Sand Casting

The Process In Brief.

1. The making of a wooden, resin or metal pattern which will form the impression of the component to be cast.
2. The actual making of the mould in sand, could be greensand or resin bonded sand.
3. The making of any cores which are made in CO2 or resin sand.
4. The preparation of the furnaces to melt the metal.
5. The pouring into the mould of the molten metal, which is then allowed to solidify.
6. The removal of the casting from the sand.
7. The fettling of the product
8. The shotblasting of the product if desired by the customer.

The mould making may be done by hand, where only a small batch is required, we usually use a loose pattern for this or by moulding machine for larger quantities where we manufacture a jig to retain the pattern and also protect it, traditionally we manufacture many small quantities in greensand and larger quantities in resin sand.
Wooden patterns are suitable for up to several hundred castings, but usually resin or metal patterns are used for larger quantities.

The core boxes can be made of wood, resin or metal and again made by hand or machine, it is always important to position cores in the correct place, quite often we use gauges to do this.
The furnaces can be ‘lift out’ or ‘tilting’ depending on the amount of metal required, the melting of the metal is crucial and needs to be monitored continually to achieve desired standards.

The removal of the sand from the casting is achieved on a KO machine, this machine is usually used for the resin sand system as we are able to reclaim 70% of the sand, therefore achieving environment goals.
The fettling involves cutting of the runners, risers, grinding and linishing.
Finally shotblasting gives an even finish.

Reasons For Using the Sand Casting Process.

1. Suitable for casting in many different metals.
2. Suitable to cast small, light parts to large heavy parts.
3. Usually prices are very competitive.
4. Possible to make almost anything if the moulder is very skilled.
5. Surface finish can be very good if certain sands are used.