No contact casting shell knockout

The task

Knocking out multiple-component ceramic moulds used in the "lost wax" casting process.

The problem

A precision casting company used a hand-held riveting hammer, of a type used in shipyards, to knock out castings from the ceramic shells in which they had been cast. This process takes approximately 20 minutes to complete per multiple component mould, exposing the operator to very high vibration magnitudes . Typically an operator would knock out 18 such moulds a day giving a possible exposure in excess of 10 m/s2 A(8).

The solution

The company developed an in-house solution by mounting a pneumatic breaker, similar to the type used to dig up the road, in a custom-built steel support frame. The mould to be knocked out is held in the frame with pneumatic jaws and vibrated by a special toolpiece fitted in the breaker.

The result

  • The operator does not come into contact with any vibrating parts.
  • The time to knock out one mould tree reduced from 20 minutes to 5 minutes.
  • There is a reduced risk of back problems as less lifting is required.
  • The machine can be partially or fully enclosed to reduce the operator's exposure to noise.

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