To predict the workability of a tool structure at the design stage, it is necessary to calculate the parameters of the cut layer when this tool is used because the cut layer’s size determines the strength and dynamic characteristics of the cutting process. It is known that the size and shape of the cut layer are affected by the allowance cutting scheme embedded in the tool design. Therefore, the parameters of the cut layer with the tool must be investigated taking into consideration the actual shapes and location of the cutting edges of the tool teeth and the cutting scheme with individual teeth. Existing analytical dependences on determining the thickness of the cut layer do not take into consideration the group arrangement of the teeth, which have a different shape and location of their cutting edges. Therefore, a procedure for determining the thickness of the cut layer analytically has been proposed, using the example of circular saws with multidirectional teeth while taking into consideration the patterns in the arrangement of the cutting edges of individual teeth and the real movements of the tool during its operation. The proposed procedure makes it possible to determine the parameters of the layer cut with the tool at both constant and progressive allowance cutting schemes. One can also specify the parameters of the cut layer at any time of the tool’s operation and analyze the change in the shape of the slice in time. Based on the analysis of the parameters of the cut layer, it has been established that saws with multidirectional teeth do not work with the entire width of the cutting edge but only in its part, whose share does not exceed 55 % of the width of the tool. The procedure reported here could be used to determine the loading of the cutting tool part with a more complex cutting scheme, which also includes tools that are operated by the form-generating method
Considered in the article. expansion of technological capabilities of machine tools mod. 528С for cutting bevel gears with a circular tooth with an increased outer taper distance of the gears with a crossing angle of 300. Optimizing programs are analyzed to determine the geometric parameters with obtaining the localization of the contact zone in height, for the tooth shape III, even on a machine tool without tilting the tool, and in the presence of a machine with the inclination of the tool spindle, widely apply the double-double-sided cutting method for a wide range of bevel and hypoid gears, and not only for gears of small modules, but also for wheels of medium modules, which was previously considered impossible without the use of special machines with helical movement. The machine settings with an increased external taper distance on a machine with insufficient adjustment offsets are analytically determined. As a result, it was found that with certain axial displacements of the headstock of the product, it is possible to place a wheel blank with an increased size of the outer conical distance. In this case, the processing is carried out by a reduced flat producing wheel. Partial displacement of the lateral surface of the wheel teeth is compensated by the optimization of the setting parameters when processing a paired gear, while the calculated displacements, due to the possible intersection of the wheel with the base parts, can be corrected upwards. The new displacement values are again entered into the optimization program as initial ones.
The questions of features of application of a mill with the separate scheme of forming are considered. The characteristic of non-uniformity of loading on the tool connected with various schemes and design features of gear cutters is given. It is shown that the nature of the torque waveforms of the cutter with a separate shaping scheme indicates a greater smoothness of the cutting process and less cutting effort. Cutters with a separate shaping scheme have 1.75 times more teeth at the length of one turn of cutting than a standard cutter. In the range of investigated feeds 3-6 mm/rev, the average torque when working with a cutter with a separate shaping scheme is 2-2.5 times less than when working with a standard cutter that treats the side surfaces and bottom of tooth cavities, and 1.5 times less when the standard cutter does not process the bottom of the teeth.
The scientific foundations of the technological regulation for the selection and assignment of processing parameters during gear milling are based on the fundamental theoretical provisions of the friction theory, mechanical engineering technology and cutting theory. For the first time, the sliding angle was scientifically substantiated during plastic displacement (pre-deformation) of the material, when the material flows around the indenter (tool) without separation from the main mass. Determination of the minimum sliding angles during the processing of large-module gear wheels by milling, based on the physicochemical processes of friction mechanics, can significantly increase the efficiency of the tooth shaping process and the operational properties of their surfaces. An atomic approach to the processes of deformation and destruction of chips during cutting is presented. The resistance to plastic deformation of the cut layer depends on the type of crystal lattice of the processed material, its stacking fault energy, and the presence of impurities at the grain boundaries. The influence of these factors is manifested through the types of dissipative structures that are formed in the process of deformation of the cut layer and determine its localization.
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