The Designer's Edge: Stationary Vent Pins and Inserts

Stationary pins or inserts, which are sometimes a necessity to assist with venting, should be designed with ease of assembly and disassembly in mind..

�

 

Stationary pins or inserts, which are sometimes a necessity to assist with venting, should be designed with ease of assembly and disassembly in mind, as they require cleaning. The vent depth and land length also become more critical when attempting to make pins and inserts as self cleaning as possible.
 
If designed properly, these inserts or pins will only need to be cleaned at normal preventative maintenance cycles. When venting stationary inserts or core pins in rib or part details, I recommend going no more than 0.030 to 0.040 land, and using maximum vent depths. This will get the inserts and pins as self cleaning as possible. 
 
Porous materials can also be used in problem or back fill areas. However, these materials require the mold shop to understand the proper machining or EDMing of the part surface to prevent plugging the pores, and vent channels or holes to reduce the area the gases need to escape. Additionally, proper cleaning methods are necessary.
 
Components, such as slides and lifters, do not always get designed with venting in mind. Typically, these actions have details that create gas traps and knit lines that need to be vented. In most cases, it is easy to add venting in the problem areas. With lifters there would be a parting line in the detail where you can add a vent track and exit down the lifter shank to atmosphere. The same goes with slides and adding venting to the shut-offs and easily exiting to atmosphere.
 
Next month,  I will examine venting shut-off details as well as a unique, rare occurrence with venting.
Comments are reviewed by moderators before they appear to ensure they meet Moldmaking Technology’s submission guidelines.
blog comments powered by Disqus