FR2506651A1 - METHOD FOR AUTOMATICALLY MINIMIZING GRINDING EFFICIENCY DURING BORING BY GRINDING HOLLOW BODIES - Google Patents

Abstract

The invention relates to a process for automatically minimising the grinding output when finish-grinding hollow bodies, the intention being to grind, with high grinding output and regulatable grinding depth, only those areas where flaws are present. For this purpose, according to the invention, the position of the extent of the flaw line or flaw location is measured. The values are introduced into a control system and, thereafter, the application pressure is changed from a value of 0, via a maximum and back to a value of 0 again in order that transmission, uniform throughout, to flawless material is achieved.

Description

 Process' gour automatically minimize the grinding performance during the reaming by grinding of hollow bodies.

 The invention relates to a method for automatically minimizing the grinding efficiency when reaming by hollow body grinding.

 In the manufacture of tubes, in particular tubes with a diameter equal to or greater than 100 mm, if interior defects occur, mechanical recovery must be carried out when these defects appear to be repairable.

 In known manner, this elimination of the faults is carried out by manually boring, by grinding, the internal surface, according to the optical examination and the appreciation of the operators.

This method of elimination has the following drawbacks a) low grinding efficiency, b) subjective influence of operators on the dta- process
damage by grinding.

 The object of the invention is to provide a method which makes it possible to automatically minimize the grinding efficiency during the reaming by grinding of hollow bodies, with which the grinding work, when iterating by grinding of the internal surfaces, is carried out automatically. so that with a high grinding efficiency and an adjustable grinding depth, we only grind where there are defects, and in which we obtain a gradual transition, on all sides, towards the material without defects.

 To solve this problem, a method is proposed according to the invention, characterized by the fact that the position and dimensions of a fault line or zone located in the axial direction are measured, that it is introduced into a system of control that can be freely programmed and that the application pressure of the tool is controlled in accordance with these values, and that at the same time an oscillating movement is imparted to the material to be ground or to the grinding tool corresponding to the width of the fault line, by varying the application pressure from zero to a maximum then again to zero.

 According to one embodiment, the application pressure is reduced to zero in the case of interior surfaces without defects or portions without defects of the interior surfaces.

 According to another embodiment, when the fault line or zone is measured, an marking detectable by sensors is applied internally or even externally so that a command can be carried out in itself known corresponding to the marking .

The method according to the invention is particularly suitable for being implemented using the apparatus described in the
DE-OS 29 29 024.

 Using the method according to the invention, not only are the existing defects precisely determined but, for example in the case of point or circular defects, a transition is so uniform towards the material without defects that it appears around the defects, in a circle a kind of isometric lines of height or depth. In the case of longer defects, possibly directed obliquely or of several closely related defects, the circular grinding surface extends into a surface of arbitrary shape.

 When applying the method according to the invention, one begins by measuring the position and the nature of the fault line using measuring devices in themselves known, mechanical, optical or electronic. The values obtained are entered into a computer capable of freely prograoxing and more precisely so that during the implementation of the process, they serve as control pulses.

 With the aid of these control pulses, the grinding apparatus is moved in such a way that during grinding boring, the geometric shapes mentioned above occur.

 A marking of the fault line can be carried out both internally and externally. The starting point for the grinding process is the marking center.

 The grinding depth is limited, when using the device according to DE-OS 29 29 024, by means of the hydraulic device of the grinding wheel, by measuring the quantity of liquid discharged.

Claims (3)

K E V X S D I C A T I O N S  1 - Method for automatically minimizing the grinding yield during reaming by grinding of hollow bodies, it characterizes by the fact that the position and dimensions of a fault line or zone located in the axial direction are measured, which 'it is introduced into a control system which can be freely programmed and that the application pressure of the tool is controlled in accordance with these values, and that simultaneously the material to be ground or the printing tool is printed grinding an oscillating movement corresponding to the width of the fault line, by varying the application pressure from zero to a maximum then again to zero.  2 - Process according to claim 1, characterized in that the application pressure is reduced to zero in the case of interior surfaces without defects or portions without defects of the interior surfaces.  3 - Method according to one of claims 1 and 2, characterized in that when measuring the line or fault zone, one applies internally or even externally a marking detectable by sensors so that one can perform a command in itself known corresponding to the marking.