It has compact structure and simple operation. It is widely used in the key processes of relatively stable products, large batch production and single piece small batch production. The advantage of using special fixture in production is that it can achieve high productivity and improve machining accuracy. Its disadvantage is that the design and manufacturing cycle is long. Due to the influence of multiple varieties, small batch and other factors in actual production, The special fixture is difficult to meet the processing requirements in terms of adaptability and economy.