Two-Color LSR Molding Fine-Tuned with Flow Simulation
CAE simulation software provider Sigma Plastic Services is demonstrating an unusual two-color LSR molding application. Egg cups of white and yellow LSR are run in a 4 + 4 cavity Elmet mold using that company’s new TOP5000 dosing system. Its closed-loop controls document the real amount of colorant used, which is particularly relevant to the healthcare industry. Especially remarkable is the special hardware system that allows two-component molding on a standard one-component Arburg injection press with only one LSR dosing system.
In this project, Sigma used its Sigmasoft Virtual Molding software to determine the filling time, injection pressure needed, and selection of the optimal LSR material grades from Momentive. Sigma’s highly developed LSR simulation can show such details as air temperature at the vents, formation of flow lines during fill, and percent cure to indicate when parts can be ejected.
Liquid silicone rubber is breaking out of its niche into a broader array of applications, helped by new developments in materials, machinery, and processing. Larger parts, micro-parts, foams, and multi-color or multi-material combinations are key areas of innovation.
A look at causes, detection, and prevention.
Because the consumer sees so many colored plastic articles, it is natural to assume that the process of achieving molded-in color is a simple one. Those of us in the industry know differently.