JULY COVER STORY: Holding a tight grip on the future

From its origins in Lauffen, Germany, Schunk has grown from a workholding specialist to a leading pioneer of automation systems for manufacturing. Ed Hill visited the company, discovering a long engineering heritage and continuing spirit for innovation.

It’s easy to overlook the fact that in any aspect of manufacturing, particularly metalworking, materials need to be loaded/unloaded, transferred, aligned, fixed securely, machined and possibly assembled during the transformation from their raw state to finished part.

In all these operations considerable reductions in cycle times and other efficiencies can be achieved by implementing the latest technology.

From its early beginnings as a small machine shop in Lauffen, Germany, in the 1940s, Schunk has grown to become a world leader and innovator in all aspects of loading, clamping, gripping and increasingly automation of these processes.

The company offers more the 11,000 standard gripping systems and clamping technologies. It has more than 2,700 employees around the world in nine plants, 33 directly owned subsidiaries and distribution partners in 50 countries. It exports around 60% of its products and in 2016 had a turnover of €400 million.

Schunk holds 200 patents and 8% of its turnover is invested back into R&D. Its customers include prominent companies like Airbus, Bosch, DMG, Rolex, Schaeffler and all major European automotive brands. Since 2012 German goalkeeping star Jens Lehmann has been employed as its brand ambassador.

Its UK subsidiary has sold more than 50,000 gripping systems and 20,000 toolholders since it was established in 1998.

Innovation is very much the ethos driving the company’s product range. The company practices a continuous tradition of invention, trialling its systems in its own production processes, and offering them to the market. Automation has become a major part of Schunk’s operations – it manufactures many end of robotic arm gripping systems, increasingly augmented with sensors to offer highly flexible solutions for pick and place tasks and other processes, along with linear motion devices combined with its grippers to offer simpler mechanised handling.

Speedy multi-axis clamping

One of Schunk’s most widely used stationary workholding devices is its Vero-S modular quick change pallet system which allows rapid and precise resetting of workpieces, clamping devices or other equipment on modern 3-, 4- or 5-axis machining centres. Schunk says it can reduce set-up times by up to 90%. The Vero-S system clamps workpieces, pallets, modules and tombstones using one or more clamping pins.

“Schunk combines Vero-S, with numerous other clamping devices to create a standardised modular system for high-efficiency workholding,” explains Marcus Kleiner, managing director at Schunk. “The system comprises more than 1,000 possible combinations: from high-efficiency raised modules for direct workpiece clamping, multi-sided tombstones, clamping pallets, pneumatic and hydraulic clamping force blocks, double and multi-functional clamping devices to chucks, magnetic clamping solutions, and modules for turning processes.

“Efficient automated machine loading is also possible with the Schunk modules like the Schunk Vero-S NSA plus standardised palletising system.”

Direct clamping with Vero S SPD pins

Schunk is increasingly supplying systems that allow direct clamping of the workpiece such as its Vero-S SPD clamping pins. With these pins users do not need conventional clamping equipment such as vices, clamping claws or lathe chucks with several chuck jaws mounted on pallets. The pins are attached directly to the base of the workpiece meaning there are no interfering contours around the edges from chuck jaws or clamps. The system means five-sided machining with maximum accessibility to the workpiece is possible and due to the existing tapped holes the parts can be exchanged on the machine precisely and within a very short time.

Vero-S SPD clamping pins are manufactured from stainless steel. They are connected with the workpiece with standard (M10) screws and have a holding force of 35kN.

In the jaws

Schunk’s expertise with chuck jaws and lathe chucks dates back more than 50 years. Some of the company’s first workholding products were created when Heinz-Dieter Schunk (son of company founder Friedrich) decided to produce a standard range of chuck jaws for nearby machine shops. Since then it has continued to innovate in this field. Its latest lightweight lathe chucks are designed to offer maximum clamping but also help improve machine tool performance.

“The lighter the clamping device, the less mass has to be moved by the machine’s drive unit,” Mr Kleiner continues: “The strengths of lightweight chucks are especially noticeable on lathes and in mill/turn centres. They are designed for much faster acceleration and deceleration with lower power consumption in comparison with conventional lathe chucks and they also reduce the table load on milling machines with a turning option, which makes it possible to machine heavy workpieces without exceeding the maximum load.

