Weld Stonecrusher

Automated rotor production for stone crushers with KUKA robot

Rotors for crushers must withstand the highest loads and require the precision of our KUKA welding robot

Lasaco has long relied on the benefits of automation for projects that require a high degree of precision and quality, made possible by the requirements and possibilities of the Industry 4.0 really come into their own. In this project, a customer required high-quality welding equipment for the production of rotors, such as those used in so-called rock crushers or crushers. Such equipment is used to process minerals, metals, rocks and other materials that are similarly difficult to crush. The aim is often not only to crushing of the fragmentsbut also the separation of different valuable materials so that they can be recycled or reused in other ways.

Why is a Kuka robot used?

Welding rotors for such crushers is a complex process that requires a high degree of uniformity and stability. Otherwise, the rotors cannot withstand the forces that occur as desired. The tractors that drive the stone crushers operate with up to 400 horsepower. The forces that have to be compensated by the rotors are correspondingly high. It is particularly important for the low-wear and reliable operation of the rotors that the teeth, which carry out the actual crushing process, are positioned with absolute precision. In addition, the welding must meet the highest quality standards and should therefore not exhibit any fluctuations, as can occur with manual production. In addition, the production of rotors is significantly faster thanks to the use of automated welding systems. These requirements are met by our KUKA robot, which not only delivers first-class weld seams, but can also repeat the production process any number of times with the same quality.

How does robotics help welding on an industrial scale?

Industrial manufacturing benefits in many ways from the use of robotics to automate welding tasks. In this case, a Kuka robot was used with Lorch S8 RoboMIG XT power source which has the appropriate level of performance for the customer’s specific requirements. The actual welding is done by a Lorch MAG welder, which is precisely controlled by the robot according to the specified program. The Lorch MAG products have proven to be particularly well suited for automation in manufacturing plants because they have been developed with the interaction with robots in mind. As a result, customers can not only produce their rotors for crushers more quickly, but also rely on consistently high manufacturing quality.

How does robotics help welding on an industrial scale?

No matter whether only one product is to be manufactured or variations in different designs are required: So that the Kuka robot knows where and how to set the weld seams and spot welds, it naturally needs precise information about the workpieces to be processed. In the case of rotor production for stone crushers, adjustments to the program are always necessary because different rotors are used depending on requirements. Different lengths and diameters require corresponding program adjustments. For each new rotor, the necessary 3D data is created once, which provides exact information about the respective position of the teeth. After the robot has been fed this three-dimensional model, it can automatically calculate the position data for all weld seams and spot welds.

The robot does the manufacturing almost by itself

Supplied with the existing data, the automatic welding system can independently position each component and specify the respective tooth positions. The human operator only has to tack the teeth there so that the robot can finish welding them on. If the system has a selection of different component sizesthese can be easily preselected at the control panel. This even makes the production of individual parts economically viable. The robot proceeds strictly according to a defined welding sequence, which helps to avoid spot heating of components. Multi-layer welding ensures maximum strength of the joints. Another major advantage in the workflow is that tacking and welding are done in a single fixture without the need for reclamping. To ensure that this automatic production runs smoothly, Lasaco carries out a complete system maintenance once a year. Of course, our technical experts are also available to assist customers at any time by phone or – if necessary – on site.


  • Position specification for tacking the teeth to be welded by the robot.
  • Automatic calculation of all welding and intermediate positions
  • Rotor production in different lengths and diameters
  • Individual positioning of all teeth
  • Multi-layer welding
  • Definition of welding sequences to avoid spot heating of components
  • Tacking and welding in one fixture without reclamping

user report

Enormous increase in productivity thanks to Lorch Trac Wheel Pro welding tractor: They have to withstand extreme forces: the stone crushers of Gipo AG. The company now welds critical weld seams with welding tractors from Lorch. This not only increases safety, but also saves significantly on costs.

13.09.2017 – Lorch – Share: – To watch list Set up the device, set the values and start welding: Compared to manual welding, the tractor is two to three times faster. “> Set up the device, set the values and start welding: Compared to manual welding, the tractor is two to three times faster.


Task: Welding particularly long and critical seams Solution: Lorch Trac Wheel Pro welding tractor Advantage: – Continuous seam in top quality – Welding speed two to three times higher than with manual welding – Easy reproducibility of welds – No reworking – Savings in material costs “Swiss Power”: Rarely does a description hit the mark as well as with the huge machines of Gipo AG from Seedorf on Lake Lucerne in Switzerland. They crush and screen up to 1,100 tons of minerals of high-quality limestone or concrete per hour. Designed for the toughest applications, the stone crushers reach a length of up to 40 m and weigh up to 140 t. “All of our machines are one-offs and are developed and designed from scratch,” says Marco Planzer, head of the metalworking department, explaining the special features of production. The company has a total of 160 employees. 25 of them work in the locksmith’s shop under Marco Planzer in two-shift operation. As a result, up to 45 new crushers leave the Gipo AG factory halls every year. The chassis of the gigantic machines is made almost exclusively of S 355 steel plate. The load-bearing elements are up to 30 mm thick. Extreme forces act on the weld seams when the minerals are crushed. “Every single weld must therefore be of absolutely high quality,” emphasizes Planzer. This also applies to the numerous extremely long welds that occur in many areas of the chassis. To ensure high quality, all seams are executed in a horizontal position and in a single layer wherever possible. Short setup time: The easily portable Lorch Trac Wheel Pro welding tractor is convenient to handle and can be brought to the job site quickly. “> Short setup time: The well portable Lorch welding tractor Trac Wheel Pro can be conveniently handled and quickly brought to the job site. “Set up the tractor, adjust the torch, set the values and start welding. I can concentrate on the short pre-adjustment for long welds, and then the tractor does the power-sapping main work.”

