Jozef Peterka

Optical 3D Scanning of Cutting Tools

The paper shortly illustrates the general concept of Reverse Engineering, which includesalso the 3D scanning. In the main part of the paper the concrete 3D scanning process of chosen individual objects are described. The problems that occurred during 3D digitizing of individual parts are step by step discussed and solved. The paper deals with 3D scanning of ball nose end mills and screw drill. The article gives a procedure for digitizing and comparing the results of the scanned digital models of the two ball nose end mills and screw drill.

Cryogenic Rotary Ultrasonic Machining of Titanium Alloys

Abstract Titanium alloys are utilized especially in applications that require a good combination of high strength, low mass and good corrosion resistance in aggressive environments. However, mechanical properties prejudge titanium alloys to hard machinability. Machining of titanium alloys is usually accompanied by cooling with liquids or gasses. One of the most effective cooling approaches is cooling by liquid nitrogen. Liquid nitrogen decreases temperature of tool, but also increases strength, hardness and brittleness of workpiece. One of the most suitable machining methods to machine hard and brittle materials is ultrasonic machining. In this article, rotary ultrasonic machining of titanium alloys under cryogenic conditions is analyzed.

Influence of Machining Parameters on Surface Topography of Cubic Boron Nitride at Rotary Ultrasonic Machining

Poly-crystalline cubic boron nitride (PCBN) is one of the hardest known material. Therefore only advanced methods are able to treat such material. Advanced machining methods, proper for machining of hard and brittle materials (such as glass and ceramics) include rotary ultrasonic machining (RUM). This method should achieve high precision and low surface roughness (at least during machining of materials such as ceramics). Achievable roughness is affected by machined material and machining parameters. This contribution investigates influence of machining parameters, such as cutting speed and feed rate, on resultant surface roughness during machining of PCBN by rotary ultrasonic machining.

On–Line Classroom for Dynamic Education

The article discusses the issue of on-line learning for Faculty of Materials Science and Technology in Trnava. This method of education was designed within the project KEGA: Realisation of on-line classroom for dynamic education of secondary technical school and university students focused on design and manufacturing of freeform surfaces. The main objective of this method of teaching is improving parent ́s faculty cooperation with detaches workplaces and increasing of the interest of secondary school students about studying on the college with technical orientation.

Using Aramis for Measurement of Deformation of Thin-Walled Parts during Milling

Using Aramis for Measurement of Deformation of Thin-Walled Parts during Milling This paper describes deformation measurement of thin-walled parts by ARAMIS measuring system. During the milling, machine and workpiece may deviate from required geometry. Thin-walled parts are primarily used in automotive, aerospace and energy industries. ARAMIS is a system for optical 3D deformation analysis for static or dynamically loaded specimens and components. ARAMIS measuring system can be used for determining the deformation of thin-walled parts during milling.

Effect of Substrate Bias and Coating Thickness on the Properties of nc-AlCrN/a-Si x N y Hard Coating and Determination of Cutting Parameters

Nitride hard coatings Al25.5Cr21Si3.5N were deposited on WC-Co substrates with a different thickness and a negative substrate bias voltage by the LAteral Rotating Cathodes Arc technology. The nanoindentation tests were performed for analysis of AlCrSiN coatings in order to determine the most promising combination of parameters for subsequent machining. On the basis of results of nanohardness measurement and Ratio H/E*, which represents the resistance to plastic deformation and cracking, deposition conditions were selected for coating of turning cemented carbide inserts. For the evaluation of coating adhesion to substrate, Mercedes adhesion test was used. Chip forming tests and long-term tool life tests were performed for determination of cutting parameters (cutting speed, feed rate and depth of cut) for AlCrSiN coated cemented carbide inserts when machining austenitic stainless steel material.

Influence of Ultrasound on Delamination during Machining of GFRP Composite Material

In many present applications is requested decreasing of weight of components and increasing of their strength. Often unique properties are required. These properties could be solved by using of composite materials. However, different material properties of matrix and reinforcing material cause issues during machining, such as rapid tool wear and delamination of composite. Therefore there is afford to enhance machining process by different ways to decrease tool wear as well as delamination of composite. This article deals with comparison of conventional milling and ultrasonic assisted milling of glass fibre reinforced polymer (GFRP) composite material by special designed cutting tool.

Influence of Ultrasonic Assistance on Delamination During Machining of CFRP Composite

Many nowadays researches are focused on decreasing the weight of components and increasing their strength, or obtaining unique properties. One of the results of the researches are composite materials. However, different material properties of matrix and reinforcing material cause certain problems during conventional machining, such as rapid tool wear and delamination of composite. Therefore, other researches start focusing on machinability of this kind of materials. Scientists have discovered several ways of how to satisfactorily machine composite materials. Seco Tools Company starts developing a new design of the tools. Researchers of the Stanford University have devised a diamond-like carbon (DLC) coating available to effectively cut matrix as well as reinforce fibers. DMG Mori Company has implemented ultrasonic assistance into machining process and reached enhanced machinability. This article compares conventional milling and ultrasonic assisted milling of the carbon fiber reinforced polymer (CFRP) composite material by a special designed cutting tool. The results could be applied to determine when ultrasonic assistance is advantageous and what advantages it brings about.

The Influence of Copy Strategy on the Tool Life of Ball End Mills and Achieved Surface Roughness

The article deals with the tool life of ball nose end mills and surface roughness of steel C45 depending on up-copying and down-copying. The cemented carbide and high speed steel was used as tool material. Furthermore, the new and sharpened cutting tools were also compared. In the experiment, the cutting speed, feed rate, axial and radial depth of cut were not changed. The results show different achieved surface roughness of machined material C45 and tool life of ball nose end mills depending on the copy milling strategy for various tool materials.

Influence of Machining Parameters on Machine Tool Loads at Rotary Ultrasonic Machining of Cubic Boron Nitride

Poly-crystalline cubic boron nitride (PCBN) is one of the hardest known material. Therefore only advanced methods are able to treat such material. Advanced machining methods, proper for machining of hard and brittle materials (such as glass and ceramics) include rotary ultrasonic machining (RUM). However, high hardness of workpiece cause higher loads and it could negatively affect achievable accuracy and surface topography. Machine loads are affected by both: machined material and machining parameters. This contribution investigates influence of machining parameters, such as spindle speed, feed rate and depth of cut, on loads of machine tool during machining of PCBN by rotary ultrasonic machining.