modulus of 2.5–3.5 GPa—retains shape under load (critical for structural parts like gears or hinges).​

• Dimensional Stability: Low coefficient of thermal expansion (CTE: 8–12 × 10⁻⁵/°C) and minimal moisture absorption (0.2–0.5%)—ensures parts fit consistently in tight assemblies.​

Chemical Resistance: Resistant to oils, greases, solvents, and most household chemicals (except strong acids/bases like nitric acid).

Our Capabilities: Delivering High-Performance POM Injection Molding

At Yigu Technology, we specialize in POM injection molding—our capabilities are tailored to handle POM’s unique processing challenges (moisture sensitivity, high crystallinity) and deliver parts that meet the strictest industry standards (e.g., ISO 9001 for automotive, FDA for medical devices).​

Core Capabilities Breakdown​

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The POM Injection Molding Process: Step-by-Step Precision

POM’s unique characteristics—high crystallinity, moisture sensitivity, and fast cooling rate—require a specialized, optimized process to maintain strength, low friction, and dimensional stability. Our workflow minimizes defects and maximizes performance, whether you’re producing 50 gear prototypes or 500,000 automotive hinges.​

Step 1: Material Preparation (Critical for POM)​

POM absorbs moisture rapidly (up to 0.5% in 24 hours at 50% humidity), which causes hydrolytic degradation (cracking, brittleness, or reduced strength) during molding. Our preparation process eliminates this risk:​

• Drying: POM pellets are dried in dehumidifying dryers at 80–100°C for 3–4 hours (homopolymer: 90°C/4hrs; copolymer: 80°C/3hrs) to reduce moisture content to <0.05%.​

• Additive/Filler Blending: Mix dried pellets with additives (UV stabilizers for outdoor use, lubricants to enhance low friction) or fillers (glass fiber for extra strength, carbon fiber for conductivity—note: fillers increase stiffness but may reduce friction performance).​

• Storage: Dried pellets are stored in sealed, heated hoppers (50–60°C) to prevent reabsorbing moisture before molding.​

Step 2: Mold Design (Optimized for POM)​

POM’s high crystallinity (60–80%) and fast cooling rate cause significant shrinkage (1.5–3.0%)—mold design must account for this to avoid warping or dimensional errors:​

• Shrinkage Compensation: Molds are sized 1.5–3.0% larger than the final part (homopolymer: 2.5–3.0% shrinkage; copolymer: 1.5–2.0%).​

• Cooling Systems: Uniform water-cooling channels (spaced 15–25mm apart) to prevent uneven cooling (which causes warping); mold temperature maintained at 40–80°C (higher temp = slower cooling = reduced internal stress).​

• Part Design Support: We advise on adding draft angles (1–2°) and fillets (0.5–1mm) to POM parts—prevents cracking during ejection and improves mold filling.​

Step 3: Injection Parameters (Tailored to POM Grades)​

POM’s narrow melting range (160–180°C for copolymer; 175–185°C for homopolymer) requires precise parameter tuning to avoid degradation (yellowing) or incomplete filling. Below are standard settings for two common grades:​

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Step 4: Post-Molding Operations​

After demolding, POM parts may undergo:​

• Trimming: Removing excess plastic (flash) with sharp, low-friction tools (to avoid scratching POM’s surface—critical for low-friction parts like bearings).​

• Annealing: Heating parts to 120–140°C for 1–2 hours, then cooling slowly (10–15°C/hour) to reduce internal stress (prevents cracking in high-stress applications like automotive gears).​

• Surface Treatment: Applying coatings, texturing, or printing (see Section 5 for details).​

• Inspection: QC checks for:​

• Dimensional Accuracy: Laser measurement (±0.002mm tolerance) to ensure parts fit in assemblies.​

• Friction Performance: Taber abrasion testing (wear rate: <10 mg/1,000 cycles for general-purpose POM).​

Strength: Tensile testing (ASTM D638) to verify strength meets specs (≥60 MPa for copolymer).

Materials: Choosing the Right POM Grade for Your Project

Not all POM is the same—each grade (homopolymer, copolymer, reinforced) is tailored to specific applications, balancing strength, flexibility, and cost. Selecting the right grade ensures your parts meet performance, regulatory, and design goals.​

Common POM Types for Injection Molding​

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Material Selection Tips​

1. Prioritize strength vs. flexibility: For high-stress moving parts (gears), choose POM homopolymer; for parts prone to impact (door hinges), pick copolymer.​

2. Consider environmental exposure: For outdoor use, select UV-stabilized POM; for chemical-rich environments (industrial machinery), use standard copolymer (better chemical resistance than homopolymer).​

Embrace sustainability: Our rPOM is ideal for brands focused on eco-friendly practices—use it for non-critical parts (e.g., toy gears) to cut costs and reduce environmental impact.

