Trouble Shooting
1. Parts Sticking
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Adjust Temperature | 1. Purge and wax clean all mold surfaces | 1. Use shorter flow |
| 2. Increase cure cycle |
2. Weak Parts
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Increase cure time | 1. Adjust height of ejector pins for even ejection | 1. Use stiffer flow |
| 2. Increase temperature | 2. Use longer glass fiber |
3. Thick or Excessive Flash
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Decrease injection pressure | 1. Adjust for proper closure | 1. Use shorter flow |
| 2. Increase clamp pressure |
4. Short Fill
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Add more material | 1. Repair worn screw | 1. Use longer flow |
| 2. Increase injection pressure | 2. Slower cure |
5. Sink Marks
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Adjust temperature | 1. Purge and wax clean all mold surfaces | 1. Use shorter flow |
| 2. Increase cure cycle |
6. Porous Parts or Trapped Gas
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Decrease injection speed | 1. Enlarge gate | 1. Use stiffer flow |
| 2. Add more material | 2. Add venting | |
| 3. Increase barrel temperature | 3. Increase barrel temperature | |
| 4. Lower back pressure | ||
| 5. Adjust molding temperature |
7. Knit Lines and White Marks
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Decrease molding temperature | 1. Move gate position | 1. Use softer flow |
| 2. Increase injection pressure | 2. Enlarge vent |
8. Low Gloss
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Increase temperature | 1. Add vents | 1. Use different flow |
| 2. Increase cure cycle | 2. Enlarge gates | |
| 3. Decrease back pressure | ||
| 4. Decrease injection speed |
9. Blisters
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Adjust temperature | 1. Polish or clean mold surfaces | 1. Use softer flow |
| 2. Increase cure cycle |
10. Distorted Parts (warpage)
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Adjust for even molding temperature | 1. Use cooling jig | 1. Use stiffer flow |
| 2. Increase cure cycle | 2. Adjust for even ejection | |
| 3. Increase injection pressure | 3. Enlarge gate or runner |
11. Precure in Nozzle or Barrel
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Decrease barrel/nozzle temperature | 1. Repair screw | 1. Use different flow |
| 2. Increase holding time | 2. Reduce screw clearance or increase nozzle size | 2. Use slower cure |
| 3. Decrease back pressure | 3. Enlarge runner |
12. Sprue Sticking
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Increase mold temperature | 1. Repair nozzle | 1. Add more lubricant |
| 2. Decrease injection pressure | 2. Increase nozzle taper | |
| 3. Increase cure cycle | 3. Polish sprue bushing |
13. Mold Staining
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Adjust molding temperature | 1. Increase venting | 1. Use different flow |
| 2. Decrease back pressure | 2. Polish sprue bushing | |
| 3. Increase cure time |
14. Screw Will Not Bottom
| Molding Conditions | Tooling | Material |
|---|---|---|
| 1. Adjust barrel temperature | 1. Use smaller screw | 1. Use different flow |
| 2. Use less feed | 2. Repair worn screw | |
| 3. Increase holding time | 3. Tighten clearance |