🧩 POM – Polyoxymethylene (Acetal / Polyacetal)
(A semi-crystalline engineering material, very hard and wear-resistant, also known as Acetal or Delrin®. It offers low friction, excellent rigidity, and dimensional stability, used in mechanical parts, hinges, gears, and automotive fasteners.)
🔹 What is POM
POM (Polyoxymethylene) is a formaldehyde polymer produced in two forms: POM-H (homopolymer) and POM-C (copolymer). It is often called “plastic metal” due to its high hardness and precise dimensional stability. It is the ideal choice for parts that move, rotate, or slide—especially in locking mechanisms, clips, bearings, and precision interior components.
🔧 Composition & Properties
- Monomer units: Polymerized formaldehyde (–CH₂O–).
- Density: 1.40–1.43 g/cm³.
- Melting Point: ≈ 165–175 °C.
- Chemical Resistance: Excellent (oils, solvents, fuels).
- Continuous Heat Resistance: 100–110 °C.
🚗 Where POM is used in the automotive industry
| Component | Example parts | Observations |
| Moving Mechanisms | Gears, bearings, shafts | Low friction, precise movement |
| Fasteners / Clips | Clips, hinges, latches | Elasticity and mechanical strength |
| Technical Housings | Covers, supports | Rigidity and dimensional stability |
| Interior Systems | Sliding parts, controls | Smooth finish, no external lubrication |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 250 – 270 °C | Fast melting, precise control required |
| Plastic Extrusion | 240 – 260 °C | For thick and technical parts |
| Heat Plate (Mirror) | 240 – 260 °C | Clean bond, no carbonization |
🔩 Material Compatibility
- ✅ Compatible: POM-H to POM-H, POM-C to POM-C.
- ❌ Incompatible: PA, PP, PE, PS, ABS, PC, PVC (completely different melting points).
💡 ReplastMD Recommendation: Use original POM rods (Delrin / Hostaform) at 260 °C. Clean the surface thoroughly as POM oxidizes easily when overheated. Avoid direct flame—it decomposes and releases formaldehyde gas.
🧠 How to Identify POM
- Engraved marking: >POM<, >ACETAL<, >DELRIN<, >HOSTAFORM<.
- Texture: Glossy, rigid, dense, with a “cold” feel.
- Color: White, black, or metallic grey.
- ReplastMD practical test: Burns with a blue flame and a strong, sharp formaldehyde scent. Softens at ≈ 170 °C without bubbling.
🛠️ POM Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional POM / Acetal welding for gears, bearings, and sliding mechanisms, ensuring a low-friction, industrial-grade finish.