BMC Parts Uniformity, High Density
BMC Parts pressing principle and its process and other thermosetting plastics are basically the same. In the suppression, a certain amount of BMC Parts into the preheated die, the pressure, heat curing molding for the required products.
1, BMC molding process characteristics
① waste less material, usually only the total consumption of 2% -5%, the actual material loss also depends on the shape of the finished product, size and complexity.
② in the molding process, BMC Parts, although it contains a lot of glass fiber, but it does not produce a strong orientation of the fiber, so the product of uniformity, high density, and residual internal stress is also small.
③ In the process of processing, because the filler and fiber rarely broken, it can maintain a high mechanical properties and electrical properties.
④ in the suppression of its flow length is relatively short, so the cavity is not serious wear, mold maintenance costs are low.
⑤ compared with the injection molding, its use of molding equipment, molds and other investment costs are low, so the entire product molding costs are low.
2. Press the molding process
In the press molding, a certain amount of prepared BMC molding is placed in a preheated steel die, and then the mold is closed at a constant speed; the BMC molding is flowing under pressure and filled the entire cavity; The required temperature, pressure to maintain a certain time, until it completed the physical and chemical process of curing, stereotypes and achieve the best performance to open the mold, remove the product. ,
BMC Partss, as wet premixes, contain volatile, reactive monomers that are not removed before they are used. Otherwise, these reactive monomers will evaporate from the BMC material to reduce the fluidity of the material, And even cause performance degradation so that scrap. Of course, for unpacked and unused BMC Parts, it must be re-sealed and sealed for the next time to suppress the use.
① calculation of the amount of feeding and weighing
In general, the first is to know the volume and density of the pressed products, coupled with burrs, burrs and other losses, and then the amount of feeding calculation. Accurate calculation of the amount of loading, to ensure the accuracy of the geometric size of the product to prevent the lack of material or due to excessive material caused by waste and waste materials, etc., have a very direct relationship, especially for the BMC after this molding can not be recycled Thermoset composites, for the preservation of materials, reduce costs, more important practical significance.
In fact, since the shape and structure of the molded article are complicated, the volume calculation is complicated and not necessarily accurate, so the loading is often based on the estimated method. For automatic operation of the machine, the amount of feed can be controlled in the total amount of soil within 1.5%, and reach 5% or more than this number, it will certainly die in the mold surface flash. This thin layer of excess material in the heating state of the role of high mold temperature, will quickly cure to form a flash.