Metal deforming – With indication of condition or position of work – product,... – Including deformation by simple bending
Reexamination Certificate
2002-12-17
2004-06-22
Jones, David (Department: 3725)
Metal deforming
With indication of condition or position of work, product,...
Including deformation by simple bending
C072S031110, C072S389300, C072S389600, C072S702000, C700S165000, 36
Reexamination Certificate
active
06751993
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to bending method and bending system and more particularly to bending method and bending system achieved by taking into account a spring back and elongation which accompany bending.
BACKGROUND ART
Conventionally, when a sheet material is bent, generally, a bending angle of the sheet material W is measured to confirm a processing accuracy. That is, if a bending load is removed from the sheet material W being bent, the sheet material W is returned to its original shape due to a spring back as shown in FIG.
1
. Thus, if the bending angle does not reach its object angle, corrective bending is further carried out so as to carry out correction. The spring back amount can be obtained from a difference in the angle of the workpiece W between before and after the load is removed.
As for measurement of the bending angle, according to a non-contact type measurement method shown in
FIG. 2
, light L is projected to the sheet material W bent by cooperation of a punch P and die D and then its reflected light is received to measure a bending angle. Alternatively, according to another method, as shown in
FIG. 3
, an indicator
101
is brought into contact with the bent flange of the sheet material W and the bending angle is measured based on a moving amount of the indicator
101
.
However, according to these conventional technologies, upon actual bending operation, a corrective bending must be carried out with measurement of the bending angle and to achieve an accurate bending, the corrective bending must be executed repeatedly, thereby necessitating much time and labor.
Further, sometimes, when the sheet material is bent, an elongation may occur, so that the bending cannot be carried out with accurate dimension.
The present invention has been achieved in views of the above described conventional technologies, and an object of the invention is to provide a bending method and bending system capable of carrying out bending with a highly accurate bending angle and dimension without executing the corrective bending repeatedly.
DISCLOSURE OF INVENTION
According to an aspect of the present invention, there is provided a bending method that includes the following steps (1) to (10):
(1) step of creating a three-dimensional stereoscopic diagram through an expansion plan based on graphic information of a product;
(2) step of displaying a major dimension and a tolerance in the three-dimensional stereoscopic diagram created in the step (1);
(3) step of displaying a test piece manufactured preliminarily of the same material as that for use in manufacturing the product;
(4) step of carrying out trial bending on the test piece displayed in the step (3) and measuring a bending angle before load removal;
(5) step of measuring a bending angle after a load is removed in the trial bending of the step (4) and measuring an elongation amount of flange width due to the bending;
(6) step of calculating a spring back amount from a bending angle before the load is removed of the step (4) and a bending angle after the load is removed of the step (5);
(7) step of obtaining an object D value from the spring back amount of the step (6) and obtaining an object L value from the elongation amount of the step (5);
(8) step of carrying out actual bending based on the object D value and the object L value;
(9) step of measuring a bending angle and a flange width after a load for the actual bending of the step
(8) is removed and determining whether or not the measured angle and the measured flange width are within tolerances relative to an object angle and an object flange width; and
(10) step in which if it is determined that the measured angle and the measured flange width are within the tolerances in the step (9), the bending is terminated; and if it is determined that the measured angle and the measured flange width are not within the tolerances, a correction value D is obtained from a difference between the object bending angle and an actual bending angle; a correction L value is obtained from a difference between the object flange width and an actual bending flange width; corrective bending is carried out according to the correction D value and correction L value; the processing is returned to the step (9); and accordingly the steps (9) and (10) are repeated.
Therefore, the three-dimensional stereoscopic diagram is produced from the product graphic information and at the same time, the major dimension and the tolerance are displayed on this three-dimensional stereoscopic diagram. On the other hand, the test piece is produced preliminarily of the same material as that for use in producing a product and this test piece is displayed and bent for trail so as to obtain a spring back amount and an elongation amount of a flange dimension. Because the test piece is manufactured of the same material as the final product, the spring back amount and the elongation amount of the flange obtained from the trial bending are the same as those obtained in an actual bending on the product. Thus, an object D value for the stroke in the actual bending and an object L value for the back gauge position are set up considering the spring back amount and the elongation amount of the flange obtained as a result of the trial bending so as to carry out the actual bending. The bending angle and flange dimension in the actual bending are measured. If they are not within tolerances relative to the object bending angle and the object flange dimension, the correction D value and correction L value are calculated to carry out the corrective bending. This procedure is repeated until they fall within the tolerances.
According to another aspect of the present invention, there is provided a bending method that includes the following steps (1) to (9):
(1) step of creating a three-dimensional stereoscopic diagram through an expansion plan based on graphic information of a product;
(2) step of displaying a major dimension and a tolerance in the three-dimensional stereoscopic diagram created in the step (1);
(3) step of displaying a test piece manufactured preliminarily of the same material as that for use in manufacturing the product;
(4) step of bending the test piece displayed in the step (3) for trial based on a spring back amount and an elongation amount obtained preliminarily under various processing conditions;
(5) step of measuring a bending angle and a flange dimension of the test piece bent in the step (4) after a load is removed and then comparing the bending angle and the flange dimension with their object values;
(6) step of calculating an object D value and an object L value considering a difference between object values and measured values and various attributes;
(7) step of carrying out actual bending based on the object D value and the object L value;
(8) step of measuring a bending angle and a flange width after a load for the actual bending of the step (7) is removed and determining whether or not the measured ending angle and the measured flange width are within tolerances relative to an object bending angle and an object flange; and
(9) step in which if it is determined that the measured bending angle and the measured flange width are within the tolerances in the step (8), the bending is terminated; and if it is determined that the measured bending angle and the measured flange width are not within the tolerances, a correction value D is obtained from a difference between the object bending angle and an actual bending angle; a correction L value is obtained from a difference between the object flange width and an actual bending flange width so as to be stored in a data base; corrective bending is carried out according to the correction D value and the correction L value; the processing is returned to the step (9); and accordingly the steps (9) and (10) are repeated.
Therefore, the three-dimensional stereoscopic diagram is produced based on the product graphic information and at the same time, the major dimension and the tolerance are displayed in this three-dimensional stereoscopic diag
Nagasawa Tadahiko
Sekita Katsuji
Amada Company Limited
Greenblum & Bernstein P.L.C.
Jones David
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