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1

Method of the environmentally friendly dry single-pass honing with use of the superimposed low frequency oscillations

Rozek Andre, Uhlmann Eckart

Journal of Machine Engineering

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2023

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Vol. 23, No. 3

116--129

EN

Single-pass honing is used as a finishing process to meet high demands regarding form and dimensional accuracy of drilled holes. The disadvantages of single-pass honing compared to the conventional long-stroke honing are high process forces and torques as well as an increased risk of chip space clogging of the abrasive stones. Following this, the oscillation-superimposed single-pass honing without cutting fluid has been conducted in this work, which is promising when it comes to the environmentally friendly improvement of machining processes. It was shown that the omitted lubrication and flushing effect of the contact zone between the tool and the workpiece could be compensated with the aid of the superimposed oscillations. The process forces of the dry honing process are up to 37% lower compared to the conventional process, the height of the surface profile Rz decreases by 33% and the form deviations decrease up to 47%. Hence, the new method allows the saving of resources, while improving the work results.

2

The decisive impact of microstructure on the machinability of pure copper

Sun Xiaoxiang, Ebrahimi Mahmoud, Attarilar Shokouh

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

852--860

EN

Ultrafine-grained (UFG) materials have been of great attention due to their considerable behavior compared to coarse-grained counterparts. Also, the machinability of these UFG materials is of great importance because of the machining significance in manufacturing the final shape of industrial components. Hence, this study dealt with machinability in relation to the microstructure and mechanical properties of the UFG pure copper processed by the twist extrusion. The remarkable microstructure evolution through the dynamic recrystallization mechanisms improved the tensile strengths and hardness of the twist extrusion processed pure copper. Also, the reduction of ductility in the UFG copper compared to the initial state was related to the change of tensile fractography mechanism in which the large and deep dimples transformed into the combined small and shallow dimples with some cleavage planes in the UFG copper. Furthermore, the enhanced machinability of the processed sample was related to its lower thermal conductivity and the development of strain localization within the narrow shear bands which lead to the production of discontinuous short chips. Hence, the formation of the UFG structure is a suitable option to attain the enhanced machinability behavior of copper as one of the most used metals.

3

Colour stability of surface finishes on thermally modified beech wood

Slabejova Gabriela, Šmidriakowá Maria

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2021

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No. 114

116--124

EN

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ΔE* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

4

Powłoka ochronna Ag do zastosowań szczególnie w systemach antenowych

Ostaszewski Dariusz, Klej Tomasz

Elektronika : konstrukcje, technologie, zastosowania

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2019

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Vol. 60, nr 12

9--13

PL

Stosowane w produkcji obwodów drukowanych standardowe powłoki ochronne (ENIG, ENEPIG, HASL) nie spełniają wymagań stawianych przez producentów systemów antenowych. Z tego względu dla układów pracujących w zakresie dużych częstotliwości > 10 GHz konieczne jest stosowanie alternatywnych powłok ochronnych. W pracy przedstawiono wyniki badań dla obwodów pokrytych warstwą srebra bezprądowego. Zastosowana powłoka jest planarna, odznacza się niskimi stratami mocy w zakresie wysokich częstotliwości i ma dobrą lutowność.

EN

Commonly used in production standard printed circuits boards protective layers (ENIG, ENEPIG, HASL) do not meet requirements of antenna systems manufacturers. Therefore, for systems operating in the high frequency range > 10 GHz, alternative protective coatings must be used. The paper presents test results for circuits covered with a layer of electroless silver. The applied coating is planar, it has low power losses in the high frequency range and has good solderability.

5

Wykrywanie i przyczyny powstawania defektu "black pad" w powłoce ochronnej ENIG

Klej T., Ostaszewski D.

Elektronika : konstrukcje, technologie, zastosowania

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2018

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Vol. 59, nr 12

58--62

PL

Zabezpieczenie pól lutowniczych jest istotnym etapem procesu technologicznego produkcji obwodów drukowanych (PCB). Wytworzone PCB muszą zachować swoje właściwości w trakcie składowania przez czas określony normą IPC-4552. Rosnące wymagania w zakresie produkcji obwodów drukowanych skłaniają konstruktorów do zabezpieczania pól lutowniczych z wykorzystaniem powłoki ENIG (Electroless Nickel / Immersion Gold). Przygotowanie powierzchni i przeprowadzenie procesu niklowania decydują o właściwościach wytworzonej powłoki ENIG. Brak właściwej kontroli nad procesem niklowania bezprądowego prowadzi do wytworzenia powłoki, która wpływa na obniżenie wytrzymałości złącz lutowanych. Główną przyczyną obniżonej lutowności pól jest wystąpienie defektu określanego w literaturze jako "black pad". W pracy przedstawiono wpływ odchyleń w składzie kąpieli do niklowania bezprądowego na możliwość wystąpienia defektu "black pad" oraz przeprowadzono analizę składu i morfologii powierzchni zdefektowanych powłok.

