Vibration-Free Machining of Pilgrim Mandrels

Abstract

A support collar plate for vibration-free holding of workpiece, i.e., pilgrim mandrel, clamped at both ends and to be processed between its ends by means of a grinding wheel, comprised of a base, arranged fixed in place in respect to the workpiece, and a clamp, which extends around the workpiece on at least two oppositely located sides. The workpiece can be clamped by a clamping force, wherein the clamp extends around the workpiece so that it is possible to perform processing in the area of the clamp on the side facing the grinding wheel, and wherein the clamp is floatingly seated in at least one direction perpendicularly in respect to a longitudinal axis of the workpiece, so that the clamp is self-centering in respect to the workpiece. By means of the floatingly seated clamp, the workpiece is maintained independent of exterior forces which change the spatial position of the workpiece.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of the priority filing date in PCT / EP2008 / 003226 referenced in WIPO Publication WO 2008 / 128758. The earliest priority date claimed is Apr. 24, 2007.FEDERALLY SPONSORED RESEARCH[0002]NoneSEQUENCE LISTING OR PROGRAM[0003]NoneSTATEMENT REGARDING COPYRIGHTED MATERIAL[0004]Portions of the disclosure of this patent document contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyright rights whatsoever.BACKGROUND[0005]The invention relates to a support collar plate for the vibration-free holding of a workpiece, in particular a pilgrim mandrel, which is clamped at both ends and is to be processed between the ends by means of a grinding wheel.[0006]To produce tubes, a piece of sheet metal, fo...

AI Technical Summary

Benefits of technology

[0018]It becomes clear that the invention is realized in every case by means of at least one floatingly seated support collar plate, which does not keep the workpiece at a defined location and squeezes it there, but instead guides the workpiece and supports its. Because of this, the workpiece maintains its full degree of freedom during processing. Workpiece tensions created during the hardening process can be reduced or equalized during pre-roughing processing. In this case, the support collar plate initially moves along with the wobble of the workpiece. Following the first pre-roughening movements, the workpiece becomes calm, and with it the support collar plate. A possible wobble can be easily deduced from the movement of the support collar plate. The support collar plate also has a certain moment of inertia, which has a positive effect on the deflection of the workpiece caused by the grinding wheel. In practical tests, this deflection has been calculated to be a few thousands of a millimeter. This small error can be compensated by placing at least one vibration-measuring finger against the grinding wheel, preferably in the workpiece center.

[0019]The floatingly seated clamp, resting dynamically free against the workpiece, together with the base arranged fixed in place in regard to the workpiece, forms a freely floating two-point support collar plate, which does not exert any horizontal or axial forces on the workpiece. This freely floating support collar plate aids the workpiece in retaining its own natural position so that, following processing, the workpiece is free of tension and therefore becomes straight-lined and wobble-free. The tensions existing in the workpiece as a result of the hardening process are released by the freely floating support collar plate in the course of processing. In this way, it is possible to create a pe

Problems solved by technology

A known and substantial problem exists in that, when coming into contact with the grinding wheel, the long and slender pilgrim mandrel makes excursions transversely to the axis of rotation of the grinding wheel.

This results in so-called chatter marks on the ground surface.

The disadvantage here lies in that, in the course of this process step, the workpiece tensions created during the hardening process are not released.

Following the removal of the support collar plate, there is a shock, resulting in a poor concentric running of the workpiece.

They do not have the ability of acting in a vibration-damping manner.

The employment of several of these types of support collar plates, distributed over the length of the workpiece, also does not result in any improvement.

If these support collar plates are employed in a topological relationship with the workpiece, they have the additional d

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