There are many types of automatic seam welding machines, and their performance characteristics are different. However, as a special resistance welding machine, it is studied from its technical part and development process. Usually, all kinds of welding machines are divided into power frequency by the power supply mode of the resistance welding transformer. There are two main ways of AC and secondary rectification.

1. Single-phase AC power supply mode (power frequency AC)

This type of welding machine is the most widely used type at present, with mature manufacturing and application technology, low cost and convenient maintenance. At present, the vast majority of products in the world belong to this type of welding machine, but their reactive power loss is large, and the reactive power accounts for about 60% of the input power, and the installed capacity is large, generally 200~250KVA. Due to the large single-phase load, the power consumption environment of other equipment is deteriorated. In order to ensure the quality of the welding seam, this type of welding machine is equipped with a special heat controller, which can perform closed-loop control of “uphill, impedance correction, downhill, and network pressure compensation” within a certain range. The welding speed is high, up to about 600 pieces/hour.

2. Secondary rectifier power supply mode

This type of welding machine is a new product developed in recent years. It has less reactive power loss, the power factor of the welding circuit is as high as 95%, and the load of the power grid is balanced, which improves the power consumption environment of other equipment. The welding efficiency is high, up to 900~1200 pieces/hour. The capacity of the welding machine is small, generally about 65% of the single-phase AC power supply mode. During the welding process, there is no need to consider the current change caused by the influence of the barrel body on the impedance, so that the welding machine can obtain More stable current and heat fields. But this type of welding machine is expensive. At present, only a few products in the world use this type of power supply, such as the Model-1424-3 of Calando Company in the United States,

In addition to the above-mentioned differences in power supply methods, at present, the products of several major manufacturers of automatic seam welding machines for steel drums in the world are almost the same in terms of mechanical structure, control methods and working conditions. – Welding – Weld seam correction” four processes, the four processes and the corresponding working parts are briefly described as follows:

(1) Roll forming:

Automatic welding machine

All are equipped with a rolling machine integrated with the whole machine, which rolls the cut steel plate into a barrel shape.

(2) Delivery:

The barrel body is transported in place by the servo motor or two-speed motor and chain transmission device, and then the barrel body is pushed to the inlet of the welding wheel by the propeller (cylinder or crank device).

(3) Positioning welding:

The welding station is composed of “Z” bar, positioning roller (three-roller or multi-roller type) or positioning and clamping cylinder, upper and lower welding wheels, and is equipped with a special heat control board, which is suitable for “uphill, impedance change, downhill, “Network pressure change” can be automatically adjusted to ensure the welding quality. The lap width is only 2~3mm, and the welding wheel can be automatically shifted laterally, which greatly prolongs the service life of the welding wheel.

(4) Weld correction:

During the working process, after the barrel body leaves the welding wheel, it enters the roller that runs synchronously with the welding wheel. At this time, the welding seam of the barrel body is still in a red-hot state. Under the rolling of a certain pressure, its internal structure becomes It is more compact, eliminating the step of the overlapping edge of the welding seam, reducing the overlapping thickness at the overlapping edge, and forming a flat and smooth plane welding seam.

All kinds of automatic welding machines except the early products, the program control system of the working process adopts a microcomputer – programmable logic controller (PC).