INCREASING THE EFFICIENCY OF THE CUTTING AND PROCESSING OF GEARS

The paper presents data on the influence of ultrasonic vibrations on the processes of cutting gears made of difficult-to-cut materials. It is shown that with the introduction of ultrasound into the processing zone, there is a significant decrease in the component of the cutting force Pz, chip shrinkage and the height of the micro-roughness. The wear of the cutting teeth with the imposition of ultrasonic vibrations becomes more stable, and the efficiency of the tooth-working tool increases.

SUBSTANTIATION OF CHIPPING FRACTURE MECHANICS DURING DRAWING OF CYLINDRICAL SURFACES WITH ALLOWANCE

The mechanics of chip fracture when cutting the allowance of pre-divisible technological grooves was studied for the first time, and the relationship between the profile and depth of the latter and the characteristics of the stress-strain state in the chip formation zone (relative shear, chip shrinkage, shear angle, front angle, contact processes . This article discusses a more complex problem - the longitudinal division of chips or allowance. Most researchers are inclined to believe that this problem should be solved by pre-dividing the allowance by a network of special chip-splitting ring or screw grooves. The depth of these grooves should be 0.6… 0.95 of the amount of rise on a single tooth of the broach. The results of the study of the mechanics of chip destruction are described when the tool meets the process groove in the drawing process. The connection between the structure of the pipe and the intensively deformed state in the zone of chip formation is shown. From the obtained results the following follows. Preliminary deformation hardening by means of deforming drawing allows to increase hardness of OM twice (steel 10), to 60% (steel 35), to 50% (steel 45) and to 25% (aluminum alloy AK6). This significantly reduces the shrinkage coefficient of chips (respectively 2; 1.4; 1.4 and 1.3 times) and the actual previous angle (at a sharpening angle γ = 15⁰, respectively: from 36⁰ to 18⁰; from 25⁰ to 17⁰; from 21⁰ to 16⁰ and from 22⁰ to 17⁰). All this indicates a decrease in the intensity of the cutting process with increasing intensity of the previous HPD The following minimum values of the groove profile angle for the investigated materials 2φmin were determined: 80⁰ (steel10); 60⁰ (steel 35); 50⁰ (steel 45 and alloy AK6). It is established that the minimum depth of the chip-splitting groove hC is determined from the condition of chip destruction when the tangential stresses in the shear zone are exceeded above the shear resistance of the processed material. The following values of the minimum depth of the chip-splitting groove for the studied materials were obtained: hCmin = (0.4… 0.55) Sz - steels 35 and 45; hCmin = (0.55 (0.6) Sz - AK6 alloy.

CHIP FORMATION DURING THERMAL FRICTION TURN-MILLING

This paper presents the results of chip formation studies in the processing of 30KhGSA steel by thermofriction turn-milling. When studying the process in this work there are presented the results of studying chip formation when the processing of chip formation there is used the metallographic method. Chip root area investigated. The dependence of the chip shrinkage coefficient on the cutting speed and feed was also investigated. It is established that with increasing supply S the value of the chip shrinkage coefficient K decreases. The higher the chip shrinkage factor, the more work will be required to cut the chips and the more complex the processing process.

Determining the Optimal Parameters of Chip Shrinkage Coefficient and Cutting Force in High-Speed Machining for Aluminum Alloy A6061

Nowadays, increasing the productivity and the quality of machining become major challenges of the metal cutting process. Due to the complexity of the chip formation process, in particular, at high cutting speeds, finite element model (FEM) has been frequently used as an alternative solution. Chip shrinkage coefficient and cutting force are the two basic parameters of the cutting process, which determines the productivity and quality of the workpiece. This study uses a Grey correlation relationship to analyze and select the common set of parameters for cutting force and chip shrinkage coefficient of the chip. Simulation of the A6061 aluminum alloy high-speed milling is done by Bao-Wierzbicki's (B-W) model. The optimal parameters are determined cutting depth 1 mm, clearance angle 6oand rake angle 10o. This parameter set adjusts the cut parameters so that the cutting process achieves the highest machining efficiency.