plastic injection with holes on a side???
July 8th, 2010 | 
Author: Question by G: plastic injection with holes on a side???
Hi. Palstic injection is when to parts of a mold come together and palstic is shaped. But what if my part needs some holes on a side. u cannot add it to the mold because the holes wont let the mold part come together
Thanx
Best answer:
Answer by walter_b_marvin
nope just put a solid tube through where the hole goes. the plastic will go around the tube forming a hole. Arrange the mould so tha the tube splits in the middle. Volia… part with a hole through it.
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Sure you can. You use a 3-part mold where the core is 1-pc and and shell is 2-pc. The core would have the thru holes and the two halves of the shell would have male pins mating to those holes in the core, thus plugging them when the shell surrounds the core mold. When hydraulic pressure is released, the shells open away from the core and the molded part is produced inside with the holes.
Well this can be accomplished several ways. The most common is the use of mechanical slides or cams. These are usually operated by the use of an angled pin running through the slide block (horn pin). As the mold opens the angled pin moves the slide laterally. Another common use is to use hydraulically operated slides or some even use electric actuators now. You can also accomplish this using a lifter which runs through the ejector plate on an angle. As the part ejects the lifter is an angled ejector insert and moves away from the part as it ejects. I’ve seen collapsible cores for adding holes to the side of small parts. If the part is of a short run or prototype hand loads can be installed in the mold. These eject with the part and are removed from the part after ejection and placed back in the mold before the next shot. Sometimes its easier to perform a secondary drilling operation on short run parts after molding. If you need help contact me.