New carousel plant for long-term Ebawe customer HTB

The HTB Company is manufacturing aggregates for mixing plants and road construction. The gravel required for this purpose originates from the company‘s own gravel plant. In addition, they are manufacturing wall and floor elements as well as customized precast concrete elements.

The history of the company dates back to 1840 when the former U. Roth‘s Dampfziegelei und Zementfabrik (a brickyard and cement factory) was founded at the foot of the Saaleberg hill. In 1957, the enterprise merged with the Otto Hoffmann KG – a facility for the production of precast concrete products. Being privatized in 1992, the company is now run by managing director, Michael Seiffarth, and general manager, Roland Troschke, as HTB Hoch- und Tiefbaustoffe GmbH & Co. KG. The precast concrete company has a current workforce of about 100 people in the field of production, vehicle fleet, administration and technical department.

Maximum planning reliability and quality

The manufacturer of precast concrete elements located in Saxony-Anhalt supplies the customers with wall elements and floor slabs, special structural precast components, concrete staircases, landings, columns, cross-beams, filling and washing stations as well as car wash boxes and facilities. The elements are planned and drawn with the aid of state-of-the-art CAD programs ensuring maximum planning reliability and quality. The company manufactures the aggregates at a nearby gravel plant. The products are subject to continuous quality control and are approved for being used as concrete aggregates and in the field of civil engineering, road construction, and hydraulic construction.

However, it is also worth mentioning that the HTB GmbH & Co. KG has already an old plant of the former Ebawe Maschinenbau GmbH. The production plant for the manufacture of lattice girder slabs that was installed in 1998 had been in operation until recently and is to be sold now. The somewhat outdated concrete spreader of the old plant was already replaced with a new model of Ebawe in 2017.

So far, the HTB Hoch- und Tiefbaustoffe GmbH & Co. KG precaster has bought double walls from external suppliers; now, the new production plant enables them to manufacture both lattice girder slabs and double wall elements. The newly built factory hall has two hall bays: one of them accommodates the new carousel plant, while the production of structural concrete components is being moved to the second hall bay.

Attention paid to automation

In the new production plant, attention was paid to automation: It is possible to manufacture four pallets per hour. The 37 pallets having a size of 12.50 x 3.55 m allow the production of double walls and lattice girder slabs in any length and height freely selectable within the pallet size. The Infinity Line shuttering system supplied provides for decisive advantages when shuttering the elements. Shuttering of straight edges of elements does no longer require any polystyrene additions if the length is in cm increments. By the configuration of different shuttering lengths, the customer can manufacture various dimensions without manually inserting filling elements. The system requires a slightly higher number of shuttering element lengths but the advantages are obvious: A reduction of manual shuttering work to a minimum and a significant improvement in quality of the finished products. Moreover, the elimination of polystyrene additions from beveled notches results in perfectly manufactured outer edges.

The shuttering elements bought from Ratec are positioned by a combined shuttering and deshuttering robot made by Progress Maschinen & Automation, a company of the Progress Group too. Storage and retrieval of these elements is carried out by the storage robot.

The reinforcement is manufactured directly in the new factory hall just in time: An MSR straightening and cutting machine is used for straightening the reinforcing steel from the coil and cutting it to the lengths required. The spacers stored in two vessels are „shot“ onto the bars fully automatically. Due to this additional automation, the customer achieves high savings on spacers, which would otherwise have to be inserted manually in larger quantities. The lattice girders are bought externally, stored in an active storage and, during production, they are cut to length by the GTA lattice girder cutting machine so as to exactly fitting to the elements to be produced. The reinforcement is inserted fully automatically with the aid of the Wire Center laying robot, positioning both the longitudinal and transverse bars as well as the lattice girders into the shuttered pallets by means of two robotic arms.

Several project partners involved

Concrete placement of the wall elements and floor slabs takes place with an automated concrete spreader of Ebawe Anlagentechnik. For the compaction of the fresh concrete, the HTB Hoch- und Tiefbaustoffe GmbH & Co. KG is provided with two compaction stations: a horizontal compaction system and a combined compaction system with motion in horizontal and vertical planes. The stacking rack accommodates 36 pallets and is served by a lifting transfer car. The heating system installed in the stacking rack was supplied by CureTec Energietechnik. Further components of the carousel plant are a turning device for the production of double walls as well as tilting equipment for lifting the wall elements. There are also cleaning devices for pallets and shuttering elements as well as a stationary release agent spraying device, wetting only those pallet surfaces with release agent which are to be placed with concrete.

In the course of the new factory hall construction, the company also invested in a mixing plant of Nisbau GmbH and a new bucket conveyor of Kübat Förderanlagen.

The entire plant was completed by the Ebos master control system of Progress Software Development, another company of the Progress Group. Besides the main module, the Könnern facility was provided with various „cockpits“, e.g., for the printing of work sheets and labels and the required subsystems programed for the machines accordingly. The Graphical Performance Analyzer – a patented analysis tool for the evaluation of production processes – allows playing black the entire process sequence like a film, thus making delays and bottlenecks easier to identify and eliminate.

Productivity increased by 100 %

The HTB Hoch- und Tiefbaustoffe GmbH & Co. KG has not only resorted to a long-term business relationship with Ebawe/Progress, but is also aiming at strengthening the regional economic power. Consequently, most of the investment was awarded to local companies which have proven a high level of efficiency.

HTB looks with optimism toward the future. The new plant also allows the production of solid concrete wall elements featuring a thickness of 16 cm. Furthermore, the manufacture of façade elements of the highest quality is ensured now – the new mixing plant enables them to manufacture concrete made of white cement and colored granules. This product is complemented by the possibility of dosing plastic and steel fibers – likewise by the mixing plant – which improve the stability and reduce cracking in the elements. The freshly concreted elements pass the curing chamber integrated in the carousel, thus ensuring a high degree of quality consistency.

Managing director, Michael Seiffarth, is very satisfied with the new pallet carousel plant: „We were able to increase our productivity by 100 %, i.e. the same number of employees produces twice the amount of floor and wall surfaces.“