Fuse Injection Molding Technology

- Sep 19, 2018-

Fuse injection molding has developed into a specialized injection molding branch. With the demand for polymer materials in the automotive industry, some parts have been mass-produced. For example, the tennis racket handle is the first large-volume production of molten core injection molded products; The all-plastic integrated intake manifold of the automobile engine has been widely used; other new uses include: automobile water pump, water pump propulsion wheel, centrifugal hot water pump, spacecraft oil pump and the like.


Plastic parts that are difficult to demould on injection-molded structures, such as automotive oil pipes and intake and exhaust pipes, are generally shaped into two halves and then assembled together, resulting in poor sealing of plastic parts.


With the increasing use of such plastic parts, a fuse forming process similar to lost wax casting has been introduced into injection molding to form a so-called molten core injection molding method.


The basic principle of the injection molding of the molten core is to first cast a fusible core with a low melting point alloy, and then insert the fusible core into the mold as an injection molding, and then cool the molded part from the cavity. Remove it and reheat it to melt the core.


In order to shorten the core melting time, reduce the deformation and shrinkage of plastic parts. Generally, the oil and the induction coil are simultaneously heated, and the induction heating melts the fusible core from the inside to the outside, and the oil heats and melts the alloy skin layer remaining on the inner surface of the plastic part.


Fuse injection molding is particularly suitable for composite articles that are complex in shape, hollow and unsuitable for machining. This molding method is more important than blow molding and gas-assisted injection molding, although it is necessary to increase the cost of casting fusible core molds and equipment and melting cores. Equipment, but can make full use of the existing injection molding machine, and the degree of freedom of molding is also large.


In fuse injection molding, the part is made around a core piece. After the core piece is finished, it seems to be similar to the traditional basic industry, and it is not new. But the key issue is the material of the core, which is not possible to use as a core in plastic processing. First of all, it is not hard enough to maintain its shape during the molding process, especially the pressure and melt impact. More importantly, the accuracy is not suitable for plastic products. Therefore, the key is to find the suitable material for the core. Sn-Bi and Sn-Pb low melting point alloys are currently used.


Fuse injection molding has developed into a specialized injection molding branch. With the demand for polymer materials in the automotive industry, some parts have been mass-produced. For example, the tennis racket handle is the first large-volume production of molten core injection molded products; The all-plastic integrated intake manifold of the automobile engine has been widely used; other new uses include: automobile water pump, water pump propulsion wheel, centrifugal hot water pump, spacecraft oil pump and the like.