Journal of Manufacturing and Materials Processing

Research

17 pages, 5869 KiB

Open AccessArticle

The Effect of Machined Surface Conditioning on the Coating Interface of High Velocity Oxygen Fuel (HVOF) Sprayed Coating

by Meik Tilger, Dirk Biermann, Mohamed Abdulgader and Wolfgang Tillmann

J. Manuf. Mater. Process. 2019, 3(3), 79; https://doi.org/10.3390/jmmp3030079 - 03 Sep 2019

Cited by 3 | Viewed by 3357

Abstract

Roughening the substrate surface is essential for thermal sprayed coatings. In this regard, sandblasting has established itself as an easy to use surface conditioning procedure. The quality of the obtained roughness depends on the conditions of the sandblasting material, adjusted parameters, and the [...] Read more.

Roughening the substrate surface is essential for thermal sprayed coatings. In this regard, sandblasting has established itself as an easy to use surface conditioning procedure. The quality of the obtained roughness depends on the conditions of the sandblasting material, adjusted parameters, and the kind of the process execution (manual or mechanical). These preconditions limit the reproducibility of the roughness obtained. Sandblasting causes residual compressive stress and may also lead to the inclusion of sand particles and notches in the roughened surface, which affects the interfacial properties of the coating, as well as the flexural strength of the coated parts. The hardness of the roughened surface plays, thereby, an important role. However, in order to reliably avoid these effects, microfinishing can be used as an alternative to generate a homogenous roughened substrate surface, control the induced residual stresses, and increase the reproducibility. In addition, the roughened surface pattern can be produced during the chip forming process of the to-be-coated parts. The utilization of the appropriate combination of machining processes and parameters should lead to the required surface pattern and thus to an enhanced coating adhesion and flexural strength of the coated part. The induced residual stresses and the quality of the obtained surface roughness have a significant influence on the coating adhesion and the lifespan of the coated parts. This paper aims to analyze, as a first step, the effect of the turning and microfinishing on the surface conditioning of the bearing steel 100Cr6 (AISI 52100). The investigation concludes by comparing the microfinished with the sandblasted surfaces with regard to the interface to and the adhesion of the WC–Co high velocity oxygen fuel (HVOF) sprayed coatings on them. Surface conditioning plays a decisive role by the induced residual stresses and the elimination of adhesion defects. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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13 pages, 7881 KiB

Open AccessArticle

Comparative Assessment of the Surface Integrity of AD730^® and IN718 Superalloys in High-Speed Turning with a CBN Tool

by Jinming Zhou, Zhe Chen, Henrik Persson, Ru Lin Peng, Rachid M’Saoubi and David Gustasson

J. Manuf. Mater. Process. 2019, 3(3), 73; https://doi.org/10.3390/jmmp3030073 - 19 Aug 2019

Cited by 4 | Viewed by 3056

Abstract

Nickel-based superalloys are typical materials used in components of aeroengines and gas turbine machinery. The strength properties of these alloys at high temperatures are crucial not only to the performance (e.g., power generation efficiency, energy consumption, and greenhouse gas emissions) of aeroengines and [...] Read more.

Nickel-based superalloys are typical materials used in components of aeroengines and gas turbine machinery. The strength properties of these alloys at high temperatures are crucial not only to the performance (e.g., power generation efficiency, energy consumption, and greenhouse gas emissions) of aeroengines and industrial gas turbines, but also to machinability during component manufacturing. This study comparatively evaluated the surface integrity of two superalloys, AD730^® and Inconel 718 (IN718), during high-speed finishing turning using cubic boron nitride (CBN) tools. IN718 is a conventional superalloy used for the hot section components of aeroengines and industrial gas turbines, while AD730^® is a novel superalloy with enhanced high-temperature mechanical properties and good potential as a next-generation superalloy for these components. High-speed turning tests of two superalloys were conducted using a CBN cutting tool and jet stream cooling. The achieved surface integrity of the AD730^® and IN718 superalloys was characterized and analyzed to assess the comparability of these alloys. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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17 pages, 8275 KiB

Open AccessArticle

Analytical and Simulation-Based Prediction of Surface Roughness for Micromilling Hardened HSS

by Alexander Meijer, Jim A. Bergmann, Eugen Krebs, Dirk Biermann and Petra Wiederkehr

J. Manuf. Mater. Process. 2019, 3(3), 70; https://doi.org/10.3390/jmmp3030070 - 12 Aug 2019

Cited by 17 | Viewed by 4468

Abstract

The high quality demand for machined functional surfaces of forming tools, entail extensive investigations for the adjustment of the manufacturing process. Since the surface quality depends on a multitude of influencing factors in face micromilling, a complex optimization problem arises. Through analytical and [...] Read more.

