The process begins by the initial phase of skin fill when the valve gate pin is retracted to the first position created by energizing ports 1 and 3 shown on the far left of the schematic. After the initial skin material enters the cavity, core material is introduced by de-energizing port 3, while port 1 remains energized (shown in the middle of the schematic). At the completion of the core filling sequence, skin material is once again allowed to flow, completing encapsulation and final pack pressure by repeating step 1.
The process begins by the initial phase of skin fill when the valve gate pin is retracted to the first position created by energizing ports 1 and 3 shown on the far left of the schematic. After the initial skin material enters the cavity, core material is introduced by de-energizing port 3, while port 1 remains energized (shown in the middle of the schematic). At the completion of the core filling sequence, skin material is once again allowed to flow, completing encapsulation and final pack pressure by repeating step 1.
Sequential molding techniques are not new. This technology has been used for a variety of molding applications with many systems in operation for more than 20 years. The original goal of this process was to remove or predictably position weld lines in parts that require multiple gates. Later demands, mostly driven by the automotive industry, lead to other applications which require sequential molding techniques. Producing interior components with a fabric or vinyl material applied during the injection process, generally referred to as “back molding”, is an example where using sequential molding techniques is absolutely necessary for good quality production.