Technological Parameters Influence to Residual Stresses at Interrupted Cut Simulator

Import 23/07/2015Diplomová práce se zabývá vyhodnocením zbytkového napětí ve dvou druzích materiálů, které byly obrobeny za různých řezných podmínek s využitím simulátoru přerušovače řezu. V teoretické části práce jsou popsány druhy zkoušek přerušovaného řezu, následně charakteristika zbytkového napětí včetně experimentálních metod na jejich zjištění. Experimentální část je zaměřena na přípravu lišt před samotným měřením pomocí simulátoru přerušovače řezu. Na základě rentgenové difrakce budou stanovena a vyhodnocena zbytková napětí v materiálech.The thesis deals with the evaluation of residual stress in two kinds of materials, which were machined under different cutting conditions with using simulator of interrupted cut. The theoretical part describes the types of tests interrupted cut and characteristics of residual stress including their methods. The experimental part is focused on the preparation materials before measuring with using simulator interrupted cut. On basis of X – ray diffraction to be determined and evaluated residual stress in the materials.346 - Katedra obrábění, montáže a strojírenské metrologievýborn

Contribution to the evaluation of the durability of cutting tools for parting-off of stainless steel

Ve strojírenství se neustále diskutuje o povýšení strategicky významných produktů tohoto oboru, jako řezné nástroje, výrobní stroje a zařízení, tvářecí stroje, anebo stroje pro aditivní výrobu. Všechny tyto produkty vyžadují potřebný výzkum a vývoj pro jejich inovaci z důvodu kladení vyšších nároků na trvanlivost, kvalitu, přesnost, produktivitu, spolehlivost, výrobní náklady, aj. Po vývoji progresivních řezných nástrojů, inovaci nových multifunkčních výrobních strojů je k dosažení předem stanovených cílů potřeba vhodně navrhnout celý proces obrábění včetně řezných podmínek a parametrů obrábění. Do návrhu procesu obrábění vstupují různé faktory, jako obráběcí stroje, materiály řezných nástrojů a řezná geometrie, obráběný materiál a jeho struktura, řezné podmínky, přičemž je nutná znalost dané technologie. Za účelem zvýšení některého ze stěžejních faktorů, trvanlivost řezného nástroje, kvalita povrchu, produktivita procesu atd., je nutné navrhnout experimentální proces obrábění na základě ověřených metod. Jednou z možností je použití metody Plánovaných experimentů, která umožňuje po zakomponování všech ovlivňujících faktorů navrhnout a analyzovat daný proces na základě výsledků zvolené odezvy. V teoretické části práce je provedena analýza současného stavu obrábění korozivzdorných ocelí se zaměřením na technologii upichování. Cílem práce je stanovit a vyhodnotit proces upichování austenitické korozivzdorné oceli, definovat řezné podmínky, vyhodnotit opotřebení řezných nástrojů, utváření třísky a kvalitu obrobeného povrchu. Na základě těchto výsledků je nutné stanovit přínosy pro VaV, praxi a doporučit další výzkum v této oblasti. Experimentální činnost je realizována ve spolupráci se společností DORMER Pramet s.r.o. a je zaměřena na proces upichování austenitické korozivzdorné oceli s označením dle W.Nr. 1.4404 (AISI 316L). Jedná se o legovanou ocel s vyšším obsahem chromu využívanou zejména ve všech oblastech strojírenství, jako letecký, chemický, energetický anebo zdravotnický průmysl. Předmětem experimentálního testování je navrhnout proces upichování založený na metodě Plánovaných experimentů pro plně faktoriální plán 2k včetně řezných podmínek a parametrů při použití prototypových povlakovaných vyměnitelných břitových destiček ze slinutého karbidu navržených společností DORMER Pramet s.r.o.In industry, a promotion of strategically significant products of this field, such as cutting tools, machine tools and device, forming machine tools or machine for additive technology, are constantly being discussed. All these products require a needed research and development for their innovation due to place demand on durability, quality, accuracy, productivity, reliability, production costs, etc. After development of progressive cutting tools, innovation of new multi-functional machine tools, it is necessary to appropriately design whole machining process include cutting conditions and machining parameters for achievement of pre-determined goals. Different factors, such as machine tools, cutting tools materials and cutting geometry, machined material and its structure, cutting conditions, are entering into design of machining process and a knowledge of given technology is necessary. For the purpose of increase one of this crucial factor, durability of cutting tool, surface quality, productivity of process etc., it is necessary to design an experimental machining process on the basis of verified methods. One of the possibilities is using Design of Experiment that enables to design and analysis the process after incorporation the all-influencing factors on the basis of the results of selected response. The analysis of current state of machining of stainless steel focusing on parting-off technology is made in theoretical part of dissertation thesis. The aim of dissertation thesis is determine and evaluate parting-off process austenitic stainless steel, define cutting conditions, evaluate cutting tools wear, chip forming and quality of machined surface. It is necessary to determine benefits for R&D, practice and recommend a next research in this field on the basis of these results. Experimental activity is carried out in cooperation with company DORMER Pramet Ltd. and it is focused on parting-off process of austenitic stainless steel marked according W. Nr. 1.4404 (AISI 316L). It is alloyed steel with high content of chromium, using especially in all areas engineering, such as air industry, chemical industry, energy industry or medical industry. The object of experimental activity is a design parting-off process based on Design of Experiment – full factorial plan 2k included cutting conditions and parameters for used prototype coated exchangeable cutting inserts made of sintered carbide designed by DORMER Pramet Ltd.346 - Katedra obrábění, montáže a strojírenské metrologievyhově