The high quality demand for machined functional surfaces of forming tools, entail extensive investigations for the adjustment of the manufacturing process. Since the surface quality depends on a multitude of influencing factors in face micromilling, a complex optimization problem arises. Through analytical and simulative approaches, the scope of the experimental investigation to meet the requirements for surface roughness can be significantly reduced. In this contribution, both analytical and simulation-based approaches are presented in the context of predicting the roughness of a machined surface. The consideration of actual tool geometry and shape deviations are used in a simulation system to achieve the agreement with experimental results. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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20 pages, 5717 KiB

Open AccessArticle

Influencing the Properties of the Generated Surface by Adjusted Rake and Clearance Angles in Side Milling of Aluminum Matrix Composites with MCD-Tipped Tools

by Benjamin Clauß, Andreas Nestler, Andreas Schubert, Dagmar Dietrich and Thomas Lampke

J. Manuf. Mater. Process. 2019, 3(3), 59; https://doi.org/10.3390/jmmp3030059 - 23 Jul 2019

Cited by 2 | Viewed by 3277

Abstract

The application of aluminum matrix composites (AMCs) allows the reduction of moving loads for increased efficiency in modern technical systems. However, the presence of reinforcing particles leads to challenges in machining of AMCs, typically requiring diamond cutting materials. Single-edged MCD-tipped tools are used [...] Read more.

The application of aluminum matrix composites (AMCs) allows the reduction of moving loads for increased efficiency in modern technical systems. However, the presence of reinforcing particles leads to challenges in machining of AMCs, typically requiring diamond cutting materials. Single-edged MCD-tipped tools are used to investigate the influence of different clearance and rake angles on the resulting surface properties in milling, while the cutting parameters are kept constant. The specimens are manufactured from an aluminum wrought alloy comparable to EN AW-2017, reinforced with 10 vol.% of SiC particles. The surface properties are evaluated considering the surface structure, the residual stress state, and the microstructure of the surface layer. A clearance angle of the minor cutting edge of about 3° on average leads to the lowest Rz values and a reduced fluctuation of surface roughness values. Using a tool with a positive rake angle of 5° entails the highest absolute values of the compressive residual stresses and an increase compared to the initial state of up to about 290%. The results contribute to an understanding of the relations between tool geometry and the generated surface properties required for a targeted enhancement of the functional performance when machining AMCs. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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17 pages, 2373 KiB

Open AccessArticle

Impact of the Process Parameters, the Measurement Conditions and the Pre-Machining on the Residual Stress State of Deep Rolled Specimens

by Nataliya Lyubenova, Dirk Bähre, Lukas Krupp, Julie Fouquet, Titouan Cronier, Jay Patel and Joachim Ernst Hoffmann

J. Manuf. Mater. Process. 2019, 3(3), 56; https://doi.org/10.3390/jmmp3030056 - 10 Jul 2019

Cited by 4 | Viewed by 3088

Abstract

Mechanical surface treatments, e.g., deep rolling, are widely spread finishing processes due to their ability to enhance the fatigue strength of the treated materials with means of cold working and inducement of favorable compressive residual stresses. Despite of the clear advantages of deep [...] Read more.

