What Is Molding Machinery?
Injection molding machinery is well known as molding machinery for plastics, but there are also press molding machines that create shapes by applying pressure, blow molding machines that create shapes by air pressure, and molding machines that use simple molds (e.g., lost wax machines).
Besides plastics, metals can also be molded. Die cast molding of aluminum and zinc can be done automatically, which often leads to cost reductions during mass production.
Uses of Molding Machinery
Molding machinery is used to mold materials to fit a mold.
Molding machines are often used when the annual production volume is large or the lot size is large. Most plastic products sold at 100-yen stores are manufactured using molding machines, because the unit price can be reduced by using molding machines. They are also used for design parts, which are becoming more demanding, since even complex shapes can be easily produced.
Aluminum die-cast parts, which are molded from aluminum, are widely used in automobile engines, internal components of measuring instruments, and tobira.
Principle of Molding Machinery
Mass production molding machinery, one type of molding machinery, is very expensive, ranging from several thousand dollars to tens of thousands of dollars, due to the robustness of the molds and other components. Therefore, it is necessary to produce a sufficient quantity of molds to amortize them. In addition, when a mold is changed due to a shape change, at least several hundred hundred dollars is required because of the labour hours required to remove the mold from the molding machinery and process it. To address these issues, there is a method in which the mold is divided into sections and only the necessary sections are taken out for modification. This method not only shortens the modification period but also reduces the cost of modification.
If the quantity is not large but the shape is complex and cutting is difficult, a simple molding machine is used to produce the product at a low cost. This equipment can produce only a few to several dozen pieces, but has the advantage of making the molds inexpensive. It is also possible to make multiple simple molds by producing a master.
Recently, a pressure forming method called “press forming” is increasingly used in sheet metal processing. Although there are some restrictions on the shape, mass production is possible at a low cost, and shape changes can be accommodated with relative flexibility. For example, drawing, one of the forming processes, requires a welding process, which used to be expensive, but now it reduces the cost of parts and improves the shape stability of products.