Saturday, February 9, 2008

Paralel and series Cooling methode at flat type plate of Mold Base

almost mold designer know that cooling is biggest part that effect cycle time of injection mold, a good design in cooling will make heat exchange between resin after injected and mold will reduce cycle time and give good product.
at flat type of mold base plate like stripper (Plate number2) plate between top plate and cavity plate, top plate it self, and support plate after core plate, at the top plate cooling not always used, it very depend on resin type,and product shape.
the picture below shown some flat mold base that we can use parallel or series cooling methods

How about core and cavity of Mold base ?

we can use both type of cooling series and parallel when design cooling at core and cavity plate, but you must careful place the cooling, because beside cavity molds it self, they are ejector at the core plate then sprue and runner system at cavity plate. the construction and how to connecting cooling at mold plate with cavity mold cooling will discuss later.

Parallel Cooling Channel
picture below shown parallel cooling channels concept

basic mold base cooling have four parts, they are :
1. Main Cooling pipe
commonly cooling pipe make by drilling using bore,the longer drilled hole, it recommended have length about 6 mm if using long nipple joint to connect with outer tube, if using nipple or inner joint plug each cooling pipe minimum have 12 mm.
2. stopper plugs, like at slider cooling and cavity cooling stopper plugs is prevent water or oil coolant flow to undesirable way.
3. Inner stopper plugs, the function is same as stopper plugs, but assembly methods and location is different, it assembled at inner of cooling pipe.

parallel cooling channels are drilled straight trough supply manifold cooling pipe, due the parallel design flow characteristics, the flow rate along various cooling will different, because each cooling pipe have their own flow resistance. as a results, cooling of the mold will not uniform. so it's clear that parallel circuit of cooling in molds are very poor flow rates.

Series Cooling
picture below shown basic series cooling construction and methods

the parts is same with parallel cooling type, but the construction is different, at the series cooling channel types, it connected in single loop from the coolant inlet until its outlet, we can configure the flow by adjust the inner stopper plug type.
when design it is recommended to use same size of diameter cooling, because it's can maintain the turbulent flow, turbulent flow enables heat to be transferred more effectively.

Long and Shorts Nipple joint plug Assembly methods

considering mold base material strength,closer distance between two nipple plug type are not advisable, look at picture below

assembly between long type and shorts type is different, by using long type minimum length from both side is 6 mm, except for little diameter hole, less then 5 mm, smaller length spacing my be acceptable.
Short nipple joint types almost assembly in inner mold base, because of that minimum length space is 12,5 mm, although 10 mm my acceptable but will difficult to assembly it using hand.