726 Bench Fixture 

The 726 Bench Fixture is the “weld head” of the Percussion Welder system. It holds the two parts, aligns them to each other and thrusts one into the other when the weld is triggered. Together with the Model 858 Percussion Welder and the 808 Actuator, it provides what is needed to make consistent, reliable weld joints.

Percussion welding starts with the two parts set a pre-defined gap apart. When the weld is triggered, a capacitor-discharge arc melts the facing surfaces and the moveable part is driven into the stationary part, so the joint is made in milliseconds with no filler, flux or solder. The fixture is what makes the gap, the alignment and the motion repeatable from one weld to the next.

The diagram on this page numbers seven adjustments and features. In the order of the callouts:

1. Moveable wireholder: holds the weldment that is thrust into the stationary weldment during welding, with a setting for the slippage pressure of the weldment.
2. Z-axis adjustment: aligns the weldments vertically.
3. Stationary workpiece holder: secures the workpiece during the weld.
4. Y-axis adjustment: aligns the weldments horizontally.
5. Initiation lever: starts the weld.
6. X-axis adjustment: a third alignment adjustment for the weldments.
7. Gap adjustment knob: sets the initial gap between the weldments.

The moveable wireholder carries one of the two weldments and is the side that moves. During the weld it is thrust into the weldment in the stationary holder. The 808 Actuator supplies the rapid motion, and the holder uses a spring-loaded thrust mechanism.

The holder also has a setting for the slippage pressure of the weldment, so you can adjust how the part is held in it. As with every other setting, change one thing at a time and check the result on your own parts. Our lab weld schedules are starting points, not guarantees.

The stationary workpiece holder secures the other weldment and keeps it still while the moveable part is thrust into it. In the photos it is the block with the red toggle clamp above it, with a clamp screw and pad that press the part against the block below.

It has an adjustable clamping system for wires, terminals, leads and small assemblies. Because the two sides of the joint are held separately, you can change the stationary part without disturbing the moving side. If your part has an unusual shape, ask us about custom tooling for your weld geometry.

Alignment is set with adjustments on the fixture, so it can be repeated and written down rather than judged by eye each time.

• Z axis moves the weldments vertically relative to each other.
• Y axis moves them horizontally.
• X axis is the third alignment adjustment shown on the fixture diagram.
• Gap adjustment knob sets the initial gap between the weldments, the starting distance the parts travel before they meet.

Set the alignment and gap, run a weld, inspect it, then change one setting at a time. We recommend validating joint strength on your own parts before production.

The weld is started by the operator. The system supports a foot pedal or a hand switch, selected by the operator, and the fixture diagram labels an initiation lever that starts the weld. The 858 receives the trigger as a closed-contact input.

Operation is manual by default, and the fixture can be integrated into automated production lines with optional tooling. The video on this page walks through operating it step by step. If you plan to automate, tell us early, because it affects how the parts are fed and clamped.

These are the 726 specifications we have confirmed. For anything not listed, such as overall dimensions or mounting, contact us.

The 726 is one of three parts of the system. The 858 is the controller and power supply, with dials for the actuator, delay and weld energy voltage and switches for mode, pulse, polarity and capacitance. The 808 Actuator provides the motion. The optional Percussion Weld Monitor compares each weld with a learned signature and gives a pass or fail.

If you run a Superior 528 or MTI 628, the 726 retrofits those systems with an upgrade kit. See the upgrade page.