PATENT DOCUMENT

Publication Number: US-9387551-B2
Application Number: US-201213605969-A
Country: US
Kind Code: B2

Title: Method, system, and computer program product for simulating friction stir welding

Abstract:
A method for simulating friction stir welding is provided. The method may include restraining first and second parts in a fixture. The method may also include axially forcing a non-rotating friction stir welding tool against a joint between the parts. Thereafter one or more resultant parameters may be measured, such as displacement of the first part, the second parts, and/or the fixture. The resultant parameters may also include the force applied to the first part, the second parts, and/or the fixture. Thereby, movement of the parts and fixture that may occur during friction stir welding may be simulated without actually completing a welding operation. A related system and computer program product are also provided.

Claims:
What is claimed is: 
     
       1. A method for physically simulating friction stir welding, comprising:
 physically restraining a first part and a second part in a fixture; 
 axially forcing a non-rotating friction stir welding test tool against a joint between the first part and the second part; and 
 measuring one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool against the joint, wherein the resultant parameters comprise a displacement of one or more of the first part, the second part, and the fixture and a force applied to one or more of the first part, the second part, and the fixture. 
 
     
     
       2. The method of  claim 1 , further comprising directing the friction stir welding test tool along the joint between the first part and the second part. 
     
     
       3. The method of  claim 1 , further comprising determining a maximum axial force that may be applied without exceeding a predetermined displacement limit. 
     
     
       4. The method of  claim 1 , further comprising employing the friction stir welding test tool as an eddy-current sensor to detect a defect in the first part or the second part. 
     
     
       5. The method of  claim 1 , wherein axially forcing the non-rotating friction stir welding test tool against the joint comprises axially forcing the friction stir welding test tool against the joint until the force reaches a desired force. 
     
     
       6. The method of  claim 1 , wherein the resultant parameters further comprise a change in the force per a unit of time. 
     
     
       7. A system for simulating friction stir welding, comprising:
 a fixture configured to hold a first part and a second part in a welding configuration with a joint defined between the first part and the second part; 
 a non-rotating friction stir welding test tool; 
 an actuator configured to apply an axial force along the non-rotating friction stir welding test tool against the first part and the second part at the joint; and 
 at least one sensor configured to measure one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool against the joint, wherein the resultant parameters comprise a displacement of one or more of the first part, the second part, and the fixture and a force applied to one or more of the first part, the second part, and the fixture. 
 
     
     
       8. The system of  claim 7 , wherein the actuator is further configured to displace the non-rotating friction stir welding test tool along the joint. 
     
     
       9. The system of  claim 7 , wherein the non-rotating friction stir welding test tool comprises a pin defining a rounded head. 
     
     
       10. The system of  claim 9 , wherein the non-rotating friction stir welding test tool comprises an eddy-current sensor. 
     
     
       11. The system of  claim 7 , wherein the non-rotating friction stir welding test tool comprises a ball bearing roller. 
     
     
       12. The system of  claim 7 , wherein the sensor comprises a force sensor mounted to the non-rotating friction stir welding test tool. 
     
     
       13. The system of  claim 7 , wherein the sensor comprises a force sensor mounted to at least one of the first part, the second part, and the fixture. 
     
     
       14. The system of  claim 7 , wherein the sensor comprises a displacement sensor configured to measure the displacement of at least one of the first part, the second part, and the fixture. 
     
     
       15. A non-transitory computer readable medium for storing computer instructions executed by a processor in a controller configured to control a system for physically simulating friction stir welding, the non-transitory computer readable medium comprising:
 computer code for axially forcing a non-rotating friction stir welding test tool against a joint between a first part and a second part restrained in a fixture; and 
 computer code for measuring one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool against the joint, wherein the resultant parameters comprise a displacement of one or more of the first part, the second part, and the fixture and a force applied to one or more of the first part, the second part, and the fixture. 
 
     
     
       16. The non-transitory computer readable medium of  claim 15 , further comprising computer code for directing the friction stir welding test tool along the joint between the first part and the second part. 
     
