When it comes to the automated feeding of machine tools, the choice of the right robot set-up and manipulator is a key element in the planning process. However, finding the right software structure is just as important as the hardware when planning the control concept.
A practical example shows how the cost-effective and user-friendly use of robots can work when configuring machine tools. Framo Morat GmbH & Co. KG is one of the world’s leading manufacturers of high quality drive solutions. The core competence of the 400-strong company is gear technology. In order to meet the high demand, all machine tools are configured for maximum performance.
In the case of one counter-spindle lathe, there was still scope to increase productivity: Framo was on the look-out for an automatic loading solution for this machine. What was required was a robust standard solution that needed to be highly flexible and easy to operate, and that had to function reliably and take up as little space as possible.
Heiko Röhrig, EGS Sales Manager, recalls: “After closely examining the requirements specification, it quickly became apparent that our standard feed system – the Flexiplex from the Sumo range – in combination with a tried-and-tested Motoman MH6 robot from the Japanese manufacturer Yaskawa could be the ideal solution. And we did, in fact, manage to meet all the customer’s requirements using this standard configuration with slight modifications.”
All work steps between the manual loading and unloading of the feeder system are carried out automatically. The task of the Motoman robot is to automate the lathe. The MH6 takes unmachined parts from the infeed conveyor and loads them with great precision into the main spindle of the lathe. The robot then removes the finished parts from the counter-spindle and sets them down on one of the four lanes of the output conveyor.
In summary, Mr. Röhrig puts forward the following arguments in support of the use of Motoman robots in the area of machine tools. “They offer a broad spectrum in the 3 to 80 kg load-bearing capacity range. They can be mounted on floors, walls or ceilings without requiring further adaptation. They are also extremely easy to programme at shop floor level. Last but not least, almost all manipulators feature a particularly slim line design.”
Another current system can be found at Högg Produktionstechnik AG in Wattwil, Switzerland. The company employs 100 people in a production facility measuring around 10 000 square meters, manufacturing precision components from almost all metal materials. Every year several hundred tons of steel, aluminium, stainless steel as well as various other materials are machined. Högg relies on the latest production technology, involving more than 50 CNC machine tools and their consistent automation.
The Swiss company has relied on Motoman robots from Yaskawa for many years. Experienced system integrator CNC-Automation Würfel in Singen recently automated a Mori Seiki NT 4250 lathe turning and milling center. At first sight, the choice of a Motoman MS80W robot, mainly known from the welding field, was surprising. On closer inspection, it quickly becomes clear why this 6-axis machine was the first choice for handling applications. Thanks to its slim shape, the MS80W manages with a relatively small footprint. At the same time, it can easily achieve any position with its impressive reach of 2 236mm. What’s more thanks to its repeating accuracy of 0.07mm, it is more than sufficiently precise for the loading and unloading of the processing machine and the picking up and loading of the parts into the workpiece carriers.
In particular, the Motoman handling robots from the MH series are predestined for all automation tasks associated with the machine tool. The Motoman MH12 is Yaskawa’s fastest model in its class. The high-speed robot is designed for a load capacity of up to 12 kilograms. In order to improve internal media guidance for the gripper, the robot manufacturer has increased the size of the hollow wrist joint of the dynamic 6-axis robot from 42 to 50mm. This significantly reduces the mechanical stress on the cables. Possible connection problems are thus eliminated and the programming and maintenance of the robot is simplified.
The slim, streamlined design of the articulated robot not only reduces interfering contours between the machine and workpiece, but is also consistently compact in design and thus enables handling in confined spaces, as well as high robot density. Interfering contours caused by external media cables are also a thing of the past on the larger MH24. This is made possible by the hollow upper arm of the 6-axis universal robot with a diameter of 50mm. Despite the hollow design, the high-speed robot is extremely powerful. It has a load capacity of 24 kilograms and a streamlined design with a small footprint. This makes the MH24 extremely versatile.
In order for industrial robots to develop their full performance capability, they must interact smoothly with production machines and control environments. For a long time, robot and machine controllers had to be programmed, controlled and maintained separately. However, while it is still technically possible, this conventional interaction between robots and machines involves a number of issues that can now be solved more simply. For example, when using the conventional method operating personnel have to be trained not just in international PLC standards but also possess skills in robot programming and control. What is more, redundant programming procedures mean that the source of failure is not readily evident. This makes it difficult to eliminate errors quickly and easily. Solutions have been put forward in the past. At the turn of the millennium, for example, the trend was towards integrating machine control systems in robot control. Given that PLCs are now high-capacity and can be expanded on a modular basis, the approach adopted today is the direct opposite. The robot is integrated directly in the machine via the PLC as one of many elements. Yaskawa offers a highly effective solution here – MotoLogix.
When it comes to the optimum, application-specific implementation of complete system solutions in the machine tool industry, robots often lie at the heart of the system. This requires a very broad range of products and solutions, such as those offered by Yaskawa, ranging from manipulators to controllers and more.