In many industries, the increasingly wide range of product variants, the ever-shorter cycle of innovation, and the increasing comparability among products are leading to an enormous pressure on costs. Experts believe that production automation will be one of the keys to business success in the coming years. These issues also apply to gripping systems: the precision, flexibility, speed and reliability of a gripping system has a significant impact on the profit margin, which they can achieve. Although pneumatic gripping systems were long considered the state of the art, mechatronic solutions have since made significant strides. As a result, users and system planners are increasingly faced with the question of which drive concept is more advantageous to handling and assembly processes: pneumatics or mechatronics? Adaptable drives, versatile controller concepts, and the large selection of standard interfaces have made it increasingly easy to integrate mechatronic modules into higher-level system controllers. At the same time, the rapid progress in electrical servo drives are making mechatronic components increasingly attractive from a price and efficiency perspective. As a result, comparing the advantages of the two drive concepts has become an increasingly important step in the process of selecting the optimal gripping system.

Pneumatic Solutions are Robust, have a Compact Performance, and are Easy to Operate

Pneumatic gripping systems have been continuously optimised over the past decades. They are generally fully developed from both a construction and mechanical point of view. Systems such as the multi-tooth guided PGN plus universal gripper, the MPG plus is a roller guided gripper for handling small components, and the most powerful SRU plus swivel unit from Schunk, the competence leader for clamping technology and gripping systems, are powerful, robust and reliable performers for even the most demanding tasks. Pneumatic systems are very easy to operate and maintain, making them well-suited to users who do not have a high level of technical knowledge. Finely graduated, standardised series and a comprehensive range of accessories make it possible to achieve a customised design at an attractive price.

On average, pneumatic modules require an investment that is one-third to one-half that of comparable mechatronic modules. Users who assemble only identical parts, who require high cycle times, and who have little mechatronic knowledge are thus well-served by pneumatic solutions. As a rule, only the sealing components of these systems require ongoing maintenance, which also helps users maintain an overview in their maintenance costs. Because of the need for compressed air, their operating costs are comparatively high; however, this can be significantly reduced by the use of micro valves. Nowadays, highly efficient valve solutions are available for many pneumatic modules, from grippers to complete pneumatic pick&place units; these solutions can reduce compressed air consumption by up to 90% while also increasing the cycle time by up to 100 per cent. By these means, pneumatic pick&place units can achieve up to 95 picks per minute with a repeat accuracy of 0.01 mm and high energy efficiency. However, air-operated rotary and linear modules are still poorly suited to particularly large translational movements over approximately 1500 mm, or to high loads over approximately 50 kg.

Pneumatic systems remain poorly suited to such conditions. By contrast, electrically driven linear modules (spindle/belt drives) can achieve linear movements up to 8000 mm, and electrical rotary modules can handle loads up to 800 kg.

Mechatronic Solutions are Energy-efficient and Versatile in their Application 

Applications that require versatile and adjustable handling are well-suited to the use of electrically driven modules. They offer particularly high versatility: they allow mechatronic grippers, rotary and linear modules to approach non-standardised sequences of intermediate positions with a high level of precision and dynamics.

During these processes, the position, stroke, speed, acceleration, force, and torque can all be individually adjusted. This makes it possible to handle a variety of parts during a process. In addition, mechatronic systems can quickly be adapted to handle new part designs. This increases the versatility of handling and assembly processes, and also provides a great deal of flexibility in the introduction of new products, sizes, and equipment specifications. The increasing wide range of product variants also makes these systems increasingly attractive. This is particularly the case for applications with a high number of cycles and many gripping processes. In such processes, electrically driven grippers operate with greater energy and cost efficiency than their pneumatic counterparts.

Even though the initial investment is usually significantly higher than in pneumatic modules, decreases in the cost of acquisition and operation have led to significant decreases in the amortization time of mechatronic modules. Their performance is now also on a par with pneumatic solutions.

Like its pneumatic counterpart, for example, Schunk's mechatronic EPG gripper for small components is now equipped with a high-performance junction roller guide, which offers unusually high efficiency and speed while maintaining consistently high gripping force.

Even very simple mechatronic modules are equipped with maintenance-free servo motors, which help make the modules extremely compact and reliable. In some cases, mechatronic modules can even be started up or maintained via the internet or a data line.

Switching Systems is Getting Easier all the Time

The start-up and integration of mechatronic modules has become much simpler due to factors such as adaptive drives. However, users continue to require significantly greater know-how for mechatronic solutions than for pneumatic ones. While intuitive plug &work concepts will at some point become available for complex systems and high-speed applications, this is not yet the case. However, the compatibility and handling of simple mechatronic applications has improved significantly in recent years. Within its mechatronic series, Schunk has developed a group of modules that have made the switch from pneumatic to mechatronic systems easier than ever before.

For example, the EGP gripper for small components is comparatively simple to control via a digital sensor distributor. In many cases, users can transfer the sensor systems used in the MPG plus to the EGP, and easily convert existing systems from pneumatic to electrical operation.

Similar to its pneumatic counterpart, the EGP can be screwed through and fixed either laterally or at the base, which also simplifies the conversion to a mechatronic solution. With these rapid advances in mechatronic modules, users and system planners can benefit from a careful assessment of the advantages and disadvantages of different types of drives. Schunk offers both pneumatic and mechatronic solutions within what is the world's most comprehensive module selection for gripping systems, which in turn provides users with significant synergy benefits.

(Schunk Intec India Private Limited, Bangalore. Tel: 080-40538999. Email: info@in.schunk.com)