     
       17. The non-transitory computer readable medium of  claim 15 , further comprising computer code for determining a maximum axial force that may be applied without exceeding a predetermined displacement limit. 
     
     
       18. The non-transitory computer readable medium of  claim 15 , further comprising computer code for detecting a defect in the first part or the second part with an eddy-current sensor. 
     
     
       19. The non-transitory computer readable medium of  claim 15 , wherein the computer code for axially forcing the non-rotating friction stir welding test tool against the joint comprises computer code for axially forcing the friction stir welding test tool against the joint until the force reaches a desired force. 
     
     
       20. The non-transitory computer readable medium of  claim 15 , wherein the resultant parameters further comprise a change in the force per a unit of time.

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to friction stir welding, and more particularly to methods, systems, and computer program products for simulating friction stir welding. 
     BACKGROUND 
     Various types of methods and apparatuses have been developed for joining two parts. Example embodiments of methods for joining two parts include adhesive bonding, welding, use of fasteners, etc. In the context of joining certain materials, such as metals, welding has been identified as a suitable method presently in use today. 
     Various forms of welding methods exist. Example embodiments of welding methods include laser welding, arc welding, gas welding, and friction stir welding. Friction stir welding may present certain advantages over other forms of welding. For example, friction stir welding may not involve heating the parts being welded to as great of an extent as other forms of welding. Further, friction stir welding may not require use of flux or gases which could introduce contaminants into the weld. However, the formation of suitably strong and aesthetically appealing welds using friction stir welding may present certain challenges. 
     Accordingly, systems, methods, and a computer program product for simulating friction stir welding are provided. 
     SUMMARY 
     A method for simulating friction stir welding is provided. The method may include restraining first and second parts in a fixture. A non-rotating friction stir welding test tool may be axially forced against the parts along a joint therebetween. The test tool may apply force at a static location or transversely move along a path that simulates a friction stir welding path. Thereby, the force transferred to the parts and the fixture and the displacement of the parts and the fixture may be measured. In this regard, the axially applied force may simulate the force applied during an actual friction stir welding operation. Thereby, for example, the sufficiency of the strength of the fixture and the parts may be determined. However, due to the test tool being pressed against the parts without actually rotating and welding, the simulation procedure may be relatively safe and not expend materials. 
     By simulating friction stir welding in this manner, a maximum axial force that may be applied without exceeding a predetermined displacement limit of one of the first part, the second part, and/or the fixture may be determined. Alternatively, a desired force may be applied to the parts, and the displacement and forces applied to the parts and the fixture may be measured. The resultant parameters may also be employed for a variety of other purposes. 
     A related system for simulating friction stir welding and computer code for controlling a system for simulating friction stir welding system are also provided. 
     Other apparatuses, methods, features and advantages of the disclosure will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the disclosure, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The included drawings are for illustrative purposes and serve only to provide examples of possible structures and arrangements for the disclosed assemblies, methods, and systems. These drawings in no way limit any changes in form and detail that may be made to the disclosure by one skilled in the art without departing from the spirit and scope of the disclosure. 
         FIG. 1  schematically illustrates a system for friction stir welding; 
         FIG. 2  illustrates a perspective view of the operations performed during friction stir welding a first part to a second part in a fixture; 
         FIG. 3  illustrates a cross-sectional view through the fixture of  FIG. 2  along line  3 - 3  prior to friction stir welding; 
         FIG. 4  illustrates the cross-sectional view through the fixture of  FIG. 2  along line  3 - 3  during friction stir welding; 
         FIG. 5  illustrates a perspective view of a non-rotating friction stir welding test tool including a rounded head according to an example embodiment of the present disclosure; 
         FIG. 6  illustrates a perspective view of a non-rotating friction stir welding test tool including a ball bearing roller according to an example embodiment of the present disclosure; 
         FIG. 7  schematically illustrates a portion of a system for simulating friction stir welding including a controller, an actuator, and a friction stir welding test tool according to an example embodiment of the present disclosure; 
