| EJECTION PROBLEMS |
|
Parts stick in mold
黏模 |
- Decrease injection pressure
- Decrease injection rate
- Decrease screw forward time
- Increase cycle (possible only temporarily)
- Use mold release temporarily
- Correct mold defects (undercuts)
|
Sprue sticking
澆口堵塞 |
- Remove burrs on sprue
- Correct alignment between sprue and nozzle
- Decrease screw forward time
- Increase nozzle temperature
- Increase mold cooling time
- Use nozzle orifice smaller than sprue bushing
- Increase taper of sprue
- Use mold release temporarily
|
| FILLING PROBLEMS |
|
Short Shots
短料 |
- Maintain uniform pad
- Repair leaking back flow value if pad cannot be maintained
- Increase injection pressure
- Increase injection rate
- Increase melt temperature
- Increase mold temperature
- Enlarge vents
- Change vent location
- Increase overall cycle
- Use screw designed for DELRIN
- Use larger machine or injection unit
|
Voids in parts
孔 |
- Increase injection pressure
- Increase screw forward time
- Decrease injection rate
- Decrease melt temperature; improve melt uniformity
- Repair leaking back flow value if pad cannot be maintained
- Enlarge vents
- Improve gate size or location
- Eliminate any restrictions in runner or nozzle
|
Weak Welds / Welding lines
熔接線 |
- Increase injection pressure
- Increase injection rate
- Increase melt temperature, but avoid excessive temperature
- Increase mold temperature
- Avoid mold release spray
- Enlarge vents
- Change vent or gate location
- Use larger machine or injection unit
|
| MELT QUALITY PROBLEMS |
|
Mold deposit
黏膜 |
- Decrease injection rate
- Decrease melt temperature
- Avoid resin contamination
- Correct hold-up spots in cylinder, screw, nozzle assembly
- Increase gate size, flare gate
- Enlarge vents
- Change vent location
- Use hopper drier to improve reground resin
|
Odor
氣味 |
- Observe melt appearance (gassing) and measure melt temperature
- Reduce cylinder temperatures if melt temperature is high.
- Avoid resin contamination
- Reduce overall cycle to decrease holdup time
- Correct hold-up spots in cylinder, adaptor, nozzle, screw tip and check value assembly
- Use smaller injection unit
|
Un-melted Particles
顆粒未融 |
- Increase cylinder temperature
- Increase back pressure
- Reduce screw RPM
- Use hopper drier to preheat resin
- Increase overall cycle
- Use screw designed for DELRIN
- Use larger machine or injection unit
|
| SURFACE PROBLEMS |
|
Black sports or brown streaks
黑點/條紋
|
- Decrease cycle
- Avoid resin contamination
- Correct hold-up spots in cylinder, screw, nozzle assembly
|
Blush, Frost, and Folds
變色/折疊 |
- Decrease injection rate
- Increase mold temperature
- Change gate location
|
| Gate Smear |
- Increase mold temperature
- Decrease mold temperature
- Change gate location
|
Jetting
擠壓 |
- Increase melt temperature
- Increase or decrease injection rate
- Increase gate size, flare gate
- Change gate location
|
Pits, Orange peel, Wrinkles
傷痕、脫皮、皺摺 |
- Increase injection pressure
- Increase injection rate
- Increase screw forward time
- Increase mold temperature
- Increase melt temperature
- Enlarge vents
- Increase gate size
|
Sinks
下陷 |
- Repair leaking back flow value if pad cannot be maintained
- Increase injection pressure
- Increase screw forward time
- Increase or decrease injection rate
- Decrease mold temperature
- Decrease melt temperature
- Increase gate size
- Change gate location
|
| Splay |
- Decrease melt temperature if it is too high
- Reduce cycle to decrease holdup time
- Avoid resin contamination
- Increase or decrease injection rate
- Correct hold-up spots in cylinder screw, nozzle assembly
- Increase size of small gate
|
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