Volkswagen Logo Optical Lens

Challenge:
The product required a two-shot molding process, and the gate locations were dense and very small. This made the hot runner design and injection balance more difficult. If the gate size, gate position, or flow balance was not well controlled, it could easily cause short shots, flow marks, weld lines, flash, color mixing, or unstable bonding between the two materials/colors.

Solution:
We optimized the hot runner layout and gate position based on the product structure, material flow path, and visible surface areas. Mold-flow analysis was used to check filling balance, pressure distribution, weld line position, and air trap risk before finalizing the design. For the dense and small gate locations, precision machining was used to ensure accurate gate size and stable material flow. The sealing area between the first-shot and second-shot parts was carefully designed to prevent flash and color mixing. During trial molding, melt temperature, mold temperature, injection speed, holding pressure, and valve-gate timing were fine-tuned to achieve stable filling, clear color separation, and strong bonding performance.