         FIG. 8  illustrates a fixture of the system for simulating friction stir welding of  FIG. 7  prior to simulating friction stir welding according to an example embodiment of the present disclosure; 
         FIG. 9  illustrates the fixture of  FIG. 8  during simulating friction stir welding according to an example embodiment of the present disclosure; 
         FIG. 10  illustrates a method for simulating friction stir welding according to an example embodiment of the present disclosure; and 
         FIG. 11  illustrates a block diagram of an electronic device according to an example embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary applications of apparatuses, systems, methods, and computer program products according to the present disclosure are described in this section. These examples are being provided solely to add context and aid in the understanding of the disclosure. It will thus be apparent to one skilled in the art that the present disclosure may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the present disclosure. Other applications are possible, such that the following examples should not be taken as limiting. 
     Friction stir welding is a method for joining two parts which may present certain advantages over other forms of welding. For example, friction stir welding may not heat the parts being welded to as great of an extent as other forms of welding. In this regard, certain materials may not be able to withstand temperatures associated with other forms of welding. Further, subjecting the parts to high heat may cause the parts to warp. Stresses may also build at the joint between the parts as a result of the heat that may eventually lead to failure of the weld. 
     Additionally, friction stir welding may be advantageous in that it may not require use of flux or gases which could introduce contaminants into the weld. Introduction of contaminants into the weld may affect other operations later performed on the parts that are welded together. For example, it may be more difficult to anodize the parts when contaminants have been introduced into the weld. 
     Friction-stir welding is a solid-state joining process (meaning the metal is not melted) and may be used in applications where the original metal characteristics must remain unchanged as far as possible. Friction stir welding functions by mechanically intermixing the two pieces of metal at the place of the joint, transforming them into a softened state that allows the metal to be fused using mechanical pressure. This process is primarily used on aluminum, although other materials may be welded, and is most often used on large pieces which cannot be easily heat treated post weld to recover temper characteristics. 
       FIG. 1  illustrates a friction stir welding system  100  according to an embodiment of the present disclosure. The friction stir welding system  100  may include a friction stir welding tool  102  configured to friction stir weld a first part to a second part along a joint therebetween. The friction stir welding tool  102  may include shoe  104  and a pin  106 . 
     A motor  108  may be configured to rotate the friction stir welding tool  102  by rotating a spindle  109  and a tool holder  110  coupled therebetween. Further, an actuator  112  may be configured to apply an axial force along the friction stir welding tool  102  against the parts being welded. The actuator  112  may also displace the friction stir welding tool  102  relative to the parts being welded along the joint therebetween. 
     In the illustrated embodiment, the actuator  112  comprises a robotic assembly. As illustrated, the robotic assembly may include one or more arms  114 , one or more joints  116 , and a base  118 . Thus, the arms  114  may be rotated about the joints  116  to position the friction stir welding tool  102  at an appropriate position to friction stir weld the joint between the parts. However, various other embodiments of actuators (e.g., gantry systems) may be employed to control the position of the friction stir welding tool  102  relative to the parts being welded. 
     Regardless of the particular embodiment of actuator employed, the friction stir welding system  100  may further comprise a controller  120 . The controller  120  may be configured to control the actuator  112 , the motor  108 , and/or or other portions of the friction stir welding system  100 . Thus, the friction stir welding system  100  may be employed to weld together parts along a joint therebetween. 
       FIG. 2  schematically illustrates an example embodiment of the friction stir welding process. The spindle  109  and tool holder  110  are shown, but the remainder of the friction stir welding system  100  is not shown for clarity purposes. Additionally, as may be understood, various other embodiments of friction stir welding systems may be employed to conduct the friction stir welding process. 
