Abstract
The purpose of this work is to provide a basic understanding of the flow mechanism during transfer molding and to suggest guidelines which would be expected to reduce the flashpad waste. It is shown that transfer rate and the flashpad waste are determined by many parameters. Among them the scorch life, charge weight (thickness), cavity layout and pressure/viscosity ratio are most important. Too short a scorch life will prevent complete fill unless the transfer rate is extremely high. Since natural rubber is crystalline up to about 90 degree C, total transfer time also includes a preheating step to bring the rubber to a flowable state. This delay time should be considered in the compound scorch life. The importance of charge weight on flow mechanism has been elucidated by the mathematical model proposed above, where the transverse flow rate shows strong dependence on charge thickness.
| Original language | English |
|---|---|
| Pages (from-to) | 785-788 |
| Number of pages | 4 |
| Journal | Annual Technical Conference - Society of Plastics Engineers |
| State | Published - 1983 |