For long and critical seams

Since spring 2016, the Swiss have been using a welding tractor from Lorch for particularly long and critical seams. The Lorch Trac Wheel Pro is a highly portable and easy-to-program welding tractor designed for particularly demanding longitudinal and curved seams in both horizontal and vertical positions, and can also handle welds with large seam volumes. With its four wheels and magnetic fixation, it can be quickly and easily attached to any workpiece. A high-performance motor driving all four wheels ensures precise feed and thus a stable welding speed in all welding positions. Thanks to the quick-release fastener and a flexible 3D fine adjustment, the torch can be set quickly and optimally. The Lorch Plug&Weld solution also ensures a simple and convenient connection to the Lorch power source. Gipo uses Lorch’s S series as the welding source and works with the innovative SpeedPulse and SpeedArc welding processes. Thanks to a magnet the tractor is easy to fix to any steel sheet. A high-performance motor drives all four wheels, thereby ensuring precise welding speed. “> Thanks to a magnet the tractor is easy to fix to any steel sheet. A high-performance motor drives all four wheels, ensuring precise welding speed. A top weld from start to finish: Thanks to the optimum weld setting, no spatter occurs – eliminating the need for time-consuming reworking. “> A top weld seam from start to finish: No spatter occurs due to the optimum weld setting – time-consuming rework is eliminated.

Info about the user

Gipo AG, the Swiss company based in Seedorf in the canton of Uri, is one of the leading manufacturers of track-mounted stone crushing plants with over 160 employees. Through the development of innovative combined plants (crushing and screening plant), the company revolutionized the processing of mineral raw materials. Thanks to their fully hydraulic drive concept with high-quality components and minimal electrics, the machines can be used in a temperature range from -55° C (e.g. in Siberia) to +55° C (e.g. in Dubai). www.gipo.ch

Continuous seam in top quality

“The tractor has proved its worth,” concludes Marco Planzer. And what is particularly important to him: “The machine is twice to three times as fast as manual welding – with a consistently excellent weld seam.” In the case of the particularly difficult seam on the box for the mobile chain drive, a welder previously had to start up at least three to four times in order to execute the seam, which was over 4.5 m long. In addition, the chamfering of the seam and the processing of the transitions consumed valuable working time. “With the tractor, we now have a continuous seam here that is top quality from start to finish. This eliminates the otherwise very time-consuming reworking,” sums up Planzer. Another advantage is that the set and stored data can be used to reproduce the weld seam again and again on other chassis. “This not only saves an enormous amount of time, but also extremely increases safety, since it doesn’t depend so much on the welder’s form on the day,” says Planzer. The welder responsible, Tobias Müller, is also very taken with the new possibilities of the automated procedure: “Using the tractor in production is absolutely uncomplicated. The machine is easy to operate and after a short training period you can also get started, as the welding process hardly differs from manual welding.” Due to the magnetic technology and the simple design of the tractor, the setup times turn out to be very short. “Put on the tractor, adjust the torch, set the values and start welding,” says Müller, describing the easy handling. For him, welding long seams has become much easier and he now also appreciates the change: “After many short seams, which we continue to weld by hand, the use of the tractor comes in very handy. I can concentrate on the short pre-adjustment and then the tractor does the main, energy-sapping work.”

Trac Wheel and Trac Rail

Paul Arnold, responsible for Lorch Service on site and managing director of Arnold Schweißtechnik GmbH, already sees further possible applications for the new technology after the good experiences: “The tractors are also ideally suited for vehicle, container or bridge construction. Especially since variants such as the Trac Rail are still available, in which the tractor runs on rails and thus the path guidance can be designed independently of the workpiece geometry, or the Trac Rail Pro with an additionally integrated pendulum unit enables weld seams with a larger seam volume.” For Marco Planzer, the manager of the metalworking shop, one thing is certain: “Using automated welding technology saves time, increases the quality of the welding results and even saves on material costs.” Solutions such as the Trac Wheel would make it easy for medium-sized industrial companies in particular to get started with automation, since robotic solutions are often oversized and also too expensive here. In general, longer weld seams could be welded very cost-effectively and efficiently with the trac wheels. And in addition to the high welding speed, the consumption of filler materials is reduced, as seam oversizing is avoided. And there is another aspect that makes him feel very positive: “Our welders immediately saw the tractor as a support and integrated it into their workflow. There can hardly be any better feedback.” Weld Stonecrusher.

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