抄録
In injection molding, the weld is formed when the flow of molding compound is injected through multi-gate or is separated by an insert followed by confluent in a cavity. Most studies on weld are concerned with strength, and little work deals with the formation and the hardening mechanism of weld. Then, the mechanism of weld formation was investigated for injection molding of Bulk Molding Compound (BMC). Forming a weld by an insert in a cavity, the behavior of a flow front and the temperature profile in the contact surface of weld were observed. The main results are as follows: The BMC being the first to flow into a cavity forms the weld after being in contact with an insert for a little while, which makes the temperature of flow front high. According, adhesion at weld becomes poor and the strength to be low. During the cross-linking reaction of resin, the reaction between radical and oxygen in air disturbs the normal hardening reaction of resin at the contact surface of weld.
