Introducing the pattern for casting process

Before production, metal foundries need to make the patterns for the casting process, and then use the pattern to produce many casting molds, then use the molds to produce the metal castings. So, one set of pattern can produce many casting molds, and one casting mold can produce one metal casting.

There are several types of patterns for casting production.

1. Wooden patterns

Wooden pattern is the cheapest casting pattern. When metal foundries start to make the casting samples, they usually use the wooden patterns. It is not only because of its low cost, but also because they are easily to be modified again and again till they are qualified.

However, wooden pattern is very soft and has low strength, and most of them are made by hand, so they can not be used for batch production and their dimensional and surface quality are not very good.

2. Resin patterns

Resin pattern is very common for sand casting process. Resin pattern is made by epoxy resin and fiber glass clothes. So, resin patterns have good strength and lifetime, and can produce thousands of casting molds. Their dimensional and surface quality are better than wooden patterns, and their cost is not high.

However, you have to use the wooden pattern to make the resin pattern, so the metal foundries usually use the wooden pattern to make the samples, and use the resin patterns for the batch production.

3. Metal patterns

Metal patterns have many advantages. Such as, better dimensions since the metal patterns are usually made by the CNC centers or digital milling machines, better surface quality, and higher strength, so have very long lifetime. Moreover, for some special casting processes such as die casting, shell molding process, automatic molding lines, the metal patterns are the only choice.

For example, as for the die casting and shell molding process, the patterns need to bear the high temperature for the hot liquid aluminum or hot resin sands, therefore, the iron patterns are necessary.

As for the automatic molding lines, the aluminum and iron patterns are needed to bear the high pressure and frequent works.

As for the lost-foam casting (LFC) process, the metal foundries need to make the metal patterns, and then use the pattern to melt the foam, then produce many foam molds.

As for the permanent mold casting process, the heat-resistant steel patterns are the needed to produce the metal castings.

Moreover, as for some complex castings, hand-made patterns can not meet the dimensions and structure requirements, so the metal patterns will be needed.

The disadvantages of metal patterns are the long lead time for the patterns, one set of metal pattern usually need about 25 to 30 days to complete, and the very high costs. The cost of one set metal pattern is usually from 800 USD to 5000 USD according to the size and complexity.

According to the experience of Dandong Foundry in China, the buyers and foundries need to consider all aspects for the casting products, then choose the most suitable pattern for the castings.

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