Schunk grippers help visions become reality

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Schunk LDx linear direct axes are already widely used today in high-performance assembly.

Admittedly, the iron hand of the legendary knight Götz von Berlichingen and Schunk’s 5-finger hand have very little in common. Yet it cannot be denied that the first personal handshake with the agile high-tech gripper creates an unnerving feeling.

The soft handshake soon dispels all skepticism, however, giving way to enthusiasm for the possibilities of modern mechatronics.

Since the Hannover Messe 2015, where the mechatronic masterpiece caused a sensation in the media, the innovative SCHUNK gripper has become the shooting star in the area of flexible handling.

Whether uncertainty, cautious fascination or endless enthusiasm: the mechatronization of handling has many facets and offers huge opportunities for users who dare to let go of convention and courageously embrace innovation.

Schunk offers a diversity of mechatronic products, enabling users to implement customized solutions. Schunk offers a diversity of mechatronic products, enabling users to implement customized solutions.

Schunk offers a diversity of mechatronic products, enabling users to implement customized solutions

While visionaries like to cultivate images of self-organizing robot fleets and skeptics just as vehemently attempt to make nonsense of the concepts of Industry 4.0, a brief look at the actual situation shows that mechatronic handling solutions are not arriving with a big bang, but rather are gradually creeping into everyday use.

And pragmatism prevails: the easier it is to integrate a mechatronic component in the process, the more reliable it will function; and the less know-how is needed during installation and operation, the greater will be the acceptance.

Linear direct axes are already an integral component in high-performance assembly applications in the electronics industry; the automotive industry unreservedly combines pneumatic and mechatronic modules to create equally reliable and flexible hybrid gripping systems; and in the handling of small components, simple mechatronic small component grippers are replacing the previously widespread pneumatic pickers.

The mechatronic pick & place units of the Schunk PPU-E series are the fastest high-performance assembly units currently available on the market. They allow a variable process design with minimal cycle times.

The leading suppliers cluster their mechatronic drive and handling components according to different levels of complexity. At Schunk the standard products extend from the simple mechatronic module that can easily replace a pneumatic component on a one-to-one basis, through adaptable modules that can be equipped with different servomotors, to intelligent mechatronic grippers.

The latter offer an entire bundle of convenient functions, such as control via an integrated web server, gripped part detection or stepless regulation of the gripping force. The mechanic who in the past put pneumatic components into operation can do the same today with simple mechatronic components, without first having to acquire extensive know-how.

Schunk LWA 4P
The Schunk LWA 4P Powerball Lightweight Arm enables very flexible and even mobile handling operations

Opening and closing of the mechatronic alternatives is no more complicated than with pneumatic grippers. Proven and efficient guidance principles, such as the junction roller guide in the case of small component grippers or the patented multi-tooth guidance for universal grippers are being transferred by SCHUNK to the mechatronic products.

This creates confidence, shortens the development time and ensures maximum process stability, since the guidances have withstood the test of time in thousands of pneumatic modules.

The more strenuous task at present is to convince users that a gripper can be positioned, that a force is returned and that the use of mechatronic modules could possibly eliminate entire stations. While enterprises in the electronics industry and medical technology are quite progressive in the case of more complex components, other sectors are only gradually starting to trust the new technology.

Schunk offers a diversity of modules as a response to these differing rates of mechatronization, therefore enabling custom solutions. They extend from conventional pneumatic components with no sensors whatsoever that fulfill only their core function, through pneumatic components with simple or complex sensors to intelligent mechatronic modules.

With the help of optional accessories such as analog magnetic switches, users and system planners can also equip pneumatic modules with intelligence. More than ever before it is possible to define how much of it should be used in the particular applications.

The Schunk LWA 4P Powerball Lightweight Arm enables very flexible and even mobile handling operations.

Three central issues currently dominate the development of mechatronic handling systems: connectivity of components all the way to the field level, functional safety and man/robot collaboration. The trend is toward field components that can do more than their actual function, i.e. more than gripping, turning or linear motion. In short: the field components of tomorrow will generate information.

Schunk SVH 5-finger gripper
In service robotics the Schunk SVH 5-finger gripper hand opens up new dimensions in gripping and manipulation. It also allows man/robot communication via gestures

The gripper not only grips, but also reports back a force, for example. Such data can be converted into useful information, such as whether or not a part is in order. This increases the functionality of the components, but also decentralizes calculation processes; in other words, data processing and information acquisition take place directly in the component and not only in the PLC.

This method of acquiring information at the component level is not entirely new, because grippers have long been able, by means of single point magnetic switches, to provide information on whether a part is gripped or not. What is changing is the depth of this information.

The use of an analog magnetic switch instead of a conventional magnetic switch, for example, enables the precise differentiation of single components. Even more advanced are mechatronic grippers with the capability of storing information about which measured value belongs to which component.

Such a gripper analyzes the acquired data, uses it to determine which component is gripped and automatically reduces the gripping force in the case of sensitive parts that are susceptible to deformation, for example. Contact pressures or torques during assembly can also be measured and monitored in real time.

New component types can easily be integrated in such processes. In addition, intelligent workpiece carriers or intelligent type plates make it possible to uniquely identify the single components, allowing adaptation of the process precisely to the particular part, as well as documentation. In extreme cases, individualization down to a quantity of one is possible.

A bus system can be used to connect the mechatronic components both with each other and with the higher level system controller to create a cyber-physical system. This connectivity of the modules is undoubtedly a major opportunity, however also one of the biggest challenges, due to the large number of real-time Ethernet interfaces, each of which creates its own standard.

In order to fully utilize the potentials of mechatronic handling, the field of mechanical engineering will have no choice but to narrow the focus to essential standards. Currently ProfiNet, EtherCAT and EtherNet/IP are the most promising worldwide standards.

In service robotics the Schunk SVH 5-finger gripper hand opens up new dimensions in gripping and manipulation. It also allows man/robot communication via gestures. In service robotics the Schunk SVH 5-finger gripper hand opens up new dimensions in gripping and manipulation. It also allows man/robot communication via gestures.

In addition to “connectivity”, “functional safety” and “man/robot collaboration” are the primary issues in mechatronic handling. Experts assume that direct collaboration between man and robot will extend throughout the entire production process in the middle and long term.

Instead of working next to each other in mechanically separated spaces as at present, man and robot will cooperate in a barrier-free environment in the future. Especially in assembly applications there will soon be a drastic increase in the number of collaborating systems. Certified safety gripping systems today already allow the functions SLS (Safe Limited Speed), SOS (Safe Operating Stop), and STO (Safe Torque Off).

In Safe Operating Stop the modules are continuously supplied with power, so that gripped parts are held safely even without mechanical gripping force in the event that a process is interrupted. As soon as the safety zone is released, the grippers directly switch back to regular operating mode without delay and without having to restart the system. Such safety functions can increase productivity and cost effectiveness especially in large systems.

Another advantage of certified safety systems is that the safety certification can be limited to the pool of system components, so that the system does not have to be certified as a whole. The functional safety of components presents new challenges to manufacturers, from separate specifications, through the actual certification and qualification of the assembly and service employees to documentation.

The mechatronization of handling systems is a process consisting of numerous small steps. The focus is on networked components and systems that continuously monitor their own status, and that of their environment, but also allow a high variance.

These components in the future will perform more than just their function; they will also generate information. In addition, collaborating and mobile systems will become increasingly important and will present new challenges with respect to process organization. To avoid being left behind by the market, companies will have to stay on the ball and continuously develop both their products and their processes, as well as the know-how of their employees.

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