     As illustrated in  FIG. 2 , a first part  122  can be joined to a second part  124  via friction stir welding using the constantly rotated friction stir welding tool  102 . A fixture  126  may be employed to retain the first part  122  and the second part  124  in the desired configuration. In some embodiments the fixture  126  may comprise multiple parts  126 A-D, which may be clamped together to retain the parts  122 ,  124  in place. As illustrated in  FIG. 3 , which is a cross-sectional view along line  3 - 3 , the first part  122  and the second part  124  may be configured perpendicularly to one another to form a joint therebetween in some embodiments. 
     As further illustrated in  FIG. 2 , in order to weld the first part  122  and the second part  124  together, the friction stir welding tool  102  may initially be inserted into the joint, for example, by directing the tool downwardly along a path  128 . The friction stir welding tool  102  may then be transversely fed along a path  130  following the desired position of the weld between the first part  122  and the second part  124 . The pin  106  may be slightly shorter than the weld depth required, with the shoe  104  riding atop the work surface. 
     Frictional heat is generated between the wear-resistant welding components defining the friction stir welding tool  102  and the parts  122 ,  124  being welded. This heat, along with that generated by the mechanical mixing process and the adiabatic heat within the material, cause the stirred materials to soften without melting. As the pin  106  is moved forward along the path  130  the plasticized material moves to the rear where clamping force may assist in a forged consolidation the weld. This process of the friction stir welding tool  102  traversing along the weld line in a plasticized tubular shaft of material may result in severe solid state deformation involving dynamic recrystallization of the base material. After traversing the path  130  at the joint, the friction stir welding tool  102  may be lifted from the material along a path  132 . Accordingly, a weld may be created between the first part  122  and the second part  124 . 
     However, friction stir welding may present certain issues that may make forming a strong and aesthetically pleasing weld difficult. In this regard, friction stir welded parts and/or the fixture holding the parts may bend or otherwise move during the friction stir welding process. For example, as illustrated in  FIG. 4 , the actuator  112  may apply a force along a rotational axis  134  of the friction stir welding tool  104 . The axial force  134 , which may be on the order of 2-5 kN (kilo-newtons) in some embodiments, may cause part and/or fixture geometry to change. 
     In this regard, as illustrated in  FIG. 3 , in some embodiments the fixture  126  may support outer edges  122 A,  124 A of the parts  122 ,  124 , while leaving inner edges  122 B,  124 B thereof unsupported. Thus, as illustrated in  FIG. 4 , the inner edges  122 B,  124 B of the parts  122 ,  124  may bow inwardly away from the fixture  126  when subjected to the force along the axis  134  during friction stir welding. Alternatively or additionally, as illustrated, the fixture  126  may bend outwardly as a result of the force along the axis  132  transferring through one or both of the parts  122 ,  124  thereto. As may be understood the force along the axis  134  may cause the parts  122 ,  124  and/or the fixture  126  to bend in other manners. 
     As a result of movement of the first part  122 , the second part  124 , and/or the fixture  126 , a weld created by the friction stir welding tool  102  may be detrimentally affected. For example, if one or both of the parts  122 ,  124  being welded is no longer in the same position as expected, defects can arise. By way of example, defects can include voids and cracks at the weld in addition to defects in the geometry of the resulting product. In this regard, the movement of the parts  122 ,  124  and the fixture  126  during friction stir welding may be difficult to predict, and accordingly use of a pre-set welding path may present issues even when the pre-set path attempts to predict movement of the parts. 
     Accordingly, embodiments of the present disclosure provided herein are directed to simulating friction stir welding. Thereby, one or more resultant parameters may be measured, as described in detail below. Accordingly, the conditions associated with friction stir welding may be measured without actually conducting a friction stir welding process. 
     In this regard,  FIG. 5  illustrates a non-rotating friction stir test tool  200 . As illustrated, the test tool  200  may be configured to couple to the tool holder  110 . The tool holder  110  may be coupled to the spindle  109  of the friction stir welding system  100  described above or various other embodiments of friction stir welding systems. 
     In the embodiment of the non-rotating friction stir welding test tool  200  illustrated in  FIG. 5 , the test tool comprises a pin  202  defining a rounded head  204 . The non-rotating friction stir welding test tool  200  may also include a sensor  206 . The sensor  206  may be configured to measure one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool  200  against a joint between two parts. In one embodiment the sensor  206  may comprise a force sensor (e.g., a strain sensor or load cell). The force sensor may be configured to determine a force axially applied through the non-rotating friction stir welding test tool  200 . In another embodiment the sensor  206  may comprise an eddy-current sensor. In this regard, the eddy-current sensor may be configured to detect cracks or other defects caused by the application of force through the test tool  200  by placing the rounded head  204  of the pin  202  in contact with one or more of the parts being tested. 