“The latest innovation in lightweight chucks from Schunk is the Rota-NCE power chuck, which can achieve significant savings especially in large-scale production.”

Tendo Slim 4ax toolholder

As well as workholding solutions Schunk also produces many toolholder products for rotational tools. One of its latest developments is the Tendo Slim 4ax toolholder which offers significant advantages over traditional heat shrink toolholders, but with a similar profile meaning they can be easily exchanged.

Using Schunk’s hydraulic expansion technology, Tendo toolholders offer better vibration damping significantly extending cutting tool life and producing less chatter for an improved surface finish on the workpiece. In one test by the Karlsruhe Institute for Technology, a trial using a Tendo E compact toolholder resulted in 300% longer tool life. The toolholders are now being used by some of Schunk’s biggest automotive customers.


Raoul Dessel, Schunk’s head of sales for Germany and Europe, explains: “The Tendo Slim 4ax hydraulic expansion toolholder has made it possible to combine the complete outer geometry of heat shrink mountings in accordance with DIN 69882-8 with the advantages of Schunk hydraulic expansion technology.

“Tests confirm that the mounting, with the vibration damping properties, significantly improves drilling processes. Since the ‘plug & work’ precision toolholders can replace heat shrink toolholders without reprogramming the machine, it is possible to test and use their advantages directly in real applications.”

Adding more and more

Schunk hasn’t stood still when it comes to the latest manufacturing technology to help manufacture and deliver its products. It has adopted 3D printing to manufacture tailor-made gripping options. Its eGrip service means customers can design gripper fingers online for specific parts. Schunk says that within 15 minutes, gripper jaws can be designed and ordered, and then delivered in ten working days. Jaws are offered in three materials, polyamide plastic, aluminium and stainless steel.

eGrippers provide additive lightweight options

One of the advantages of using additive manufacturing to produce jaws is that intrinsic lightweighting benefits can be introduced into the design. The aluminium and stainless steel fingers have an integrated hollow or grid structure, reducing weight between 10-50%. It means quicker production and less material is used without reducing the performance characteristics of the jaws. Lightweight fingers also reduce power consumption of gripping systems and enable shorter cycle times.


“Our customers can easily configure and order suitable gripping fingers for their workpiece online,” explains E-business product manager Felix Giese. “Egrip reduces the design costs for gripper fingers by up to 97%, delivery time by 88%and reduces the price for gripper fingers by up to 50%. Additive processes are generally attractive when geometries or lightweight structures are required that cannot be manufactured using conventional processes, at least not without great expense.”

 

 

Solutions in-hand

Schunk’s end of arm robotic products offer ever more flexible handling solutions, particularly with the introduction of collaborative technology, which means employees can safely work in close proximity to this equipment.

Recently the company won the prestigious Hermes Award for its JL1 Co-act Gripper, said to be the world’s first intelligent gripping module for human/robot collaboration that directly interacts and communicates with humans.

Complex sensor systems and artificial decentralised intelligence allow it to constantly gather information about the component being gripped and about its environment. This means it can process this information and execute appropriate responses based on the specific situation. The gripper is equipped with innovative kinematics, which enable both parallel and angular gripping which allows maximum flexibility in the handling of alternating component variants. Tactile sensors in the fingers monitor the gripping process to ensure reliability and adapt the gripping parameters independently to prevent damage to sensitive components.

Not all of Schunk’s automation solutions rely on robotic arms. For the smaller machine shop making its first steps towards automation the company has developed a workpiece gripper that enables a machine tool to become its own robot.

A Schunk PGN or PZN-plus universal gripper powered by the machine’s coolant system can be mounted on the tool rack and then installed on the machine’s spindle just like a toolholder. This allows the machine to pick parts from a magazine on its work table and insert them into a workholding device for machining. As well as fingers the system can use magnetic or vacuum gripping.

Generation to generation

Now run by the third generation of the Schunk family (Henrik and Kristina) it’s hard to imagine a company as passionate and forward thinking as Schunk about its products and advances it offers its customers.

As founder Friedrich Schunk stated: “A company needs innovations in order to make progress.”

SCHUNK https://gb.schunk.com

Company

Schunk

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