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Centreless grinding simulation part II

Final Report Summary - CEGRIS II (Centreless grinding simulation part II)

The industrially applied centreless grinding and centreless through-feed grinding process is characterised by its complexity and sensibility. This process is mainly used for the mass-production of rotationally symmetrical industrial items such as valves and piston rods.

The aim of the project CEGRIS II is to minimise the long set-up times of the centreless grinding process in order to enhance manufacturing productivity by at least 40 % for European companies employing the technology. As well as reduction of the centreless grinding system set-up time, higher process flexibility can be achieved, which can also increase productivity.

CEGRIS II is developing a three-dimensional (3D) simulation model of the complex centreless through-feed grinding process. The model is computer-aided with a software tool that will not only help to set-up the machine-tool, but will also be able to simulate the process at a particular grinding system set-up. In addition, the 3D model and the software tool will be embedded in a CAVE environment for a virtual reality (VR) visualisation of the workpiece movement through the set-up grinding gap. This can be used for process demonstration and also for identification of specific centreless grinding related problems. The developed software tool has a 3D model embedded in a CAVE VR environment, which represents the state-of-the-art in centreless grinding technology.

Another important goal for CEGRIS II has been the reduction of water pollution by about 80 %. Employment of newly designed filtering system will yield significant ecological benefits that are also aimed within this project. For this, different geometries of the wheels, workpieces and the grinding gap set-up have been analytically described with a two-dimensional (2D) model. Investigations and calculations on geometrical stability have been carried out.

Through the use of the software model a virtual workpiece shape after grinding process can be calculated. With regard to the geometry of a 3D grinding gap, an analytical display of the control wheel has been developed. In the next stages of the project, the geometrical and kinematical stability calculations will be extended to the 3D model and visualised in a CAVE environment. A software tool for stability calculations will also be implemented into the machine-tool CNC system in order to reduce set-up times and to monitor the process. This simulation software will also be connected to a measurement system in the grinding gap, which monitors the polygon order. By an adaptive workrest blade it will be possible to adjust the grinding gap set-up automatically and to reduce the roundness error.

Research on coolants, coolant filtering and coolant conditioning has been carried out in order to reduce water pollution. Analyses of the different possibilities of coolant filtering systems have led to the design of a new system. This new floatation system has been implemented into the test machine-tool and first examinations have been realised. The floatation system could reduce the amount of bacteria from 17 000 000 per gram to less than 1 000 per gram, which is outstanding. This big effort in coolant conditioning leads to better working environment for the machine-tool operators as well to enhancement of coolant life-cycle.

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