Pulsating supply of the cooling lubricant during the turning of difficult-to-machine materials under elevated pressures

 

The project aims to solve a known problem in the turning of materials that are difficult to machine. Although the constant supply of cooling lubricants (coolants) used so far minimizes machine downtimes by largely avoiding band and tangled chips, it generates flying, short-brittle chips with a high impulse which contribute to contamination of the working area and can damage workpieces, resulting in rejects. The targeted supply of the cooling lubricant to the cutting point at high pressure (high-pressure coolant supply) represents a potential technology for increasing productivity and process reliability, especially in turning operations. Despite its high performance potential, this innovative cooling lubricant strategy is still used today primarily for roughing difficult-to-machine materials.

Due to the process, short-chipped chips often occur during machining under high pressure coolant supply, which are whirled around in the working area of the machine by the high dynamic pressure and the resulting outlet speed of the coolant lubricant. On the one hand, this makes it more difficult to clean the exhaust air due to strong mist or aerosol formation. On the other hand, the briefly broken chips collide with the newly generated workpiece surface. This can lead to undesirable surface anomalies, so that the components have to be sorted out as rejects. Based on this, the objective of the present research project is to eliminate the technological disadvantages of a permanent high-pressure cooling lubricant supply by means of an innovative cooling lubricant pulsation technology and thus to enable an expansion of the areas of application of high-pressure technology, in particular in SMEs. The focus of the work is on the mechanisms of action during turning with pulsating high-pressure coolant supply, the development of technically suitable supply concepts, the determination of suitable operating conditions and the evaluation of the energetic and economic potential of pulsating high-pressure coolant supply, especially for SMEs.

The final report of the project was published by the Technical Information Library Hannover (TIB).