LUXURY IN THE KITCHEN:
A CUTTING-EDGE SOLUTION FOR GRANITE

The latest innovation in the area of natural stone processing is this robot-based cutting center that works marble, granite and other natural stones in a cost-effective manner.

For many people today, kitchens are more than just a room for cooking, baking and eating. They are seen as living space, and are proudly presented, with all their high tech features, to guests. Just a few years ago, plain laminated particleboard was all that was used for the work surfaces, and only professional chefs appreciated the qualities of fine granite or marble. Today, even hobby chefs like to enhance their kitchens with gleaming stone and get to feel a bit like Paul Bocuse.

The latest innovation in the area of natural stone processing is the robot-based cutting center from USG Robotics, Inc. (Crystal Lake, IL). An intelligent combination of saw and waterjet technology makes it easy for manufacturers to work marble, granite and other natural stones in a cost-effective manner. Robots are the ideal alternative for heavy-duty tasks, as they guarantee 100 percent quality with their flexibility and constant accuracy.

WHY INDUSTRIAL ROBOTS IN THE STONE SECTOR?
A well-known problem in the stone sector is that, before the mason sees the outcome of his work, he must first carry out the laborious, arduous, strenuous and time-intensive preparation of the raw material. In this day and age of cost pressure and intense competition, this is a major economic aspect, even in the natural stone industry.

This is precisely where industrial robots from KUKA Robotics Corporation (Augsburg, Germany) come in. The Augsburg-based company is a pioneer in the field of robotics. Thanks to the company’s focused attention to the requirements of its customers, KUKA is now able to offer an initial range of stoneworking applications that will ease the workload of any mason or company involved in the processing of natural stone. Six-axis robots can be used for a wide range of applications in the stoneworking industry. Depending on the size and weight of the workpiece, they can be used for handling or machining marble, limestone, sandstone or natural stone.

When modeling stone, masons put their faith in manual work. Today, however, certain tasks can also be delegated to a robot. These robots cover a wide payload range, from 150 kg to 1300 kg, and can naturally also change tools. From simple saws with diamond blades to fine work with a milling spindle or high-pressure waterjet, numerous options are open to the robot for processing stone surfaces.

Furthermore, it can even do this while in motion: for work on large sculptures or columns, the robot can be easily mounted on a linear unit. This allows the seamless removal of material along the length of the workpiece. The workpiece can also be machined on a turn-tilt table, however. The turn-tilt table communicates with the robot during modeling and its motions are coordinated with those of the robot.

Robots that are frequently used in the natural stone industry belong to the 2000 Series line that includes robots with a wide variety of powerful drives and gearmotors, as well as varied reaches and payload capacities from 150 kg to 360 kg. The KR 500-2 MT is ideally suited to the milling of hard, heavy materials. This robot has special gear units allowing versatile, high-precision motions with high process forces. Robots designed for payloads ranging from 150 kg to 1,300 kg can also be used for handling heavy, unprocessed blocks or finished work surfaces, and also for palletizing concrete, bricks or tiles – the optimal solution for the natural stone industry.

In many companies that process natural stone, use of machinery is restricted exclusively to CNC bridge saws. Meanwhile, however, robots are also being used in the innovative form of a robot-based machining center with a KR 210 L150 robot in the foundry version that cuts kitchen work surfaces, steps and sink tops at USG Robotics. With the specially developed RoboCut system, cutting marble or granite is no problem at all. The complete system with saw and waterjet technology eliminates the need for additional cutting on other machines. This intelligent combination helps to optimize the cutting process and minimizes wastage.

A double-table cutting system equipped with a camera system helps to achieve maximum productivity. The twin cutting tables minimize the loading and unloading times, allowing the robot to work continuously on the granite slabs. The camera system is used for automatic position detection. The slab to be processed is scanned and the data are transferred to the robot with the precise orientation of the slab.

Using the RoboCut software, as many countertops as possible are projected onto the uncut slab. The robot can then start cutting the granite slab straight away. In the first step, the straight edges are sawn using the 400 mm saw blade at highly cost-effective cutting speeds of up to 4.6 m per minute. In the second step, the waterjet technology is used to cut sink or washbasin outlines, holes or curves. With a pressure of 4,000 bar, the waterjet achieves cutting speeds of up to 440 mm per minute.

The robot does not need to change its tool at any point during the cutting process. Merely from the use of the system, production capacity can be increased by 20 percent (compared with a conventional system). “Nonetheless, the robot requires an operator who is familiar with the niceties of working natural stone. As well as monitoring the stone cutting process, he checks the loaded customer data before work is commenced and inspects the finished countertop at the end of the process. It is the teamwork between the skilled operator and the robot that makes the product,” explains Stefan Ender, the Industrial Business Development (IBD) Manager for the Stone Industry at KUKA Roboter GmbH.

The most important thing for a customer using a robot is familiarity with the application, and he has to invest time in this. The starting point is therefore intensive training in use of the robot system. It goes without saying that service personnel from KUKA Roboter are on hand for the first production runs, to ensure that everything goes smoothly later on and that the user is satisfied.

www.kuka-robotics.com