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J. Manuf. Mater. Process., Volume 2, Issue 1 (March 2018)

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Editorial

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Open AccessFeature PaperEditorial Acknowledgement to Reviewers of Journal of Manufacturing and Materials Processing in 2017
J. Manuf. Mater. Process. 2018, 2(1), 2; doi:10.3390/jmmp2010002
Received: 9 January 2018 / Revised: 9 January 2018 / Accepted: 9 January 2018 / Published: 9 January 2018
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Abstract
Peer review is an essential part in the publication process, ensuring that JMMP maintains high quality standards for its published papers. In 2017, a total of 22 papers were published in the journal.[...] Full article

Research

Jump to: Editorial

Open AccessArticle Batch Processing in Preassembled Die Sets—A New Process Design for Isothermal Forging of Titanium Aluminides
J. Manuf. Mater. Process. 2018, 2(1), 1; doi:10.3390/jmmp2010001
Received: 30 November 2017 / Revised: 18 December 2017 / Accepted: 19 December 2017 / Published: 1 January 2018
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Abstract
Titanium aluminide (TiAl) turbine blades produced by isothermal forging have recently been implemented in the low-pressure part of commercial aircraft jet engines. However, the slow speed of isothermal forging, costly molybdenum-based dies and the required protective forging atmosphere makes the process rather expensive.
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Titanium aluminide (TiAl) turbine blades produced by isothermal forging have recently been implemented in the low-pressure part of commercial aircraft jet engines. However, the slow speed of isothermal forging, costly molybdenum-based dies and the required protective forging atmosphere makes the process rather expensive. Currently, industrial forging is done by closed-die isothermal forging processes with stationary dies. Idle time occurs when single parts are inserted and extracted from the dies. As an interesting alternative for forging small parts, a new set-up is devised and explored in this work, i.e., batch processing. Using a die set which allow for off-line preassembly and preheating, multiple parts can be forged in one stroke. The design of the batch process was based on a new material model, which was implemented into a finite element system to identify the forging parameters. The setup of the press transport system for batch processing, as well as the results of the simulations and forging experiments are presented. A cost comparison between the new process and conventional forging with stationary dies concludes that for smaller parts such as compressor blades, batch processing offers advantages regarding productivity and cost. Full article
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Open AccessFeature PaperArticle Developing a Zener–Hollomon Based Forming Limit Surface for Warm Sheet Forming of Magnesium Alloy
J. Manuf. Mater. Process. 2018, 2(1), 3; doi:10.3390/jmmp2010003
Received: 3 October 2017 / Revised: 17 December 2017 / Accepted: 26 December 2017 / Published: 11 January 2018
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Abstract
The concept of Zener–Hollomon (Z) based Forming Limit Surface (Z-FLS)—which has minor strain, major strain, and ln(Z) as its three axes—was initially proposed in a previous study. In the Z-FLS diagram, strain rate and temperature effects on the major limit strain
[...] Read more.
The concept of Zener–Hollomon (Z) based Forming Limit Surface (Z-FLS)—which has minor strain, major strain, and ln(Z) as its three axes—was initially proposed in a previous study. In the Z-FLS diagram, strain rate and temperature effects on the major limit strain are reflected by ln(Z). In the current study, the concept of Z-FLS is revisited to provide a practical approach to construct Z-FLS. A Z-FLS then is constructed for magnesium alloy AZ31B sheet material using available experimental forming limit curves. The constructed Z-FLS is used to identify fracture in a non-isothermal warm cup forming process, which was modeled as a coupled thermo-mechanical process. Based on the Z-FLS, the determined limiting draw ratio (LDR) matches well with the published experimental results. Full article
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Open AccessArticle Error Separation Method for Precision Measurement of the Run-Out of a Microdrill Bit by Using a Laser Scan Micrometer Measurement System
J. Manuf. Mater. Process. 2018, 2(1), 4; doi:10.3390/jmmp2010004
Received: 27 November 2017 / Revised: 9 January 2018 / Accepted: 9 January 2018 / Published: 12 January 2018
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Abstract
This paper describes an error separation method for a precision measurement of the run-out of a microdrill bit by using a measurement system consisting of a concentricity gauge and a laser scan micrometer (LSM). The proposed error separation method can achieve a sub-micrometric
