Wednesday, May 27, 2009

Circular H type Runner Layout in Mold Design

It’s called H type because the runner shape from the top similar with “H”, it’ use in both circular layout and rectangle layout system, in circular type the runner doesn’t similar with H but it more similar with fork, circular type use in various type of product, like gear, cylinder shape, etc.
Total length of H circular type in each part of runner
8.801 x 16 = 140.816
7.491 x 8 = 119.856
18.83 x 8 = 150.64
Total length of runner in H circular type runner system
140.816 + 119.856 +150.64 = 410.912
Let’s compare with previous type runner system, direct runner system both circular and rectangle type,
Direct circular type = 448 mm
Direct rectangle type = 495.04 mm
H circular type = 410.912 mm
So the conclusion is from three example runner systems for these part and layout type, H circular type has the minimum length of runner,

1.Flow length in the runner more stabile, cause we can add runner slug before branched the runner, see picture above
2.When designing the runner, runner volume is made small as possible, this type is smallest than two type runner before.
3.All the cavities fill at the same time possibility is high, balanced runner have an equal flow length and runner size form sprue to all cavities also same, so that each cavity can fill in nearly condition.


Excellent post! I just started blogging about plastics mould technology. However, i had been posting only generic topics in it. Your blog has inspired me to provide technical details. thanks