Meaning
Auxiliary mechanical or pneumatic devices used in thermoforming and blow molding help stretch and distribute heated plastic sheets or preforms into the mold cavity. During the forming process, a tooling assist prevents excessive wall thinning by physically pushing the heated plastic into the mold before the vacuum or pressure is applied. This assist is typically made of syntactic foam or nylon to avoid cooling or scratching the hot polymer.
It ensures a more uniform wall thickness in the finished part.
Process Optimization
The speed, depth, and temperature of the assist must be carefully controlled to match the material’s properties. If the assist is too cold, it can cause surface defects and chill marks on the plastic. If it pushes too fast, it can tear the heated polymer sheet.
Material Distribution
By pushing the material deeper into the cavity before forming, the assist allows for more uniform stretching of the polymer. This is especially important for deep-draw parts where the corners would otherwise become dangerously thin. It improves the structural strength of the finished part.
Cost Impact
Using an assist allows manufacturers to use thinner starting sheets while maintaining the required part strength. This reduces material usage and lowers the cost per part. It also reduces cycle times by improving heat transfer and cooling.
