Due to the high development of powder metallurgy technology, mold manufacturing technology, and numerical control sharpening technology, the cutting part of modern metal cutting tools can be made into very complicated shapes, and the cutting process is also very complicated. A real metal cutting tool can be regarded as a combination of a series of unit tools. Research shows that the natural value of the chip removal vector (including chip removal direction and chip removal speed) of the unit tool always makes the cutting power tend to be extremely small, which is the so-called principle of minimum energy in unit tool cutting.
In the cutting process, the unit tools cut in parallel, each trying to discharge chips according to its natural chip removal vector. The chip removal vectors of these “do it all” are bound to interfere and conflict with each other; and in order to maintain the integrity of the common chips discharged by each unit tool, the unit tools must coordinate their chip removal vectors to determine the overall chip removal movement. Studies have shown that the natural law that restricts the overall chip removal movement is still the “minimum energy principle”: that is, among all possible overall chip removal movements that meet the constraints set by the control parameters, the overall chip removal that can be achieved Movement, the total cutting power consumed by the entire tool (that is, the sum of the cutting power consumed by the unit tools) must be minimized.
The cutting process that must be coordinated due to chip removal interference is called “non-free cutting”. Almost all actual cutting processes are non-free cutting. In the non-free cutting process, the principle of minimum energy ensures that the cutting energy consumption of the entire tool is minimized, but it cannot make the actual chip removal vector of each unit tool consistent with its natural chip removal vector. In fact, after chip removal coordination, generally speaking, each unit tool has to make appropriate concessions instead of chip removal according to its natural chip removal vector. Therefore, the total cutting power of a tool is often greater than the sum of the energy consumption of all the unit tools contained in it when they work individually. This reflects the strong nonlinear characteristics of the non-free cutting process. This feature makes the cutting energy consumption increase; chip deformation is complicated, and the surface finish of the machined surface deteriorates; the cutting force increases, the deformation of the process system increases, and the machining accuracy decreases; the cutting temperature rises, the tool life is shortened, the stop time for tool changes increases, and the efficiency decreases ,Increased costs. Many problems in modern cutting often originate from these drawbacks of non-free cutting.