The pallets with the clamped workpieces are stored in a workpiece storage unit and automatically loaded onto the machine. (Image: Schunk)

The individual pallets are each equipped with an interface to the zero-point clamping system on the underside, via which they are connected to the machine. Special components, such as the Vero-S NSA plus palletizing module, were developed specifically for robot-assisted machine loading. They are extremely flat, can be integrated directly into the machine table and leave plenty of space in the machine room for the workpiece and axis movements.

With the help of a patented rapid and clamping stroke, they achieve pull-in forces of up to 20,000 newtons and holding forces of over 100,000 newtons. The robust modules ensure a precise hold even during demanding volume machining. To prevent chips and dirt from jeopardizing the process when changing pallets, a forced air flow cleans the flat surfaces and the short taper. This ensures that the pallet is flattened without chips. Insertion radii on the clamping module enable fast and reliable joining even if the pallet is offset in the middle or slightly inclined. In this way, tolerances of the handling system can be optimally compensated. Centring rings then ensure accurate positioning before clamping slides ensure positive, self-locking clamping with a repeat accuracy of < 0.005 millimetres.

Excavation bolts facilitate removal

After processing, a lifting pin lifts the pallet by up to five millimetres to change the workpiece, simplifying the changeover process. All process steps, i.e. the "module open", "module closed" and "pallet present" states, are monitored via a dynamic pressure monitor. Unlike other clamping systems, the Vero-S NSA plus palletizing module does not consume any energy during processing.

The workpieces remain securely clamped even if the pressure in the air system suddenly drops. A pneumatic system pressure of six bar is sufficient to open the modules. This saves on expensive hydraulic systems and complex piping. To ensure a long service life, all functional parts such as the base body, clamping slide and clamping rings are made of hardened stainless steel and are therefore absolutely corrosion-resistant.

The four clamping rings lie flat on the outer diameter of the zero point clamping module. This results in optimum support for the transmission of high torques. (Image: Schunk)

To ensure process-stable pallet changing in fully automated operation, the use of special handling modules such as the slim, lightweight Vero-S NSR coupling with minimized interfering contours is recommended. This can also be used in confined spaces and enables pallets to be loaded extremely close to the machine table. It can be used to create particularly low superstructures consisting of a clamping station and pallet. With a dead weight of just 1,600 grams (NSR 160), the module allows a high torque absorption of up to 1,600 Newton meters (Mz) or 600 Newton meters (Mx).

There is also the Vero-S NSR mini miniature clutch with a robot-friendly weight of just 400 grams (Mx maximum 75 Newton meters, Mz maximum 200 Newton meters) and, at the other end of the weight scale, the Vero-S NSR maxi heavy-duty robot clutch for heavy pallets and clamping towers (Mx maximum 4,000 Newton meters, My maximum 4,000 Newton meters). The couplings are completely sealed against chips and cooling lubricants to ensure reliable operation in demanding environments. In addition, a standard cleaning function ensures chip-free flat contact between the pallet and the robot coupling. Steel inlays at the contact points make the couplings extremely wear-resistant.

The clamping pallets can be equipped with various clamping devices from Schunk's modular system for stationary workpiece clamping. For example, the manually operated Kontec KSC basic clamps are efficient all-rounders for raw and finished part machining on pallet systems. They combine high clamping forces, convenient operation and short set-up times. Even with a comparatively low torque, they achieve high clamping forces of up to 50 kilonewtons (size 160), so that a separate embossing station can be completely dispensed with for positive clamping.

As the clamping is tensile, the bending load on the base body and thus the rearing of the clamps is minimized, which benefits the accuracy and rigidity of the clamping. A preloaded center bearing without spindle backlash and specially fitted sliders ensure excellent repeat accuracy of plus/minus 0.015 millimeters. The fully encapsulated drive and an integrated chip drain ensure particularly high process stability and minimal wear.

The Kontec KSC basic clamps offer high clamping forces, convenient operation and high accuracy. They can be used to dispense with an embossing station when clamping raw parts. (Image: Schunk)

The basic clamps are available as centric clamps or as single clamps with fixed jaws. With quick adjustment of the clamping range, a flat design and low weight, they offer perfect conditions for unmanned workpiece handling. If several workpieces are to be clamped next to each other in a confined space, Kontec multiple clamps are the ideal solution. A single clamping key is all that is needed to clamp the parts, remove the clamping jaws completely with a quick change or quickly and flexibly convert the clamping system to other workpieces.

Spring-loaded tandem clamping force blocks, on the other hand, enable particularly compact setups. Rota-S-plus-2.0 three-jaw chucks can be used to clamp cylindrical parts. Clamping towers with interfaces to the Vero-S zero-point clamping system can now also be handled by robots. as