     In an alternate embodiment, as illustrated in  FIG. 6 , a non-rotating friction stir test tool  300  may comprise a ball bearing roller  302 . The ball bearing roller  302  may be retained in a housing  304  which allows the ball bearing roller to roll, even when force is applied to the ball bearing roller. In this regard, the ball bearing roller may comprise a ball bearing roller employed in conveyance systems. The non-rotating friction stir welding test tool  300  may additionally include a sensor  306 . The sensor  306  may be configured to measure one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool  300  against a joint between two parts. In one embodiment the sensor  306  may comprise a force sensor (e.g., a strain sensor or load cell). The force sensor may be configured to determine a force axially applied through the test tool  300 . 
       FIG. 7  illustrates a partial view of an example embodiment of a system for simulating friction stir welding  400 . The system  400  may comprise many of the components of the above-described friction stir welding system  100  illustrated in  FIG. 1 . In this regard, the system of simulating friction stir welding  400  may comprise the actuator  112 , the spindle  109 , the tool holder  110 , and the controller  120 , as described above. However, various other embodiments of actuators (e.g., gantry systems) may be employed in other embodiments, and the robotic assembly illustrated in  FIG. 7  is provided for example purposes only. 
     However, instead of including the friction stir welding tool  102 , the system for simulating friction stir welding  400  comprises a non-rotating friction stir welding test tool. For example, the embodiment of the friction stir welding test tool  200  illustrated in  FIG. 5  is included in the example embodiment of the system for simulating friction stir welding  400  illustrated in  FIG. 7 . However, various other embodiments of non-rotating friction stir welding test tools may be employed, such as the embodiment of the friction stir welding test tool  300  illustrated in  FIG. 6 . The non-rotating friction stir welding test tool  200 ,  300  may couple to the tool holder  110  in the same manner that the friction stir welding tool  102  couples thereto. 
     As further illustrated, the system for simulating friction stir welding  400  may optionally include the motor  108 . However, as noted above, the friction stir welding test tools  200 ,  300  may be non-rotating. Non-rotating, as used herein refers to a lack of rotation about a longitudinal axis of the friction stir welding test tool  200 ,  300 . In this regard, the motor  108  may be either excluded from the system for simulating friction stir welding  400 , or the controller  120  may be configured to retain the motor  108  in an off configuration such that the friction stir welding test tool  200 ,  300  is not rotated. 
       FIG. 8  illustrates additional components of the system for simulating friction stir welding  400 . Further,  FIG. 8  illustrates inclusion of the embodiment of the non-rotating friction stir welding test tool  300  from  FIG. 6 , rather than the non-rotating friction stir welding test tool  300  from  FIG. 5 . In this regard, as noted above, various embodiments of non-rotating friction stir welding test tools may be employed in the system for simulating friction stir welding  400 . 
     As illustrated in  FIG. 8 , the system for simulating friction stir welding  400  may additionally include a fixture  402  configured to hold a first part and a second part (e.g., the first part  122  and the second part  124  described above) with a joint  404  defined between the first part and the second part. The actuator  112  may be configured to apply an axial force along the longitudinal axis of the non-rotating friction stir welding test tool  300  against the first part  122  and the second part  124  at the joint  404  therebetween. In this regard, the system for simulating friction stir welding  400  may additionally include a sensor configured to measure one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool  300  against the joint  404 . The resultant factors may include a displacement of one or more of the first part  122 , the second part  124 , and the fixture  402 . The result factors may additionally or alternatively include a force applied to one or more of the first part  122 , the second part  124 , and the fixture  402 . Various other resultant parameters may also be measured. 
