528 628 858 Upgrade 

If you run a Superior 528 or an MTI 628, the question is usually what comes next and whether the weld schedules you have built up will carry over. The Model 858 Percussion Welder is the direct successor to both. It is the same arc-percussive process with updated controls.

All three generations use a short, high-energy capacitor discharge and rapid mechanical motion to make a direct joint with no filler. The 858 did not change the process. It changed how much of it you can adjust from the front panel. The sections below set out what stays the same, what is new and what to bring when you talk to us.

• Superior Model 528 series: the older Superior-built power supplies. They proved the process in production, including for dissimilar metal combinations.
• MTI MicroWelding Model 628: built on the 528 and added selectable polarity from the front panel.
• Model 858 Percussion Welder: the current model. Dials for actuator, delay and weld energy voltage and switches for mode, pulse, polarity and capacitance, all on the front panel. It is paired with the 726 Bench Fixture and the optional Percussion Weld Monitor.

Three machines, one process. Each generation changed the controls rather than the physics.

• The process: a capacitor-discharge arc between two parts set at a pre-defined gap, then the molten surfaces are thrust together and bonded within milliseconds.
• No filler, flux or solder. The joint is made from the base metals themselves.
• No electrodes to wear out. There are no consumable electrodes in percussion welding.
• Dissimilar metals. Joining different metals directly was always part of what the process does.
• Weld time: measured in milliseconds on all three. The gains from the 858 are in control and repeatability, not in a faster process.

The 858 puts the parameters on the front panel:

The full 858 specification, including AC input, is on the 858 page.

Your weld schedules. Parameters you have worked out on a 528 or 628, such as actuator setting, capacitance, voltage and polarity, are your starting points on the 858. Because the process is the same, you are not starting from zero. Expect to refine them. Confirm each one on your own parts before production.

Your process knowledge. What your operators know about material preparation, fixture alignment and how polarity affects a joint still applies.

Your qualification data. The 858 uses the same arc-percussive process and produces the same type of metallurgical bond. Re-qualification requirements depend on the application, so discuss your standards with your quality team and ours. For reference data, our lab database has 131 weld schedules: see the weld schedules.

The 528 and 628 were standalone power supplies. The 858 is the controller of a three-part system:

• 858 Percussion Welder: energy and process controls on the front panel.
• 726 Bench Fixture: the weld head, with alignment adjustments and a gap adjustment knob. It also retrofits 528 and 628 systems with an upgrade kit.
• Percussion Weld Monitor (optional): learns a signature waveform and gives a pass or fail on each weld, with data collection for QC.

The 808 Actuator provides the motion in the fixture.

Bring your current weld schedules and, if you can, your materials. We will show you how they translate to the 858, live, on your parts at our facility in Denver. Free applications tests of your materials are available.

It helps to bring:

• the material pair and wire or part sizes you weld now
• your current settings: actuator, capacitance, voltage and polarity
• a note on the fixture you use today
• any qualification or inspection requirements the weld has to meet

To book a time, use schedule a meeting, call 303-536-7838 or email sales@percussionwelder.com.