Mechanical surface treatments, e.g., deep rolling, are widely spread finishing processes due to their ability to enhance the fatigue strength of the treated materials with means of cold working and inducement of favorable compressive residual stresses. Despite of the clear advantages of deep rolling, the controlled generation of compressive residual stresses is still a challenging task, as the process can be influenced by the pre-machining stress state of the treated material. Additionally, the exact characterization of the induced residual stress field is impacted by the specific characteristics of the applied measurement technique. Therefore, this paper is focused on the X-ray diffraction residual stress analysis of deep rolled specimens, pre-machined to achieve rough or polished surface. The deep rolling process was realized as a single-trace to avoid the influence of the other process parameters and the resulted residual stress field on the surface and in depth was investigated. Additionally, the surface residual stress profiles were determined using two different measuring devices to analyze the impact of the different measurement conditions. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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11 pages, 1671 KiB

Open AccessArticle

Prediction of Surface Quality Based on the Non-Linear Vibrations in Orthogonal Cutting Process: Time Domain Modeling

by El Mehdi Kibbou, Sofiene Dellagi, Ilias Majdouline and Abdelhadi Moufki

J. Manuf. Mater. Process. 2019, 3(3), 53; https://doi.org/10.3390/jmmp3030053 - 26 Jun 2019

Cited by 3 | Viewed by 2933

Abstract

This work presents an analysis of relationships between the non-linear vibrations in machining and the machined surface quality from an analytical model based on a predictive machining theory. In order to examine the influences of tool oscillations, several non-linear mechanisms were considered. Additionally, [...] Read more.

This work presents an analysis of relationships between the non-linear vibrations in machining and the machined surface quality from an analytical model based on a predictive machining theory. In order to examine the influences of tool oscillations, several non-linear mechanisms were considered. Additionally, to solve the non-linear problem, a new computational strategy was developed. The resolution algorithm significantly reduces the computational times and makes the iterative approach more stable. In the present approach, the coupling between the tool oscillations and (i) the regenerative effect due to the variation of the uncut chip thickness between two successive passes and/or when the tool leaves the work (i.e., the tool disengagement from the cut), (ii) the friction conditions at the tool–chip interface, and (iii) the tool rake angle was considered. A parametric study was presented. The correlation between the surface quality, the cutting speed, the tool rake angle, and the friction coefficient was analyzed. The results show that, during tool vibrations, the arithmetic mean deviation of the waviness profile is highly non-linear with respect to the cutting conditions, and the model can be useful for selecting optimal cutting conditions. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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9 pages, 4577 KiB

Open AccessArticle

Prediction of Ground Surfaces by Using the Actual Tool Topography

by Rolf Hockauf, Volker Böß, Thilo Grove and Berend Denkena

J. Manuf. Mater. Process. 2019, 3(2), 40; https://doi.org/10.3390/jmmp3020040 - 13 May 2019

Cited by 5 | Viewed by 2632

Abstract

This paper presents a prediction model for ground surfaces that uses the actual grinding wheel topography to perform a grinding simulation. Precise knowledge of expected machined surfaces plays an important role in process planning. Here, the main criterion is the achievement of the [...] Read more.

This paper presents a prediction model for ground surfaces that uses the actual grinding wheel topography to perform a grinding simulation. Precise knowledge of expected machined surfaces plays an important role in process planning. Here, the main criterion is the achievement of the components’ function after manufacturing. Therefore, it is essential to consider the surface roughness to enable a function-orientated workpiece surface. The presented approach uses a real grinding tool topography, which is measured by a 3D laser triangulation sensor in the machine tool. After a data processing step, the measured topography is imported into a material removal simulation. A kinematic simulation of the realistic ground surface enables the data-based confirmation of the envelope profile theory for the first time. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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18 pages, 6018 KiB

Open AccessArticle

Interplay of Process Variables in Magnetic Abrasive Finishing of AISI 1018 Steel Using SiC and Al₂O₃ Abrasives

by Mohammad Sharif Uddin, Vincent Santos and Romeo Marian

J. Manuf. Mater. Process. 2019, 3(2), 29; https://doi.org/10.3390/jmmp3020029 - 28 Mar 2019

Cited by 11 | Viewed by 3675

Abstract

This paper investigates the underlying interplay between the key process parameters of magnetic abrasive finishing (MAF) in improving surface quality. The five process parameters considered were the working gap, rotational speed, feed rate, abrasive amount, and abrasive mesh when MAFed independently with two [...] Read more.