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This paper describes an error separation method for a precision measurement of the run-out of a microdrill bit by using a measurement system consisting of a concentricity gauge and a laser scan micrometer (LSM). The proposed error separation method can achieve a sub-micrometric measurement accuracy of the run-out of the microdrill bit without the requirement of ultra-precision rotary drive devices. In the measurement, the spindle error motion of the concentricity gauge is firstly measured by using the LSM and a small-diameter artifact, instead of the conventionally used displacement probes and large-diameter artifact, in order to determine the fine position of the concentricity gauge when the spindle error motion is at its minimum. The microdrill bit is rotated at the fine position for the measurement of the run-out, so that the influence of the spindle error motion can thus be reduced, which could not be previously realized by commercial measurement systems. Experiments were carried out to verify the feasibility of the proposed error separation method for the measurement of the run-out of the microdrill bit. The measurement results and the measurement uncertainty confirmed that the proposed method is reliable for the run-out measurement with sub-micrometric accuracy. Full article
(This article belongs to the Special Issue Precision Manufacturing)
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Open AccessArticle Influences on the Fabrication of Diffractive Optical Elements by Injection Compression Molding
J. Manuf. Mater. Process. 2018, 2(1), 5; doi:10.3390/jmmp2010005
Received: 15 December 2017 / Revised: 9 January 2018 / Accepted: 10 January 2018 / Published: 15 January 2018
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Abstract
Polymer optics are widely used in various applications, replacing traditional glass lenses. The ability to create free-form and micro-structured optics, as well as fast replication, gives them major advantages over traditional glass lenses. However, the fabrication of complex optical components requires full process
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Polymer optics are widely used in various applications, replacing traditional glass lenses. The ability to create free-form and micro-structured optics, as well as fast replication, gives them major advantages over traditional glass lenses. However, the fabrication of complex optical components requires full process control and understanding of influencing factors on the quality of the polymer optical parts. In this work, a curved diffractive optical element (DOE) is fabricated using injection compression molding. Different gate designs were evaluated and the movement of the compression stamper was optimized to obtain good filling behavior. The process stability was analyzed and improved by controlling the melt temperature precisely. Finally, the molding parameters were optimized, focusing on the mold temperature, melt temperature and compression force. Curved diffractive optical elements were replicated with feature sizes of 1.6 μm. The experiments showed that all aspects of the molding process have to be controlled perfectly to produce complex polymer optics. High mold temperatures and compression force are necessary to replicate micro-structured features. The work presents a broad investigation and description of the fabrication process and their influences. Full article
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Open AccessFeature PaperArticle Improvement of Numerical Modelling Considering Plane Strain Material Characterization with an Elliptic Hydraulic Bulge Test
J. Manuf. Mater. Process. 2018, 2(1), 6; doi:10.3390/jmmp2010006
Received: 22 December 2017 / Revised: 9 January 2018 / Accepted: 11 January 2018 / Published: 16 January 2018
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Abstract
A precise characterization of material behavior is necessary to identify yield criteria or hardening laws for an accurate numerical design of sheet metal forming processes. Current models like Yld2000-2d or Hill’48 do not consider the plane strain state, though this condition is primary
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A precise characterization of material behavior is necessary to identify yield criteria or hardening laws for an accurate numerical design of sheet metal forming processes. Current models like Yld2000-2d or Hill’48 do not consider the plane strain state, though this condition is primary cause of failure in deep drawing. It is anticipated that an improved yield locus contour which considers the stress under plane strain conditions leads to better results in numerical simulations of a deep drawing process. Within this contribution, a new experimental setup to characterize both principal stress components under plane strain as additional input data for material modelling is presented. Therefore, hydraulic bulge tests are carried out with a novel elliptical die, which implements a plane strain condition. Moreover, the improvement of the material model is investigated exemplarily for the three sheet metal alloys DC06, DP600 and AA5182. The resulting material parameters are used to identify the yield locus for plane strain by varying the yield locus exponent of Yld2000-2d. The results prove that considering plane strain yield locus results in a better sheet thickness distribution in comparison to conventional modelling of the deep drawing process. Full article
(This article belongs to the Special Issue Analysis and Modeling of Sheet Metal Forming Processes)
