Friction stir welding travel axis load control method and apparatus
First Claim
1. A friction stir welding travel axis load control method for controlling a travel axis load applied to a friction stir welding setup during the joining of at least a first workpiece and a second workpiece by friction stir welding wherein the workpieces are placed in close proximity to one another thereby forming a joint and wherein the friction stir welding setup includes a friction stir welding tool having a probe for plunging into the joint comprising the steps of:
- rotating the tool and plunging the probe into the joint thereby creating a plasticized region, characterized by a plasticized size, having a plurality of dimensions, in the first workpiece and the second workpiece;
applying the travel axis load to the friction stir welding setup to create relative motion parallel the joint between the tool and the first and second workpieces;
generating a reference signal representative of at least one of the plasticized region dimensions;
comparing the reference signal with a predetermined signal representative of at least one of a plurality of predetermined plasticized region dimensions, thereby generating an error signal representative of the difference between the at least one plasticized region dimension and the at least one predetermined plasticized region dimension; and
controlling the travel axis load based upon the error signal to maintain one of the at least one plasticized region dimensions substantially equal to one of the at least one predetermined plasticized region dimensions.
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Accused Products
Abstract
A friction stir welding (FSW) travel axis load control method and apparatus for controlling a travel axis load applied to a FSW setup during the joining of workpieces by FSW. The method and apparatus recognize that controlling certain attributes of a friction stir welding plasticized region are key to controlling the quality of the resulting weld. This invention controls any of a number of qualities associated with the plasticized region thereby producing welds having improved mechanical and aesthetic properties, as well as extending the life of the FSW tool. The method and apparatus may control the FSW process to obtain a predetermined optimum size of a heat affected zone. The plasticized region may be monitored in a number of ways including, but not limited to, force on the tool, torque applied to the tool, workpiece temperature, plasticized region physical dimension, as well as changing surface characteristics such as color and reflectivity.
29 Citations
29 Claims
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1. A friction stir welding travel axis load control method for controlling a travel axis load applied to a friction stir welding setup during the joining of at least a first workpiece and a second workpiece by friction stir welding wherein the workpieces are placed in close proximity to one another thereby forming a joint and wherein the friction stir welding setup includes a friction stir welding tool having a probe for plunging into the joint comprising the steps of:
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rotating the tool and plunging the probe into the joint thereby creating a plasticized region, characterized by a plasticized size, having a plurality of dimensions, in the first workpiece and the second workpiece; applying the travel axis load to the friction stir welding setup to create relative motion parallel the joint between the tool and the first and second workpieces; generating a reference signal representative of at least one of the plasticized region dimensions; comparing the reference signal with a predetermined signal representative of at least one of a plurality of predetermined plasticized region dimensions, thereby generating an error signal representative of the difference between the at least one plasticized region dimension and the at least one predetermined plasticized region dimension; and controlling the travel axis load based upon the error signal to maintain one of the at least one plasticized region dimensions substantially equal to one of the at least one predetermined plasticized region dimensions. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A friction stir welding travel axis load control method for controlling a travel axis load applied to a friction stir welding setup during the joining of at least a first workpiece and a second workpiece, each workpiece having a plurality of surface characteristics, by friction stir welding wherein the workpieces are placed in close proximity to one another thereby funning a joint and wherein the friction stir welding setup includes a friction stir welding tool having a probe for plunging into the joint, comprising the steps of:
- rotating the tool and plunging the probe into the joint thereby creating a plasticized region, characterized by a plasticized size, having a plurality of dimensions, in the first workpiece and the second workpiece;
applying the travel axis load to the friction stir welding setup to create relative motion parallel to the joint between the tool and to first and second workpieces; generating a reference signal representative of at least one of the plurality of surface characteristics; comparing the reference signal with a predetermined signal representative of at least one of the plurality of surface characteristics, thereby generating an error signal representative of the difference between the at least one of the plurality of surface characteristics and the related at least one of the plurality of predetermined surface characteristics; and controlling the travel axis load based upon the error signal to maintain one of the at least one plurality of surface characteristics substantially equal to one of the at least one plurality of predetermined surface characteristics. - View Dependent Claims (9, 10, 11)
- rotating the tool and plunging the probe into the joint thereby creating a plasticized region, characterized by a plasticized size, having a plurality of dimensions, in the first workpiece and the second workpiece;
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12. A friction stir welding apparatus capable of controlling a travel axis load applied to a friction stir welding setup during the joining of at least a first workpiece and a second workpiece by friction stir welding Wherein the workpieces are placed in close proximity to one another thereby forming a joint, comprising:
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a friction stir welding tool having a probe for plunging into the joint, whereby a plasticized region characterized by a plasticized size, having a plurality of plasticized dimensions is created by the rotation of the plunged probe; a load actuator for applying the travel axis load to the friction stir welding setup to create relative motion parallel to the joint between the tool and the first and second workpieces; a sensor for sensing at least one of the plasticized region dimensions and generating a reference signal representative of the sensed dimension; and a load control center capable of receiving the reference signal, comparing the reference signal with a predetermined signal representative of at least one of a plurality of predetermined plasticized region dimensions, generating an error signal representative of the difference between the at least one plasticized region dimension and the at least one predetermined plasticized region dimension, and transmitting the error signal to the load actuator for controlling the travel axis load to maintain one of the at least one plasticized region dimensions substantially equal to one of the at least one predetermined plasticized region dimensions. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A friction stir welding apparatus capable of controlling a travel axis load applied to a friction stir welding setup during the joining of at least a first workpiece and a second workpiece, each workpiece having a plurality of surface characteristics, by friction stir welding wherein the workpieces are placed in close proximity to one another thereby forming a joint, comprising:
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a friction stir welding tool having a probe for plunging into the joint whereby a plasticized region characterized by a plasticized size, having a plurality of plasticized dimensions is created by the rotation of the plunged probe; a load actuator for applying the travel axis load to the friction stir welding setup to create relative motion parallel to the joint between the tool and the first and second workpieces; a sensor for sensing at least one of the plurality of surface characteristics and generating a reference signal representative of the sensed characteristic; and a load control center capable of receiving the reference signal, comparing the reference signal with a predetermined signal representative of at least one of a plurality of predetermined surface characteristics, generating an error signal representative of reference surface characteristics and the predetermined surface characteristics, and transmitting the error signal to the load actuator for controlling the travel axis load to maintain at least one of the plurality of surface characteristics substantially equal to at least one of the plurality of predetermined surface characteristics. - View Dependent Claims (25, 26, 27, 28, 29)
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Specification