Flexible, dual welding concept for reinforcement cage welding machines

mbk Maschinenbau has introduced a welding concept that combines the advantages of resistance welding and inert gas shielded arc welding: the Dual Weld process, which is unique in the industry in this form.

The aim of this combined welding technology is to continuously weld using both welding processes and to seamlessly flex and incorporate the advantages offered by both processes directly in the production process as and when required.

This enables welding to be performed in certain phases or component sections both with maximum strength and at high speed. It is also possible to work with both processes at the same time in specific work steeps or on particular components.

mbk’s focus is always on the needs of the customer. With their requirements for automation, flexibility and quality the customer challenges the status quo and drives future-oriented developments. The requirement at hand was to develop a high-speed cage welding machine for bored foundation piles that combined the advantages of both welding processes.

As component geometries are constantly being optimised in structural design it is often necessary to provide reinforcement for concrete elements with a filigree appearance and relatively thin longitudinal diameters of 8 – 25 mm and solid components with very thick longitudinal diameters of 25 – 45 mm.

Fast-rotating resistance welding machines are used for manufacturing the long reinforcement cages necessary for foundation piles, columns and beams as a result of their superior efficiency.

This method allows longitudinal wires up to a diameter of 25mm to be firmly welded together with cross wires up to a diameter of 12mm. Resistance welding is only suitable to a limited extent for reinforcement cages with a longitudinal wire diameter > 25 mm, because the amount of energy required to fuse the thick wires firmly and permanently cannot be applied in the short welding sequence.

At a particular point the inert gas shielded arc welding process becomes more efficient than resistance welding.

This process has the advantage that significantly greater wire thicknesses (longitudinal wire diameter 25 – 45 mm with winding wire diameter up to 14 mm) can also be welded without difficulty. The benefits of integrating both welding processes is a challenge that mbk has successfully addressed with the combined DualWeld welding concept.

The new welding unit exhibits a high level of time saving potential and welding quality compared to current machines. It is able to adjust and react to changing diameters, axial welding positions and angles without any problems and decide which welding process is used for any particular welding spot.

This is made possible by the innovative dual welding technology and intelligent control system. The new technology also satisfies the high demands in automation, working speed, repeat accuracy of the welding process and process reliability even where contamination is present. DualWeld is already patent pending. mbk currently offers both LSM and ASM with the new dual welding concept.

The cage welding machine LSM 150 was designed for the production of round and square reinforcement for both driven piles and drilled piles, columns and beams and ensures a constant daily production routine for companies processing reinforcing steel as well as in concrete and precast plants.

The LSM 150’s high speed (up to 5 times faster than the classic inert gas shielded arc welding process) and the high-speed welding performance of the LSM have been achieved to date with electronic spot-welding control. The control allows precise metering of the welding power, the contact pressure and the duration of the respective welding pulse.

This is possible without consuming inert gas and electrodes. The new optional DualWeld welding concept has provided the LSM further performance optimisation and greater flexibility in terms of diameter range, welding and cage stability. The basic LSM cage welding machine is still available with conventional welding technology.

A range of welding processes are available with the ASM cage welding machine, which was developed for the flexible manufacture of reinforcements with a varying number of longitudinal wires for driven and drilled piles, columns and masts; manual inert gas shielded arc welding, single and multiple inert gas welding robots and resistance welding.

The ASM cage welding machine is now also available with the new dual welding technology DualWeld. As with the LSM, the ASM cage welding machine is still available with the conventional welding technology.

mbk offers automation solutions for all of their machines. This ranges from the automatic cutting of the longitudinal wire from the coil through to the removal and further processing of the finished reinforcement cage.

The mbk DualWeld technology reduces the amount of space and resources required by the processing plant. The output of cages with smaller wire diameters is up to 5 times higher than with the classic inert gas technology.

Reinforcement cages manufactured with this process are stronger. This enables efficiencies such as the omission of some of the stiffening rings, resulting in significant time savings. Both techniques can be used for cages with larger wire diameters.

This development will bring about increased flexibility, which will become increasingly important in the future. DualWeld is an investment in the future in which the requirements for optimised production processes will continue to increase.