The size of general-purpose machine tools used in production tends to be oversized for the parts being produced. Downsizing these machine tools can reduce manufacturing costs by decreasing the size of large production lines. Additionally, smaller machine tools can be easily transported and installed, facilitating the construction of flexible production lines that can adapt to changes in demand. However, downsizing machine tools reduces structural rigidity, leading to deformation due to cutting forces. The displacement of the tool from the target position caused by this deformation makes high-precision machining of hard materials, such as steel, difficult. This study proposes a method to reduce machining errors in small machine tools by predicting deformation during cutting and compensating for tool position based on the results of a simple static load test. To verify the effectiveness of the proposed method, a new small 3-axis NC milling machine was developed. The proposed method successfully reduced machining errors by 87% in the side cutting of a steel workpiece.

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