This paper investigates the underlying interplay between the key process parameters of magnetic abrasive finishing (MAF) in improving surface quality. The five process parameters considered were the working gap, rotational speed, feed rate, abrasive amount, and abrasive mesh when MAFed independently with two abrasive particles—SiC and Al₂O₃. A series of experiments were conducted with an in-house built MAF tool. Based on the main effect results, a model predicting roughness reduction was developed. Results show that surface quality improvement and the underlying dominant process parameters seem unique to the abrasive type used. When MAFed with SiC, the abrasive quantity and rotational speed influence the most. On the other hand, when MAFed with Al₂O₃, the trend is different to SiC, i.e., the abrasive mesh size and the working gap are dominant. The prediction model was well validated by independent experiments, indicating its accuracy in estimating and optimizing the process outcome. MAF is a simple process with a complex interplay between parameters. This is very crucial when abrasive type, size, and amount to be used are concerned, which warrants a deeper investigation in terms of underlying dynamics, interactions, and the deformation of abrasive, magnetic, and workpiece materials. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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15 pages, 9530 KiB

Open AccessArticle

Chip Morphology and Delamination Characterization for Vibration-Assisted Drilling of Carbon Fiber-Reinforced Polymer

by Ramy Hussein, Ahmad Sadek, Mohamed A. Elbestawi and M. Helmi Attia

J. Manuf. Mater. Process. 2019, 3(1), 23; https://doi.org/10.3390/jmmp3010023 - 12 Mar 2019

Cited by 8 | Viewed by 4598

Abstract

Carbon fiber-reinforced polymers (CFRP) are widely used in the aerospace industry. A new generation of aircraft is being built using CFRP for up to 50% of their total weight, to achieve higher performance. Exit delamination and surface integrity are significant challenges reported during [...] Read more.

Carbon fiber-reinforced polymers (CFRP) are widely used in the aerospace industry. A new generation of aircraft is being built using CFRP for up to 50% of their total weight, to achieve higher performance. Exit delamination and surface integrity are significant challenges reported during conventional drilling. Exit delamination influences the mechanical properties of machined parts and, consequently, reduces fatigue life. Vibration-assisted drilling (VAD) has much potential to overcome these challenges. This study is aimed at investigating exit delamination and geometrical accuracy during VAD at both low- and high-frequency ranges. The kinematics of VAD are used to investigate the relationship between the input parameters (cutting speed, feed, vibration frequency, and amplitude) and the uncut chip thickness. Exit delamination and geometrical accuracy are then evaluated in terms of mechanical and thermal load. The results show a 31% reduction in cutting temperature, as well as a significant enhancement in exit delamination, by using the VAD technology. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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12 pages, 3998 KiB

Open AccessArticle

Investigations on Material Loads during Grinding by Speckle Photography

by Andreas Tausendfreund, Florian Borchers, Ewald Kohls, Sven Kuschel, Dirk Stöbener, Carsten Heinzel and Andreas Fischer

J. Manuf. Mater. Process. 2018, 2(4), 71; https://doi.org/10.3390/jmmp2040071 - 16 Oct 2018

Cited by 14 | Viewed by 3338

Abstract

The knowledge of the loads occurring during a manufacturing process (e.g., grinding) and of the modifications remaining in the material is used in the concept of process signatures to optimize the manufacturing process and compare it with others (e.g., laser processing). The prerequisite [...] Read more.

The knowledge of the loads occurring during a manufacturing process (e.g., grinding) and of the modifications remaining in the material is used in the concept of process signatures to optimize the manufacturing process and compare it with others (e.g., laser processing). The prerequisite for creating a process signature is that the loads can be characterized during the running process. Due to the rough process conditions, until now there is no in-process technique to measure the loads in the form of displacements and strains in the machined boundary zone. For this reason, the suitability of speckle photography is demonstrated for in-process measurements of material loads in a grinding process without cooling lubricant and the measurement results are compared with finite element method (FEM) simulations. As working hypothesis for the simulation it is assumed, that dry grinding is a purely thermally driven process. Despite the approximation by a purely thermal model with a constant heat source, the measured displacements differ only by a maximum of approximately 20% from the simulations. In particular, the strain measurements in feed speed direction are in good agreement with the simulation and support the thesis, that the dry grinding conditions used here lead to a primarily thermally affecting process. Full article

(This article belongs to the Special Issue Surface Integrity in Machining)

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