One of the important physical parameters in the process of cutting gray cast iron is cutting force. In the process of cutting gray cast iron, the cutting heat of gray cast iron is directly affected by the cutting force of gray cast iron, which affects the wear of cutting tools and the surface quality of machined workpieces. In actual production, the necessary basis for calculating the cutting power of gray cast iron, using and designing machine tools, tools and fixtures is also the cutting force of gray cast iron.

Therefore, it is necessary to accurately evaluate the cutting force of gray cast iron, but people often change the tool when cutting gray cast iron because they are afraid of tool wear or the impact of different materials on the cutting force of gray cast iron. However, due to the small deviation in the process of tool change, no one considers the consideration of the cutting force of gray cast iron. Maybe the tool reassembly and tool change have a great impact on the cutting force of gray cast iron, It even exceeds the influence of the material itself on the cutting force of gray cast iron. These two aspects will be explored and studied.

The cutting force evaluation material of gray cast iron is 45 steel cylindrical sample treated by quenching and tempering. This paper considers that each layer of gray cast iron cut by 45 steel cylindrical sample is homogeneous. Specification is Φ seventy × 350 mm。 Before cutting gray cast iron, turn the sample on the lathe with an old knife Φ sixty-seven point eight × 300 mm. When cutting gray cast iron, adjust the spindle speed of the machine tool to 160 R · min-1, keep the feed rate unchanged at 0.294 mm · R-1, only change the cutting depth of gray cast iron to 2 mm, 1.25 mm, 1 mm and 0.5 mm respectively, and the tool tip walking length is 65102 mm, 66122 mm, 66632 mm and 67142 mm respectively. When the cutting depth of gray cast iron is 0.5 mm, the cutting length of the tool tip for cutting a complete sample is the longest, which is 67142 mm. The cutting force of gray cast iron has not changed in the process of cutting a complete sample. We believe that the tool tip is not worn.

In the test of the impact of reassembly and tool change on the cutting force of the sample and the subsequent test of the cutting force of the sample, the cutting length of the tool tip is 10000 mm, which is far less than 67142 mm. The impact of blade wear on the cutting force of gray cast iron is not considered. During the cutting test of gray cast iron, the new cutter shall be reassembled and replaced under the same cutting depth of gray cast iron. The turning tool is machine clamp turning tool, and the blade is YG8 cemented carbide blade of the same batch of products produced by the same manufacturer (as shown in the figure).