SU1523237A1 - Method of producing chipless screw taps - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used for the manufacture of chipless taps. The goal is to increase the durability of taps by reducing the torques. The radius of the vertices of the deforming edges of the tap ρ is performed in accordance with its parameters and the workpiece material being processed according to the following relationship: ρ = P (1.68529-0.005294HB) where P is the thread pitch of the tap, mm

HB is the Brinell hardness of the material being processed. Smaller radii ρ are taken for harder metals, larger ones for softer ones, which allows for improved deformation conditions, improved thread quality and durability of taps. 1 il.

Description

This invention relates to the field of metal forming and can be used to make chipless taps.

The purpose of the invention is to increase the resistance of taps for various materials of the workpiece by reducing the torques.

The drawing shows a tap, cross section.

Each deformed face of the tap consists of apex 1 (working section), a transition curve 2 and non-working sections 3, which are tapped along the thread profile by an amount K. where HB is the hardness of the metal being machined according to Brcnel, P is the thread pitch.

Tap works as follows.

During the direct course, the tops of the deformed faces of the tap inlet part begin to gradually be inserted into the workpiece metal, squeezing out a helical groove and forming the thread profile. The deforming edges of the tapping part of the tap finally form the prof. Thread. During the return stroke, the tap ejects from the machined hole. Since the vertices of the deforming faces have an optimal value of the radius fi determined depending on the parameters of the tap and the metal being processed, the conditions of the plastic deformation process are most favorable. It is known that; 1l provide normal conditions for the process of plastic deformation. The metal of the fence with a tap and the radii and holes of the tire to deform the edges should be within the limits ((0.6 -1.5) P. rv P. thread pitch. Moreover, lower values of npib are not possible for harder metals, oo .ibs - d, 1 b. soft mild. A differential dependence will know the differential (1; 1no assign values 1 () depending on sioit; processed metal. For example, d.IM tap M6x1 when processing copper ililb 35 KG / MM) f) l, 5 mm, when processing lags:

SP Gch5

WITH

with

(kg / mm), 42 mm, when processing steel 20 (kg / mm), 6 mm.

Improving the process of plastic deformation of the metal allows to obtain the smallest M values for each particular metal, and this in turn provides a number of advantages: the durability of taps increases, the quality of the thread being cut improves (the roughness of the profile decreases, there are no breaks in the threads, scoring on the surface of its profile, etc.), the accuracy of the obtained thread is improved, etc.

Claims (1)

Invention Formula A method of making chipless taps with a radial tip deformed five edges, including the grinding of the contour of the tap with a grinding wheel, installed with the possibility of oscillatory movement in a direction perpendicular to the axis of the tap, characterized in that, p at the top of the deforming edges are formed taking into account the hardness of the material of the workpiece according to the following relationship  (1.68529-0.005294NV), where p is the thread pitch of the tap; HB is the hardness of the material, for a Brinell blank, for which the tap is made.