Miyachi Unitek's micro welding technology offering includes High Frequency (HF) Inverter welders, Linear DC welders, Capacitive Discharge (CD) welders and AC welders.

High Frequency (HF) Inverter Welders use submillisecond pulsewidth modulation (switching) technology with closed-loop feedback to control weld energy in submillisecond increments. The high-speed feedback circuitry enables the inverter power supply to adapt to changes in the secondary loop resistance and the dynamics of the micro welding process. The high frequency closed loop feedback can be used to control (maintain constant) either current, voltage, or power while also monitoring another of the same three parameters.

Linear DC Welders produce much the same results as high frequency inverters by using a high number of power transistors as the direct energy source. This technology provides clean, square wave forms with extremely fast rise times. Used primarily in constant voltage feedback control, transistor DC power supplies are effective in thin foil and fine wire micro welding applications and for extremely short welds.

The Capacitive Discharge or ‘CD’ Welder, extracts energy from the power line over a period of time and stores it in welding capacitors. This stored energy is rapidly discharged through a pulse transformer producing a flow of electrical current through the micro welding head and workpieces. Some power supplies provide a “Dual Pulse” feature which allows the use of two pulses to make a weld. The first pulse is generally used to displace surface oxides and plating, and the second pulse welds the base materials.

The AC welder extracts energy from the power line as the weld is being made; for this reason, the power line must be well regulated and capable of providing the necessary energy. All Miyachi Unitek AC micro welding machines include a line voltage compensation feature to automatically adjust for power line fluctuations. The welding current that flows through the secondary of the transformer, and its connected load, is very high, ranging from 10 to more than 100,000 amps. This welding current is allowed to flow for very short periods of time, typically .001 to 2 seconds. AC micro welding machines can operate at rates up to 5-6 welds per second.