New Frontiers in Press Shop Automation. How robots are bringing high production rates and flexibility to the factory floor.
Press Excellence Center Manager, Comau Robotics
Press shop lines characterized by their high reliability, flexibility and productivity. This is how Comau is helping deploy new technologies, skills and solutions to automate a new generation of sheet metal stamping lines.
What can you tell us about Comau’s approach to Press Shop automation?
Comau is a pioneer in this type of application. Already in the mid-70s we were developing specific robots to automate the handling of sheet metal inside molding lines, leading to a significant increase in productivity and operator safety. When we realized that traditional robots were not able to meet the market’s productivity requirements, we responded by developing our robots together with software dedicated to production rate improvements and optimized syncing with the molding machines. Over time, our solutions have evolved to better meet the changing needs of customers, in terms of the size of the molded parts, the number of production lots and the new materials being employed. Today, after 30 years of activity and hundreds of lines installed, we continue to develop our robots and supporting technologies to provide our customers with increasingly efficient and advanced solutions. Our solutions are broad and wide-ranging, because we know that the press-to-press robot does not necessarily meet all the possible needs of our customers. Both the performance of the robot and the robotic system must be maximized, which is where we focus our efforts.
What are the key drivers for a modern Press Shop?
First, there are different types of press shop customers. We work primarily with car manufacturers who produce their own sheet metal components, and with tier one companies who manufacture both structural and external parts for multiple clients. As you might expect, the market drivers are different for each of these. Car manufacturers tend to be large and have big production lots, which means they need to ensure high productivity rates. Tier one companies, on the other hand, tend to be smaller as are their production lots. For these companies, the flexibility of the system is more important than the productivity rate. Both types of customer share the goals of reducing costs and increasing quality. I think it’s important to point out that what I’ve described above is similar for situations in which the robot is limited to tending the molding machines, or when the robot is used in cells where multiple phases are integrated such as sheet metal stripping or brushing, washing, racking of the components in containers which are subsequently transported to the assembly lines, and other processes.I should also add that the use of servo-controlled molding machines is increasing at the expense of hydraulic presses – which are more precise and offer better control of the process, but are slower – and mechanical presses – which are faster but less precise and more difficult to control. With the arrival of these servo-controlled machines comes the need for a closer link between the robot and the molding machine, in order to manage the machine as if it w100 a controlled axis. In this way, their synchronization can be optimized to create a continuous movement in the molding machine. It’s a topical issue on which we are working, both at a software level and through the mechanics of the robot.
Please describe the process challenges of hot stamping.
The process of hot sheet metal forming is becoming increasingly important in the automotive industry together with the use of new types of boron steel that offer better mechanical properties than the traditional materials used in the industry. During a hot forming process, the metal sheets go through a furnace that heats them up to about 950°C. They are subsequently inserted into the machine through molds equipped with a cooling circuit that brings the temperature of the sheets down to 250°C. It’s a process, therefore, that forms and quenches the sheets used in the production of structural elements for small and medium sized cars. The primary challenge concerns the extreme conditions required by the process itself. In fact, Comau has responded by developing solutions that are specifically designed for press operations while taking into account the fact that the robot will be working in a high-temperature environment.
Can you give us an example of how your robots are automating the press shop?
Comau offers three types of articulated robots for metalworking, which are part of the Smart Press Booster series: NJ 100 3.2 (100 kg of payload and 3.2 meters of reach), NJ 130 3.7 (130 kg of payload and 3.7 meters of reach) and NJ 140 3.7 (140 kg of payload and 3.7 meters of reach). The Comau NJ 100 3.2 has a payload of 100 kg and is primarily used on small to medium lines. An example could be molding machines that do not exceed 1,200 tons and are placed within 7 meters from one another, and where the robots are used to work metal sheets weighing up to 25 kg, the typical weight of car hoods or doors. The NJ 130 version 3.7 is mounted in ‘shelf’ mode, which means at the top of a column or on a beam secured in between two molding machines that are placed at a distance of 9 meters. Its use is intended for larger pieces that weigh up 50 kg. Here, the value of the allowable payload is very important and can reach 125 kg. The NJ 140 3.7 robot is characterized by a seventh axis, and has a double engine on axis 1 in order to increase the performance (speed) of the robot in acceleration. The seventh axis helps transfer the sheet metal from one mold to another following a straight trajectory, which reduces the distance between the machines and, therefore, reduces the cycle time. All three robots are prepared for the assembly of gripping tools available from the market – either vacuum or magnetic.
How are PressBooster robots different from traditional automation solutions?
Comau has significant experience in both cold forming and hot stamping sheet metal, largely for the automotive sector. Because high productivity in this sector is important, we have developed specific machines to optimize efficiency in the press shop. Unlike standard robots, our PressBooster models have been designed to ensure a high production rate, thanks to features such as more efficient hydraulic servo presses and better execution for operations requiring high flexibility and high operational precision, such as the flaking, the centering of the sheet, washing, storage of finished parts, and so on.One of the most important things in a molding line is to have a robot manipulator that minimizes the enslavement time of presses, thus ensuring the ability to obtain the maximum cadence of the line. This reduction in cycle time helps increase the performance of the plant itself, making it more productive. PressBooster robots are characterized by dedicated on-board equipment, including 600V ventilated motors, special gearboxes on some axes, and are controlled by digital drives. They can reach cadence of up to 16 pieces per minute, and have a payload of up to 130 kg and a reach of up to 3700 mm, which enables them to be placed within the spaces between decidedly large presses. And because the newest generation machines are sturdy but with a reduced overall weight of 30% compared to previous models, they are more flexible and ensure lower energy consumption.We have also designed dedicated software for sheet metal forming, including SMART IP, which is able to optimize the production flows. By using this software, our Customers can calculate the cycle times of the robots, and obtain perfect synchronization between their activity with that of the presses. SMART IP utilizes a simplified programming mode, allowing operators to monitor the correct functioning of the line together with the instantaneous display of its productivity. Ultimately this software controls the operation of the robot servo and promptly reports anomalies in the process, thereby reducing or avoiding production down-time.
What about the racking process?
Press-to-press plant operators often need to manage the end-of-line handling of sheet metal parts characterized by a high flow and high cadences. To make automated stamping lines more efficient and safer, we have developed automated racking solutions in which the storage of processed materials, in specific containers, is managed by multiple articulated robots without the need for human intervention. The automatic racking system enables organizations to optimize the entire production flow of the lines, while the use of articulated robots, which are flexible, precise and aided by vision systems, offers significant advantages. For example, the robots can place items of different sizes in dedicated containers, they can also manipulate the finished steel or aluminum parts even if they differ in weight and size. In addition, they enable a more correct and precise positioning of the components in the storage containers, arranging them in a such a way that they can be sent directly to the welding line for the subsequent processing steps.
Is there anything else you would like to add?
Given that much of Comau’s experience is rooted in the automotive sector, it’s only natural that we’ve grown by developing solutions and applications with high added value. In this context, the innovative technology found within Comau robots together with the related integrated solutions, the turnkey systems and the robotized cells implemented with the support of highly qualified system integrators, are all dedicated to helping companies meet increasingly stringent market challenges.Such excellence is mirrored in the full range of pre- and post-sales services we offer to help our Customers meet their goals and maximize production efficiency while reducing losses, waste and maintenance costs. Backed by reliability, efficiency and decades of field-proven experience, the Comau service network, which is present in all major countries around the world, delivers a 360° assistance activity that covers the entire life cycle of the plant – from the free development of a complete project to its design, implementation, installation, testing, launch and maintenance.
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