Materials for Mold Making

Although copper is another metallic alternative material for mold making due to its corrosion resistance and higher thermal conductivity than steel and aluminum, it is not as commonly used as steel and aluminum. 

Today, the question of what is the right material for mold making cannot be answered as easily as it used to be. 

TABLE 3.5 Classification and composition of selected aluminum materials for mold making... 

For decades now, RTV-2 silicone rubber has been the top material available for mold making, which is proved by its continuously increasing consumption for this application (current global use is more than 20 000 tons per year). This is due to the unique combination of properties offered by this material ... 

A few examples of thermosetting materials are epoxies often used for mold making and tools. In fact, we will be discussing the use of aluminum filled epoxy to make molds later in the book. Melamine, (Dishes are often made of melamine). Phenol resins are commonly used in higher temperature and strength applications such as home appliance handles and parts. Other uses for phenol resins would be distributor caps, coil tops, phone housings and tool housings to name a few. 

Aluminum is the key for mold making for even faster production times (see also Chapter 3,2), The search for cost and time savings requires permanent alternative and innovative approaches. Thus, even in prototype making, an area in which mainly steel was used in the past, the materials are tested for their suitability. 

Table 3.5 summarizes the DIN/EN designations, material numbers, international registration numbers, as well as the composition of the aluminum alloys suggested for mold making. 

Aluminum is thus the most important material in mold making after steel to meet the requirements of faster availability of molds and plastic parts on the market, and not at least because, once produced from raw materials, aluminum is available for generations due to its recyclability. 

In electroplating, all the advantages offered by the nickel material are used for mold making. The most important properties of nickel for the processing of plastic materials are ... 

Structural binder A wide range of applications in electronics makes use of the plastics as a structural binder to hold active materials. For example, a plastic such as polyvinylidene fluoride is filled with an electroluminescent phosphor to form the dielectric element in electroluminescent lamps. Plastics are loaded with barium titanate and other high dielectric powders to make slugs for high K capacitors. The cores in high frequency transformers are made using iron and iron oxide powders bonded with a plastic and molded to form the magnetic core. 

Using low cost material to meet high performance requirements will compromise their integrity. As an example, the cost of a mold cavity and core materials, for more than 90% of the molds, is less than 5% of the total mold cost. Thus it does not make sense to compromise mold integrity to save a few... 

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