ABSTRACT
Since the temperature and wear requirements in most injection molding processes are low, plastic mold steels tend to have leaner alloy designs and metallurgical properties when compared to other tool steels. In fact, they may be considered simple or easy-to-produce steels within steel mill processes. However, the requirements for the final applications, in terms of surface finishing, and the involved cost of mold manufacturing make plastic mold steels tricky. To understand this point, Figure 6.3a may be considered, which shows the main cost item of a typical mold. By having an unusually low alloy content, the tool steel cost is approximately 10%–20% of the total mold cost. The remaining 80% of the cost is incurred during the manufacturing steps, which comprise the amount of machining added to the molds, as shown in the examples of Figure 6.3b.
