Improved design of chip breaking groove of the hot

Improved design of indexable blade chip breaking groove

Abstract: This paper focuses on the improved design of general chip breaking groove for rough machining, gives the experimental comparative data of cutting force components before and after the groove shape improvement, and carries out the comparative test of tool life for the turning of different workpiece materials

I. preface

one inspection rod should be machined. Chip control is an important problem that needs to be studied and solved in metal cutting production. Bad chips will hurt operators, affect the surface quality of machined parts, damage machine tools and tools, increase auxiliary working hours and affect productivity. With the development of CNC, FMS, CIMS and other automation technologies, the problem of chip control has become more important, because bad chips will make the automatic production line unable to operate normally. One of the basic problems of chip control is to make chips break reliably. At present, the most commonly used method is to use chip breaking groove to break chips. Chip breaking groove chip breaking is the principle of using the work hardening, impact and extrusion of materials to achieve destructive strength. Due to the important role of the indexable blade chip breaking groove in chip treatment, cutting resistance, tool life, machining accuracy and other aspects, the groove type of the chip breaking groove has also been continuously improved in the past two decades. The chip breaking groove with the best institutional arrangement line edge, broken line edge, curve edge and curved surface, polyhedral convex, concave and other surfaces has been developed successively, and the groove surface has become more and more complex, Its chip breaking performance is also continuously improved. Developing a new type of chip breaking groove is one of the effective ways to develop a new type of blade and improve the cutting performance of the blade

II. Improved design of chip breaking groove type

chip breaking groove can usually be divided into fine machining, semi fine machining and rough machining chip breaking groove according to its purpose. In order to improve the cutting performance of M5 cemented carbide indexable blade in rough turning steel, stainless steel and cast iron and improve the service life of the blade, the M5 chip breaking groove was improved. Figure 1 shows the chip breaking groove type before and after the improvement. The key point of the improved design is to adopt the chip breaking groove type with the combination of negative chamfer and pit. Because in the cutting process, when the chips flow out of the front face of the tool, there is a strong friction between the bottom layer of the chips and the bottom of the chip breaking groove, which will generate a lot of heat. The cutting heat is constantly transferred from the chip (5) to the blade by uncovering the iron door chips of the hydraulic control box, causing the blade to wear. As shown in Figure 2, cutting a pit at the bottom of the chip breaking groove can minimize the contact area between the blade and the chip bottom layer, so as to reduce the wear of the blade and improve the service life of the blade. The negative chamfering design of 5 ° positive rake angle is to reduce the cutting force generated in the cutting process

III. comparison of cutting performance of the blade before and after improvement

1) comparison of cutting force

the improved M5 (New) chip breaking groove adopts negative chamfering with a positive front angle of 5 °. The design of negative chamfering is the main factor affecting the cutting force, mainly the axial force and radial force. Fig. 3, FIG. 4 and Fig. 5 are the comparative data of cutting force components of the blade before and after the improvement when vc=150m/min and ap=4mm turning workpiece material is ss1672. The results show that when cutting steel and stainless steel, the axial force and radial force of M5 (New) and M5 are reduced by 8% - 10% and 12% - 14% respectively, and the tangential force is basically unchanged

Figure 3

Figure 4

Figure 5

2) comparison of tool service life

the improved design of M5 cemented carbide indexable blade is mainly to improve its cutting performance in processing steel, stainless steel and cast iron. Table 1, table 2 and table 3 show the comparison of tool life of M5 and M5 (New) when turning steel, stainless steel and cast iron under the same cutting conditions. Table 1 shows the outer circle of steel hub with C45 turning workpiece material; Table 2 shows the inner hole of cast iron hub with turning workpiece material of ggg50; Table 3 shows the outer surface of stainless steel flange with turning workpiece material F51. Obviously, compared with M5, M5 (New) greatly improves the tool life under the same cutting conditions. Table 1

cutting conditions blade tool life vc=320m/min end of use

f=0.4 ~ 0.5mm/r

ap=1 ~ 2mm

coolant: emulsion cnmg120412-m5

tp100185 pieces cnmg120412-m5 (New)

TP pieces

Table 2

cutting conditions blade back flank wear vc= 250m/min

f=0.25 ～ 0.5mm/r

ap=3mm

coolant: emulsion

processing workpiece: 40 cnmg160612-m5

tx15o0.26mmcnmg160612-m5 (New)

tx1500.1mm

Table 3

cutting conditions blade tool life vc=130m/min

coolant: emulsion cnmg120412-m5

tp2009mincnmg120412-m5 (New)

tp20011min

conclusion

by comparing the cutting performance of the indexable blade before and after improvement, the under the same cutting conditions, the improved design of chip breaking groove with the combination of negative chamfer and pit is adopted, The service life of the blade is greatly improved. (end)