     As described above, in one embodiment the sensor may be mounted to the non-rotating friction stir welding test tool  300  (see, e.g., sensor  306 ). However, the sensor(s) may additionally or alternatively include a force sensor mounted to at least one of the first part  122 , the second part  124 , and the fixture  402 . For example, in the illustrated embodiment a force sensor  406  is mounted to the first part  122 , a force sensor  408  is mounted to the second part  124 , and a force sensor  410  is mounted to the fixture  402 . These sensors  406 ,  408 ,  410  may be mounted around the perimeter of the first part  122 , the second part  124 , and the fixture  402  in some embodiments. The force sensors  406 ,  408 ,  410  may thereby measure the force transferred to the components  122 ,  124 ,  402  to which they are attached. In some embodiments the force sensors  406 ,  408 ,  410  may comprise strain gauges. The location of the force sensors  406 ,  408 ,  410  may vary from the locations shown in the illustrated embodiment. In this regard, the illustrated embodiment is provided for example purposes only. 
     The sensor(s) may additionally or alternatively include a displacement sensor configured to measure a displacement of at least one of the first part  122 , the second part  124 , and the fixture  402 . For example, in the illustrated embodiment first, second, and third displacement sensors  412 ,  414 ,  416  are mounted such that the displacement sensors can respectively determine a distance to the fixture  402 , the first part  122 , and the second part  124 . These sensors  412 ,  414 ,  416  may be mounted around the perimeter of the first part  122 , the second part  124 , and the fixture  402  in some embodiments. In the illustrated embodiment the fixture  402  is provided with through holes  418 ,  420  that respectively allow the second and third displacement sensors  414 ,  416  to determine the distance to the first part  122  and the second part  124 . The displacement sensors  412 ,  414 ,  416  may comprise optical or laser sensors in some embodiments, although various other embodiments of sensors configured to determine distance may be employed. 
     As illustrated in  FIG. 9 , the actuator  112  may apply an axial force along a longitudinal axis  422  defined by the non-rotating friction stir welding test tool  300  against the first part  122  and the second part  124  at the joint  404  therebetween. As described above, this may cause force to be transferred to the first part  122 , the second part  124 , and/or the fixture  402 . These forces may be respectively measured by the force sensors  406 ,  408 ,  410 . Further, the total force axially applied by the friction stir welding test tool  300  may be measured by the sensor  306  at the friction stir welding test tool. 
     Additionally, the displacement sensors  412 ,  414 ,  416  may respectively measure the displacement of the fixture  402 , the first part  122 , and the second part  124 . In this regard, the axial force applied through the friction stir welding test tool  300  may simulate the force applied during friction stir welding, and hence the first part  122 , the second part  124 , and/or the fixture  402  may receive force and move in a manner similar to that which occurs during friction stir welding. Accordingly, the force received and movement of the first part  122 , the second part  124 , and/or the fixture  402  may be simulated without actually conducting a friction stir welding process, which involves use of rotary tools and heat, which may present danger when conducted without proper safety precautions. Further, friction stir welding may involve expenditure of materials. 
     A first (initial) position of the fixture  402 , the first part  122 , and the second part  124  may be determined by respectively measuring a first distance  424 ,  426 ,  428  from the displacement sensors  412 ,  414 ,  416  to the fixture, the first part, and the second part, as illustrated in  FIG. 8 . Thereafter, when the force is applied along the axis  422  of the friction stir welding test tool  300 , the displacement sensors  412 ,  414 ,  416  may respectively measure a second (displaced) position of the fixture  402 , the first part  122 , and the second part  124  by respectively measuring a second distance  424 ′,  426 ′,  428 ′ from the displacement sensors  412 ,  414 ,  416  to the fixture, the first part, and the second part, as illustrated in  FIG. 9 . Accordingly, the first  424 ,  426 ,  428  and second  424 ′,  426 ′,  428 ′ distances may be compared to determine the displacement of the fixture  402 , the first part  122 , and/or the second part  124 . 
     By axially applying force at a static location, resultant parameters such as the force applied to the first part  122 , the second part  124 , and/or the fixture  402  and/or the displacement of the first part, the second part, and/or the fixture may be measured. However, friction stir welding additionally typically involves transversely directing a friction stir welding tool along a joint between parts, as described above. 
     In this regard, the actuator  212  may be further configured to displace the non-rotating friction stir welding test tool  300  along the joint  404  between the first part  122  and the second part  124  in a manner mimicking the transverse movement that occurs during friction stir welding. Whereas the non-rotating friction stir welding test tool may comprise a flat head in embodiments in which the friction stir welding test tool is not displaced along the joint  404  between the first part  122  and the second part  124 , it may be desirable to provide the non-rotating friction stir welding test tool with certain features configured to more accurately simulate friction stir welding when the non-rotating friction stir welding test tool is displaced along the joint. 