EN

One of the most important stages of producing printed circuit boards is protecting solderable pads. Manufactured PCBs must keep their properties during storage according to IPC-4552. Growing requirements for the production of printed circuit boards leads designers to choose ENIG (Electroless Nickel/Immersion Gold) as a final finish. Surface preparation and nickel process are crucial for determining of surface properties. Lack of proper control over electroless nickel bath leads to nickel layer, that leads to lower durability of solder joints. The main cause of lower solderability is appearance of defect known as "black pad". The work shows influence of deviations in nickel bath parameters on possibility of occurrence of "black pad" defect. The surface composition and morphology were also tested.

6

Elektropolerowanie stali nierdzewnych

Brytan Z.

Stal, Metale & Nowe Technologie

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2017

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nr 1-2

55--57

PL

W artykule scharakteryzowano główne cechy procesu elektropolerowania, podając jego wady i zalety. Opisano wpływ wykończenia powierzchni na skłonność do elektropolerowania oraz wpływ elektropolerowania na chropowatość powierzchni. Opisano również zjawiska występujące w trakcie procesu elektropolerowania i ich wpływ na końcowy efekt wizualny stanu powierzchni. Omówiono preferowane do tego procesu gatunki stali nierdzewnych. Przedstawiono także zastosowania tego procesu w różnych gałęziach przemysłu.

EN

The paper characterises the main properties of the electropolishing process, giving its drawbacks and advantages. The influence of surface finish on the susceptibility to electropolishing and the influence of electropolishing on surface roughness have been described. The phenomena occurring during the electropolishing process, as well as their influence on the final visual effect of the surface, have been also addressed. Stainless steel grades preferred for such a process have been discussed. The applications of the process in different industrial branches have been also presented.

7

Zastosowanie innowacyjnych technologii PCB w konstruowaniu systemów antenowych

Klej T., Ostaszewski D.

Elektronika : konstrukcje, technologie, zastosowania

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2016

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Vol. 57, nr 6

113--116

PL

Współczesne systemy antenowe wymagają kompleksowego i innowacyjnego podejścia do kwestii wytwarzania, konstrukcji i zabezpieczania obwodów drukowanych. Poprawa parametrów elektrycznych płytki, zmniejszenie ilości możliwych błędów w procesie produkcyjnym poprzez zastosowanie nowych rozwiązań, zmniejszenia ilości operacji technologicznych – te trzy cechy pozwalają na uzyskanie anten o bardzo dobrych parametrach użytkowych. W pracy przedstawiono możliwości jakimi dysponuje Instytut Telei Radiotechniczny w celu wytwarzania nowoczesnych systemów antenowych przy wykorzystaniu innowacyjnych technologii.

EN

Modern antenna system requires multidisciplinary and innovative approach in terms of production, design and protection of printed circuit boards. Improvement of electrical parameters, decreased number of possible failures in production process by implementing new solutions, decreased number of technological operations – those three characteristics allow to achieve antennas with very good parameters. In this paper Tele and Radio Institute’s potential in manufacturing of microstrip antennas using innovative technologies is shown.

8

Effect of magnetorheological fluid on tool wear during hard turning with minimal fluid application

Sam Paul P., Varadarajan A. S., Mohanasundaram S.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 1

124--132

EN

Tool wear is a very complex phenomenon which can lead to machine down time, product rejects and can also cause problems to personnel. The present investigation aims at developing a magnetorheological fluid setup that can be attached to the tool holder for reducing tool wear during hard turning with minimal fluid application. The magnetorheological fluid acts as a viscoelastic spring with non-linear vibration characteristics that are controlled by parameters like the viscosity index of the fluid medium, shape of the plunger, current through the coil and size of the ferromagnetic particles. Cutting experiments were conducted to arrive at a set of magnetorheological fluid parameters that can offer better damping characteristics to minimize tool wear and promoting better cutting performance during turning of AISI 4340 steel of 46 HRC with minimal fluid application using hard metal insert with sculptured rake face. From the results, it was observed that the presence of magnetorheological fluid setup during hard turning with minimal fluid application attached to the tool holder reduces tool wear and brought forth better cutting performance. Commercialization of this idea is sure to benefit the metal cutting industry.

9

Improving surface finish quality of FDM prototypes

Gajdos I., Slota J.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2010

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z. 80 [274]

87-90

EN

Rapid prototyping technologies decrease production time and costs in engineering industry but also in other industries. One of most widely used technology FDM suffers under low surface finish quality. This paper is aimed on research of surface finishing technologies applicable to improve the quality of FDM prototypes surface finish. Pretreated samples were blasted with sodium bicarbonate and glass beads. The values of Ra and Rz were measured on the samples and compared the impact of selected blasting medium and blasting conditions on surface finish quality of FDM prototypes.

10

Polishing of poly(methyl methacrylate), polycarbonate, and SU-8 polymers

Zhong Z. W., Wang Z. F., Zirajutheen B. M. P., Tan Y. S., Tan Y. H.

