Why The Venting Is So Important For Tooling ?

- Dec 05, 2016-

 Why the venting is so important for tooling ?


   The venting is very important for the plastic injection tooling designers, but people always look down on it. At the molding process, there is much air inside of the tooling cavity space, the molding machine inject the material with very high speed and fill in the mold to get the part what we need. In this so fast material filling speed, the air must go out easily and smoothly. If not, It will cause some serious problems .


The main issues as below:

1)      The material is hard to fill in the plastic inject mould, it will cause short shot or material burning if we rise the injection speed. .

2)      If we use big molding pressure or holding pressure, the mold is easy to be damaged for the week area and reduce the mold life. Sometime will cause bad deformation or the Not good surface finishing. E, g , shining finish, different finishing or air flow marks

3)      If the venting is too big and too much molding pressure to fill the material, it will cause very big flash.

   So we need to define the plastic injection tooling venting spec  as possible as we can in your tooling standards. Here we will teach you how to use a suitable venting for your component or tooling .

  Many toolmakers always cut the venting slot by experienced , but actually it is not correct or not too precise , The venting study need to according to the mold flow analysis, the material melt flow rate , product structure , gating location and experience. We need to cut them using precision equipment for better control.

a) The location and depth is very important, we need to consider of the gating side and wall thickness to make sure there is no venting in the very near area of gating  , because the gating area normally use big pressure and long time holding pressure , It is very easy to have flash.

b) The venting depth what we use are always same for many China Plastic Tooling Companies, but it is a wrong experience. As we know the starting area need just a little venting, but the welding line or big space cavity area need much more venting. We need to add the venting depth a little from the material filling beginning to the ending .the runner end area need to cut a venting to make the material is not too much air bubble inside the resin. For the deep ribs or deep slot, we need to use insert solution and cut some venting of them .

  c) However somebody still ask me one question, we already cut the venting slot, but the air trap is still same , Here we suggest you to check you venting details , Have you lead your small venting to the main venting and lead you main venting to the environment. Additionally the venting need to always clean in a regular time when we do the mold maintenance .


The tinny things always have big effect for your final result. The venting is one of those troubles of our Plastic Injection Tooling Manufactures. If you can’t use or define a proper venting for your production, you even can’t get the production and final whole project failed.

  Asia Billion Industry Co Limited is a best Plastic Injection molding Manufacturer in China, we win our competition from others because we always do better of the details works than the others.  If you want to have a credible partner for your plastic injection molding projects, Please contact us at : sales@ab-industrt.com  and we will help you that what you imagine .


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