What are the differences between Sand Castings and Permanent Mould Castings?

What are the differences between Sand Castings and Permanent Mould Castings?

Whether you need Sand castings or Permanent Mould castings depends on your industry application. This blog will cover some of the salient features that differentiate Sand Castings and Permanent Mould Castings.

Sand Castings: In this process, a one-time sand mould is produced, which would have one or more impressions of the desired part. Molten metal is poured into the sand mould, then subjected to solidification and cooling; the sand breaks away and the casting removed. More often than not, the sand is recycled and reused. Sand casting, as a process, is most suitable for low and high volumes as it involves mechanical casting property needs and material; only dimensional tolerances, low tooling costs, and reasonable surface finishes are required. When configurations and size are the only criteria, then the part you require is made only as a sand casting. There are many other things to consider too; therefore, do consult with the foundry before part design is finalized.

Permanent Mould Castings:
Compared to sand casting, the mould is made steel or iron, and this allows for one or multiple cavities that are based on the geometry of the required part. The process is highly applicable for mid to higher volumes, particularly when the part configuration is the base for this type of casting, or the process is best suitable for casting applications. The moulds, more often, are completely CNC machined with the parting surface having aligned with a locking system giving excellent, consistent casting dimension state.

In comparison with sand castings, permanent mould castings provide better surface finishes, reduced machining allowances and closer net-shaped profiles enabled by the metal mould configurations.

All said and done, permanent mould castings, unlike sand castings, are pretty much limited in size and the tooling is found to be tad expensive (although the part price can be lower). Are you at crossroads whether to select sand castings or Permanent Mould castings? Simply consult with us to find out which process fits your requirements.