Materials Science Poland

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2007

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Vol. 25, No. 1

103--112

EN

Polymers such as poly(methyl methacrylate), polycarbonate, and SU-8 epoxy resin replace silicon as the major substrate in microfluidic system (or BioMEMS) fabrication. Chemical-mechanical polishing is an important technology for many advanced microelectromechanical systems (MEMS) and microoptoelectromechanical system applications. In this study, the chemical-mechanical polishing of polycarbonate, poly(methyl methacrylate), and SU-8 polymers was investigated. Four types of slurry were tested for chemical-mechanical polishing of polycarbonate and poly(methyl methacrylate). Experiments were then designed and performed to investigate the effects of two key process parameters. Experimental results show that an increase in head load or table speed causes an increase in material removal rates. Within the chosen experimental parameter ranges, the variation of table speed introduced a more significant change in material removal rates than that of head load. An analysis of variance was also carried out, and it was found that the interaction of head load and table speed had a significant effect (95% confidence) on the surface finish of polished poly(methyl methacrylate) samples, while table speed had a significant effect on the surface finish of polished polycarbonate samples. Chemical-mechanical polishing is also a process well suited for polishing SU-8 structures with high aspect ratios. Polished polycarbonate, poly(methyl methacrylate), and SU-8 surfaces had nanometer-order surface roughness, acceptable for most MEMS applications.

11

Predykcja numeryczna chropowatości dla powierzchni toczonej

Jabłoński W.

Mechanika / Akademia Górniczo-Hutnicza im. St. Staszica

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2004

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T. 23, z. 4

461-469

PL

Integralną częścią każdego wyrobu wykonanego metodą obróbki skrawaniem jest warstwa wierzchnia. Jej cechy w dużej mierze decydują o własnościach detalu, a tym samym o zdolności spełniania przez niego określonych funkcji użytkowych. Własności geometryczne warstwy wierzchniej opisywane są m.in. przez parametry chropowatości. Istnieje wiele metod pomiaru chropowatości, jednak każda z nich posiada pewne wady ograniczające jej zastosowanie. W artykule zaproponowano metodę modelowania chropowatości opracowaną w oparciu o model procesu skrawania. Model reprezentuje układ o dwóch stopniach swobody, dla kierunku posuwowego i odporowego. W modelu uwzględniono główne czynniki dyssypatywne procesu: efekt regeneracyjny, wzrost dynamicznego tłumienia w obszarze bardzo małych wartości kinetycznego kąta przyłożenia. Model pozwala na przeprowadzenie symulaqi procesu skrawania. Wyniki mogą być uzyskiwane między innymi w postaci dyskretnych przebiegów czasowych. Aktualne położenie narzędzia skrawającego rejestrowane jest co jeden obrót. Punkty odpowiadające odkształceniu narzędzia w kierunku odporowym połączone odcinkami linii prostych odpowiadają przybliżonemu profilowi chropowatości. Dla tak zdefiniowanego profilu obliczono wartości parametrów chropowatości dla danych odpowiadających różnym prędkościom i różnym kierunkowym współczynnikom sztywności narzędzia. Uzyskane wyniki są zbliżone do rezultatów eksperymentalnych. Stanowi to uzasadnienie dla stosowania i dalszych badań nad opracowanym modelem.

EN

Surface finish is an important element of each part produced by cutting. The features of surface finish to a large degree determine the characteristics of product and his ability to satisfy the needs of the customer. Roughness parameters arę the crucial factors describing the surface finish . There are many methods of roughness measurement but each of them has its own disadvantages and limitations. In the paper the worked out model of cutting process was described and the method of roughness modelling was proposed. The model represents system of two-degree-of-freedom: for feed and thrust direction. It considers two main dissipative effects: 1)regenerative effect, 2)dynamie dumping by the cutting forces increase while the kinetic clearance angle tends to null. The results of the cutting process simulation can be presented as a time series of the tool deflection. This deflection in thrust direction can be regularly register at every turn of the item. Thus the information on the position of characteristics points of modelled profile is obtained. Connecting the points by a straight line one can achieve the approximation of the roughness profile. For the profile defined in that way one can estimated the basie roughness parameters (i.e. Ra and Rq). The roughness parameters computing in that way are relatively close to the experimental ones. It justifies the application and improving proposed method.

12

Wykończenie powierzchni posadzek przemysłowych

Rokiel M.

Materiały Budowlane

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2002

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nr 9

41-41

13

An experimental study of the nonlinear dynamics of orthogonal metal cutting

Foong Ch.-H., Wiercigroch M, Deans W. F.

Mechanics and Mechanical Engineering

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2001

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Vol. 5, nr 1

55-68

EN

The elimination of chatter is one of the major aims in machining to improve geometrical accuracy and surface finish. In this study, occurrence of chatter was investigated experimentally using a specially designed rig by examining time histories of the cutting and thrust force components. Broad experimental studies were conducted using brass, cast iron and aluminium samples. It was shown that by changing the horizontal stiffness of the rig, the thrust force variations (in the vertical direction) were completely eliminated for the cast iron samples. A systematic analysis of chip formation for an aluminium alloy is presented.