|Introduction to insulated runner molding|
plastic injection molding using insulated runner molds, an excellent option when a large number of plastic parts need to be manufactured quickly.
Advantages Over Hot Runner Systems
Dependable reproduction – no "dead spots" in mold
Uniform temperature distribution – thermal insulation forms through melt deposited at the wall
Economical process for continuous operation of uniform cycles without extended interruptions
Easy to maintain – quick to clean
Fast production color changes
Molds are less expensive to build and to maintain than hot runners
Minimal heat loss – thermal equilibrium reached quickly
Low energy input on startup – reduces energy cost
More consistent volume of polymer per part
Faster molding cycles
Elimination of runner scrap — less regrind
Improved part finish
Decreased tool wear
Insulated runner systems are inexpensive alternatives to traditional hot runners, where the mold is not heated, but the runner channels are extremely thick and stay molten during continuous cycling.
This feature provides the flexible gating advantages of hot runners without the added cost of the manifold and drops of a heated hot runner system.
Cold Runner Molding Has Advantages
More complicated mold design
Higher mold costs
More difficult start-up procedures
Possible thermal degradation of the polymer melt
More difficult color changes than with cold runners