Retrofitting with gripping systems and clamping technology

Ever-shortening product life cycles, the trend towards automation and development leaps in the field of peripherals lead to individual processes as well as entire machine and system concepts being made available today much earlier than was the case a few years ago. In order to keep up with the market, the equipment in particular offers a great deal of potential for efficient retrofitting. Above all, in the field of gripping systems and clamping technology, there are a whole host of possibilities for shortening the main and idle times, increasing the process stability or saving costs on tools.

The principle of direct clamping with SCHUNK VERO-S is increasingly gaining in importance in mechanical engineering, such as the retrofitting here.

In times of target costings, digitalization and mechanization, the term retrofit is experiencing a fundamental transformation. Barely any operations can still afford to use systems until failures and repairs accumulate, quality can no longer be maintained, and ultimately a reaction must be made. Those wishing to maintain their foothold on the market will use the proactive instruments of total productive management instead, in order to avoid losses and waste of any kind and increase system availability. Above all, retrofitting has noticeably gained in significance within this context, because unlike new investments, retrofitting scores points with lower investments, short downtimes, no change in terms of space requirement, and low training expense. The main objectives besides adherence to legal requirements are above all an increase in productivity and process stability as well as minimizing set-up times and costs, for instance energy, tools or unplanned machine downtimes. The equipment offers particularly outstanding starting points for effective retrofitting, because modern gripping systems and clamping devices are right at the forefront when it comes to the cost-benefit aspects of modernizing machines and systems.

5-sided machining with no interfering contour

The SCHUNK VERO-S WDB modular system for direct workpiece clamping is also suitable for retrofitting. It allows users to achieve optimum accessibility and a defined clamping application in tool and mould making.

Particularly in the area of production, SCHUNK is considered a pioneer when it comes to effective upgrades of existing tooling machines. SCHUNK consciously combines the SCHUNK VERO-S – the most groundbreaking quick-change pallet system currently available – with a multitude of other clamping devices to create an impressive, modular system for high-efficiency workpiece clamping. The program includes more than 1,000 possible combinations. It ranges from highly effective module height extensions for direct workpiece clamping, through multi-sided tombstones, clamping pallets, pneumatic and hydraulic clamping force blocks, to chucks, magnetic clamping solutions, and modules for turning operations. The system program is highly compatible and covers numerous applications. This is how users from mechanical engineering achieve reductions in set-up time of 60 to 80% on average for individual component and small-batch production with the aid of the modular system. Even when eroding, users benefit from significant set-up time savings on retrofitted machines due to the hermetic sealing of the clamping modules. Especially for tool and mould making, SCHUNK has recently started offering a system program for direct workpiece clamping that is suitable for retrofitting to T-slot plates, grid plates and VERO-S clamping stations. With the aid of SCHUNK WDB basis, WDS stacking and WDN direct clamping modules (Ø 99 mm), which can be flexibly combined with clamping pillars in various heights, molding plates, freely molded parts and other workpieces can be clamped directly in a matter of seconds. This enables 5-sided machining with excellent accessibility. Regardless of the height of the clamping pillars, the direct clamping modules are supplied with compressed air via a media transfer for which the patent is pending. The presence of a workpiece can also be queried. The clamping pillars ensure a defined clamping situation, a reliable simulation and collision-free, highly efficient machining. Added to this is the fact that workpiece changes can be achieved in no time at all due to the high accuracy of the clamping solution: for this, the parts are clamped precisely and easily using this retrofitting plan and processed again. Applications from the automotive industry show that the chip-to-chip time for the production of pressing tools for outer shell components can be reduced from approximately two hours to between 15 and 20 minutes with the help of direct clamping.

With the aid of the SCHUNK PRONTO quick-change inserts, the clamping range of conventional lathe chucks can be extended in a matter of seconds by up to 55 mm, without having to offset the supporting jaw.

