Ján Žitňanský

Effect of Type of Cutting Tips on Cutting Forces in Turning

Abstract The aim of this article is to demonstrate the efect of cutting materials and geometry of cutting tips on cutting forces in turning as well as the quality and precision of machined surface. The experiment focuses on measuring cutting forces when turning a sample of steel 11 523 at a constant feed rate and cut depth and at varying speeds of a spindle. Measurements were made using exchangeable cutting tips of diferent types. The results will be evaluated in terms of the impact of diferent characteristics of cutting tips and variable spindle speeds.

Cutting inserts effect on heat generation in turning process

The paper is focused on confirmation of an effect of cutting materials and cutting inserts geometry on cutting forces and temperature, quality and accuracy of machined surface in turning. The main part is devoted to description of advanced turning tools and cutting materials. The experimental part is focused on cutting forces and temperature measurement and machined surface quality in turning of steel grade 11 523 samples with one feed and depth of cut value and varying spindle speed. Measurements were performed with various types of indexable cutting inserts used. Measured values were evaluated in terms of the effect of different properties of cutting inserts and various spindle speed values.

Influence of the Type of Inserts on Dimensional Accuracy in Turning Process

This article is aimed to demonstrate the effect of cutting material and geometry of inserts chip breaker for dimensional accuracy in turning. The experiment is aimed on measuring compliance with dimensional accuracy in turning of samples from steel 11 523 at a constant feed rate and depth of cut, with varying spindle speeds. Machining was performed by using a different types of replaceable inserts. The measurement results will be evaluated in terms of the impact of different geometry characteristics and changing speeds spindle. INFLUENCE OF THE TYPE OF INSERTS ON DIMENSIONAL ACCURACY IN TURNING PROCESS INTRODUCTION Machining of materials is a working process, which changes the work piece into desired dimensions and shape by removing of material from surface layer. The most common method of machining is turning. Material during turning is removed in form of chips and those are generated by the interaction between the tool and machined material [1, 2]. Based upon long-term development of cutting materials we can ́t expect in near future that new cutting material will be discovered. Therefore, the research of the leading manufacturers is focused on improvement of existing cutting materials, the specification and exact determination of their optimal application. In the process of turning the cutting edge of tool is exposed to high thermal load, mechanical stress, friction, vibrations and sudden thermal and mechanical shocks. Therefore, measurement and examination of behavior under these conditions is an inseparable part of research and development of cutting materials [5, 7]. The aim of this paper is to monitor and evaluate the dimensional accuracy in turning caused by different properties of individual inserts and monitoring of changes in these characteristics at three different values of spindle speeds [3, 4]. MATERIALS AND METHODS We have focused on monitoring the influence of cutting material and the chip breaker geometry on dimensional accuracy of machined sample. In order to study the influence of only one factor, it was necessary to set the conditions that other factors were eliminated. These other factors could influence measured parameter. We have used one size of cutting inserts – DNMG 150608, made of different cutting materials and with different chip breaker geometry. In assessing the influence of cutting material were compared only the cutting inserts, whose only distinguishing feature was just cutting material. We have also followed in assessing the impact of inserts geometry. We were interested in behavior of inserts at different spindle speeds – at 710 rpm, 1400 rpm and 2240 rpm. Other cutting conditions remained constant – depth of cut ap = 1 mm and feed rate f = 0.1 mm. As the sample of the material steel 11523 was used. Inserts used in measurement are designed especially for machining this type of material. Characteristics of used sample For the experiment were used samples of the same shape, dimensions and material (see Table 1). Pavel POLÁK, Ján ŽITŇANSKÝ, Michal ADAMIK Slovak University of Agriculture in Nitra

CAPABILITY ASSESSMENT OF MEASURING EQUIPMENT USING STATISTIC METHOD

Capability assessment of the measurement device is one of the methods of process quality control. Only in case the measurement device is capable, the capability of the measurement and consequently producƟon process can be as‐ sessed. This paper deals with assessment of the capability of the measuring device using indice s Cg and Cgk.

Boroscopy Application in Assurance of Technological Equipment Operational Capability

This paper is focused on an emphasis of the preventive maintenance effect on reliable and safe operation of technological equipment, in view of technical diagnostics. Problems of the boroscopy as a diagnostics method providing fast information acquiring of inner parts of technological equipment turbomachinery RB211 DLE assembled in combined cycle gas turbine (CCGT) in selected company [. Observations were focused on high pressure axial compressor, being the main part of monitored technological system. From quality point of view the paper provides new perspective of internal inspection of technological equipment covering possible damages locating and qualifying of qualitative characteristics of equipment inner parts. The problems solved were based on particular practice demands and it reflects state-of-art in concerned scientific field [.

Boron Effect on Mechanical Properties and Structure of Steel STN 41 5230 Surface Layer

This paper deals with the possibility of applying controlled diffusion processes in the remelting of steel surface layers using the electric arc of non-consumable electrode in the environment enriched with selected elements. The objective was to achieve an increased wear resistance. Boron was used in experiments as an alloying element. An assumption was stated in the experiment design that environment dissociation and ionisation can be achieved using electric arc, allowing diffusion processes initiation in the surface layer of remelted steel. Conditions for hard and stable structures formation with required properties should be achieved by surface layers enriching. Steel grade STN 41 5230 was used in experiments. Hardness and relative abrasive wear resistance values were measured on samples after remelting, being crucial as for required properties of surface layers. Not only hardness values were measured in the remelted layer but also their course inwards the material up to reaching the depth of base material not affected by heat. The metallographic analysis of remelted samples was made as well. A significant increase of parameters observed in the boron remelting environment was found. The dependency of the environment effect on the change of properties and boron content in the remelting environment was observed.

Analysis of Physical Effects in Cutting Machining

This contribution focuses on hole drilling into grey cast iron and steel 11 523. The most used method of hole machining is the one using a screw drill HSS to reach the accuracy class from IT 11 up to IT 14. Surface roughness ranging between Ra 3.2 μm and Ra 6.3 μm depends on the parameters of the drill used and drilled material. An emphasis is put on the accuracy of shape and dimension as well as on meeting the tolerance limits of holes [1,2,3,4,5]. In most cases, it is possible to reach those conditions using the common methods of hole drilling. Finishing such as roughing, reaming and countersinking is used for meeting high-quality requirements [6,7,8,9].

Effectiveness of Hard Turning

Hard turning is a turning operation performed on hard materials (hardness more than 45 HRC) in order to reach surface roughness close to that obtained in grinding. The development of this technology was accompanied by the development of new cutting materials such as cutting ceramics, cubic boron nitride and polycrystalline diamond. Especially cubic boron nitride has found its use in hard part turning operations because of its characteristics. However, new cutting materials result in new questions, which researchers are trying to solve. The major consideration for a user of this relatively new technology is the quality of parts produced and how the new cutting material will behave during machining. This paper aims to document and describe the process of wear on the cutting edge of a tool made from cubic boron nitride of a different grade and with a different geometry of the cutting edge, and its influence on surface roughness and quality. Wear was documented by a digital microscope with measurement option. Surface roughness was measured by a roughness meter. A notable observation from this research is that the flank wear of the cutting tool has a large impact on the quality of machined parts (especially surface finish and surface integrity) [1].