Injection molding and casting are two rather different fabrication methods. While some don’t believe that plastic molded parts can replace metal castings, the two processes are often interchangeable. Further, there are many advantages that injection molding has over metal casting, including:

Benefits of Plastic Injection Molding

  • Cost-effective – plastic parts can be produced quickly and more efficiently and in higher volumes over casting. Once they’re molded, plastic parts are ready for use while casted parts often need to have secondary operations to make them functional. Utilizing multi-cavity molds significantly lowers the cost per unit for large-scale production.
  • Surface Finish – with injection molding, plastic parts are ready to use with perfect surfaces when they come out of the mold. Conversely, cast parts often need to have surface refinishing. This adds complexity and cost, and extends lead times.
  • Material Properties – plastics can endure harsh environments: they do not corrode, rust, or conduct electricity.
  • Automation – injection molding jobs can by run lights out, which is not feasible with casting.
  • Wall Thicknesses – is often a critical attribute for a fabricated part. Injection molding can hold wall thicknesses to tight tolerances repeatably, while the casting process is subject to variability from part to part.
  • High-volume Production – thanks to multi-cavity molds, injection molding is ideal for mass-producing precise plastic parts efficiently.
  • Complex Shapes – molding produces intricate designs with high accuracy, creating diverse functional and aesthetic possibilities.
  • Lightweight/Diverse Materials – choose from a wide range of engineered plastics, offering versatility, corrosion resistance, and recyclability in some cases.

Benefits of Casting:

  • High Strength and Durability – metal casting produces metal parts with high strength and heat resistance.
  • Unique Material Properties – metal can offers characteristics such as conductivity, magnetism, or high melting points.
  • One-off or Small-batches: – casting is suitable for creating single units or small batches of custom parts.

Casting vs Injection Molding – Which Wins?

For applications requiring specific metal properties, or small-batch/customized parts, metal casting may be more suitable. For high-volume, cost-effective production of intricate plastic parts, injection molding offers a clear advantage.

To find out how injection molding can save money by replacing your casted parts, contact us today.