Ac spot welder is a machine that solders parts together firmly. Ac spot welding machine is composed of step-down transformer, current regulator and cooling system as well as welding wire, handle and other accessories. Welding does not need to use electrode, only to welding the two workpiece as two electrodes of the circuit, using the contact resistance generated at the high temperature, the metal will melt instantly, so that the workpiece firmly welded together.

Advantages of ac spot welding machine:

1. Good economic benefits: three-phase input, high power factor and energy saving

2. Welding condition range expanded

3. The welding circuit is small and lightweight

4. It can be widely used for spot welding of different metals

(1) pre-pressing stage -- the electrode drops to the current connection stage to ensure that the electrode presses the workpiece and there is appropriate pressure between the workpiece.

(2) welding time -- the welding current passes through the workpiece and generates heat to form the core.

(3) maintenance time -- the welding current is cut off and the electrode pressure continues to maintain until the nugget solidifies to sufficient strength.

(4) rest time -- the electrode begins to lift until the electrode begins to drop again, starting the next welding cycle.

In order to improve the performance of welded joints, it is sometimes necessary to add one or more of the following items to the basic cycle:

(1) increase the pre-pressure to eliminate the gap between thick workpiece, so as to make it closely fit.

(2) the preheating pulse is used to improve the plasticity of the metal, so that the workpiece is easy to fit tightly and prevent spatter; During projection welding, multiple projection points can be in uniform contact with the plate before welding, so as to ensure consistent heating of each point.

First, determine that the welder is black metal, the general choice of ac spot welder. Because ac spot welding machine is using an alternating current discharge welding, especially suitable for resistance material, at the same time, ac spot welding machine by using single pulse, the pulse signal, frequency, time, voltage, current, application of various control methods, for the welding workpieces single point, two point continuous welding, automatic control, artificial control. Suitable for welding of tungsten, molybdenum, iron, nickel, stainless steel and other metals.