New possibilities in the production of ram piles
The goal was no less than to produce the baskets of his construction piles fully automatically. Swedish company Skanska found advice, deeds, know-how and, above all, concrete hardware at MBK. 20 square-type welding machines convinced with their data.
MBK Maschinenbau was able to score with outstanding references and technical facilities. The more than 20 square welding machines with their great performance data were convincing. Skanska’s focus was on high automation on the complete handling of the reinforcement rods fed in through to the finished cage – including further processing of the formworks. The bar was exceptionally high: With approx. 1,000 running metres per shift, just two operators had to satisfy the requirements profile. But for MBK this was no unattainable goal: much higher metre numbers had previously been achieved in similar tasks.
MBK Maschinenbau produces welding machines for the reinforcement of concrete pipes and shafts. 1,000 units have been being built since 1961. Around 16 years ago, the company started to secure the construction industry market segment as well and, since then, has been producing welding machines for round, square, round edged, oval and conical cages for supports, masts, piles, foundation piles, beams et cetera. In addition, multiple mesh welding machines favourably support day-to-day production for some prefab manufacturers.
VSM is time-tested and has more than proven itself in the production process. A modification was now envisaged with the aim of automating the longitudinal wire feed using a chain conveyor. The rods are thus isolated using a wire straightening and cutting unit and fed into the chain magazine. After each rod, cycling on occurs automatically thus also allowing different diameters to be processed alternately. Before the VSM, there is a longitudinal wire magazine. This longitudinal wire magazine takes single or double wires at four corner positions. After approval from the control system, the chain conveyor loads the four or eight rods into the magazine, which turns automatically. All rods are thus fed into the VSM at the same time.
An interconnected feed unit allows the simultaneous production of tighter winding at the start of each cage with a maximum protrusion of 15mm to 20mm of the longitudinal wire. On a VMS, longitudinal wires of 8mm to 20mm as well as double wires of 12mm to 16mm can be welded into cages with winding wires of between 5mm and 8mm. wires and in combination – and 20mm diameter wire is also used as individual wires. The VSM welds the winding wire onto the longitudinal wires fed into the machine at up to 50rpm. Cage production can thus be realised in the impressive sizes of between 92mm x 92mm and 375mm x 375mm in lengths of up to 14,000mm. Each cage requires tight winding at both ends, while for the rest it is practical to operate with the largest possible gradient. The electronic control of the VSM performs this task as a fully automated function.
In order to maximise the added values, it is wise to fully exploit the system’s performance potential. The automatic unloading of the cage and its removal from the cage processing system, which allow for fitting with spaces, ensure rationality and thus efficiency. Once the safety sector approves the cage, the cage processing system automatically places it on a chain conveyor from which the cages are positioned, in bundles, in a cage store using a special crane.
For Skanska, it was very important to find a partner who was able to ensure compliance with the precise tolerances for these exacting products. Several parameters needed to be taken into account here, such as the precise position of the longitudinal wires, the straightness of the winding wire and the smallest possible amount of twisting of the cages. If all of these considerations are satisfied, then production with optimal concrete cover is ensures at Skanska.
Skanska Sverige AB
Contact person is Mr. Fredrik Andersson
Tel.: +46 10 4480000
MBK Maschinenbau GmbH
Contact person is Mr. Michael Raich
Tel.: +49 7563 9131-0