Selecting the right Injection Mold Steels
Selecting the right steels for the injection mold base and molding surfaces has an impact on cost, cycle time and life of the injection mold.
Depending on your requirements we customize the solution and certify the steels used in manufacturing and the heat treating process.
We will comply with any customer request for any Worldwide Steel sourced. Our Primary supplier Is LKM for quality steel.
Injection Mold Makers Concerns
Machinability – Reduces machining time and cost.
Polishability – Parts that require a mirror-like finish.
Heat-Treating Dimensional Stability – For dimensional accuracy.
Weldability – For either part design and engineering changes or future repairs.
Nitriding Ability – Nitriding gives a very hard surface layer to the steel and very good resistance to abrasion or corrosion. However, the nitriding layer can be brittle and crack.
Injection Mold Steels
Wear Resistance – Molding surfaces will wear if the plastic material is abrasive, filled with glass or minerals.
Compressive Strength – Needed to withstand mold clamping forces to minimize damage to shut off areas.
Heat Treated – Needed when molds operate at high temperatures.
Corrosion Resistance – Very important in two major aspects – first when corrosive plastics or additives are used; and second, when molds operate in high-humidity areas or regions where the water is particularly corrosive.
Thermal Conductivity – Can have an impact on the cycle time of high-production molds and although it’s not often a major factor in selecting mold steels, it is a reason for choosing beryllium copper instead of steel in some cases.
Pre-hardened steel molds are less wear resistant and are used for lower volume requirements or larger components. The steel hardness is in the range 38-45 on the Rockwell-C scale. Hardened steel molds are heat treated after machining. These are by far the superior in terms of wear resistance and lifespan. Typical hardness ranges between 50 and 60 Rockwell-C (HRC).
Most of the steel that Total Solution Plastic uses in our molds is purchased from LKM (Lung Kee Metal), which is a very fine and reputable company traded on the NY Stock Exchange. Their quality has been compared to DME here in the USA. We also purchase from Uddeholm …of course the ultimate decision is made by our customer.
