Improving performance of a sandblasting process

A sandblasting operation is performed to make the job surface clean and smooth prior to the application of zinc coating through the galvanising process. A high amount of variation in profile depth is observed on surfaces after the sandblasting operation, resulting in quality problems and increasing operational cost during the subsequent galvanising process. A study is carried out to reduce the variation and to improve the performance of the sandblasting process. An orthogonal array experiment is conducted to find the optimal combination of input controllable factors at this process. Experimental data are analysed using Taguchi's signal-to-noise ratio method. An advanced method of optimisation using 'minimising mean squared error' criterion is also used to obtain the optimal condition. The air pressure from the compressor machine is observed as highly influential in controlling the profile depth variation during the sandblasting process. The recommended optimal combination is implemented resulting in much better conformance of profile depth to the specified limits.