Automated welding
The skills shortage is driving the development of collaborative robots (cobots), which are now even taking on complex joining processes such as welding. DAST Schweisstechnik GmbH, for example, has decided to use the “INNA” robot cell for the series production of components. Besides being easy to operate and delivering impressive results, this highly versatile robot cell can turn its hand to more than just welding.
Cobots are bang on trend – and it isn’t just large companies that are using them in production operations these days. Many small and medium-sized enterprises (SMEs) are also considering a switch to automated processes. This is down to the current skills shortage. Especially when it comes to complex production processes such as welding, experienced specialists are a must, but they are proving increasingly hard to find. Can robots step into the breach to solve the problem? item pluspartner INperfektion GmbH in Wegberg addressed this issue, collaborating with Niederrhein Automation GmbH and item Industrietechnik GmbH to develop the multifunctional “INNA” robot cell.
The robot cell’s design
The basic construction for “INNA” was created with profile technology from item. Line XMS was used to build a machine enclosure 1.60 m long, 1.50 m wide and 2.20 m high. The cell has a total weight of around 500 kg, which makes it far lighter than a comparable steel structure. Inside is a cobot from Doosan Robotics with a 2.20 m range of motion. This robot is mounted on a functional adapter plate from item. Given that the welding cell is intended to minimise setup times, the companies involved in the project opted for a rotary table in the front section. The welding and setup processes run almost in parallel. The rotary table has two devices to clamp the workpiece in place. These are separated by a screen to provide protection during welding. While the cobot is welding inside the cell, the next component can be clamped in place outside the cell. Once the cobot has completed the welding process, the table rotates and the finished component is removed. At the same time, the robot is already welding the workpiece previously clamped in place.
Intense heat is just one of numerous challenges
The final design was agreed on in close consultation between the three partners. item focused on the basic construction, Niederrhein Automation supplied the ideal cobot and INperfektion handled the planning and implementation stages. Various project engineering requirements had to be met. For example, it was necessary to protect the plastic sections of the robot arm against excessive heat transfer. “A large number of aspects influenced the robot cell’s design,” says Dennis Edelmann, Project Manager at item. “Due to the heat, we had to maintain certain minimum distances and also protect components against weld spatters,” he explains. It was also important not to lay cables out in the open in the cell. Other aspects to consider included integrating a device to extract gases and dust, and providing a container for the weld slag that was generated.
Modular machine housing
Line XMS from item is ideal for integrating robotics. That’s because the individual components are suitable for universal use and offer free scalability. They are also easy to fasten together and are all compatible with each other. That makes extending and adapting existing constructions a quick and easy process – a big advantage over welded structures. The internal cable conduits of Line XMS profiles provide cables with optimal protection against weld spatters and heat. With this “inside-out” principle, item also enables easy maintenance, because the cables can be accessed from the outside. That also means they can be directly inspected following installation and further cables can be added at any time. What’s more, the inside of the construction is kept tidy and unnecessary parts are avoided. The smooth profiles’ easy-to-clean surface is an added bonus.
Benefits thanks to repeatability
Welders faced with the task of manually welding lots of identical components one after the other soon become fatigued. This continuous stress can result in mistakes being made. What’s more, these welders are exposed to harmful welding fumes. The robot cell solves these problems and ensures long-term process reliability. Once programmed, the cobot repeats the processes with maximum accuracy and precision. “Even so, the robot cell isn’t intended to replace specialist staff, but rather to support them,” insists Wissam Nehme, a member of INperfektion’s sales team. “After all, the lightweight robot always has to be programmed or parameterised by a welder who teaches it what to do, as it were. The rest of the work can then be done by staff who don’t necessarily need to have this expert knowledge, though,” he adds. This relieves the strain on welders and means they can be deployed more efficiently. The fact that the welding process takes place behind glass in the closed cell means staff are protected from hazards such as welding fumes. “You don’t need a great deal of programming know-how to teach our robot, because the process is highly intuitive,” explains Sven Gerards, Managing Director of Niederrhein Automation. “A further advantage is that, once the program has been entered, it’s stored in the system and can be called up again at any time, if necessary,” he continues. Last but not least, the Doosan cobot offers good value for money, which also makes it particularly suitable for SMEs.
