Gyula Varga

Possibility of reducing environmental load in hard machining

Abstract. The development of metal machining processes and procedures has been characterized by aiming at accuracy and economy for decades. The applied coolants and lubricants helped this process; however, they are polluting the environment. For today that is a social demand and technical possibility that environmental aspects should predominate better in production engineering. In the frame of this article, through the application of dry hard turning we shall spotlight on its economy and efficiency. We shall prove that, keeping the same accuracy and economic efficiency, it is possible to choose a machining process by which the environmental load can be reduced compared to the most frequently applied grinding.

Effect of Environmentally Conscious Machining on Machined Surface Quality

Modern machining processes continuously face cost pressures and high quality expectations. To remain competitive a company must continually identify cost reduction opportunities in production, exploit economic opportunities, and continuously improve production processes. A key technology that represents cost saving opportunities related to cooling lubrication, and simultaneously improves the overall performance of cutting operations, is dry machining. The elimination of coolants or significant reduction in cooling lubricants affects all components of a production system. A detailed analysis and adaptation of cutting parameters, cutting tools, machine tools and the production environment is mandatory to ensure an efficient process and successfully enable dry machining. Case study is shown for examination of cylindricity error and surface roughness of helical milling machined surfaces by environmentally conscious way.

Advantages of the CCD Camera Measurements for Profile and Wear of Cutting Tools

In our paper we prepared an evaluating study of which conclusions draw mainly two directions for our fields of research. On the one hand, this means the measuring of fix, standing workpieces, on the other hand this means geometrical measurement of moving tools. The first case seems to be solved in many respects (in general cases), but the second one is not completely worked out according to the relevant literature. The monitoring of tool wear, the determination of geometrical parameters (this is mainly in case of gear-generating tools) is not really widespread yet, mainly, if optical parameters have influence on the evaluating procedure (e.g. examination of profiles of grinding wheels). We show the elaboration of a process for the practical application of measuring techniques performed by image processing CCD cameras on the basis of wearing criteria of different cutting tools (drilling tool, turning tool). We have made a profile and cutting tool wear measuring program.

Some Aspects of the Hard Machining of Bore Holes

The machining of hardened surfaces can be done even fulfilling the ever stricter accuracy and quality prescriptions, besides the economic efficiency. Decisively, hard machining is highlightedly important in finish processes because the components must meet increased functional demands. Therefore the number and/or the hardness of the hard surfaces on the components is continuously increasing. In practice the demand for such components is high since they are more wear resistant and their tool life may be higher. Today there are several possibilities for finish machining of components having hard surfaces. We have done experiments for hard machining of inner cylindrical surfaces. The examined procedures were as follows: grinding, hard turning, combined machining. The first two procedures (hard turning, grinding) have got different procedure-specific advantages and disadvantages. Combining these two procedures, using-up the advantages of them, the efficiency of the production can be increased. This paper outlines these procedures of hard machining, their applicability, the increase of their efficiency, and the possibilities provided by the combination of the procedures.

Effects of Technological Parameters on the Surface Texture of Burnished Surfaces

In this study we analysed the process of diamond burnishing. We examined the effect of burnishing technological parameters on the surface roughness of the burnished surface, and on the improvement ratio of surface roughness. Parameters taking into consideration during examinations are burnishing speed, burnishing feed, and burnishing force. We determined a formula suitable for determination of the improvement ratio of surface roughness by the Factorial Experimental Design which is valid in the examined parameter range.

3D Topography for Drilled Surfaces

Nowadays more and more scientific papers deal with drilling. The drilling process has been used for more than 5000 years and the development of conventional drills is more than 200 years old. In recent years there have been limited changes to the drill design but considerable improvements have been made in the selection of drill materials, drill coatings, flute design and cutting fluid guiding methods. The paper briefly describes the development of surface characterisation including its current 3D capability. It shows how selected parameters can assist with drill process analysis and how this can be supported through the introduction of the planned new ISO International Standard for 3D Surface characterisation. The paper is supported by a sample drilling test to demonstrate the power of the proposed analysis.

Possibility to Increase the Life Time of Surfaces on Parts by the Use of Diamond Burnishing Process

New trends appeared in product design and technological planning, which contributed in the development of new finish machining procedures like diamond burnishing. With the influence of diamond burnishing process, the surface roughness, the hardness of machined surface, and the dimensional accuracy can be improved. In this paper the effect of burnishing technological parameters on the cylindricity error of the burnished cylindrical surface and furthermore on changing of hardness of the burnished surfaces were examined, too. Burnishing parameters, which were taken into consideration during the examinations, are burnishing speed, burnishing feed, and burnishing force. Formulas suitable for determination of the improvement ratios of cylindrical shape error and improvement of hardness were determined by the Taguchi type Factorial Experimental Design.

Preliminary investigations for the effect of cutting tool edge geometry in high-feed face milling

The increasing of the cutting speed and/or the feed rate is often chosen to increase the efficiency of the material removal. Of course, there are limits to the selection of specific values in both cases, such as the rigidity of the machining system or the loadability and lifetime of the cutting edges. When increasing the feed rate in face milling, the conditions of chip removal are changing considerably, because at low feed values, the material forming effect of the side edge (i.e. the edge on the lateral surface of the tool) is the most critical and the chip deforms perpendicular to it, while increasing the feed gradually moves the primary part of the chip removal to the edge lying perpendicular to the tool axis. Therefore, both two edges have a distinct role in chip removal due to their position and geometry. As the two edges are located on one cutting insert, their geometry needs to be examined individually and collectively, and searching for the most suitable combination for effective chip removal is needed. Therefore, preliminary investigations were performed to aid in the constructional design of the tool as well as the proper design of the seat of the inserts. The simulations were carried out by the AdvantEdge Finite Element Method (FEM) software. The article shows the results of this analysis, which can be utilized to increase the efficiency of face milling, which is often used in the machining of automotive parts.

Effects of technological parameters on surface characteristics in face milling

The experimental and theoretic examination of conventional manufacturing procedures continue to be a topic of modern research. It is assisted, to a great extent, by the spread and the possibility of the application of high level software and more accurate measuring equipment. The research results obtained by the use of new equipment can open new ways for further development of conventional manufacturing procedures and their more intensive, more productive application. In this paper, an experimental method is used for examination of the surface features (e.g. flatness, 2D and 3D surface roughness parameters) of face milled aluminium parts. The aim of experiments was to determine the effect of change of the technological parameters (feed rate and cutting speed) on flatness and surface roughness features in of face milling of aluminium parts.

3D topography for environmentally friendly machined surfaces

Nowadays more and more scientific paper deals with drilling. In recent years there have been limited changes to the drill design but considerable improvements have been made in the selection of drill materials, drill coatings, flute design and the cutting fluid guiding methods. All of these improvements have been introduced to improve the surface finish of the drilled hole, reduce the energy during drilling process and to reduce ecological damage to the cutting fluids, which carry away heat and debris from the cutting zone. The paper briefly describes the development of surface characterization to its current 3D capability. It shows how selected parameters can assist with drill process analysis and how this can be supported through the introduction of the planned new ISO International Standard for 3D surface characterization. The paper is supported by a sample-drilling test to demonstrate the power of the proposed analysis.