Why change from metal to plastic?

It’s hard to break old habits — like using metal parts and metal products. However, there are three good reasons for changing from metal to plastic:

  • Lower manufacturing cost
  • Lighter weight
  • Zero corrosion

What many manufacturers don’t know is that — when done properly — plastic parts can be injection molded with the same tight tolerances and perform just as well (or even better) than their metal counterparts.

How Can Plastic Parts Perform Just as Well or Better Than Metal?

Careful design and planning, selection of appropriate materials, and use of scientific molding principles will control the main factors that affect precision, accuracy, and tight tolerances. These include material preparation, melt flow index, machine processing parameters, and most importantly, using sophisticated sensor technology to track what is happening inside the mold in real time. Making these kinds of high-performance plastic parts and products therefore also requires a robust quality system that can monitor every step of the injection-molding process. 


When injection molding vendors consistently fail to meet tolerances with plastic parts, this creates additional machining costs, quality costs to sort or even re-call parts, and possibly even litigation. 

Advantages of Plastic vs. Metal

It only takes one bad experience with plastic parts to drive a company back to metal. But, with an experienced metal-to-plastic-conversion injection molder, there are some big advantages in going with plastic such as:

  • Lower cost to produce
    • No secondary process to prevent oxidation
    • May be able to eliminate some assembly
    • Plastic is generally less expensive than metal
    • May be able to eliminate costly machining operations
    • Lighter weight means lower shipping charges
    • No painting needed, molded in color/graphics
  • Lighter weight
    • Helps automotive companies meet EPA standards
    • Less fatigue on a person if it is carried
    • Might make a product go faster

Keys to a Successful Conversion

The key to a successful metal-to-plastic conversion is understanding the limitations of the process, materials, and tools are before committing to the project. Every part or product is not necessarily a good fit for metal-to-plastic conversion: important factors that must be carefully considered are the expected tolerances, materials, specific part design/configuration, and initial mold flow/analysis.

Read about metal-to-plastic conversion solutions with Gates Corporation:

Gates Case Study


Gates Case Study