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Open AccessArticle Manufacture of Profiled Amabilis Fir Deckboards with Reduced Susceptibility to Surface Checking
J. Manuf. Mater. Process. 2018, 2(1), 7; doi:10.3390/jmmp2010007
Received: 22 December 2017 / Revised: 16 January 2018 / Accepted: 22 January 2018 / Published: 24 January 2018
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Abstract
Machining grooves and ridges (peaks) into the surface of wooden deckboards reduces undesirable checking that develops when “profiled” boards are exposed to the weather. We aim to develop improved profiles for amabilis fir decking to reduce its susceptibility to checking, and also to
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Machining grooves and ridges (peaks) into the surface of wooden deckboards reduces undesirable checking that develops when “profiled” boards are exposed to the weather. We aim to develop improved profiles for amabilis fir decking to reduce its susceptibility to checking, and also to examine whether profiling influences distortion (cupping) of deckboards. We systematically varied radii of grooves and peaks, and the heights and widths of peaks in profiled deckboards, exposed them to the weather, and measured checking and cupping of boards. Profiling significantly reduced the numbers and sizes of checks in amabilis fir deckboards, but increased cupping. Profiles with narrow grooves and tall peaks were generally better at restricting checking than profiles with wide grooves and shorter peaks. Our results suggest that one of the profiles we tested would be better at restricting checking than profiles used previously to manufacture profiled decking from amabilis fir. We conclude that the surface checking of profiled amabilis fir decking can be significantly reduced by altering the geometry of surface profiles. In principal, the same approach could be used with other softwood species that have potential to capture a share of the large and important market for wood decking. Full article
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Open AccessFeature PaperArticle Modal Analysis, Metrology, and Error Budgeting of a Precision Motion Stage
J. Manuf. Mater. Process. 2018, 2(1), 8; doi:10.3390/jmmp2010008
Received: 18 December 2017 / Revised: 12 January 2018 / Accepted: 15 January 2018 / Published: 24 January 2018
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Abstract
In this study, a precision motion stage, whose design utilizes a single shaft supported from the bottom by an air bearing and voice coil actuators in complementary double configuration, is evaluated for its dynamic properties, motion accuracy, and potential machining force response, through
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In this study, a precision motion stage, whose design utilizes a single shaft supported from the bottom by an air bearing and voice coil actuators in complementary double configuration, is evaluated for its dynamic properties, motion accuracy, and potential machining force response, through modal testing, laser interferometric metrology, and spectral analysis, respectively. Modal testing is carried out using two independent methods, which are both based on impact hammer testing. Results are compared with each other and with the predicted natural frequencies based on design calculations. Laser interferometry has been used with varying optics to measure the geometric errors of motion. Laser interferometry results are merged with measured servo errors, estimated thermal errors, and the predicted dynamic response to machining forces, to compile the error budget. Overall accuracy of the stage is calculated as peak-to-valley 5.7 μm with a 2.3 μm non-repeatable part. The accuracy measured is in line with design calculations which incorporated the accuracy grade of the encoder scale and the dimensional tolerances of structural components. The source of the non-repeatable errors remains mostly equivocal, as they fall in the range of random errors of measurement in laser interferometry like alterations of the laser wavelength due to air turbulence. Full article
(This article belongs to the Special Issue Precision Manufacturing)
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Open AccessFeature PaperArticle Precise In-Process Strain Measurements for the Investigation of Surface Modification Mechanisms
J. Manuf. Mater. Process. 2018, 2(1), 9; doi:10.3390/jmmp2010009
Received: 8 December 2017 / Revised: 24 January 2018 / Accepted: 25 January 2018 / Published: 30 January 2018
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Abstract
The question, how certain surface layer properties (for example, hardness or roughness) can be specifically influenced in different manufacturing processes, is of great economic interest. A prerequisite for the investigation of the formation of surface layer properties is the metrological assessment of the
