SU727274A1 - Cutting-out punch - Google Patents

Description

The invention relates to the processing of metals by pressure, in particular to the separating operations of cold sheet stamping, performed on die-cutting shears and coordinate turret presses in the sequential die-cutting mode, and can ₅ be used in the processing of holes of various sizes and sizes in sheet metal parts in instrumentation and mechanical engineering , as well as in the manufacture of aircraft.

A punch is known for cutting 10 holes of various sizes and sizes in sheet parts on nibbling scissors and coordinate turret presses [1]. However, when cutting with this punch, due to the intermittent nature of the material separation process inherent in this deformation scheme, pointed irregularities (protrusions, scallops) remain on the treated surface, the value of which varies between 0.1-0.32 mm.

A die-cutting punch with a shank, a persistent protrusion and a working part bearing a cutting edge bounded by equal arcs intersecting in pairs at points located on a common circle is also known [2]. The use of this punch makes it possible to reduce the magnitude of pointed irregularities due to the choice of the radius size of the mentioned circular arcs and the feed rate for one double stroke of the punch and to bring the value of the irregularities to the minimum limits of 0.04-0.08 mm.

Thus, the discontinuity of the separation process in combination with the cutting edge of the punch, made in the form of a convex circular arc, does not completely eliminate the pointed irregularities, which leads to a decrease in the relative length of the supporting profile tp according to GOST 2789–73. To eliminate irregularities and increase the relative reference length of the profile tp, additional operations of metalwork filing or contour milling are used, which increases the complexity of processing.

The possibility of obtaining minimum values of the magnitude of peaked irregularities is associated with a decrease in the feed rate of the material in one double stroke of the cut punch.

In order to improve the quality of the cut surface and reduce the complexity of manufacturing parts in the proposed punch, the arcs are made convex in the direction of the axis of the punch.

In FIG. 1 shows the proposed punch, General view; in FIG. 2 - section A — A, in FIG. 1; in FIG. 3 is a schematic diagram of die cutting and 5 forming a profile of the treated surface.

The punch has a shank 1, a cylindrical part 2 with a diameter D _p , a conical thrust protrusion 3 with a diameter D _{at the} largest part of the cone, an annular recess 4 ¹⁰ around the conical thrust protrusion and longitudinal grooves 5 bounded by cylindrical surfaces with a radius R _K , the cross sections of which are arcs with chords a. These arcs limit the cutting edge and intersect at points lying on a circle located on a cylindrical surface with a diameter of Di.

In FIG. 3 the following 'designations are given: 20 and 7 - elementary processed surfaces;

R. max — the depth of the depression between surfaces 6 and 7;

S is the pitch of material supply in one double stroke of the punch, determined by the half difference between the diameter D _{and the} cylindrical part of the punch and the diameter D of _the conical thrust protrusion.

In FIG. 2 it can be seen that the cutting edge J0 is bounded by a number of concave arcs of circles with radius bm of curvature R _K. The value of the chord a is equal to the side of the inscribed regular polygon into a circle with a diameter of D „.

Die cutting by the proposed punch (see ^Ji . Fig. 3) is as follows.

The processed material is fed under the cutting edge to the feed step S, determined by the half difference between the diameter D _p 40 and the diameter D _y .

The roughness on the elementary surfaces 6 and 7 of the cut-out contour is in the range of 0.04-0.08 mm, and the depth of the depression R \ m> ®, which depends on the radius of curvature Rk of the cutting edge and the feed pitch S, does not significantly affect the decrease in the relative value supporting surface profile. The combination of the cutting edge of the punch, made in the form of 'concave arcs of circles, with the intermittent nature of the process of separation of the material leads to the elimination of pointed irregularities and an increase in the relative length of the supporting profile of the machined surface.

Thus, the invention makes it possible to 'completely eliminate gouging irregularities on the treated surface, thereby increasing the relative reference length of the profile. The required values of the roughness parameters can be achieved at maximum values of the feed material.

Claims (2)

(54) CROSSBAND PUNCHANT The laziness of the details in the proposed arc punch is convex in the direction of the punch axis. FIG. 1 shows the proposed punch, a general view; in fig. 2 is a section A-A, in FIG. one; in fig. 3 is a diagram of die-cutting and forming a profile of the treated surface. The punch has a shank 1, a cylindrical part 2 with a diameter Dp, a conical thrust protrusion 3 with a diameter Dy of the largest part of the cone, an annular recess 4 around the conical thrust protrusion and longitudinal grooves 5 bounded by cylindrical surfaces with radius R, whose cross sections are arcs with chords a. These arcs limit the cutting edge and intersect at points lying on a circle located on a cylindrical surface with a diameter of D. FIG. 3 the following notation is given: 6 and 7 - elementary machined surfaces; R.MAxt - depression depth between surfaces 6 and 7; S is the material feed pitch in one double punch stroke, defined by the half difference between the diameter of the D-cylinder part of the punch and the diameter D of the conical thrust protrusion. FIG. 2 that the cutting edge is bounded by a series of concave circular arcs with a radius of curvature RK. The magnitude of the chord a is equal to the side of the inscribed, regular polygon in a circle with a diameter D. The cutting by the proposed punch (see Fig. 3) is carried out as follows. The material to be processed is fed under the cutting edge to feed bar S, determined by the half-difference between diameter D and diameter DN. The roughness on the elementary surfaces 6 and 7 of the contour to be cut is within 0.04-0.08 mm, and the depth of the depression, depending on the radius of curvature RK of the cutting edge and feed slot S, does not have a noticeable effect on the decrease in the relative value of the reference surface. profile The combination of the cutting edge of the punch, made in the form of concave arcs of circles, with the intermittent nature of the material separation process leads to the elimination of pointed ridges and an increase in the relative length of the reference profile of the treated surface. Thus, the invention makes it possible to completely eliminate the pointed irregularities on the treated surface, thereby increasing the relative support length of the profile. The required values of the roughness parameters can be achieved at maximum feed rates. Claims of the invention: A vortex punch having a shank, a thrust protrusion and a working part equipped with a cutting edge bounded by equal arcs intersecting in pairs at points located on a common circle, characterized in that, in order to improve the quality of the cut surface and reduce the labor intensity of manufacturing parts, the arcs made convex in the direction of the axis of the punch. Sources of information taken into account in the examination 1.Waintraub D. А., Klepikov Yu.M. Cold stamping in small-scale production, reference book. M., “Mechanical Engineering, 1975, p. 158, FIG. 63. 2. USSR author's certificate number 376186, cl. 23 D 35/00, 05/30/73 (prototype).