Mold types Runnerless

These materials have been successfully molded in all types of mold, for example, 2-plate, 3-plate, insulated runner, stack and hot runner, en using the hot manifold type of runnerless mold, the runner channel must be streamlined so that there are no dead spots (nil flow areas) which are likely to cause degradation accurate temperature control of the manifold is essential. To maintain the sparkling clarity of this material, use vacuum smelted steel as this can take a very high polish and is non-porous. 

Runnerless molds are highly suitable for cellulosic materials however, the types of components that are used for runnerless type molds (for example toothbrush handles etc.) require to be produced in many different colors. One of the main problems associated with runnerless type molds is the amount of material that is wasted during a color change and therefore the selection of the specific, runnerless design is very important with respect to overall production costs. To overcome this problem, the use of an insulated, hot tip, runnerless-type design should be considered for cellulosics. 

Runnerless molds eliminate the runner system entirely (and usually the sprue system as well). The basic idea behind the runnerless mold is that, although sprue and runner channels are included in the mold, the sprue and runners are kept molten and are never formed as items that are ejected. The resin is maintained in the fluid state by various techniques, which include several types of supplementary heaters in the runner plate. 

The insulated runner type of runnerless mold and certain types of hot sprue bushings can be used for UPVC, however careful consideration needs to be given to the relative thermal stability of the molding compound (i.e. the type of stabilizer system used) and the anticipated cycle time at which the mold is expected to run at before deciding which approach to opt for. 

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