Common cylindrical helical cutters include cylindrical milling cutters, end milling cutters, staggered three face edge milling cutters, etc. The milling of spiral tooth cutter slots is generally carried out on a horizontal universal milling machine, and the milling method is basically the same as that of machining cylindrical spiral slots. Because the tooth surface of the cutter is a spiral surface, in addition to the factors such as the tooth groove angle and rake angle, the spiral angle must also be considered in machining.
Cylindrical helical tooth cutter
1. Selection of working milling cutter
Profile selection of working milling cutter: when milling the slots of cylindrical helical tooth cutters, you can choose double angle milling cutter or single angle milling cutter. When milling with a single corner milling cutter, the "over cutting" phenomenon of cutting part of the metal in front of the workpiece cutter teeth is more serious than when milling with a double corner milling cutter, so the asymmetric double corner milling cutter is generally selected for milling.
Selection of cutting direction of working milling cutter: except for symmetrical double angle milling cutter, angle milling cutter can be divided into left cutting and right cutting. Viewed from the side of the small cone edge of the asymmetric double corner milling cutter or the end edge of the single corner milling cutter, if the milling cutter rotates clockwise, it is called a left cutting milling cutter; On the contrary, if the milling cutter rotates counterclockwise, it is called right cutting milling cutter.
2. Determination of workbench corner
The deflection direction of the workbench is the same as that of milling general spiral grooves, that is, when milling left-hand spiral grooves, the workbench deflects clockwise; When milling the right-hand tooth groove, the workbench deflects in a counterclockwise direction. Only in this way can the direction of the spiral tooth groove be consistent with the rotation plane of the work milling cutter, so that the normal section of the spiral tooth groove of the workpiece is as close as possible to the profile of the work milling cutter.
The deflection angle of the workbench should be determined according to the type of milling cutter and the spiral angle of the workpiece.
2、 Milling of tooth slots with staggered three face edge milling cutter
The staggered three face edge milling cutter is a kind of cylindrical helical tooth groove cutter, and its circumferential tooth groove is helical. The selection of cutter during milling, the determination of workbench angle, the adjustment of milling cutter cutting position, etc. are the same as the calculation and adjustment methods of general cylindrical helical tooth cutters. The difference is that the circumferential spiral groove of the staggered three face edge milling cutter has two rotation directions, that is, the 1/2 cutter teeth are left-hand and the 1/2 cutter teeth are right-hand, and the left-hand cutter teeth and the right-hand cutter teeth are staggered on the cylindrical surface, and the tooth back of the cutter teeth is polygonal. In addition, the staggered three face edge milling cutter has end face teeth.
1. Milling of circular spiral grooves
When selecting a working milling cutter, it is best to select two milling cutters with opposite cutting directions to mill spiral grooves with different rotation directions respectively.
2. Milling of end tooth grooves
The end tooth slot milling method of the staggered trihedral edge milling cutter is similar to the end tooth slot milling method of the cylindrical straight tooth slot cutter. Because the front of the circumferential tooth of the staggered trihedral edge milling cutter is a spiral surface, which forms a certain intersection angle with the axis of the cutter, its end tooth has a certain rake angle. When milling the end face teeth on the horizontal universal milling machine, in addition to raising the dividing head by an angle and offsetting the workbench laterally by a distance, it is also necessary to tilt the main shaft of the dividing head by an angle in the plane perpendicular to the workbench table along the transverse moving direction, so that the front of the end face teeth can be smoothly connected with the front of the circumferential spiral teeth.
3、 Quality analysis of tool slot milling
Tool slot milling is a kind of comprehensive and complex slot milling, which involves a wide range of contents, high operation requirements and certain difficulties. Among them, the slot milling of cylindrical straight slotting tools is the basis of all kinds of tool slot milling.