Improvement of the surface treatment of wood with geometrically defined cutting edges through linear cutting movement

Summary

In the period from 01.09.1996 to 30.09.1998, the research project "Improvement of the surface treatment of wood with geometrically determined cutting edges by linear cutting motion" was carried out at the Institute for Wood and Paper Technology at the TUD Dresden University of Technology.
The aim of the project was to create the basis for the technical realization of cutting processes using the principle of linear cutting motion when processing the surfaces of wooden workpieces. In addition, a way was to be found to replace the main process currently in use for this machining task, i.e. peripheral milling.
The latter objective could not yet be achieved to a satisfactory degree.
During the research period, conceptual studies were carried out on the subject and various implementation options were tested, some of them in practice. Both process sketches with moving and stationary tools were included in the considerations. The results of these investigations clearly showed that it is currently impossible to implement the principle with moving tools (rotating, reversing) to the required quality. The main focus here is on the necessary guide quality, the dynamic behavior of the tools and ultimately the cutting speeds to be achieved. As a consequence of this finding, more attention was paid to existing processes with fixed tools, such as finishing.
The problems to be solved are the low chip removal rate of the process, which currently restricts it to the areas of finishing, the inadequate possibility of preselecting a target thickness of the workpiece and the low cutting speeds.
The first prototypes of multi-bladed tools arranged in a cascade, which allow a significantly higher chip removal rate, were developed as a solution. The use of chip breakers and pressure bars in front of the cutting edge can effectively counteract the restriction of low cutting speeds.
The analysis of the linear cutting process on a standard finishing machine produced initial results in the determination of cutting values such as cutting forces, friction conditions, surface, noise and wear parameters as a function of a wide range of cutting parameters and cutting conditions. These determined dependencies and variables represent an indispensable prerequisite for future development tasks in the field of linear cutting. It has been demonstrated that the machining process involves lower specific cutting forces, a significantly reduced, approximate noise level, virtually no dust and increased work safety compared to peripheral milling.
The path taken towards the use of stationary tools in throughfeed edge processing systems has shown that even the processing of wood-based materials is possible with a very large working intervention (millimeter range). However, the limited time available within the research project prevented further development of this favored process design.
The energy prices, which are certain to rise in the future, as well as the potential savings in costly extraction and noise protection measures justify a continuation of the development and investigation of the topic in any case.
The objective of the project was partially achieved.

The research project (No. 10811 B) was financially supported by the German Federation of Industrial Research Associations "Otto von Guericke" e. V. (AiF).