How to Improve Demolding Efficiency for LSR Parts?
Appropriate draft angles, typically 1° to 3°, allow parts to release smoothly from vertical walls. Undercut management through side-actions or collapsible cores eliminates mechanical interference.
What Is Flash in LSR Molding and How to Prevent It?
Flash occurs when LSR leaks out of the mold cavity at parting lines or ejector pins due to excessive injection pressure or insufficient clamping force. Microscopic gaps from worn mold components or improper alignment also contribute.
How to Ensure Dimensional Stability in LSR Molding?
LSR's high coefficient of thermal expansion means parts shrink significantly during cooling. Mold temperature uniformity is crucial to prevent differential shrinkage that causes warpage.
Flash formation, incomplete fills, and dimensional variations are frequent issues during first runs. Material degradation from overheating or improper mixing can occur.
Thin walls, deep cavities, and intricate undercuts pose filling and ejection challenges due to LSR's low viscosity and high thermal expansion. Air entrapment becomes more likely in complex geometries.
LSR overmolding involves injecting liquid silicone rubber over a pre-formed substrate, such as plastic or metal. The process creates a strong bond between materials without adhesives.
Tool steels like P20, 420 stainless, and hardened H13 are commonly used for LSR molds. P20 offers good machinability and moderate wear resistance, suitable for medium-volume production.
LSR mold design hinges on understanding the material's low viscosity and high thermal expansion. Unlike thermoplastics, LSR requires precise venting and degassing systems due to its rapid cure and gas generation.
The Science Behind Venting Strategies in Liquid Silicone Rubber Molds
The science behind venting strategies in liquid silicone rubber molds centers on gas evacuation preventing defects effectively. Entrapped air causes burn marks, voids, or incomplete fills detrimentally.