Surface Treatment: Enhancing POM’s Function & Aesthetics

POM’s natural surface is smooth (supports its low-friction properties) but can be modified to improve grip, durability, or branding—without compromising its core performance. We offer five core treatments tailored to POM:​

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Advantages: Why Choose POM Injection Molding?

POM injection molding offers unmatched benefits for engineering applications requiring a blend of strength, low friction, and dimensional stability—often replacing metal to reduce weight, cost, and maintenance.​

Key Advantages of POM Injection Molding​

• High Strength & Stiffness: Stronger than most plastics (ABS, PP) and comparable to brass (tensile strength: 60–70 MPa vs. brass’s 70–80 MPa)—ideal for structural parts that replace metal.​

• Low Friction & Wear Resistance: Coefficient of friction (0.15–0.30) and wear rate ( <10 mg/1,000 cycles) make POM parts last 3–5x longer than ABS or PP in moving applications (e.g., gears).​

• Dimensional Stability: Minimal moisture absorption (0.2–0.5%) and low thermal expansion (8–12 × 10⁻⁵/°C)—ensures parts fit consistently in tight assemblies (e.g., electronic connectors, automotive sensors).​

• Cost-Effectiveness: Cheaper than metal (POM: ​3.50–5.00/kg vs. brass: ​8.00–12.00/kg) and requires less post-processing (no machining like metal parts); injection molding drives unit costs down to ​0.15–0.80 per part.​

• Chemical Resistance: Resists oils, greases, and solvents—ideal for parts exposed to harsh fluids (e.g., automotive engine components, industrial machinery).​

POM vs. Other Engineering Plastics & Metal​

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Applications Industry: Where POM Injection Molding Excels

POM’s unique blend of low friction, high strength, and dimensional stability makes it indispensable in engineering-focused industries—often replacing metal to cut costs and weight while maintaining performance. Below are real-world use cases and our tailored solutions:​

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Case Studies: Our POM Injection Molding Success Stories

We’ve helped clients across industries solve complex challenges with POM injection molding—delivering parts that replace metal, reduce maintenance, and improve performance. Below are three standout projects:​

Case Study 1: POM Copolymer Automotive Door Hinges​

• Challenge: A leading automaker needed 500,000 door hinges that were lightweight (to improve fuel efficiency), impact-resistant (to withstand 100,000+ door openings), and cost-effective (to replace brass hinges). Their previous brass hinges were heavy (adding 0.5kg per car) and prone to rust.​

• Solution: We recommended POM copolymer for its balance of flexibility (impact resistance: 10 kJ/m²) and strength. Our custom molds included shrinkage compensation (2.0% for copolymer) and uniform cooling channels to prevent warping. We added a minor texturing to the hinge surfaces to reduce friction and improve wear resistance.​

• Results: The POM hinges were 60% lighter than brass (reducing per-car weight by 0.3kg and improving fuel efficiency by 1.5%) and cost 40% less. They passed 150,000 door-opening tests with no cracks or deformation, and showed no signs of wear after 3 years of real-world use. The automaker expanded their order to 1 million hinges/year for all their sedan models.​

Case Study 2: POM Homopolymer Industrial Conveyor Gears​

• Challenge: A logistics company needed 10,000 conveyor gears that could withstand 24/7 operation, resist lubricating oil, and have low friction (to reduce energy use). Their previous ABS gears failed after 3 months due to high wear and poor oil resistance.​

• Solution: We used POM homopolymer for its exceptional wear resistance (Taber wear rate: <5 mg/1,000 cycles) and oil resistance. Our molds were polished to Ra 0.1 μm (to enhance low-friction properties) and included optimized gating to ensure full filling of the gear teeth. Post-molding, we annealed the gears at 130°C for 1 hour to reduce internal stress.​

• Results: The POM homopolymer gears lasted 18 months (6x longer than ABS) and reduced conveyor energy use by 8% (due to lower friction). They showed no swelling or degradation after 12 months of exposure to lubricating oil, and the client now uses our POM gears for all their global conveyor systems—saving $200,000/year in replacement costs.​

Case Study 3: FDA-Compliant POM Copolymer Syringe Plungers​

• Challenge: A medical device company needed 200,000 syringe plungers that were biocompatible (meets ISO 10993), smooth (to ensure precise fluid control), and sterilizable (via autoclaving). Their previous PP plungers were too flexible, causing inconsistent fluid delivery.​

