POM YUNTIANHUA GM90
POM YUNTIANHUA GM90
POM YUNTIANHUA GM90 is medium‑viscosity standard‑flow copolymer acetal with balanced overall performance. It possesses good comprehensive mechanical properties, stable dimension, excellent chemical‑resistance and wear‑resistance, suitable for various general‑purpose mechanical parts.
Main Applications
Automotive: gears, bearings, auto components, machine‑tool & instrument inner skeleton parts, pump parts, valve components, under‑hood parts, automotive electronics and exterior parts. Electrical & electronic: gears, bearings and structural components for home appliances such as washing‑machine & juicer parts, timer assemblies, keyboard & switch parts, as well as electronic connectors. Precision mechanical & industrial parts: gears, bearings, cams, screws, levers, pulleys, sprockets, pipe valves and other high‑precision, wear‑resistant, low‑friction structural components. Consumer & others: toys, sports goods, zippers, lighters, buckles and other daily‑use articles.
Physical Properties
| Property Category | Item | Test Standard | Typical Data | Unit |
|---|---|---|---|---|
| Physical Properties | Density | ISO 1183 | 1.41 | g/cm³ |
| Water absorption (23℃,24h) | ISO 62 | 0.60 | % | |
| MFR (190℃/2.16kg) | ISO 1133 | 9.0 | g/10min | |
| Mechanical Properties | Tensile yield strength (23℃) | ISO 527‑2 | 61‑64 | MPa |
| Elongation at break (23℃) | ISO 527‑2 | 30‑35 | % | |
| Tensile modulus (23℃) | ISO 527‑2 | 2550‑2700 | MPa | |
| Flexural strength (23℃) | ISO 178 | 88 | MPa | |
| Flexural modulus (23℃) | ISO 178 | 2500‑2600 | MPa | |
| Charpy notched impact (23℃) | ISO 179/1eA | 5.5‑6.0 | kJ/m² | |
| Rockwell Hardness (M‑scale) | — | ~80 | — | |
| Thermal Properties | HDT (1.8 MPa) | ISO 75‑2/A | 90‑95 | ℃ |
| Others | UL94 rating | UL94 | HB | — |
Injection Molding Parameters
| Process Stage | Parameter | Recommended Range | Unit | Remarks |
|---|---|---|---|---|
| Pre‑treatment | Drying temperature | 80‑90 | ℃ | Drying recommended for better dimension & appearance, avoid bubbles/silver streaks despite low moisture absorption |
| Drying time | 3‑4 | h | ||
| Injection | Rear zone | 160‑180 | ℃ | Narrow processing window; strictly avoid＞230℃, formaldehyde gas will be generated by decomposition |
| Middle zone | 170‑200 | ℃ | ||
| Front zone | 190‑210 | ℃ | ||
| Nozzle temperature | 180‑210 | ℃ | Slightly lower or close to front zone to prevent drooling | |
| Melt temperature | 190‑210 | ℃ | Typical range for copolymer POM‑C | |
| Mold temperature | 60‑90 | ℃ | Higher mold temp improves crystallization, dimensional stability, gloss & reduces sink marks | |
| Injection pressure | 80‑130 | MPa | Higher value for thin‑wall parts, lower value for thick‑wall parts | |
| Hold‑up pressure | 40‑80 | MPa | Proper hold‑pressure to reduce shrinkage & sink marks | |
| Back pressure | 0.5‑2.0 | MPa | Keep low; excessive back‑pressure causes shear‑heating degradation | |
| Injection speed | Medium | — | Slow speed causes ripple; excessive speed brings jet mark & shear degradation | |
| Screw speed | 50‑100 | rpm | Avoid excessive shear heat leading to material decomposition | |
| Barrel residence time | ＜20‑30 | min | Max 1 h at 190℃ to prevent decomposition | |
| Short‑term shutdown | Drop barrel temp to 150 | ℃ | Purge barrel thoroughly for long‑term shutdown | |
| Barrel purging material | PE / PP | — | Must purge with PE/PP after halogen‑containing polymers to prevent violent reaction | |
| Post‑treatment | Annealing (optional) | 120‑130, 2‑4 | ℃‑h | For high‑quality parts working under non‑ambient condition to release internal stress |
Note: All information above is for reference only!
