With the rapid development of the manufacturing industry, the requirements for processing efficiency and quality are increasing day by day. Although the traditional grinding method for the barrel of large extrusion granulation units achieves high precision, the straightness and parallelism of the double holes often exceed the tolerance range, and the processing cycle is long and the cost is high. To overcome these challenges, our company has explored a new processing method in practice-using self-made tools for boring instead of grinding. The "boring instead of grinding" manufacturing optimization project has significantly improved the surface quality and dimensional accuracy of the barrel, reduced the rate of product non-conformity caused by processing errors, ensured the stability and consistency of the extrusion granulation process, and thus improved the overall quality of the product. This project has filled the gap in our company's processing technology and achieved good results and benefits.