Automated portable friction welding system and method of operation

An automated portable friction welding system for friction welding a workpiece onto a substrate at an interface between the workpiece and the substrate, said system comprising:

• a pneumatic power source for providing an air supply;
• a portable friction welding tool operably connected to the pneumatic power system, said portable friction welding tool comprising:
• a tool housing having a longitudinal axis;
• a forging piston received in an axially slidable relation within the tool housing;
• a rotary air motor disposed in the tool housing and engaged to said actuator to slide therewith;
• a collet configured to receive the workpiece;
• a drive train within the tool housing connecting the air motor to the collet;
• a start input;
• an automated control system, comprising:
• a motor control system operably connected to and responsive to a signal from the start input to cause supply air to flow to the motor to spin the workpiece;
• an FPC module operably connected to start input and disposed to control input from the air supply to begin a first input to an axial thrust building cycle acting upon the forging piston upon receipt of the signal from the start input;
• and
• an FAC module responsive to axial advancement of the forging piston whereby the end of the desired forging piston stroke operates to cut off the air supply to the air motor off and to initiate and then hold a second input to the axial thrust cycle acting on the forging piston and therethrough to the interface of the workpiece and substrate;
• and
• a reset input operable to release the axial thrust building cycle in the actuator at the end of a cool down phase.

An automated process for friction welding a workpiece onto a substrate at a weld site using a portable friction welding system, said process comprising:

• installing the workpiece into a collet of the portable friction welding system;
• positioning the workpiece at the weld site and securing a tool housing of the portable friction welding system to the substrate with a clamp;
• initiating an automated friction weld cycle beginning with a burn off phase, comprising:
• engaging a rotary drive to rapidly spin the workpiece about a longitudinal axis;
• and
• engaging a first thrust cycle which progressively builds axial force driving the workpiece against the substrate at the weld site;
• whereby rapid spinning and axial thrust of the workpiece against the substrate combine to frictionally heat a localized segment of the weld site;
• initiating an upset phase in the automated friction weld cycle, comprising:
• plasticizing localized heated material at the weld site;
• axially translating the workpiece into the substrate at the weld site;
• using the control instruction to disengage the rotary drive to stop spinning the workpiece about its longitudinal axis;
• using the control instruction to engage a second axial thrust component acting on the workpiece to advance the workpiece to a final weld position and maintain force pressing the workpiece into substrate at the weld site during a cool down phase;
• and
• releasing the workpiece from the collet and withdrawing the collet away from the substrate after the cool down phase;
• and
• releasing the clamp to release the portable friction welding system from being secured to the substrate.

An automated portable friction welding tool for receiving power from a power source and friction welding a workpiece onto a substrate, said tool comprising:

• a tool housing having an axis;
• an actuator axially slidably received within the tool housing;
• a rotary motor disposed in the tool housing and engaged to said actuator to slide therewith;
• a collet configured to receive the workpiece;
• a transmission within the tool housing connecting the motor to the collet;
• a start input;
• an automated control system, comprising:
• a motor control system operably connected and responsive to a signal from the start input cause the motor to spin the workpiece;
• a first axial thrust control system operably connected to start input and disposed to begin a first input to an axial thrust building cycle acting upon the actuator upon receipt of the signal from the start input;
• an upset phase control system responsive to axially sliding of the actuator whereby the end of the desired actuator stroke operates to cut the motor off and to initiate and then hold a second potential input to the axial thrust cycle acting on the actuator and therethrough to the interface of the workpiece and substrate;
• and
• a reset input operable to release the thrust in the actuator at the end of a cool down phase.

A portable friction welding tool operably connectable to a pneumatic power system, said portable friction welding system comprising:

• a tool housing having a longitudinal axis;
• an axially aligned forging piston received within the tool housing;
• a rotary air motor disposed in the tool housing and engaged to said forging piston to slide therewith;
• a collet configured to receive the workpiece;
• a drive train within the tool housing connecting the air motor to the collet;
• a start input;
• an automated control system, comprising:
• a motor control system operably connected and responsive to a signal from the start input to cause supply air to flow to the motor to spin the workpiece;
• an FPC module operably connected to the start input and disposed to begin a first thrust building cycle acting upon the forging piston upon receipt of the signal from the start input;
• an FAC module responsive to axial advancement of the forging piston whereby the end of the desired forging piston stroke operates to cut off the air supply to the air motor off and to initiate and then hold a second axial thrust cycle acting on the forging cylinder and therethrough to the interface of the workpiece and substrate;
• and
• a reset input operable to release the thrust in the actuator at the end of a cool down phase;
• and
• a Bellville spring stack biasing the forging piston to withdraw from a workpiece when the trust is released.

A method for welding an aluminum workpiece to an aluminum substrate at a weld site in an underwater environment, said method comprising:

• installing the workpiece into a collet of a portable friction welding tool;
• clamping a housing of the portable friction welding tool to the substrate;
• initiating a burn-off phase, comprising:
• engaging a rotary drive to rapidly spin the aluminum workpiece about a longitudinal axis;
• engaging a first thrust cycle which progressively builds axial force driving the aluminum workpiece against the aluminum substrate at the weld site;
• whereby rapid spinning and axial thrust of the aluminum workpiece against the aluminum substrate combine to frictionally heat a localized segment of the weld site;
• initiating an upset phase in an automated friction weld cycle, comprising:
• plasticizing localized heated material at the weld site;
• axially translating the workpiece into the substrate at the weld site;
• using a control instruction to disengage the rotary drive to stop spinning the aluminum workpiece about its longitudinal axis;
• initiating a cool down phase whereby a weld is allowed to fully solidify, comprising:
• holding thrust across the weld;
• allowing the weld to fully solidify;
• releasing the workpiece from the collet and withdrawing the collet away from the substrate;
• and
• releasing the portable friction welding system tool from being secured to the substrate.

A method for welding an aluminum workpiece to an aluminum substrate at a weld site in an underwater environment using an automated friction weld cycle, said method comprising:

• installing the workpiece into a collet of a portable friction welding tool;
• clamping a housing of the portable friction welding tool to the substrate;
• initiating a burn-off phase, comprising:
• engaging a rotary drive to rapidly spin the aluminum workpiece about a longitudinal axis;
• engaging a first thrust cycle which progressively builds axial force driving the aluminum workpiece against the aluminum substrate at the weld site;
• whereby rapid spinning and axial thrust of the aluminum workpiece against the aluminum substrate combine to frictionally heat a localized segment of the weld site;
• initiating an upset phase, comprising:
• plasticizing localized heated material at the weld site;
• axially translating the workpiece into the substrate at the weld site;
• using a control instruction to disengage the rotary drive to stop spinning the aluminum workpiece about its longitudinal axis;
• initiating a cool down phase whereby a weld is allowed to fully solidify, comprising:
• selectively engaging a potential second thrust cycle following disengagement of the rotary drive as a function of the trust remaining from the first thrust cycle
• holding thrust across the weld;
• allowing the weld to fully solidify;
• releasing the thrust;
• releasing the workpiece from the collet and withdrawing the collet away from the substrate;
• and
• releasing the portable friction welding tool from being secured to the substrate.