Molin Concrete Company modernises plant in Minnesota
Four years ago, the US precast concrete parts producer, Molin Concrete Products Company, decided to expand its production capacity. In their search for a suitable partner, Molin invited various plant manufacturers to develop a concept for a modern circulation system and to present it to the company's top management. Weckenmann made the right impression and was awarded the contract to plan and produce a new plant. The result was presented to a very interested public in September 2015 at a “Grand Opening”.
The Molin Concrete Products Company was founded in 1897 and is an industry leader in the precast concrete industry in the Upper Midwest region of the US. Its range includes pre-stressed concrete slabs, beams, columns and solid, insulated wall panels. The company management decided in 2011 to modernise their factory in Ramsey, Minnesota. In their quest to find the appropriate technical capabilities, Molin spared no effort and also looked to Europe – among others also in Dormettingen – for a suitable supplier. Weckenmann was finally awarded the contract in 2013 to design and build the plant for Ramsey. The challenge: The new production facility had to be fitted into the existing building. This did not intimidate the plant manufacturer, though. The delivery of the plant components started towards the end of 2014, which were installed in the first half of the year, with the first slabs already rolling from the production line in June 2015.
Pallet circulation systems are not yet widely used in the United States. The precast concrete parts are traditionally produced there on flat, stationary tables, with the concrete being delivered in buckets or transport vehicles. The Weckenmann plant introduced a new technological era at Molin, because in this circulation system the pallets are moved from one processing station to the next. In addition, the entire production process is controlled by the WAvision® master Computer.
Automatically step by step
The cleaning, plotting and oiling of the pallet is carried out right at the beginning of the work process. This so-called CPO station is also equipped with a spray unit to apply the retarding lacquer. The next step is the shuttering on the formwork station using the handling crane. Here, the innovative M-Basis/M-Top formwork system is used. It is a magnet-fixed formwork system equipped with interchangeable attachments, which allows the production of a wide variety of panel thicknesses with very little effort. After the pallet has left the formwork station, it moves via the reinforcement station, where both the reinforcement is inserted and mounting parts such as conduits are put in position. Then it moves to the concreting area consisting of two distributors. This is followed by the automatic, very quietly working compacting station before the concrete slabs are transported to the curing chamber. There they remain for approximately one to two hours at about 49 °C. An automated storage and retrieval system removes the pallet from the chamber so that it can be smoothed with a helicopter smoothening machine. Finally, it goes back into the curing chamber for final curing.
The last station in the pallet circulation system is the demoulding station consisting of a tilting station. Once the magnetic shuttering is removed, the pallet is positioned almost vertically, so that the finished part is lifted to be transported to the storage area or directly to the construction site.
Technically up to date
With this modern circulation system Molin sets standards – both in terms of production capacity and in the level of automation of the production processes. The company now owns one of the few automated circulation systems in the US and so could already increase its productivity many times over. The objective is to produce around 140,000 m² of wall panels per year. “To survive in the market and to remain a leader, we must always operate at the current state of technology,” explains John Saccoman, vice president of Molin. “We have come to Europe to find the best solution for us. We are convinced that Weckenmann offers us this.” The fact that the plant has already convinced manufacturers and customers is demonstrated by the company's future plans. The next project is the installation of a processing line for the manufacture of precast concrete with coloured and washed – so-called exposed aggregates – or sandblasted architectural surfaces. For this purpose Weckenmann supplied a curve-tracked monorail system to handle façade elements weighing up to 25 tons