Heat Treating Tool Steel - How To Choose The Right Treatment For Injection Molds

Heat treating tool steel is a very complicated task. Choosing the right type of heat treatment in plastic injection mold making can also be very difficult if you don’t have the knowledge.

The bottom line is that the heat treatment selected for an injection mold must keep the mold in good working condition for the life of the mould.

So how to choose the right treatment for your mould?

The type of heat treatment depends upon the following factors:

• Choice of tool steel. The choice of steel largely dictates the type of heat treatment.
• Mould price. This should take into account the type of heat treatment. If the price is too low then there is probably not going to be any heat treatment at all.
• Part design. If part has deep undercuts or threads then mould design will need some moving components in order to release the part from the mould. Moving components require special attention so that the surfaces don’t wear out quickly or get damaged.
• Mold design. This is heavily influenced by the part design.
• Annual production quantities. Small quantities can use softer, less expensive materials but high volume moulds require long lasting materials and heat treatments.
• Environmental factors. Does the molding take place in a corrosive environment?
• Mould maintenance issues such as corrosion.

Types of Heat Treatments For Tool Steels:

1. Surface treatment – the surface of the work piece becomes harder than the inside. Treatments include case hardening, nitriding, flame hardening, hard chromium plating, nickel plating, titanium nitride and titanium carbide.
2. Through hardening treatment – gives uniform hardness throughout the entire work piece.