Depending on the size and temperature of the molded product, when the mold release resistance is increased, mold release failure occurs. Although it is also affected by resin characteristics and molding conditions, the main reason is the shape of the molded article and the structure of the mold. Of particular note is the case when the slender ribs, the hub and the plastic plug are held together.
When the molding shrinkage around the plastic plug or the like is too large, the holding force on the plastic plug is increased, and the mold release is likely to occur. In terms of molding conditions, when the mold temperature is low and the holding pressure is too large, mold release failure is likely to occur.
When overfilling occurs in a erected product such as a long rib or a hub, these ribs or hubs become difficult to fall off, resulting in poor mold release. In terms of molding conditions, when the mold temperature is low and the holding pressure is too large, mold release failure is likely to occur. This is exactly the opposite of the plastic hole bolt.
When the draft angle of the cavity portion is small, the mold release resistance is large, so that mold release failure is likely to occur. The position of the ejector pin also has a large effect (it is best to set the ejector pin at a place where the draft resistance is too large). In addition, the surface finish or damage of the cavity surface also affects the mold release resistance, resulting in poor mold release.