Case Studies Of Industrial Robots

Robots in action can be found everywhere. Robot Manufacturers give examples of robot applications in different industries.

KUKA Roboter, Germany - IFR Partner

A robot mills one-off workpieces

One of the oldest sewage systems in the world was discovered by scientists in Mohenjo-daro, near the Indus River in Pakistan. The walled drainage system, 4,000 years old, can still be seen today. In Germany, the oldest sewers are to be found in Cologne. They are made of clinker and are over 100 years old. Today, in Germany, there has to be a manhole every 50 meters. This adds up to several million manholes, all of which are made of concrete and have different drains and connections. Each manhole base is thus a one-off design.

monolithic manhole basePRINZING GmbH, based in Blaubeuren, was founded in 1862 and offered a wide range of ironware. Starting out as a company specializing in manual craftsmanship, it rapidly developed into an innovative, state-of-the-art machine manufacturer and quickly and flexibly adapted to new market conditions. As early as 1907, the company began manufacturing systems for the production of precast concrete parts, such as building and curbstones, concrete pipes and manhole rings. In 2009, PRINZING once again set new standards. Introduction of the PRIMUSS system enabled the automatic production of monolithic manhole bases, consisting of a single piece of concrete, for the first time. When it came to automation, the innovative company with its headquarters in the Swabian town of Blaubeuren opted for an industrial robot from KUKA Roboter GmbH to perform milling tasks in the system.

The PRIMUSS process

"The ideal manhole base is a monolithic concrete element which permits any type of drain geometry and connection. Its drain features regular circular arcs, thereby offering excellent flow properties," explains Richard Kraiß, senior manager at PRINZING GmbH. The newly developed PRIMUSS machine fully covers all of these specified requirements, while offering maximum economic efficiency. Satisfied purchasers of the systems include manufacturers of precast concrete parts and construction companies.

Until now, the production process for manufacturing order-specific manhole bases was complicated, costly and labor-intensive; nor was it particularly environmentally friendly, as many resorted to polystyrene models. "During development of the PRIMUSS system, we constantly looked for - and found - ways of simplifying the production process," affirms Richard Kraiß, and adds: "one major factor was the use of KUKA robots".

The manhole model program

PRIMUSS includes an enterprise resource planning system for the preparation of quotations. The manhole data are computerized and subsequently communicated to the milling station. Bertram Schiebel, application engineer at KUKA Roboter GmbH, developed a software module for this purpose that takes the contour data of the manhole drain from the process host system at the concrete plant via TCP/IP and uses them to generate finished KRL programs for the robot. The programs are automatically loaded into the robot controller and started. A downstream software program ensures that only the robot program actually required at a given moment is loaded into the robot controller. Memory management thus remains straightforward, despite the large number of different manhole configurations, and the risk of operating errors, e.g. during maintenance, is minimized. Additional motion parameters allow optional fine optimization of the milling operations, e.g. adaptation of the milling feed to the hardness of the concrete. Prior to integration, the entire software package was tested in continuous operation in a 3D offline simulation environment in order to check the accessibility and risk of collision for all drain geometries that could theoretically occur.

"Our team develops customized solutions together with the customer," explains Dieter Rothenfusser, Head of Engineering Services at KUKA Roboter GmbH. "Cooperation with experienced application engineers in the fields of robot and PLC programming, sensor systems and software development is an important step on the road to innovative automation solutions, particularly for customers who are new to robotics," says Dieter Rothenfusser.

PRIMUSS SystemThe PRIMUSS system

Following acquisition of the data, the monolithic element is manufactured on the "Atlas" module. The no-slump concrete is compacted within about four minutes by vibration with frequency and amplitude control. The concrete must then cure for up to four hours. Only then can the freshly-produced monolithic element be milled at high speed. "Concrete is the most widespread construction material, and also the most environmentally friendly, and can be shaped in many different ways. With PRIMUSS, we have achieved a leap in technology that allows robot-based forming of manhole bases," explains Kraiß.

Once the monolithic element has partially hardened, it is placed on the milling station and machined by the suspended KR 100-2 P-C robot. This special robot type, with an extra long reach of 3,500 mm, can consecutively machine two manhole bases positioned two meters apart. The milling station has two processing stations to ensure that the robot can always machine one monolithic element while the finished manhole base is being changed. The KR 100-2 P-C can only process the concrete block if it has not yet hardened completely, but enough to prevent deformation. First of all, the drain is milled from underneath using a ball milling cutter. The connections are then cut out from the outside using a side milling cutter. The milling operation for one monolithic element takes about 12 minutes. "In just four hours, 20 manholes can be produced, including the time taken for tool changes on the milling robot," emphasizes Ralph Nitsche from KUKA Roboter with pride.  "Production with a batch size of ONE is possible, and the system has much more potential besides."

The final steps are to leave the manhole base to harden completely and to turn it into its installation position.

Sustainable amortization

The PRIMUSS system also contributes to sustainability. The removed concrete falls unimpeded to the floor where it can be taken away without difficulty and immediately re-used. The machine has completely paid for itself after approximately three years. "If you don't do this you lose money. I am not aware of any other system that pays for itself so quickly," asserts Richard Kraiß. "Customized manhole bases produced faultlessly, sustainably and cost-effectively."

 

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