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1

Evaluation of Machinability Indicators in Milling of Thin-Walled Composite Structures

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

202--212

EN

Composite materials are alternative materials to aluminum and titanium alloys. The wide-spread use of this materials makes it necessary to gain insight into the phenomena occurring in machining processes for thin-walled structures. This paper shows the investigation of the machinability of thin-walled composite materials. The study involved milling glass and carbon reinforced plastics using tools dedicated to the processing of this type of material. Their machinability was determined based on the measured feed force, deformation and surface roughness. In addition, surface analysis was performed by SEM. The results showed that the feed had the greatest impact on the feed force, deformation and surface roughness, followed by cutting speed. Lower values of the measured machinability indicators such as the maximum feed force and roughness were obtained for composites with glass fibers. Lower deformations were induced in the machining of composites with carbon fibers. The study also involved conducting a recurrence analysis in order to select the most appropriate quantifications depending on the technological parameters of milling. It was found that the most appropriate indicators related with the technological parameters for both materials were laminarity and averaged diagonal length.

2

Analysis of the Surface Layer and Feed Force after Milling Polymer Composites with Coated and Uncoated Tools

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 4

70--78

EN

Polymer composites are widely used in various fields and industries. This study investigated milling of four different glass and carbon fiber reinforced plastics. First, feed force values were determined in the milling process conducted using tools with polycrystalline diamond inserts, with titanium nitride-coated cemented carbide inserts and with uncoated ground cemented carbide inserts. Machined surfaces were then examined for roughness. Using scanning microscopy (SEM), differences in the surface layer were also determined. Results showed that the lowest force values were obtained in milling of glass fiber reinforced plastics using tools with polycrystalline diamond inserts. The best machining results in terms of roughness were obtained after milling glass fiber reinforced plastics.

3

Study on the Machinability of Glass, Carbon and Aramid Fiber Reinforced Plastics in Drilling and Secondary Drilling Operations

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 2

57--66

EN

Composite materials are usually subjected to machining processes, especially when they are used to for the aviation and automotive industries. Apart from side surface milling and face milling, these materials are subjected to machining to make holes and countersinking holes, cuts of complex shape, recesses, and grooves. One of the many machining methods for polymer composites is drilling. The accuracy of a drilled hole is very important for operational reasons, because it has impact on the quality and strength of the connection between polymer composite elements and structural elements. This paper shows the results of a study investigating the impact of drilling and secondary drilling as well as technological drilling parameters on the maximum feed force, surface roughness and hole quality. Holes were drilled in glass, carbon and aramid fiber reinforced plastics. The study has shown that the highest maximum feed force occurs when drilling in aramid fiber reinforced plastic. The lowest values of the maximum feed force were obtained when drilling in glass fiber reinforced plastic. The influence of drilling parameters on surface roughness during drilling holes in composite materials was also determined. The highest values of roughness parameters were obtained in the machining of aramid fiber reinforced plastic, while the lowest roughness parameters were obtained on the hole surface when drilling in carbon fiber reinforced plastic.

4

Experimental Investigation and Optimization of Machining Parameters in Turning of Aluminum Alloy 075-T651

Srivastava Arpit, Verma Mukesh Kumar, Niranjan Ramendra Singh, Chandra Abhishek, Patel Praveen Bhai

Production Engineering Archives

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2021

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Vol. 27, Iss. 4

296--305

EN

Aluminum alloy 7075-T651 is a widely used material in the aviation, marine, and automobile sectors. The wide application marks the importance of this material’s research in the manufacturing field. This research focuses on optimizing input process parameters of the turning process in the machining of Aluminum 7075-T651 with a tungsten carbide insert. The input machining parameters are cutting speed, feed, and depth of cut for the output response parameters cutting force, feed force, radial force, material removal, and surface roughness of the workpiece. For optimization of process parameters, the Taguchi method, with standard L9 orthogonal array, is used. ANOVA is applied to obtain significant factors and optimal combinations of process parameters.

