Enjection problems and troubleshooting

Enjection problems and troubleshooting (1)

2022.07.19

Injection molding problems and Troubleshooting (1)
一. 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

二. 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

三. 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