Foam rubber products are produced by physical or chemical foaming method with rubber as the base material to obtain sponge-like rubber porous structure products. This technology has been widely used in various production industries, such as automobile door and window seals, cushioning pads, building construction gaskets, seismic materials, sports protection facilities, etc.
Generally speaking, rubber molded products must be molded through the corresponding mold for molding processing, a rubber product after high temperature, high pressure vulcanization, from the mold cavity or mold core is commonly known as mold release. Poor demolding is one of the important reasons for the quality defects of rubber products and the impact on production efficiency. It can cause defects such as distortion and tearing of parts, and some even damage the mold, bringing trouble to normal production. Studying the unfavorable factors affecting the demolding of rubber products is of great significance to ensure the quality of products, prevent defects, prevent scrap, and improve production efficiency.
Common quality problems and solutions in rubber foaming 1、Insufficient foaming holes 2. Insufficient filling mold 3. Uneven foaming holes (too big or too small) 4. over-vulcanization or under-vulcanization
Many rubber products are molded, and after molding, vulcanization to obtain products with qualified physical properties, the appearance of the product does not have major defects, but the conventional trimming method can not repair the appearance requirements of the product, there are small burrs can not be removed, manual repair or scrapping causes a lot of economic waste. At this time, the structural design of the mold clamping line of the product is particularly important, how to design the lip, overflow line and overflow groove, etc., will not be explained here, you can refer to the "Rubber Mold Design Manual". The focus of this article is to explain from the formula and process, because the mold is often designed can not often modify or scrap the mold (economic waste), often find a formula engineer to modify the formula or change the process to achieve easy tearing.