American Technical Molding provides plastic injection molding using insulated runner molds, an excellent option when a large number of plastic parts need to be manufactured quickly.
Insulated Runner Molding: Advantages Over Hot Runner Systems
Properly designed insulated runners, with thermally controlled gates, offer several advantages over hot runner mold systems, including:
- 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.
Insulated Runner Molding: Cold Runner Molding Has Advantages
However, as with hot runners, the insulated runner system also has disadvantages when compared to cold runner molding in certain situations. The increased level of technology required to manufacture and operate the insulated mold results in:
- 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
