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In this third edition of the “Did you know that?” column, we'll be looking at the subject of transfer and handling; in other words, picking up products from one place and putting them down in another.

Today we're going to speak about palletizers and Cartesian “pick & place” devices, then we'll complete the topic in one of the forthcoming editions, analysing the robotics in some detail. The design of Cartesian systems implies a mechatronic approach involving mechanics, electronics and pneumatics.

Rexroth was one of the first to introduce and apply linear systems (linearmodules) as standard elements of Cartesian mechanics. It is, in fact, a standard system that's customised according to the specific requests. Rexroth's strength is its combination of good application experience and the notable attention paid to sizing, as both these elements are fundamental for creating an efficient system.

All this means the utmost flexibility, an excellent quality/price ratio and, above all, a considerable reduction in design, assembly and installation times. The main elements to be considered are: the work environment, the type of product to be handled, its length, the loading factors and moments, speed and acceleration, precision, repeatability, drive and control, the type of grip, maintenance, and every possible specific request. And all this while bearing in mind the interaction of all these elements in the case of multi-axis systems.

The portfolio of systems available includes drives using screws, belts and racks, handling with ball bearing guides, precision wheels or sleeves (electrically-operated - rotary or linear motor, or pneumatically-operated), or with a clean profile suitable for the food sector. Certain particular devices should be highlighted, such as the OBB “Omega construction” module which, thanks to the concentrated masses, can be used in high dynamics applications or as a vertical axis, the bridge modules (BKK or BKR) with their free-standing structure with 90° guide system and EMC electro-mechanical cylinders with screw drive (fully interchangeable with the ISO pneumatic cylinders), the VKK module with its screw drive and ball bearing guides (highly compact and designed for vertical applications), and finally a mention for the mini slides (electrically or pneumatically operated).
For the sizing of the drive, Rexroth uses the Indrasize software (www.boschrexroth.com/indrasiz) which not only guarantees optimised sizing but also allows an evaluation - and therefore a reduction - of energy consumption thanks to the simulation of cam profiles.
The grip area has an equally important role, usually making use of pneumatic actuators such as cylinders, clamps or suction cups. Of these, we can't forget the now-famous NCT pneumatic contact-free gripping unit; there's now a version made entirely of materials suitable for contact with foodstuffs and certified by the FDA regulations.