• Solution: We selected FDA-compliant POM copolymer (meets USP Class VI standards) for its stiffness (flexural modulus: 2.8 GPa) and smooth surface. Our molds had mirror-polished cavities (Ra 0.05 μm) to ensure plunger smoothness, and we optimized injection parameters (170°C barrel temp, 90 MPa pressure) to avoid surface defects. Post-molding, we performed 100% dimensional checks (±0.002mm tolerance) to ensure consistent fit in syringes.​

Results: The POM plungers provided 30% more precise fluid control than PP (per clinical tests) and passed 50+ autoclave cycles (121°C) with no warping. They met all ISO 10993 biocompatibility standards, and the client expanded our partnership to produce plungers for their entire line of insulin and vaccine syringes.

Why Choose Us for Your POM Injection Molding Needs?

With countless injection molding suppliers offering POM services, Yigu Technology stands out for our deep specialization in POM, uncompromising quality, and ability to solve engineering challenges. Here’s why leading brands in automotive, industrial, and medical sectors trust us:​

1. Specialized POM Expertise​

We don’t just mold plastics—we specialize in Polyoxymethylene (POM). Our engineers have 15+ years of experience optimizing processes for POM’s unique traits:​

• Moisture sensitivity: Proprietary drying protocols (to <0.05% moisture) that eliminate cracking and brittleness.​

• Shrinkage control: Mold design techniques (shrinkage compensation, uniform cooling) that ensure dimensional accuracy (±0.002mm).​

• Low-friction optimization: Mold polishing (Ra 0.1–0.2 μm) and coating solutions that enhance POM’s natural low-friction properties.​

We’ve worked with every POM grade (homopolymer, copolymer, glass-filled, recycled) and know how to tailor solutions for metal replacement, high-wear, or precision applications.​

2. Rigorous Quality Assurance​

Quality is critical for POM parts—especially those replacing metal or used in safety-critical applications. We hold ISO 9001 (general manufacturing) and ISO 13485 (medical device manufacturing) certifications, with a 99.6% defect-free rate for POM components. Our quality checks include:​

• Pre-molding: Moisture testing (Karl Fischer titration) to ensure POM pellets are dry (<0.05%).​

• In-molding: Real-time laser measurement for dimensional accuracy and vision inspection for surface defects (scratches, flash).​

• Post-molding:​

• Wear testing (Taber abrasion) for moving parts (gears, bearings).​

• Tensile testing (ASTM D638) to verify strength (≥60 MPa for copolymer).​

• Regulatory compliance (FDA 21 CFR 177.2470 for food/medical POM; UL94 V0 for flame-retardant POM).​

3. Customer-Focused Service​

We treat your project as a partnership—our goal is to solve your problems, not just deliver parts. From day one, you’ll work with a dedicated account manager who:​

• Provides free material/design consultations (e.g., helping you choose between POM homopolymer and copolymer for metal replacement).​

• Shares 3D mold designs and sample parts (within 4 days) for approval before full production.​

• Offers flexible lead times: 3–5 days for prototypes (aluminum molds), 2–4 weeks for high-volume runs (steel molds).​

• Provides 24/7 support for urgent issues (e.g., expediting parts for broken industrial machinery).​

4. Innovative Solutions​

We invest 7% of our annual revenue in R&D to push the boundaries of POM injection molding. Recent innovations include:​

• Metal-Replacement POM Blends: A proprietary mix of POM homopolymer and glass fiber (POM-GF15) that matches 90% of brass’s strength at 50% the weight and cost.​

• Self-Lubricating POM: POM grades infused with solid lubricants (PTFE particles) that reduce friction by 30% vs. standard POM—ideal for oil-free applications (e.g., food-processing machinery).​

• Fast-Cycle Molding: Custom cooling systems that cut POM cycle time by 20% (from 25s to 20s) without compromising quality—speeding up production for high-volume orders.​

5. Sustainable Practices​

We’re committed to reducing our environmental impact while delivering top-tier POM parts:​

• Recycled POM (rPOM): We source 40% of our POM materials from post-industrial waste (e.g., POM scrap from automotive manufacturing) and offer rPOM grades that cost 15–25% less than virgin POM.​

• Waste Reduction: We recycle 96% of production scrap (flash, defective parts) back into the molding process—sending only 4% to landfills.​

Energy Efficiency: Our injection molding machines use variable-frequency drives (VFDs) to reduce energy consumption by 22% vs. standard equipment—lowering our carbon footprint and your costs.

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