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The question, how certain surface layer properties (for example, hardness or roughness) can be specifically influenced in different manufacturing processes, is of great economic interest. A prerequisite for the investigation of the formation of surface layer properties is the metrological assessment of the material stresses during processing. Up to now, no commercial in-process measuring system exists, which is able to determine material stresses in the form of mechanical strains in high-dynamic manufacturing processes with sufficient accuracy. A detailed analysis of the resolution limits shows that speckle photography enables deformation measurements with a resolution in the single-digit nanometer range. Thus, speckle photography basically offers the potential to measure material stresses during processing. Using the example of single-tooth milling, the applicability of speckle photography for in-process stress measurements is demonstrated. Even in such highly dynamic manufacturing processes with cutting speeds up to 10 m/s, the absolute measurement uncertainty of the strain is less than 0.05%. This is more than one order of magnitude lower than the occurring maximal strain. Therefore, speckle photography is suitable for characterizing the dynamic stresses and the material deformations in manufacturing processes. Full article
(This article belongs to the Special Issue Precision Manufacturing)
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Open AccessArticle Discrete Element Simulation of Orthogonal Machining of Soda-Lime Glass
J. Manuf. Mater. Process. 2018, 2(1), 10; doi:10.3390/jmmp2010010
Received: 29 December 2017 / Revised: 19 January 2018 / Accepted: 22 January 2018 / Published: 1 February 2018
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Abstract
Transparent, brittle materials, like glass, are used in various applications due to their advantages of mechanical and optical properties. However, their hard and brittle nature causes significant challenges to researchers when they design and test a new machining process. In order to optimize
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Transparent, brittle materials, like glass, are used in various applications due to their advantages of mechanical and optical properties. However, their hard and brittle nature causes significant challenges to researchers when they design and test a new machining process. In order to optimize this time-consuming process, discrete element method (DEM) is applied to simulate the cutting process of soda-lime glass in this study. The first step is to create a synthetic material that behaves like soda-lime glass. Then, the macroproperties are calibrated by adjusting the microparameters of the DEM model to match the mechanical properties of the real soda-lime glass. Finally, orthogonal machining simulations are conducted and model validation are conducted by comparing the predicted cutting forces with those from the orthogonal cutting experiments. Full article
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Open AccessArticle Environmental Emissions from Chemical Etching Synthesis of Silicon Nanotube for Lithium Ion Battery Applications
J. Manuf. Mater. Process. 2018, 2(1), 11; doi:10.3390/jmmp2010011
Received: 10 December 2017 / Revised: 13 January 2018 / Accepted: 17 January 2018 / Published: 1 February 2018
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Abstract
Silicon nanotubes (SiNTs) have been researched as a promising anode material to replace graphite in next-generation lithium ion batteries. Chemical etching synthesis of SiNTs is a simple, controllable and scalable process for SiNT fabrication, but the environmental emissions are of grave concern. In
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Silicon nanotubes (SiNTs) have been researched as a promising anode material to replace graphite in next-generation lithium ion batteries. Chemical etching synthesis of SiNTs is a simple, controllable and scalable process for SiNT fabrication, but the environmental emissions are of grave concern. In this paper, the process emissions from chemical etching synthesis of SiNTs as anode for lithium ion batteries is studied through experimental techniques, considering the categories of aqueous wastes, gaseous emissions, aqueous nano-particle emissions, and gaseous aerosol emissions. The synthesized SiNTs are measured at 10 μm length and 1–2.2 μm diameter, and can maintain a specific capacity of over 800 mAh/g after 100 cycles in battery testing. In aqueous waste, the chemical compositions of all elements participating in the chemical etching are experimentally determined, with AgNO3 and Co(NO3)2 identified as the major pollutants. The only gaseous emission generated from the chemical etching synthesis process is H2, with 0.0088 ± 0.0002 mol H2 generated to produce 1.0 mg SiNTs. The aqueous nanoparticle sizes are found to be between 250 nm and 1540 nm. A large number of aerosol nanoparticle emissions of up to 2.96 × 107 particles/cm3 are detected through in situ experimental measurement. Full article
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Open AccessArticle Characterization and Processing Behavior of Heated Aluminum-Polycarbonate Composite Build Plates for the FDM Additive Manufacturing Process
J. Manuf. Mater. Process. 2018, 2(1), 12; doi:10.3390/jmmp2010012
Received: 31 December 2017 / Revised: 13 February 2018 / Accepted: 14 February 2018 / Published: 16 February 2018
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Abstract
One of the most essential components of the fused deposition modeling (FDM) additive manufacturing (AM) process is the build plate, the surface upon which the part is constructed. These are typically made from aluminum or glass, but there are clear disadvantages to both
