MFDC Welding vs. AC Welding , Which is Better?

MFDC (Medium frequency) welding and AC welding are two common welding processes that have different characteristics during the welding process. Here, we will introduce to you, MFDC welding VS AC welding, which is better?

1. MFDC & AC Welding Working Theory

1.1 MFDC / Inverter Welder Working Schematic

MFDC Discharge Curve

Firstly, the three-phase AC (alternative current) passes through the rectifier filter;

Secondly, the IGBT switch converts the current into 1000HZ medium frequency current and passes it to the welding transformer;

Finally, a high-power rectifier diode outputs the welding current into a smooth direct current.

1.2 AC Welder Working Schematic

Input power is alternative current. After passing through the power switch, it enters the main circuit and control circuit. Then transformer steps down the high-voltage alternative current into suitable welding low-voltage alternative current. The alternative current has the alternating characteristics of positive and negative changes. When it passes through the electrode and welding parts, it generates high temperature and melts the solder, thereby achieving welding.

2. MFDC Welder VS AC Welder, MFDC Welder is Better

2.1 High stability

a. MFDC welder is one of the internationally recommended high-end resistance welding products that increases the stability of welding process. DC welding technology has better workmanship and a wide adaptable range of welding parameters. The secondary current ensures the real constant current,making it more widely applicable than AC welding.

b. The intermediate frequency output power is a very small waveform direct current. There are no current peaks, and almost no spatter is generated during welding.

c. The welding current's adjustment is precisely controlled by 1,000 times per second, and the response speed is counted by millisecond level. Its accuracy is over 20 times more than the traditional AC welder.

d. MFDC welder will not be affected by parts' shape and material, and there is no inductance loss.

2.2 High efficiency

The welding power factor of MFDC welder is above 98%, while AC welder is only 60%. You can see that the efficiency of MFDC welding is greatly improved.

2.3 Cost effective

a. Since the initial value of welding current has been greatly increased, the actual welding time is reduced by more than 20%. It also greatly reduces the demand for welding pressure.

b. Lower demand for factory power grid. MFDC welder is only 2/3 of AC welder, and it has much lower welding pressure demand. Even with power grid voltage fluctuations, MFDC welder still can accurately control the welding current.

Therefore, the power consumption of the MFDC welder is significantly reduced, and energy saving is over 40%.What's more, since using three-phase balanced loads, no phase is peek overloaded. It has satisfied the need for economical energy charges.

2.4 Lightweight

Compared to AC welder, the weight of welding transformer of MFDC welder is greatly reduced, making the equipment more lightweight. It is only 1/3 of the weight and volume of the AC transformer, and is suitable for robot welding systems. 

2.5 Environmental friendly

Eliminating pollution from the power supply, this is a green welding method. There is no need to provide a separate power grid as it can be used together with the robot welding tooling control system.

In summary, MFDC welding is better than AC welding in terms of welding stability, welding quality, welding efficiency, energy saving and reduced consumption, equipment lightweight and reduced power requirements for the power grid system.

Heron has a full range of MFDC spot/projection welders. Medium frequency resistance welding technology has reached an international advanced level. The maximum short circuit current reaches 250,000 amps. It is widely used in the spot and projection welding processes of various alloy steels, high-strength steels, hot stamping steels and aluminum alloys, and provides high-end equipment and reliable services to world-renowned fortune 500 companies.

 Please find more products and exciting information from our website. If you need business consultation, please visit our contact page, and learn how Heron can help your company achieve higher production!