5

Effect of Composite Material Fixing on Hole Accuracy and Defects During Drilling

Ciecieląg Krzysztof

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 3

54--65

EN

This study investigates the effect of composite material stiffness on the accuracy of drilled holes and delamination in the drilling process. Two types of composite materials were tested: glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP). The drilling process was performed using dedicated drill bits. Samples were clamped in a vice of the Avia-VMC 800 HS vertical machining center. Drilling parameters were maintained constant but unsupported element length was changed. The unsupported element length was defined as an unsupported distance between the drilled hole axis and the sample attachment location. The maximum feed force Ff was determined in the experiments. The accuracy of drilled holes was estimated by optical microscopy. Diameters of the drilled holes were measured. Results made it possible to determine the recommended unsupported element length at which the hole dimensions were within the dimensional tolerance. The study showed a clear decrease in the drilled hole quality and a significant increase in the feed force, especially in the area of tool exit from the workpiece. In addition, the number of delaminated fibers increased with unsupported element length was determined in the study.

6

Wpływ wybranych parametrów skrawania na dokładność obróbki w procesie wiercenia stopu Ti6Al4V

Szwajka Krzysztof, Zielińska-Szwajka Joanna

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2019

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z. 91 [299], nr 1-2

79--92

PL

Wiercenie materiałów ciągliwych, do których zalicza się Ti6Al4V, często wiąże się z niewystarczającym odprowadzeniem wiórów, co prowadzi do wystąpienia zakłóceń procesu obróbki. Wióry powstające w trakcie procesu wiercenia materiałów plastycznych są ciągliwe i mają skłonność do gromadzenia się w rowkach wiórowych narzędzia. Takie gromadzenie się wiórów może skutkować zarysowaniami powierzchni otworu, przyklejeniami materiału do narzędzia skrawającego, a także do przyśpieszonego zużycia ostrza skrawającego. W niniejszym artykule przedstawiono wyniki badań uzyskane w procesie wiercenia stopu tytanu Ti6Al4V w aspekcie dokładności wymiarowo-kształtowej uzyskanych otworów. Obróbkę prowadzono bez chłodziwa (na sucho) przy różnych zestawach parametrów skrawania. W ramach badań monitorowano siłę posuwową i moment skrawania, dokładność kształtowo-wymiarową, jakość powierzchni otworu oraz kształt wiórów. Wyniki badań pokazują, że zarówno jakość otworu, jak i jego dokładność wymiarowo-kształtową można poprawić przez odpowiedni dobór parametrów skrawania. Ponadto, obserwacja powierzchni na wyjściu narzędzia z materiału wskazywała na występowanie odkształceń plastycznych (zadziory) związanych z parametrami skrawania. Wyniki eksperymentu wykazały także, że na kształt i wielkość zadziorów istotny wpływ ma prędkość posuwu.

EN

The drilling of ductile materials, such as Ti6Al4V, is often associated with insufficient chip evacuation, resulting in disturbances in the machining process. Chips formed during the drilling process of plastic materials are ductile and tend to accumulate in the chip flutes of the tool. Such chip formation may result in scratches on the hole surface, sticking the material to the cutting tool, and also on accelerated wear of the cutting edge. This article presents the analysis of the drilling process and assessment of the quality of the hole after drilling Ti6Al4V titanium alloy without coolant at various processing parameters. As part of the research, the feed force and cutting moment were monitored, the shape and dimensional accuracy and the quality of the hole surface and the shape of the chips. The test results show that the hole quality can be improved by appropriate selection of cutting parameters. Observation of the surface at the exit of the tool from the material indicated plastic deformation (burrs) in different cutting conditions. The results of the experiment also showed that the shape and size of burrs is strongly influenced by the feed speed.

