Actually, the overall structure of SMC molds ensures that the molding pressure is effectively applied to the product with a vertical parting structure design, so that the product has a good surface and there is enough clearance for air to escape. The length of the parallel section of overflow gap varies, depending on the size and shape of a specific product.
Precision of SMC molds
The overflow gap for small products should be 0.08mm, while for large products it should be increased and the maximum should be about 0.18mm. If the overflow gap is too small, it is difficult for air to escape; if it is too large, it will assist the flow in that direction, resulting in fiber orientation, causing ripples and weakening the strength of the product. The length of the parallel section of the overflow area is determined by the degree of no overflow required by the mold. Generally speaking, the longer the parallel section, the higher the degree of no overflow, and the better the surface quality of the product, which is beneficial for SMC molds to enter the position of the ribs and grooves. However, if the parallel section is too long and the degree of no overflow is too high, it is easy to entrap air, causing surface pores in complex shaped products. For molds of complex shaped products, it is more difficult and expensive to manufacture molds with vertical parting structure. It is more appropriate to use semi-overflow horizontal parting mold structure.
The overflow gap and gap of vertical parting structure are within the same range. The slope of the mold groove wall is also 2°, but in some cases, the slope can be appropriately reduced to increase the no-overflow property of the mold. The distance from the edge of the product to the mold wall can be changed, but the width of the convex area must be kept in the range of 2.0-5.0mm. As the convex area bears a certain pressure, it reduces the effective pressure borne by the product. Generally, the gap between the convex surfaces is designed to be 0.08-0.13mm, and there should be a gap of 1.0-1.5mm from the convex area to the overflow line to avoid flow restriction at that point. Only in this way can high-quality molds be produced during the production process, improving the accuracy of SMC molds and achieving a leading level, which is recognized by customers.
Innovation of SMC molds in the Market
With the shortage of global energy and the development of new energy, the lightweight of vehicles has led to the extensive development and application of fiber-reinforced thermoplastic composites (FRTP) for automotive parts made by the GMT/LFTD process using a new material. Both SMC/BMC and GMT/LFTD materials, as well as the formed products, have emerged in hundreds of hot-molded products enterprises and supporting enterprises of materials, molds, and additives, forming a huge industrial cluster.
Because of the performance and standard requirements of the formed products, the composite of the resin, fiber, and additives is a redesign process and is manufactured through molding and injection molding for a wide range of products used in different fields. In recent years, as the market develops, a series of processes are facing technological innovation and are facing innovation in the entire market.