SU1152966A1 - Method of manufacturing spiral knives for leather shaving machines - Google Patents

Abstract

A METHOD FOR MANUFACTURING SPIRAL KNIVES OF PLANING LEATHER MATERIALS, including rolling the ribbon into: a flat spiral, cementation, quenching, tempering and bending of knives, characterized in that, in order to increase the durability of the knives, after bending on the front surface of the knife, roughness R is created, in order to increase the durability of the knives, after bending on the front surface of the knife, roughness R creates a roughness of the knives, in order to increase the durability of the knives, after bending on the front surface of the knife, roughness R creates a roughness of the knives, in um, applying transverse scratches. S

Description

FIELD OF THE INVENTION The invention relates to mechanical engineering for the leather industry and can be used in the woodworking industry and in other areas where required. cutting fibrous structures. In modern engineering, methods are known for the manufacture of spiral knives, including rolling, bending and heat treatment with hardening of the side surfaces D and 2. There is also known a method for manufacturing spiral leather knives by the method of one-sided hardening of the front surface {s. Knives made according to this technology have, after thermal processing, a mechanically untreated surface, the quality of which is characterized by a surface roughness of R 5-10 µm with a chaotic distribution of i-microrelief elements. When planing natural leather in LIA cutting with spiral knives

the helix angle of the knives, the bluntness of the cutting edge, the friction of the converging chips on the front surface and the skin on the rear surface are made.

Due to the presence of roughness on the front surface of knives with a chaotic & 1 distribution of U1-relief elements, which basically determines the formation of the profile of the cutting edge of the knife, the helix angle of the helix on the micro-sites at all points of the cutting profile is almost equal to the helix elevation angle oi. At the same time: (as for cutting all points of the cutting profile are crushed are the same, and a slight blunt edge leads to an increase in cutting forces and, as a result, to a low resistance of the knives between regrindings at a fixed hardness of the cutting edge.

The purpose of the invention is to increase the durability of knives.

This goal is achieved by the fact that according to the method of making spiral knives of planing tanning machines, including rolling the ribbon into a flat helix, cementation hardening, tempering and bending the knife after bending on the front surface of the half of; rev, sections of profile with elevation angles smaller and greater than the elevation angle of the screw

the lines follow each other, and their sizes correspond to the distances between the micro unevenness of the front surface. The cutting of the material being processed is carried out as the first,

and the second microsites, however, the ability of the cutting edge to retain its cutting properties longer is determined mainly by microsites with lifting angles smaller than

- lifting the helix, since the latter have better cutting conditions. At the same time, the cutting process consists of alternating processes of deformation of the material by microsites with

large lifting angles of irregularities and cutting the deformed material by micro-segments with smaller lifting angles. Optimal roughness is dependent on the method.

and processing modes by a statistical distribution of the micron-roughness sizes and the angles of inclination of the side surfaces of the scratches to the knife edge,. i

The analysis of the roughness profile of various chip surfaces with the definition of the functions cf fCR). Accepting a statistical distribution of tilt angles of 62 MW creates a roughness of 15–20 μm by applying transverse scratches. It uses the fact that the elevation angles of the lateral surfaces of the microscopic irregularities when grinding the front surface lie in the plane perpendicular to it, which also contains the constructive elevation angle of the helix of the spiral knife. Thus, micro-sites with different helix elevation angles equal to 6 are formed on the cutting edge of the knife (1 g,, where g is the angle of inclination of the side surface and risks to the edge of the knife; it is the constructive angle of elevation of the helix. Since the effect of positive and negative angles of inclination of the microroughness to the edge of the knife, one half of the length of the cutting profile has a helix angle) ij c ci, the other is normal, the average angle of inclination and the roughness parameters of the ground surface are determined. The condition of high durability of knives is oCi c {+, since the micro-section of the cutting edge with negative angles is not accepted in the operation. At a 95% confidence level of the scraper, the roughness of the ground front surface of the planer knives with an elevation angle of helix ot 23 is set ( minimum for all types of planer knives). The minimum value of the elevation angle of the cutting micro sections eij corresponds to the average angle of inclination fcp. 1, obtained when the roughness of the front surface R-15-20 microns. With RJ; The 20 µm value of the average angle increases and negative angles appear, which worsens the cutting conditions. On the other hand, at R 15 microns, the value of the average angle decreases and the elevation angles of the micro-sites {ci, - k - f;) increase, which entails an increase in cutting forces. PRI me R. Grinding of planing knives on the front surface is carried out. The knives are preselected according to the hardness of the hardened layer (HRA 78-82 Grinding of knives on the front surface is carried out on a special device with the following conditions: Cutting speed, m / s8 ... 12 0.1-0.15 m Manual feed, m / minO, 5 ... 6 ПП 250 16 V Abrasive wheel х76 63С40 СМ1 7 К5 Direction of thread Normally to the fouval marks of the cutting edge. The sample is tested for strict weight loss in chrome halves tanning after dividing operation according to standard technology The treatment of the skin, the thickness of the sample is 2.3-3.5 mm, the humidity is 60%, the thickness of the finished product is 1.6-1.9 mm. The tests are carried out on three types of knives. The average angle of inclination of the sides of the marks is determined by profilograms. The planing and sharpening modes of the knives on the back surface are set with odiakovymi for all variants.With each experiment, no less than 200 experiments are carried out (one experience sharpening the blade shaft and the subsequent planing until blunting). A 95% confidence interval is determined by Student's t test. The results of stochastic tests are given in the table. As can be seen from the table, the durability of knives, polished on the front surface by 70%, is higher than the durability of knives without machining the front surface. The economic effect from the introduction of the proposed method is 309 thousand rubles. in year.

vy 78-82 5-10 t) (Direction of the risks chaotic)

78-82 5-10

(Direction of scratches normal to the edge of the knife)

. 78-82 15-20

(Direction of scratches normal to the edge of the knife)

5.37iO, 47

23 ± 6.7

7.23 + 0.53

1.35

23i16

9.21 + 0.71

1.72

Claims (1)

METHOD FOR MANUFACTURING SPIRAL KNIVES OF STROGEN LEATHER MACHINES, including rolling the tape into: a flat spiral, cementation, hardening, tempering and bending of knives, characterized in that, in order to increase the resistance of the knives, a roughness of 15-20 microns is created on the front surface of the knife after bending by applying transverse scans.