Tool steel or Aluminum are often used on injection molds. Mild steel, nickel, or epoxy are only suitable for prototype or very short production runs.
High grade aluminum is fast becoming the material of choice for injection molds, as it offers substantially lower tooling costs and better molding process conditions. Aluminum is used in both prototype and production molds. With high grade aluminum, you can expect to get ten to hundreds of thousands of parts. It is recommended to shop injection molding companies that only use high grade aluminum such as QC-7 or QC-10.
The article comes from China injection mold manufacturer - Mold Best Assurance Company Limited, website is www.mbamoldanddesign.com