Welding 3500 boilers in eight days
The extent of the support provided by “INNA” is demonstrated by a project at DAST Schweisstechnik GmbH in Wegberg-Wildenrath. Dieter Wagels set up this family business in 1999 and it currently has 16 employees. Besides offering a variety of welding apprenticeships and qualifications, the company also carries out contract welding work for single-part and series production. One customer enquiry related to the production of 3500 boilers per month and included the requirement to weld brackets onto two sides so that they were parallel to each other. “We would have required complex equipment and three full-time welders for this project,” explains the founder’s daughter, Denise Wagels. DAST would not have been able to stick to the desired budget under those circumstances and would have been forced to turn down the project. This led Denise Wagels to get in touch with INperfektion, which is located nearby. “My father was initially very sceptical and didn’t see how investing in a robot would be worthwhile for our SME. He had a complete change of heart, though, because the results won him over,” she reveals. INperfektion and a specialist from DAST programmed the cell together. It was set up in no time at all and the project was able to start. “INNA” produced 3500 boilers in just eight days. The robotic welding cell takes a lot of strain off the welders, who can now carry out other tasks. A trained assistant is responsible for setting up the system with new components. “Now that ‘INNA’ handles the monotonous tasks, everyone involved benefits. Besides the repeatability and consistently high quality of the components, further advantages of the robot cell include its permanent availability and a reduced error rate and setup time. It goes without saying that the expertise of our specialists is still required for tasks such as checking the results, but they can now be deployed far more efficiently,” explains Denise Wagels. Given that no in-depth programming knowledge is needed to operate the lightweight robot, a DAST employee is now responsible for this. “If we have any questions, we can contact INperfektion at any time and we have so far received excellent support, along with fast, straightforward assistance. In the future, we’re planning to use ‘INNA’ not just for resistance spot welding, but also for friction welding. That will open up other areas of application for us,” she emphasises.
An economically attractive robot cell for a whole host of tasks
SMEs, too, can venture into the world of automated production, thanks to “INNA”. This multifunctional robot cell doesn’t just help with welding, though. It is highly versatile, because replacing the welding attachment with a different end effector is extremely straightforward. As a result, “INNA” can also carry out other tasks such as painting, engraving, grinding, drilling and brushing. The cobot can be reconfigured for the relevant task in no time at all. What’s more, the cell benefits from a highly variable design. “Users decide how they want to utilise our cell. Although we use standard components, custom applications are still possible,” explains Edelmann. For example, the standard door can be replaced by double doors at the customer’s request. That provides even easier access to the interior and also makes it possible to handle larger components. Thanks to the versatile “INNA” robot cell’s straightforward and seamless integration into an existing production operation, even small series can be produced efficiently in addition to large batch sizes. For SMEs, too, it’s well worth investing in cobots of this kind to relieve the strain on their specialist staff, who can then carry out value-adding work.
Length: 10,033 characters including spaces
Date: 9 May 2023
Photos: 5 (Source: DAST Schweisstechnik GmbH / INperfektion GmbH
Caption 1: The basic construction for the “INNA” multifunctional robot cell was created with profile technology from item.
Caption 2: The welding and setup processes run almost in parallel. The rotary table has two devices to clamp the workpiece in place. While the cobot is welding inside the cell, the next component can be clamped in place outside the cell.
Caption 3: The internal cable conduits of Line XMS profiles provide cables with optimal protection against weld spatters and heat.
Caption 4: The robot cell ensures long-term process reliability and repeatability. Components such as this aluminium half-round tube with a material thickness of 3 mm can therefore be produced with a high level of precision. Cold wire feed TIG welding was used for this application.
Caption 5: MAG welding is also possible with “INNA”. Steel material 10 mm thick is welded using a fillet weld.
