Northern Concrete Pipe Inc., which is headquartered in Bay City, Michigan, USA, has been producing box culverts, catchment tanks, retention systems, oil separators, concrete pipes and manholes as well as other precast products ever since its establishment in 1958. Two cage welding machines from the German company mbk Maschinenbau GmbH have been used successfully for many years at the plant in Grand Rapids, Michigan.
In summer 2018 Northern Concrete Pipe decided to modernise and, in association with that, to automate their production, in the course of which one of the existing cage welding machines was to be replaced. The contract for this was awarded to the tried-and-trusted reliable partner for reinforcement solutions – mbk Maschinenbau GmbH from Kisslegg.
The order focused on the customer’s wishes for the highest possible output and above all universal automation in the cage manufacturing process. The goal was to achieve fully automatic operation of the machine with minimal manpower. An operator is only required to select the appropriate cage program and if necessary to convert the machine and refill the required raw materials from time to time. The actual cage production takes place unmanned. Following a detailed analysis of the actual situation and the visions for the future, the choice fell on a cage welding machine of the type BSM-190-O.
Equipped with 24 longitudinal wires, this machine can be used to produce cages with selectively 6, 12 or 24 longitudinal wires of up to 2.5 m (8 ft) in length and diameters from 330 mm (13″) up to maximally 1.90 m (74″). Apart from round cages it is also possible with this machine to manufacture cages for oval and arch-shaped products, with which the customer intends to supplement its product range at a later point in time.
The new version of the automatic longitudinal wire feeder type ALZ-M opens up new dimensions with regard to the realistic cage output per hour: the new feeding system allows all of the longitudinal wires required for the cage to be inserted fully automatically in one step for all the cage diameters that can be manufactured by the machine. This variant of the longitudinal wire feeder operates with pre-cut longitudinal wires from the magazine, which can be filled with up to a tonne of material. Alternatively, a version is also possible with an integrated wire straightening and cutting system, which works directly off the coil. However, the version with pre-cut bars allows much shorter times for conversion to other wire diameters and was the solution favoured in this case.
In conjunction with double wire guidance up to the welding position, two motor-driven wire unwinders for coils of up to 3 t in weight enable either the provision of two different wire diameters or, in the case of identical wire diameters, direct continuation of production if one of the coils runs out.
A particular challenge that had to be overcome was the fitting of the machine with all of its accessories and automation into the available space: The machine itself is placed in a hall extension, but the downstream pipe production takes place in the main building. The cages are removed by an automatic cage handling device of the type KEG II, transported to the main building and supplied to the pipe making machine there.
A modernisation of the pipe making machine is also contemplated in the mid-term in order to achieve the completely universal automation of the production process.
In order to achieve the desired increase in output, the complete machine process was adapted and optimised for maximum output in addition to the automatic feeding of the longitudinal wires and the cage handling. Other measures carried out include drives matched to the requirement profile, the spreading of the cage diameters, the perfecting of the clamping units for the longitudinal wires and the alignment of the complete machine program to very short cycle times. The result of this, apart from a fully automatic production process, is a significantly higher throughput: depending on the cage design, up to 50 cages can be produced per hour in this way.
However, mbk Maschinenbau GmbH is not only known for its inventiveness and professional new and further developments, but also impresses its customers with a convincing service network. A highly motivated, competent service team is available worldwide for the assembly, commissioning, service and maintenance of the machines as well as training. Local service points all over the world ensure the fast supply of spare and wearing parts. Good coverage of all time zones is guaranteed.
mbk Maschinenbau GmbH’s branch in the USA was an important decision-making criterion for Northern Concrete Pipe, because mbk Sales & Service, which is based in Burlington, Iowa, has a large spare and wearing parts warehouse as well as a professional service team and guarantees fast reaction times.