Metal deforming – With use of control means energized in response to activator... – Including plural sensors or sensor responsive to comparison...
Patent
1994-11-09
1997-01-28
Larson, Lowell A.
Metal deforming
With use of control means energized in response to activator...
Including plural sensors or sensor responsive to comparison...
72271, B21C 3100
Patent
active
055968953
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of extruding profiles of material, such as metal or plastic, comprising the steps of: product rises above a predetermined optimum temperature, and reversely, increasing the speed of extrusion if the temperature falls below the predetermined optimum temperature, all in such a manner that the temperature of the extruding product is maintained as constant as possible.
The present invention also relates to an apparatus for the working method according to the invention.
In the extrusion of metal or plastic profiles some mal formations or irregularities in the structure of the extruded product occur during the extrusion operation, in particular in profiles having varying temperatures in the different areas of the profile, and such malformations and irregularities of the material structure will result in an unsatisfactory quality of the end product.
Generally, such malformations and irregularities are the result of varying temperatures of the extruding product during the extrusion operation, due to the the forces which effect the material in order that it may be pressed through the extrusion outlet.
To counter these malformations and irregularities attempts: have been made to optimize the extrusion process in various ways.
GB Patent Specification no. 1.431.884 describes a method of substantially the kind described in the introduction.
In this known method, the temperature is measured by direct contact at the foremost portion of the extruding product near the outlet in order to form an estimate of the temperature. At the same time the thermal radiation of the extruding product is measured without contact by means of an instrument responsive to heat, and a thermal radiation temperature is determined, which is then corrected on the basis of the estimate of the extrusion temperature. During the extrusion operation determination of a corrected thermal radiation continues without contact, whereupon the speed of extrusion is reduced, if the thermal radiation temperature rises above a predetermined optimum temperature, and the speed of extrusion is reversely in creased if the thermal radiation temperature falls below the predetermined optimum temperature.
The above method, however, has some drawbacks. Thus, measuring the temperature of the extruding product by direct contact in order to obtain a correction of the thermal radiation temperature is a difficult procedure, and in addition, the method is complex and time-consuming so that a production capacity, which can be considered optimum as compared to the performance of modern extrusion apparatuses cannot be obtained.
The said patent specification also provides an apparatus for use in the extrusion of profiles, and this known apparatus is of the type which comprises a machine having an extrusion outlet and means for pressing material suitable for extrusion, such as metal or plastic, through the outlet.
It is therefore an object of the present invention to provide a method, whereby the malformations and irregularities of the material structure referred to above can be reduced considerably and possibly avoided altogether, and at the same time an optimization of the process must be obtained in view of a rational production of profiles.
This object is achieved by means of a method of the kind described in the introduction, said method according to the invention comprising the features of: contact; thermal radiation on the basis of a calculation of the values measured; extruding product and comparing to the predetermined values; on one hand the quality of the profile checked as well as the geometric dimension, and on the other hand the predetermined values; previously and controlling said pressure in such a manner that the temperature of the extruding product is maintained as constant as possible; and the remaining data relating to the extrusion pressure.
An extrusion of profiles having a constant or at least fairly constant temperature over the entire profile is hereby accomplished, which will result in a uniform standard of quality
REFERENCES:
patent: 2863557 (1958-12-01), Munker
patent: 3157281 (1964-11-01), Schnettker et al.
patent: 5009091 (1991-04-01), Hinterman et al.
patent: 5237844 (1993-08-01), Duri
Larson Lowell A.
Vigil Thomas R.
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