An automatic pipe spinning machine in a foundry was generating A-weighted noise levels in excess of 90 dB. The pipe mould was housed in a sheet steel cabinet with the pipe being spun at high speed before molten metal was fed into the centre. The spinning action forced the molten metal to the outside of the mould while the cabinet was filled with water to cool the mould and solidify the spun pipe.
The primary source of noise was mechanical vibration in the hydraulic drive mechanism and main mould bearings being radiated from the sheet steel surfaces of the water cabinet and the machine support structure. Noise also came from the cabinet roof, steam vents and the hydraulic power pack.
A number of modifications to the machine were made, including the following:
About £2000. (1995)
An overall noise reduction in the mould shop of 6 to 7 dB.
Photographs courtesy of Glynwed Foundries. Consultants' report supplied by Sound Research Laboratories Limited, Wilmslow.