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One of the most essential components of the fused deposition modeling (FDM) additive manufacturing (AM) process is the build plate, the surface upon which the part is constructed. These are typically made from aluminum or glass, but there are clear disadvantages to both and restrictions on which materials can be processed on them successfully. This study examined the suitability of heated aluminum-polycarbonate (AL-PC) composite print beds for FDM, looking particularly at the mechanical properties, thermal behavior, deformation behavior, bonding strength with deposited material, printing quality, and range of material usability. Theoretical examination and physical experiments were performed for each of these areas; the results were compared to similar experiments done using heated aluminum and aluminum-glass print beds. Ten distinct materials (ABS, PLA, PET, HIPS, PC, TPU, PVA, nylon, metal PLA, and carbon-fiber PLA) were tested for printing performance. The use of a heated AL-PC print bed was found to be a practical option for most of the materials, particularly ABS and TPU, which are often challenging to process using traditional print bed types. Generally, the results were found to be equivalent to or superior to tempered glass and superior to standard aluminum build plates in terms of printing capability. Full article
(This article belongs to the Special Issue Additive Manufacturing)
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Open AccessArticle The Prediction of Surface Error Characteristics in the Peripheral Milling of Thin-Walled Structures
J. Manuf. Mater. Process. 2018, 2(1), 13; doi:10.3390/jmmp2010013
Received: 16 January 2018 / Revised: 9 February 2018 / Accepted: 17 February 2018 / Published: 22 February 2018
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Abstract
Lightweight design is gaining in importance throughout the engineering sector, and with it, workpieces are becoming increasingly complex. Particularly, thin-walled parts require highly accurate and efficient machining strategies. Such low-rigidity structures usually undergo significant deformations during peripheral milling operations, thus suffering surface errors
[...] Read more.
Lightweight design is gaining in importance throughout the engineering sector, and with it, workpieces are becoming increasingly complex. Particularly, thin-walled parts require highly accurate and efficient machining strategies. Such low-rigidity structures usually undergo significant deformations during peripheral milling operations, thus suffering surface errors and a violation of tolerance specifications. This article introduces a general approach to mitigating surface errors during the peripheral milling of thin-walled aluminum workpieces. It incorporates an analytical approach to predicting surface-error characteristics based on geometrical quantities and process parameters, which is presented in detail. Milling experiments, including geometrical measurements of the samples, have been performed to verify the approach. The approach allows for a pre-selection of parameter sets that result in surface errors that can be compensated with minimal effort. Additionally, the introduced model offers a simple criterion to assess potential error mitigation by applying the respective tool-path adjustments. In doing so, the amount of costly numerical simulations or experiments is significantly reduced. Full article
(This article belongs to the Special Issue Precision Manufacturing)
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Open AccessArticle Modelling Machine Tools using Structure Integrated Sensors for Fast Calibration
J. Manuf. Mater. Process. 2018, 2(1), 14; doi:10.3390/jmmp2010014
Received: 26 January 2018 / Revised: 18 February 2018 / Accepted: 18 February 2018 / Published: 23 February 2018
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Abstract
Monitoring of the relative deviation between commanded and actual tool tip position, which limits the volumetric performance of the machine tool, enables the use of contemporary methods of compensation to reduce tolerance mismatch and the uncertainties of on-machine measurements. The development of a
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Monitoring of the relative deviation between commanded and actual tool tip position, which limits the volumetric performance of the machine tool, enables the use of contemporary methods of compensation to reduce tolerance mismatch and the uncertainties of on-machine measurements. The development of a primarily optical sensor setup capable of being integrated into the machine structure without limiting its operating range is presented. The use of a frequency-modulating interferometer and photosensitive arrays in combination with a Gaussian laser beam allows for fast and automated online measurements of the axes’ motion errors and thermal conditions with comparable accuracy, lower cost, and smaller dimensions as compared to state-of-the-art optical measuring instruments for offline machine tool calibration. The development is tested through simulation of the sensor setup based on raytracing and Monte-Carlo techniques. Full article
(This article belongs to the Special Issue Precision Manufacturing)
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