🧩 POM-H – Polyoxymethylene Homopolymer (Acetal Homopolymer)
(A variant of POM with maximum hardness and rigidity, widely known by the trade name Delrin® (DuPont). POM-H offers superior mechanical strength, low friction coefficient, and precision finish, used in gears, levers, and motion components.)
🔹 What is POM-H
POM-H (acetal homopolymer) is the pure form of polyoxymethylene, resulting in a highly crystalline and dense structure. This provides greater stiffness, fatigue resistance, and tensile strength than POM-C. In automotive applications, POM-H is the go-to material for parts subjected to repeated mechanical stress, such as gears, linkages, door locks, sliders, and precision bearings.
🔧 Composition & Properties
- Base: Pure polymerized formaldehyde (–CH₂O–).
- Density: 1.41–1.43 g/cm³.
- Melting Point: ≈ 175–180 °C.
- Chemical Resistance: Very good (oils, fuels, organic solvents).
- Continuous Heat Resistance: 100–115 °C.
🚗 Where POM-H is used in the automotive industry
| Component | Example parts | Observations |
| Moving Mechanisms | Gears, axles, levers | Excellent dimensional precision |
| Locking Systems | Door locks, rods, clips | Wear and fatigue resistance |
| Technical Housings | Supports, guides | Rigidity and superior finish |
| Interior Parts | Sliding components | Low friction, no external lubrication |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 250 – 270 °C | Fast melting, requires fine control |
| Plastic Extrusion | 240 – 260 °C | Ideal for thick and mechanical parts |
| Heat Plate (Mirror) | 240 – 260 °C | Precise bonding without bubbles |
🔩 Material Compatibility
- ✅ Compatible: POM-H, Delrin®, POM-C, Hostaform®, Ultraform®.
- ❌ Incompatible: PA, PP, PE, PVC, ABS, PC (completely different melting points).
💡 ReplastMD Recommendation: Use original POM-H or Delrin® rods at 260 °C. Surface cleanliness is vital as POM oxidizes quickly at high temperatures. Avoid direct flame—overheating releases formaldehyde gas.
🧠 How to Identify POM-H
- Engraved marking: >POM-H<, >DELRIN<, >TENAC<, >DURACON<.
- Texture: Highly glossy, dense, and very rigid.
- ReplastMD practical test: Clean, crisp edges when cut. Burns with a blue flame and a strong, sharp formaldehyde scent. Softens at ≈ 175 °C.
🛠️ POM-H Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional POM-H / Delrin welding for gears and mechanical linkages, ensuring a high-strength, precise finish.