DD256838A1 - GEOMETRY AND GRINDING DEVICE FOR RIBBON MILLING INSERTS - Google Patents

Abstract

The invention relates to a special geometry and a grinding device for indexable inserts of Waelzfraesern, especially for processing hardened serrations. The invention has for its object to largely avoid the profile distortions when using inserts with straight cutting. According to the invention this is achieved in that the profile deviation occurring from the straight edge depending on the construction dimensions of the Waelzfraesers is approximated by a symmetrically arranged over the Schneidplattenlaenge circular arc, the negative mold is sunk into the bottom of the turning-Schneidplattentasche the Schneidplattentraegers and that by Topfschleifkoerpern with negative camber relative to the direction of movement of the indexable insert is ground.

Description

a _s -turn angle of the cup grinding body in degrees

B -Height of the circle segment (profile deviation in center of insert) in mm

d _s -active grinding wheel diameter in mm

l _w p length of indexable insert in mm

embodiments

The invention will be explained in more detail with reference to an embodiment

 It shows

Fig. 1: Profile deviation of the hob cutters due to negative Kopfspanwinkels Fig. 2: grinding device for producing the indexable inserts with a circular arc-shaped cutting edge

The calculation of the cutting profile of hobs results in accordance with FIG. 1, a profile deviation 6 at negative head rake angle (-y _a ) relative to the cutting edge position at a head angle of zero degrees. In addition, the Schheidensollprofil 7 differs by the profile shape deviation 8 from the profile deviation 6. If the profile deviation 6 of the indexable insert is eliminated by taking into account the angle of its arrangement in the rake surface plane when determining the angle of engagement of the hob 10 (rotation of the coordinate system xy in the xy system) 9, the profile deviation B of the straight insert 9 as the profile deviation on the to be produced Precise correction of the profile deviation requires tool-specific indexable inserts that can only be produced by profile grinding, and the placement of the indexable inserts in the plate pocket bottom is unstable and the insert can only be turned once.

For this reason, the profile shape deviation is approximated by a circular arc with the diameter d _B , so that the chord of the circular section is embodied by the cutting edge position 9 corrected by the profile deviation. Since the cutting diameter d _B depends only on basic module-dependent design measures of the indexable hobs and is symmetrical, can the circular cutting profile 11 as shown in Figure 2 in the face grinding Topfschmifkörper with negative abrasive protection - produce a _s results in arcuate Schneidplattentaschengrund safe insert plate and allows the use of all four uniform cutting edges by turning three times.

Claims (3)

claims: 1. geometry for hob cutters, characterized in that the profiled shape deviation (8) is circular arc approximated such that the chords of the resulting uniform circular sections of the opposite edges are arranged parallel to each other and the centers of the circular arc are on a common normal in indexable insert center. 2. Grinding device for hob indexable inserts according to claim 1, characterized in that on the grinding carriage (5) by means of a negative camber angle (~ a _s ) arranged Topfschleifkörpers (1) in the face-ground circular arc produced indexable insert (3) is arranged. 3. grinding device for hob indexable inserts according to claim 1 and 2, characterized in that the cup grinding body ( 1) has a camber angle (-a _s ) of -a _s = arc sin \ - f having.
For this 2 pages drawings Field of application of the invention The invention relates to a special geometry and a grinding device for indexable inserts of hobs, especially for machining hardened serrations. Characteristic of the known state of the art For hobbing traditionally profiled tools are used, the cutting edges are reground at blunting. In recent times, however, hobs are used with indexable inserts whose cutting to reduce the impact load of the generally high-hardness and brittle materials are arranged with negative acute end gauges of -5 to -30 degrees, with larger negative values of the head saw angle are voltage technically advantageous, but to larger profile deviations the toothing and thus lead to larger Fertigschleifaufmaßen, since the nominal profile of the eccentric arranged to the axial plane of the cutting edges of the straightness of the cutting edge cutting edge deviates (DE OS 3128563). As a result, newer indexable insert mill designs use lower negative chuck angles and eliminate the advantages of machining technology. Object of the invention The object of the invention is the development of a special insert geometry and the grinding device required for its production, which causes smaller deviations of the tooth profile or finished grinding allowances and thus reduced manufacturing costs and makes the use of inserts universally possible in indexable hobs. - Explanation of the essence of the invention The invention has for its object to largely avoid the profile distortions when using inserts with straight cutting. According to the invention the object is achieved in that the occurring from the straight edge depending on the design dimensions of the hob profile deviation is approximated by a symmetrically arranged over the cutting plate length circular arc whose negative mold is inserted into the bottom of the indexable insert of the cutting plate and that by means of cup grinding bodies with negative Camber relative to the direction of movement of the indexable insert is ground, the fall of the cup grinding body is calculated as follows: {2 B \
f (1) ds (1 - v "l - lXp / ds