Robotic Freedom [November 2012]

November 23, 2012 6:16 am

KUKA.CNC can be used to execute DIN 66025-compliant CNC programs directly with the robot controller. Direct integration of the CNC kernel on the robot controller turns the industrial robot into a machine tool with an open kinematic system that combines the advantages of an industrial robot with those of a CNC controller
Machining with industrial robots is a wide spread application. The flexibility of industrial robots opens up a large range of application that until now has involved primarily the finishing of series products. Taps and fittings are ground and polished under robotic guidance, injection moulded parts are trimmed and cut to size by robots, and castings are finished, fettled or deburred.
While many CAD/CAM-based systems already exist for the offline programming of robots, there has never yet been an integrated approach to process data all the way to the robot controller. The prerequisite for processing programs until now was the compilation of the CNC programs into the corresponding robot language with the aid of an adapted post-processor. This automatically resulted in a loss of information, as functions from the CNC program were not always supported in the widely differing robot languages.
KUKA.CNC dispenses with the old constraintsKUKA.CNC has eliminated this limitation. The direct integration of a CNC kernel on the robot controller gives the robotic machining system an inherent range of additional functions.
With KUKA.CNC, KUKA Roboter GmbH offers the possibility of executing DIN 66025-compliant CNC programs directly with the robot controller. The complete standard code can be interpreted by KUKA.CNC and implemented by the robot (G functions, M/H/T functions, local and global subprograms, control command structures, loops, etc.). These options broaden the range of applications for an industrial robot, particularly in the following fields:• Milling of shaped parts made of soft/semi-hard materials, such as wood, plastic, aluminium, composite materials, etc.• Polishing and grinding of shaped parts• Coating and surface treatment of complex workpiece surfaces• Trimming and cutting of complex workpieces and workpiece contours• Laser, plasma, waterjet cutting of complex workpieces.
Direct integration of the CNC kernel on the robot controller turns the robot into a machine tool with an open kinematic system that combines the advantages of an industrial robot, such as the large workspace, high flexibility, low investment costs and 6-axis machining, with those of a CNC controller, such as G-code programming, CNC user interface, tool radius compensation, extensive point anticipation, advanced spline path planning and user-friendly tool management.
Integration of the CNC kernel also enables direct processing of the CNC program on the robot controller. Both CAD/CAM programmers and CNC machine operators can thus program and operate an industrial robot with their existing knowledge.
KUKA.CNC: Robotic machining and machine tool automationIn addition to the general possibility of executing programs using the CNC kernel integrated into the robot controller, KUKA also continues to offer the full range of functions of a robot controller. In this way, it is possible to switch between CNC operation and conventional robot operation for different applications. This allows selection of the ideal controller, programming and operator control environment for the process in question.
Advantages for CP processesCNC mode is particularly advantageous for continuous-path processes. Machining programs with a large number of points on the path can be executed more precisely and with shorter cycle times using the CNC kernel and its sub-functions. These improvements in accuracy and cycle times are due to the advanced path planning functions in the CNC kernel. Path planning with point anticipation for more than 500 points makes it possible for the robot above all to maintain constant velocities during the machining process and to plan optimal acceleration/deceleration ramps. The path accuracy is also improved by means of various spline interpolations in the CNC kernel. Akima and B-Spline calculations ensure that the robot executes its set path as accurately as possible. These typical CNC functions are combined with the conventional functions of a robot controller, thus achieving optimal machining results.
Simplified robot integration holds advantages for machine operatorMoreover, the use of robots in the domain of conventional CNC machine tools redefines the possibilities of G-code processing. In automated machining systems, it will in the future be possible to program and operate not just the machine tool, but also the robot by means of DIN 66025-compliant code. This facilitates robot integration and offers a crucial advantage especially for the machine operator. In the future, the operator will no longer need robot-specific programming knowledge, but will be able to operate the robot using his existing CNC expertise. 
Machine tool & automation system are merged into a single unitA special case in the field of automated machining is the processing of workpieces handled by the robot. The combination of machining and handling makes this process variant particularly efficient. Since the robot picks up the workpieces, guides them to a machining station for processing and then transfers them to a storage facility, no further transfer or handling kinematic system is required for automation of the process. In this example, the machine tool and automation system are combined to form a single unit, with a great influence on the aspect of cost-effectiveness.
CNC programming opens up a whole new range of programming systems for robotics. The CAD/CAM system market offers specially adapted solutions for a wide range of different machining applications. Robot programming and application possibilities will thus also multiply in the future. CAD/CAM systems are increasingly recognising this development and providing their software with corresponding modules for robot programming and simulation.  Advantages of KUKA.CNCThe great advantage of this solution lies precisely in the combination and integration of the entire process chain from the CAD system via a connected CAM module to he robot-specific path and process planning. The process chain is closed and kept to a compact size by the directly connected robot system including the CNC kernel. Detours into post-processor tools are not necessary and optimisation is possible at every process level on account of the direct integration with the CAD/CAM system. (Author: Alexander Bay, Product Manager, KUKA Roboter GmbH)