In this post I will explain injection molding runner components of mold part. There are 4 main items of runner components: runner lock pin, runner lock pin lock, runner lock pin bushing, ejector runner. It is different functions between the two mold plate and three plate mold, but there are several components that can be used in general without looking at the type of mold construction.
1. injection molding runner lock pin
Runner lock pin have undercut shape at end of pin. When injection mold open, this undercut will pull runner, this force will cut gate from product. Runner lock pin does not move during the injection process. Mold base plate moves accordance with the mold opening sequence, the tip of the runner lock pin is the part that greatly affects the success or failure of the gate runner cutting process.
2. Injection molding runner lock pin lock
Runner lock pin lock have function to maintain runner lock pin order not to loose from its position. There are various ways to lock them runner lock pin
+ Closed with a locating ring or sprue bush or heat insulation board.
+ Using a plate
+ Use a screw plug
3. Bushing runner lock pin
High cycle time mold or need durability are advised to use the bushing,the benefits include easy maintenance of runner lock pin, more resistant to wear due to friction so it’s can avoid direct contact between Runner lock pin and mold plate that can caused wears, this method will shorten maintenance time.
4. Ejector runner
Use to push runner out of the mold.