     In this regard, the non-rotating friction stir welding test tool  200  illustrated in  FIG. 5  comprises a rounded head  204 , which may allow the non-rotating friction stir welding test tool to more easily move traverse a path along the joint (e.g., along the path  130  illustrated in  FIG. 2 ). However, some friction may occur between the rounded head  204  and the second part  124  during the transverse movement. In this regard, the ball bearing roller  302  of the embodiment of the non-rotating friction stir welding test tool  300  illustrated in  FIG. 6  may be configured to reduce any frictional forces associated with transverse movement of the non-rotating friction stir welding test tool. Reduction or elimination of frictional forces associated with transverse movement may be desirable because axially applied forces may typically cause the undesirable deformation of the parts being welded and/or the fixture therefor, and hence simulating only axial forces may be desirable. 
     The various sensors described above (e.g., sensors  206 ,  306 , and  406 - 416 ) may be in communication with the controller  120 , or a separate controller. Thereby, the feedback from the sensors may be employed in a variety of manners. For example, the controller  120  may be configured to apply a predetermined desired axial force to the parts  122 ,  124 . In this regard, the sensor  206 ,  306  mounted to the friction stir welding tool  200 ,  300  may indicate when the desired force is applied. As noted above,  5  kN axial forces are not uncommon in friction stir welding, and hence this force may be applied. Thereby, resultant parameters in terms of the force and/or displacement applied to the first part  122 , the second part  124 , and/or the fixture  402  may be determined. 
     During application of the force, the change in the force per a unit of time detected by the various force sensors  206 ,  206 , and  406 - 410  may also be measured. Rapid changes in the force per unit of time may be indicative of a movement of the parts  122 ,  124  and/or the fixture  402 . In an additional embodiment a predefined force may be applied and the displacement sensors  412 - 416  may be employed to determine the locations at which the parts  122 ,  124  and/or the fixture  402  moves the most. Thereby, the parts  122 ,  124  and/or the fixture  402  may be strengthened at these locations. 
     In another embodiment the controller  120  may be configured to apply an increasing force until the displacement sensors  412 - 416  detect a displacement above a predetermined limit. In this regard, by way of example, the maximum force that may be applied without moving the parts  122 ,  124  or the fixture beyond the predetermined limit may be determined. The predetermined limit of displacement may correspond to a maximum amount of displacement at which defects in the resulting weld are below an acceptable threshold. The maximum allowable force which may be applied which falls within the acceptable predetermined maximum amount of displacement may be determined for each point along the joint  404  between the parts  122 ,  124 , or an overall maximum allowable force may be determined, which may correspond to the lowest of the acceptable forces along the joint. However, the controller  120  may employ the information measured by the sensors  206 ,  206 , and  406 - 410  in other manners, as may be understood by one having skill in the art. 
     A related method for simulating friction stir welding is also provided. As illustrated in  FIG. 10 , the method may include restraining a first part and a second part in a fixture at operation  500 . Further, the method may include axially forcing a non-rotating friction stir welding test tool against a joint between the first part and the second part at operation  502 . The method may also include measuring one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool against the joint at operation  504 . The resultant parameters may comprise a displacement of one or more of the first part, the second part, and the fixture and a force applied to one or more of the first part, the second part, and the fixture. 
     The method may further comprise directing the friction stir welding test tool along the joint between the first part and the second part. Additionally, the method may include determining a maximum axial force that may be applied without exceeding a predetermined displacement limit. The method may also include employing the friction stir welding tool as an eddy-current sensor to detect a defect in the first part or the second part. In some embodiments axially forcing the non-rotating friction stir welding test tool against the joint at operation  502  may comprise axially forcing the friction stir welding test tool against the joint until the force reaches a desired force. Additionally, the resultant parameters may further comprise a change in the force per a unit of time. 
       FIG. 11  is a block diagram of an electronic device  600  suitable for use with the described embodiments. In one example embodiment the electronic device  600  may be embodied in or as the controller  120  for the system for simulating friction stir welding  400 . In this regard, the electronic device  600  may be configured to control or execute the above-described friction stir welding simulation operations. 
