Used Machinery: Metal connecting machines

The welding machines belong to the field of manufacturing technology. Welding devices, also known as welding machines, are part of the “joining material” manufacturing process. When exposed to heat, parts are firmly joined together. As a rule, the joining should be as homogeneous as possible without impairing the properties of the base material.

In addition to its use in the metal industry, there is also the welding process in the field of plastics. The plastics sector, where welding takes place at significantly lower temperatures than metal welding, is not considered in this paper. A welding process known from the plastics industry is for example ultrasonic welding.

The term welding unit or welding device is often used in connection with manual use. Manual means that the course of the weld seam is defined and guided by hand. Another definition is that welding devices are mobile and welding machines are more of a stationary facility.

If the course of the weld seams is determined mechanically or mechatronically, we speak of welding machines. Welding machines can be designed as semi or fully automatic machines. The welding robot then allows more complete flexibility. A welding device at the tip of a robot arm enables the welding head to be rotated in many directions and thus also to run complex weld seams. The welding robot is also an ideal combination for spot welding machines. This is best known from the automotive industry. There, the car bodies are welded together in a complex manner on welding lines using robot-guided welding machines. Welding devices in connection with welding robots are primarily used within production lines.

Before we dive further into the field of welding devices as joining machines, let's consider a special form of welding, build-up welding. Overlay welding is used to fill a worn surface with weld metal or to coat a base material with a different material quality. But build-up welding should not be confused with metal spraying, in which liquid metal is applied to a surface.

The quality of a welding seam depends to a large extent on how much oxygen comes into contact with the weld during the welding process. The oxygen causes slag formation. The slag produced during welding covers the weld seam and must be removed. Only then can the quality of the weld seams be checked and cleaned. The formation of slag is limited by the use of protective gas. Shielding gas creates low-squirt patter welding.

In most cases, the names of the individual welding processes indicate the variance of the process.

There are, for example, roller seam welding machines, resistance welding machines, friction welding machines, electric welding machines, laser welding machines, electric arc welding machines, pressure welding machines, spot welding machines, pipe welding machines, inert gas welding machines or the welding robot already mentioned.

Despite different names, welding machines very often have similar functions. An arc welding device can also be referred to as an electric welding device, since the required heat is generated by an electric current which then ends in an arc.

Another special case of a welding device is the autogenous welding device, also known as a welding burner or welding torch. The welding burner can be used to heat parts (e.g. for shrink connections) or to cut them. This is necessary, for example, if a part can no longer be dismounted.

The inert gas welding devices already mentioned also have different names. These include MSG welding devices (metal shielding gas welding devices), WIG welding machines (wolfram inert gas welding) and the similar MIG process (metal inert gas process).

A wire electrode fed centrally from the machine generates an arc to the workpiece. The protective gas is supplied through a nozzle arranged around the electrode. The protective gas ensures that the melt created by the heat is protected from the negative influences of the atmospheric gases. Inert gas welding also offers the possibility of welding higher-alloy steels. Cast material can also be welded.

Another variation in welding is the orientation and shape of the welding seam. For example, curved weld seams can also be machined using roller seam welding devices. This is used for welding sheets together. Of course, any curves can also be generated in three dimensions by welding robots using a CNC input.

Proper weld preparation is also a factor that is important for the quality and strength of a weld. The best-known forms are the fillet weld, the butt weld, the U-seam and the J-seam. All seams can be produced by welding machines in single and double side versions.

As in many other areas, the possible degree of automation is also a question of investment. Welding robots can be linked together in production lines.

The operator then mainly takes on control tasks and tasks such as setting and setting up. The personnel deployed must be very qualified.

Typical automation features for welding machines are:

•       Automatic weld seam preparation by upstream milling machines

•       Automatic cleaning and sanding with brushing or sanding machines

•       Automatic control of the weld seams

•       Chaining in process lines

This list does not claim to be complete.

The areas of application of welding devices and welding machines

There are many classic areas of application for welding machines. Starting with handicraft businesses up to industrial production lines, welding devices are mainly used in the metalworking industry. Mobile welding devices are indispensable for the maintenance of systems in all areas. Mobile devices are also required in outdoor areas such as pipeline construction. Special processes also allow welding under water.

The welding machines and the corresponding category

At tramao, we have decided to classify welding devices into categories in the area of joining machines (metalworking machines). Of course, the processing of plastic using special welding processes is also conceivable.

tramao offers you a large selection of used welding devices and machines. You will also find the right service companies for repairs and spare parts procurement on tramao.de.

If you decide to buy a used welding machine, you will find a large selection of well-known manufacturers such as Migatronic, Messer Griesheim, Jaeckle, Celtic, Schussler, EMAG, Reis or ESAB on tramao.