The influence of surface treatment of PVD coating on its quality and wear resistant

The article deals with a determination of the influence of a cutting edge preparation on the quality and wear resistance of coated cutting tools. Cutting inserts made from a sintered carbide with a deposited layer of PVD coating were selected for measurement. Non-homogeneity caused by the creation of droplets arises in the application layer during the process of applying the coating by the PVD method. These droplets make the surface roughness of the PVD coating worse, increase the friction and thereby the thermal load of the cutting tool as well. Also, the droplets could be the cause of the creation and propagation of droplets in the coating and they can cause quick cutting tool wear during machining. Cutting edge preparations were suggested for the improvement of the surface integrity of deposited layers of PVD coating, namely the technology of drag finishing and abrasive jet machining. After their application, the areal surface roughness was measured on the surface of coated cutting inserts, the occurrence of droplets was tracked and the surface structure was explored. A tool-life test of cutting inserts was carried out for verification of the influence of surface treatment on the wear resistance of cutting inserts during the milling process. The cutting inserts with a layer of PVD coatings termed as samples A, B, and C were used for the tool-life test. The first sample, A, represented the coating before the application of cutting edge preparations and samples B and C were after the application of the cutting edge preparation. A carbon steel termed C45 was used for the milling process and cutting conditions were suggested. The visual control of surface of cutting inserts, intensity of wear and occurrence of thermal cracks in deposited PVD layers were the criterion for the evaluation of the individual tests.Web of Science97art. no. 43

THE INFLUENCE OF CUTTING CONDITIONS ON THE SELECTED PARAMETERS OF THE SURFACE INTEGRITY

The article deals with an investigation of residual stress in machined surface under conditions of high-feed milling and determination of the influence of machining conditions on the size and types of stress resulting from cutting into the machined surface. As a testing material, the hardened tool steel W. Nr. 1.2343 (CSN 19552) was used. For the realization of the experimental activity, a high-feed milling head was used with exchangeable cutting inserts marked H600 WXCU 070515T. All surfaces were machined under different cutting conditions (200, 300, 350, 400 and 500mmin−1 cutting speed) in regard to the recommended parameters and machine tool options. The evaluated residual stress was measured in the depth of 8 μm under the surface with the device PROTO iXRD working on the principle of the X-Ray diffraction. Monitoring was carried out using an analysis of occurrence of tensile or compressive residual stress, and from these results, a possible dependence of the residual stress on the cutting conditions during milling process was determined

Testing ceramics inserts at irregular interrupted cut on material 14MoV6

This article deals with the test of removable ceramic cutting inserts during machining with an irregular interrupted cut. Tests were performed on a lathe, with a preparation which simulated an interrupted cut for us. By changing the number of slats mounted in the preparation, it simulated a regular or irregular interrupted cut for us. When it had four slats, it was a regular interrupted cut, whereas the remaining three variants were already irregular cuts. This paper examined whether it would have an irregular interrupted cutting effect on the insert and possibly how it would change the life of the inserts during an irregular interrupted cut (a variable delay between shocks).Web of Science371736

Effect of cutting tool microgeometry on the aluminium alloy machining process

The paper deals with the determination of the effect of controlled tool cutting edge preparation on AlCu4SiMg (EN AW - 2014) aluminium alloy machining process as well as on tool wear. To conduct the experiment, the authors have chosen longitudinal turning technology and cutting geometry of indexable cutting inserts marked CCGT 120408F-AL, and proposed suitable cutting conditions. By controlled tool cutting edge preparation (brushing), the desired edge rounding of indexable cutting inserts of 0-5 mu m, 10-15 mu m and 20-25 mu m has been achieved. Depending on the radius r(n) and the roughness of the cutting edge, the course of wear of the cutting inserts, the flow direction of the shaped material and its effect on the formation and size of the build-up were monitored during machining of the aluminium alloy.Web of Science20192919291

Tracking of the development wear of cutting tools with different geometry during parting-off

The article deals with the tracking of the wear development of cutting tools made from sintered carbide during parting-off of steel C45 (ČSN 12 050.1). For experiment were selected inserts from two producers of cutting tools with different geometry. The parting-off was realized in the workpiece axis and the whole experiment was divided into two parts, parting-off to zero and parting-off to pre-drilled hole into material. The experiment was evaluated on the principle direct microscopic method and was observed the wear on the flank of cutting tool VBB. Tests were realized in cooperation with Pramet Tools Šumperk, Czech Republic

Tracking of the development wear of cutting tools with different geometry during parting-off

The article deals with the tracking of the wear development of cutting tools made from sintered carbide during parting-off of steel C45 (ČSN 12 050.1). For experiment were selected inserts from two producers of cutting tools with different geometry. The parting-off was realized in the workpiece axis and the whole experiment was divided into two parts, parting-off to zero and parting-off to pre-drilled hole into material. The experiment was evaluated on the principle direct microscopic method and was observed the wear on the flank of cutting tool VBB. Tests were realized in cooperation with Pramet Tools Šumperk, Czech Republic

The evaluation of the surface quality after laser cutting

The contribution deals with the evaluation of the surface quality after laser cutting and determination of the influence individual input laser parameters at the whole process. There were selected samples for experiment made from S235JR material with the thickness 10 mm and 15 mm. There was set up values of process parameters, such as laser power, focal spot position, cutting speed and shield gas pressure. The final surface quality was measured and evaluated on the basis of the selected surface roughness parameters and material ratio. The surface quality was evaluated from point of view of defects emerging after thermal splitting according to standard ČSN EN ISO 17 658