7

Analysis of the delamination in drilling of particleboard

Szwajka K.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2014

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z. 86 [290], nr 4

621--628

EN

Particleboard is a wood based composite extensively used in wood working. Drilling is the most commonly used machining process in furniture industries. The surface characteristics and the damage free drilling are significantly influenced by the machining parameters. The thrust force developed during drilling plays a major role in gaining the surface quality and minimizing the delamination tendency. In this study eighteen durability tests of tools for different values of the analyzed cutting parameters were carried out. Based on the obtained results, the effect of cutting parameters of selected signals of axial force and cutting torque was found. Mathematical models using ANOVA, allowing to estimate the value of cutting forces was proposed.

PL

Płyta wiórowa jest kompozytem, którego podstawowym składnikiem jest drewno. Ma szerokie zastosowanie w przemyśle. Proces wiercenia to najpopularniejszy proces obróbki stosowany w przemyśle meblarskim. Siła osiowa i moment skrawania występujące podczas procesu wiercenia odgrywają ważną rolę w uzyskaniu odpowiedniej jakości powierzchni. W przeprowadzonych badaniach wykonano osiemnaście prób trwałościowych narzędzia dla różnych wartości analizowanych parametrów skrawania. Na podstawie wyników uzyskanych z przeprowadzonych badań określono wpływ wybranych parametrów skrawania oraz zużycia narzędzia na wartość siły osiowej i momentu skrawania. Zaproponowano modele matematyczne, wykorzystując analizę wariancji ANOVA, pozwalające oszacować opory skrawania.

8

Thrust force and torque in the drilling process laminated chipboard

Zielińska-Szwajka J., Szwajka K.

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

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2014

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No. 88

248--254

EN

Thrust force and torque in the drilling process laminated chipboard. Particleboard is a wood based composite extensively used in wood working. Drilling is the most commonly used machining process in furniture industries. The surface characteristics and the damage free drilling are significantly influenced by the machining parameters. The thrust force developed during drilling play a major role in gaining the surface quality and minimizing the delamination tendency. In this study trials were made eighteen durability tools for different values of the parameters analyzed cut. Based on the results obtained from the study, the effect of cutting parameters selected signals of axial force and torque cutting. Proposed mathematical models using ANOVA, allowing to estimate the cutting forces.

9

Proposal for an Indexical Method of Evaluating Risk of Hand Tool Operators’ Exposure to Mechanical Vibrations

Engel Z., Kowalski P., Zawieska W. M.

International Journal of Occupational Safety and Ergonomics

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2002

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Vol. 8, No. 2

183--194

EN

The article presents proposals for an indexical evaluation of exposure of hand tool operators to vibrations. The presented indices have been developed on the basis of the results of laboratory tests. The examinations studied the effect of pressure force and grip force exerted by an operator on a hand tool as well as the amplitudes and frequencies of an exciting signal on vibrations transmitted in the hand-tool handle system.

10

Potentials and limitations of tool condition monitoring for MoS/sub 2/- and TiN-coated drills with acoustic emission in dry machining

Krimmel O., Tonnessen K., Zhong Wen Li

Prace Naukowe Instytutu Technologii Maszyn i Automatyzacji Politechniki Wrocławskiej. Konferencje

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2000

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Vol. 76, nr 35

138-149

EN

Tool condition monitoring is a means to increase the reliability and efficiency of machining through tool breakage detection and wear monitoring. This paper provides the relevant knowledge about the state of the art in monitoring drill condition with acoustic emission to support a successful choice of sensors for a monitoring system. In drilling acoustic emission (AE) sensors are successfully applied for breakage detection. Attempts have been made to monitor wear with acoustic emission. The theory for the effect of wear on acoustic emission is reviewed. A set of experiments has been evaluated in order to illustrate characteristics of the AE-signal in drilling. Experiments for 4 and 10 mm drills with MoS/sub 2/- and TiN-coating have been chosen to show the effect of the coating on acoustic emission. The soft MoS/sub 2/ coating provides a dry lubrication layer whereas the hard TiN coating protects the tool through wear resistance. Additionally, the feed force, which is the common signal used for drill wear monitoring, has been recorded during the experiments to illustrate the difference in the validity of the signals.