Márton Takács

Material Structural Aspects of Micro-Scale Chip Removal

In these days one of the most important field of interest lies i n the manufacturing of miniaturized parts. The economical and flexible alternative for produc tion in small and medium lot sizes is machining with miniature, fine-grained carbide end mill. The experimental research and analytical observations of the authors in connection with material st ructural aspects of micro scaled chip removal and the effects of the very thin micro milling tool are described in this pa per.

Actual Feed Rate per Tooth at Micro Milling

Miniature structures can be produced economically by micro end milling as single parts or parts in small and medium lot sizes. The micro end milling process has to be analyzed particularly for the purpose of applying a well controlled and repeatable process. There are many specific characteristics in the micrometric scale of dimensions, whose role is negligible at the conventional processing technologies. One of these special features of micro end milling is the observation that the set value of the feed rate per tooth generally differs from the thickness of the actual removed material layer. Feed rate per tooth is practically defined as the distance, which is run by the edge lengthwise of the groove during one revolution of the tool. Accordingly the feed rate per tooth corresponds to the thickness of the material layer removed by one edge of the tool. This correspondence exists at conventional manufacturing methods but not at micro end milling. This fact is attended by more special features of the micro end milling process, which are multiple cutting, different machining conditions of the edges and tool deflection. This paper introduces the results of improvement of my earlier research on this field [1]. An enhanced flowchart was constructed, which provides the calculation of the thickness of the actual removed material layer at micro end milling under all possible circumstances.

Validation of 3D Finite Element Simulation of Chip Removal Process Performed by Unique Insert Geometry

Main aim of our current research activity is experimental and theoretical investigation of cutting process performed by unique insert geometries. The new geometries should affect smaller cutting forces, less vibration, and better surface quality. Other aspect can be the higher productivity. Economical investigation requires single production, which can be realized by micro EDM process. This paper gives summary about preliminary investigation of application of DEFORM 3D software for simulation of chip removal process performed by cutting insert with unique geometry. Fabrication of unique geometry means modification of the rake face in this case. Experiments were carried out on workpiece material AISI1045. Feed rate and cutting velocity were changed; cutting forces (Fc) and surface roughness (Ra) were measured. Exact geometrical model of the modified cutting insert were applied for FEM simulation. Results of numerical simulation and experiments show good agreement.

Standardized Investigation Methods of Self Compacting Concrete and Effect of Sand Content on Properties in Fresh State

Investigation methods of self-compacting concrete (SCC) in fresh state in virtue of the new Hungarian standard are summarized. The referenced testing methods of former technological guidance were finally replaced by the MSZ EN 12350:2010 standards, part 8, 9, 10, 11 and 12, however momentarily these are only available in English. Besides testing methods, the requirements of MSZ EN 206-9:2010 Additional rules for self-compacting concrete reference titled standard are precedent. Neither of the currently used and standardized testing methods is suitable for collective evaluation of each special feature of SCC, thus these should be used coinstantaneously. Results of recent research work regarding change of SCC features by adding different amount of sand aggregate are presented in this article, too.

Investigation and Application of High Performance Concretes

Recent research work of the authors is dealing with preparing, investigation and application of high performance concretes (HPC) produced by the mean of results of modern concrete technology. These special types of concrete have one or more outstanding properties conversely the normal concrete. This article is focusing on the results of the experiments regarding self compacting concrete (SCC). During the investigation, effects of the fine-graded fraction was studied, which is indispensable component of the SCC. The effects of bulk density, consistency, air content, compressive strenght were analysed on fresh and hardened concrete.

3D Milling by Micro Electrical Discharge Machining

One of the most important tasks of the manufacturing engineering of our accelerated world is giving suitable answer to the ever growing demand on miniaturization arising on every field of the industry. Our institute has been carried out theoretical and experimental research work on micro machining since 10 years. Micro machining can be defined as formation of structures smaller than 1 mm. Our previous research activity focused primarily on micro milling process carried out by carbide end mill. Milling offers the most various machining method among the chip removal processes. Investigation of formation of micro structures by electrical discharge machining (EDM) is a perfect continuance of the research work. A process similar to micro milling can be realized by the lateral moving of the miniature cylindrical electrode of an EDM machine, just the physical principle of material removing is different. This paper introduces the latest results of our research work, including

Investigation of Plasticizing Admixtures Used in Hungarian Building Industry

There is no doubt that concrete makes a massive contribution to sustaining the quality of life. Properties of concrete can be expediently modified by adding special chemical materials called admixtures. Admixtures for concrete are now widely accepted as materials that contribute to the production of durable and cost-effective concrete structures [1]. Plasticizing admixtures reduce water needed to achieve a given workability of the fresh mix. This main effect can be utilized in three ways: increased strength, increased workability, or economies in mix design [2]. In this research work effect of type and dosage of different plasticizing admixtures available in Hungary were investigated in detail. Standard test methods such as flow table test, compressive test, and shrinkage test were applied to obtain effectiveness of the admixtures. Results were compared with the requirements of the harmonized admixture standard MSZ EN 934-2:2002.

Investigation of Performance of Superplasticizing Admixtures Used in Hungarian Building Industry

Concrete is the strongest candidate to be the most important construction material of the 21st century. This can be ensured by the continuous research and development of new materials and technologies regarding concrete construction. Properties of concrete can be expediently modified by adding special chemical materials called admixtures. In this research work effect of type and dosage of different superplasticizing admixtures available in Hungary were investigated in detail. Standard test methods such as flow table test and compressive test were applied to obtain effectiveness of the admixtures. Regarding the examinations done in the course of the research, we refer to the regulations of the EU harmonized admixture standard currently valid in Hungary MSZ EN 934-2:2002. In connection to that we will precisely quote the requirements specified in the standard regarding superplasticizers and will also mention the main differences compared to the plasticizer additives. Types, properties and use of superplasticizers are introduced in detail, too. Experimental results are evaluated to rate the efficiency in compliance with the requirements of the standard.

Pulse plated amorphous Fe-P thin layers for high frequency magnetic applications

Amorphous and partly nanocrystalline amorphous iron-phosphorus (Fe-P) layers have been deposited by pulse electrochemical technique. X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) have been used to characterize the structure in the layers. Depending on the pulse parameters, the structure of Fe-P layers changed from mostly amorphous to partly nanocrystalline amorphous. The magnetic coercivity and the frequency limit of the samples are discussed in terms of the structure of the Fe-P layers. The frequency limit as determined from the permeability spectra is above 10 MHz, which makes these layers suitable for high frequency inductive element applications.