     The electronic device  600  illustrates circuitry of a representative computing device. The electronic device  600  may include a processor  602  that may be microprocessor or controller for controlling the overall operation of the electronic device  600 . In one embodiment the processor  602  may be particularly configured to perform the functions described herein. The electronic device  600  may also include a memory device  604 . The memory device  604  may include non-transitory and tangible memory that may be, for example, volatile and/or non-volatile memory. The memory device  604  may be configured to store information, data, files, applications, instructions or the like. For example, the memory device  604  could be configured to buffer input data for processing by the processor  602 . Additionally or alternatively, the memory device  604  may be configured to store instructions for execution by the processor  602 . 
     The electronic device  600  may also include a user interface  606  that allows a user of the electronic device  600  to interact with the electronic device. For example, the user interface  606  can take a variety of forms, such as a button, keypad, dial, touch screen, audio input interface, visual/image capture input interface, input in the form of sensor data, etc. Still further, the user interface  606  may be configured to output information to the user through a display, speaker, or other output device. A communication interface  608  may provide for transmitting and receiving data through, for example, a wired or wireless network such as a local area network (LAN), a metropolitan area network (MAN), and/or a wide area network (WAN), for example, the Internet. 
     The electronic device  600  may also include a simulation module  610 . The processor  602  may be embodied as, include or otherwise control the simulation module  610 . The simulation module  610  may be configured for controlling or executing friction stir welding simulation operations, as described herein. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling simulation operations. In this regard, a computer readable storage medium, as used herein, refers to a non-transitory, physical storage medium (e.g., a volatile or non-volatile memory device, which can be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     Thus, a non-transitory computer readable medium for storing computer instructions executed by a processor in a controller configured to control a system for simulating friction stir welding is provided. The non-transitory computer readable medium may comprise computer code for axially forcing a non-rotating friction stir welding test tool against a joint between a first part and a second part restrained in a fixture; and computer code for measuring one or more resultant parameters associated with axially forcing the non-rotating friction stir welding test tool against the joint. The resultant parameters may comprise a displacement of one or more of the first part, the second part, and the fixture and a force applied to one or more of the first part, the second part, and the fixture. The non-transitory computer readable medium also include computer code for directing the friction stir welding test tool along the joint between the first part and the second part. The non-transitory computer readable medium may further comprise computer code for determining a maximum axial force that may be applied without exceeding a predetermined displacement limit. Additionally, the non-transitory computer readable medium may include computer code for detecting a defect in the first part or the second part with an eddy-current sensor. The computer code for axially forcing the non-rotating friction stir welding test tool against the joint may comprise computer code for axially forcing the friction stir welding test tool against the joint until the force reaches a desired force. Also, the resultant parameters may further comprise a change in the force per a unit of time. 
     Although the foregoing disclosure has been described in detail by way of illustration and example for purposes of clarity and understanding, it will be recognized that the above described disclosure may be embodied in numerous other specific variations and embodiments without departing from the spirit or essential characteristics of the disclosure. Certain changes and modifications may be practiced, and it is understood that the disclosure is not to be limited by the foregoing details, but rather is to be defined by the scope of the appended claims.

Metadata:
Filing Date: 20120906
Publication Date: 20160712
Grant Date: 20160712
Priority Date: 20120906
Inventors: CASTILLO ALFREDO
Assignee: APPLE INC
CPC Classifications: [{"code": "B23K31/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K31/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K20/122", "inventive": true, "first": true, "tree": "[]"}, {"code": "B23K20/123", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K20/123", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K31/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K31/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K20/122", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 50188613