Enjection problems and troubleshooting (1)

HO Shing Traffic Engineering Co., Ltd.

Enjection problems and troubleshooting (1)

Injection molding problems and Troubleshooting (1)

Short shot 產品未完成

 

Short shot occurs when insufficient material is enjected and can't completely fill cavities.

Short shot can be caused by machine, mold or material.

當射出的材料不足且無法完全填充型腔時,就會出現短射。短射可能是由機器、

模具或材料造成的。

Possible Cause

Correction action

Melt temperature too slow
原料溫度過低

Adjust melt temperature upward 提高料管溫度

Insufficient feed
塑膠原料不足

Increase shot size 增加原料用量

Short injection time
射出時間過短

Increase injection time 增長射出時間

Injection speed too slow
射出速度太慢

increase speed 加快射出速度

Low mold temperature
模具溫度過低

Increase mold temperature 增高模具溫度

Non-uniform cooling
模具溫度不均

Check water throughtput and line layout 重整模具水管

Poor venting in the mold
模具排氣不良

Adjust proper vent position or add vents 調整合適位置或加適度之排氣孔

Clogged nozzle
射嘴阻塞

Clean the nozzles 清洗阻塞

Feed material unbalanced
進膠不均勻

Redesign correct gates position 重開模具溢口位置

Gate or spill hole too small
澆口或溢口太小

Increase gate diameter 加大澆口或溢口

Inadequate lubricant for plastic
原料內潤滑劑不夠

Increase lubricant in material 酌加潤滑劑

Poor melt plastic flow
塑膠原料流動性不良

Add lubricant or change plastic 酌加潤滑劑或更換使用原料

Damage on check ring
螺桿止逆環(過膠圈)磨損

Check and replace 拆除檢查修理

Non correct machine
機器效能不適合

Use proper machine 更換適合的機器

 

.  Shrinkage / 縮水

 

Shrinkage is the contraction of a plastic moulded component

as it begins to cool after the injection process

塑料成型部件開始冷卻後, 會發生收縮. 收縮比率應塑料而異, 設計模具時要考量之。             

Possible Cause

Correction action

Insufficient filling
塑膠原料不足

Increase filling vollume 增加原料用量

Injection pressure too low
射出壓力不足

Raise injection pressures 提高射出壓力

Short injection time

 
射出時間太短

 

Increase injection time 增長射出時間

Injection speed too fast
射出速度太快

Reduce speed 減少射出速度

Unbalanced feeding to gate
溢口不平衡

Adjust gate positions or gate diameter 調整模具入口大小或位置

Clogged nozzle
射嘴阻塞

Clean the nozzles 清洗阻塞

Melt Temperature too high
溫度過高

Reduce temperature 降低溫度

Insufficient cooling
冷卻溫度不夠

Add cooling time 酌延冷卻時間

Poor venting 排氣不良

Add vents on shrinking parts 在縮水處設排氣孔

Injection nozzle too small
料管太小

Replace larger diameter nozzle 更換較大規格料管

Insufficient pressusre holding time
保壓時間不足

Increase holding time 延長保壓時間

Damage on check ring
螺桿止逆環(過膠圈)磨損

Check and replace 拆除檢查修理

Material too soft
材料過軟

Change material 更換原料

Large shrinking rate
收縮率過大

Change material 更換原料

 

.  Parts Sticking  成品黏模

When the mold is opened, the product get stuck to the mold, it cannot fall off 

開模時,產品粘在模具上,不能脫落.                                                                                        

 

Possible Cause

Correction action

Injection pressure too high
射出壓力太高

Reduce injection pressures 降低射出壓力

Over filling
射膠量過多(填料過飽)

Use release agent 使用脫模劑

Pressure holding too long
保壓時間太久

Reduce injection time 減少射出時間

Injection speed too fast
射出速度太快

Reduce injection speed 降低射出速度

Melt material temperature too high
料溫太高

Reduce material melt temperature 降低料溫

Unbalanced filling
進料不均使部分過飽

Adust gate hole diameter or posiiton 變更溢口大小或位置

Insufficient cooling time
冷卻時間不足

Increase cooling time 增加冷卻時間

Mold temperature too high or too low
模溫過高或過低

Adjust mold temperature 調整模溫

Undercuts in the mold
模具內脫模倒角

Eliminate undercuts 修模具除卻倒角

Mold walls not smooth
模具內壁不光滑

Polish mold walls 拋光模具