Some new investors of can making industry now and then have difficulty in selecting can welder between automatic can welding machines and semi automatic seam welding machine, the welding principle is identical, but the process is different, the most important is that they have huge difference in on-site production, such as the production speed, the convenience, the management etc.
In order to compare the difference, and know which type of can body welding machine is suitable for you, in this article, we will explain each distinctly, we are going to look at the key difference between automatic can welder and semi automatic can welder, not only at the point of technology and know how of machine, but also from the customer’s standpoint to consider each detail.
Resistance welding is the joining of metals by applying pressure and passing current for a length of time through the metal area which is to be joined. The key advantage of resistance welding is that no other materials are needed to create the bond, which makes this process extremely cost effective.
There are several different forms of resistance welding (e.g. spot and seam, projection, flash, and upset welding) which differ primarily by the types and shapes of weld electrodes that are used to apply the pressure and conduct the current. The electrodes, typically manufactured from copper based alloys due to superior conductive properties, are cooled by water flowing through cavities inside the electrode and the other conductive tooling of the resistance welding machine.
The can body welding technology is one type of the electric resistance welding, all the can body welders employ seam welding solution to design.
Resistance seam welding is a process that produces a weld at the faying surfaces of two similar metals. The seam may be a butt joint or an overlap joint and is usually an automated process. It differs from flash welding in that flash welding typically welds the entire joint at once and seam welding forms the weld progressively, starting at one end. Like spot welding, seam welding relies on two electrodes, usually made from copper, to apply pressure and current. The electrodes are often disc shaped and rotate as the material passes between them. This allows the electrodes to stay in constant contact with the material to make long continuous welds. The electrodes may also move or assist the movement of the material.
A transformer supplies energy to the weld joint in the form of low voltage, high current AC power. The joint of the work piece has high electrical resistance relative to the rest of the circuit and is heated to its melting point by the current. The semi-molten surfaces are pressed together by the welding pressure that creates a fusion bond, resulting in a uniformly welded structure. Most seam welders use water cooling through the electrode, transformer and controller assemblies due to the heat generated.
Seam welding produces an extremely durable weld because the joint is forged due to the heat and pressure applied. A properly welded joint formed by resistance welding can easily be stronger than the material from which it is formed.
A common use of seam welding is during the manufacture of round or rectangular steel tubing. Seam welding has been used to manufacture metal cans or pails.
The front feeding welder is totally manual, the worker sits opposite to the welding roller, and feed the can body manually forwardly, then the welded can return back, and the worker get out the welded cans, the whole process is slow, and the weld seam is very wide, this type of welder is outdated in can making industry, only applied in stainless steel containers such as tanks.
The back feeding welder is semi automatic, the worker sits after the lower arm, and fed the can forwardly, then the can is conveyed automatically to the welding roller, after being welded, the can is not necessary to return back, convey to the next station directly, due to the lower arm can be connected to the coating machine. so the process is smooth and continuous, the speed is faster, and the weld seam is smaller than that on fronting feeding welder, the detail of the back feeding welder please refer to our GB-30D can body welder.
Whether the front feeding manual welder or the back feeding semi automatic welder, they totally need the rolling machine to roll the tinplate first, then the worker picks up the rolled body blank and feed it piece by piece, so the speed is not as fast as the automatic welder. For the automatic welder, it is equipped and combined with rolling forming machine, so the stack of body blank is put on the magazine or roller of roll forming station, then sucked by the suction cup, and fed to the welding roller along lower arm, after being welded, the can is fed to the next station due to the lower arm can be connected to the coating machine. So the whole process is fully automatic and continuous, the speed is faster, the weld seam is more beautiful, due to the overlap can be minimized through Z bar. The details of automatic can welding machine please refer to the GW series can welder.
Production Speed
The production capacity is the determined factor, if the machine speed can not meet the requirement, then no matter how cheap it is, it is not suitable for the project.
Product Types
The semi automatic welder can be used commonly in wide range of can body diameter, from small can such as aerosol can to big can such as conical pail. The automatic welder also can be changed over for different size of metal cans, but the diameter range is not as wide as semi automatic machine.
Budget
If the speed requirement is not so high, then the back feeding welder and automatic welder are totally suitable, the budget for machine should be considered.
Cost
For the semi automatic welder, the speed is slow, and it requires one worker to sit after the machine, the manufacturing cost is a little higher than the automatic welder. But for the automatic welder, the worker just needs to put the stack on the roll forming machine, even the slitter could be connected to the welder, feeding can body blank directly, so it does not require worker to sit after the machine, and one worker can manage multi automatic can making line, the manufacturing is more cost effective.
If you need the can welder for metal cans, please send the information as below to us.
Can diameter
Can height
Can production speed
Base on the ease to run a can making line and the cost in an era of inflation, we recommend you to use the automatic welder if possible. In this industry, many can makers still ask us to retrofit its manual welder as automatic. This is the trend of industry, thanks for reading, all the best.