Accelerated jaw change for lathe chucks

In the area of lathe chuck technology, lathe chucks with jaw quick-change systems have already long since proved themselves for retrofitting, for instance the powerful manual lathe chuck SCHUNK ROTA-S plus 2.0. And this is not all: with the retrofittable jaw quick-change system PRONTO, SCHUNK has transferred the effect of the highly efficient jaw quick change directly onto the chuck jaws. The system can be retrofitted to all 3-jaw chucks of model sizes 200, 250/260 and 315 as well as to diverse 2, 4 and 6-jaw chucks. It reduces the pure set-up time for a complete set of jaws to just 15 seconds – roughly 95% less than conventional screwed solutions. Users report on conventional lathe chucks in soft machining with around six retrofitting procedures per shift of an hour retrofitting time savings each day – and this is with a comparatively low investment. SCHUNK PRONTO supporting jaws are available in two versions: one with fine serration (1/16″ x 90° or 1.5 mm x 60°) for set-up time optimization of conventional lathe chucks; the other with straight serration, in order to achieve the possibilities of the PRONTO system on modern quick-change chucks as well. The supporting jaws can be combined with a wide range of quick-change inserts, for instance soft jaws, claw jaws or prism jaws. By means of the quick-change inserts, the clamping diameter when clamping round parts with soft jaws can be extended by up to 55 mm, by up to 45 mm with claw jaws, without the base jaw having to be displaced – eight times more than with conventional lathe chucks. Prism jaws on the other hand facilitate maximum flexibility for the workpiece geometry, be it when clamping rough and finished parts, flanges, bars, square or free-form surfaces. For rapid jaw changes with high repeat accuracy, it is sufficient to loosen the interchangeable insert locking with an Allen key, remove the insert, and fit a replacement. As required by the application, different supporting jaw variants are available for small, medium, and large clamping ranges. The PRONTO configurator, which is available free of charge, makes selecting and positioning supporting jaws and interchangeable inserts child’s play. After entering the chuck type and the workpiece diameter, the tool determines the necessary interchangeable inserts and the correct position of the supporting jaws at the press of a button.

TENDO Slim 4ax is the world’s first hydraulic expansion toolholder in standardized heat shrinking contour. It scores points in retrofitting by simple handling, the shortest set-up times and long tool lives.

Efficient upgrade for toolholders

At the latest since SCHUNK brought the attractively priced high-performance hydraulic expansion toolholder TENDO E compact onto the market, the subject of retrofitting also rapidly gained in significance. Since then, it is possible to cover the entire spectrum of machining cost-effectively with a hydraulic expansion toolholder. The mounting with a diameter of 20 mm and torques of up to 900 Nm convince with dry clamping. At a diameter of 32 mm, torques of even up to 2,000 Nm are achieved: 60% more than conventional hydraulic expansion toolholders. At the same time, it has a permanent precise run-out accuracy of up to 0.003 mm at an unclamped length of 2.5 x D, and a balancing grade for HSK mountings of G 2.5 at 25,000 rpm. It is therefore suitable both for finishing and roughing as well as for boring, thread tapping, and reaming. Moreover, tool change is possible within seconds by using an Allen key. A systematically organized study carried out by the wbk Institute of Production Science at the Karlsruhe Institute of Technology (KIT), whereby the behavior of various toolholders during full and half slot milling was examined, showed in 2015 that the SCHUNK high-performance hydraulic expansion toolholder TENDO E compact allows up to 300% longer tool lives than other clamping systems. While the machining performance remains identical, the amount of tools required drops by two thirds. Since then, countless users have chosen this toolholder to standardize their toolholder range to existing machines. With TENDO Slim 4ax, SCHUNK is in the process of launching a new highlight onto the market. TENDO Slim 4ax combines the complete external geometry of heat shrinking toolholders in accordance with DIN 69882-8 with the impressive qualities of SCHUNK hydraulic expansion technology and develops its strengths with interfering conformal boring, chamfering, reaming and threading in 5-axis centers. Considerably longer service lives are made possible by reducing the load on the cross cutter and the cutting edge. Users also benefit from precise gauges and maximum precision on the workpiece. Particularly in the automotive industry, the mounts promise significant potential when retrofitting to existing machines. As TENDO Slim 4ax can replace conventional heat shrinking toolholders via Plug & Work without having to reprogram the external contour, the advantages can be immediately tested in real applications and be used in the long-term.

In this application, pneumatic linear modules were replaced by the linear direct-driven SCHUNK ELP linear axis. The result is significantly reduced vibrations, a minimized wear of the used components and a shortened cycle time.

Mechatronization of gripping systems

In automation, the success of mechatronic gripping system components in particular is opening up new ways in retrofitting. At the latest since barely any mechatronic expertise is required for the use of mechatronic grippers, linear axes, and gripping rotary modules, outdated pneumatic components are increasingly being replaced one to one with low-wear and energy-efficient mechatronic components. The biggest advantage is undoubtedly the high flexibility: position, stroke, speed, acceleration, power or torque can be individually regulated. This means it is possible to adjust mechatronically adapted systems to new part designs in no time at all. This increases the versatility of handling and assembly processes, and also results in a great deal of flexibility in the introduction of new products, sizes, and equipment specifications. Particularly when it comes to the increasingly wide range of product variants, mechatronics-based retrofitting opens up a great deal of new potential. Added to this is the fact that electrically driven gripping system components for applications with a high number of cycles and many gripping processes usually operate with greater energy and cost efficiency than their pneumatic counterparts. They reduce the consumption costs and have a very positive effect on the CO2 balance. Even though the initial investment for mechatronic modules is higher than in pneumatic components, decreases in the cost of acquisition and operation have led to significant decreases in the amortization time. The performance of the smart modules is now also on a par with pneumatic solutions.

Compact, flat and easy to control: the SCHUNK EGP small components gripper provides the optimum requirements for efficient retrofitting.

Plug & Work

The best example is the clever 24V linear module SCHUNK ELP, the use of which requires neither mechatronic expertise nor space in the electrical cabinet. The drive, the control unit, and specially developed auto-learn technology are completely integrated into the module. It takes two to five strokes to complete automatic programming. If the component weight changes during the process, the axis automatically adjusts its movement profile within just a few strokes. In contrast to pneumatic modules, no throttles have to be adjusted, and compared to electrically controlled modules, no new sequences have to be added. Since the compact units do not require hydraulic shock absorbers, commissioning and maintenance work is virtually eliminated. What’s more, there is no need to worry about potential damage to your system or long downtimes due to defective shock absorbers. The electric axes also score points due to their long lifetime, lower operating costs, minimized noise emissions and outstanding process stability. In the area of electric grippers, SCHUNK has made progress with the electric small components gripper SCHUNK EGP and received a great deal of positive feedback in no time at all – particularly also when retrofitting. Here, the small components gripper scores points with its flat design, simple control via digital I/O and a gripping force that can be adjusted in four increments. If pneumatic small components grippers are replaced with the SCHUNK EGP, there are even more advantages. This way, valve terminals and pneumatic feed-throughs can be omitted depending on the application. What is more: compared to pneumatic modules, the peak value for the SCHUNK EGP, i.e. the temporary force peak when closing the gripper, is significantly lower. In connection with the adjustable gripping force, deformations can be significantly minimized when retrofitting for flexible parts. The fact that the flagship gripper SCHUNK PGN-plus is also provided as a smart mechatronic version is more than consistent. Like its role model, it also has a modified multi-tooth guidance for high maximum moments, a continuous lubrication pocket in the guidance contour, and the proven diagonal-pull kinematics with a high surface coverage in all stroke positions. The mechatronic universal gripper, with its easy-to-use design, makes the change from pneumatic to electric components particularly easy: it has an identical screw connection pattern to its pneumatic counterpart, and the 24-V gripper is controlled via digital I/O.


More information

On SCHUNK’s official website.