Manufacture Parts Research Articles

Full liquid phase sintering of binder jetting printed magnesium alloy

Migration and diffusion of materials play a critical role in densifying magnesium alloy parts made by binder jetting technology, which is closely related to the sintering temperature. However, the native oxide film of the magnesium alloy forms a barrier between particles, hindering the migration and diffusion processes and making it challenging to manufacture parts with the desired properties. To overcome this issue, this study employs a full liquid sintering method to achieve densification by breaking the oxide film at high temperature, allowing particles to diffuse and migrate. The density, microstructure, grain growth, phase change, cross-sectional morphology and mechanical properties of the manufactured samples at different sintering temperatures were investigated. The results showed that the density and mechanical properties of the samples first increases and then decreases with increasing temperature. The best properties are obtained at 620 °C where the density, the compressive strength and the tensile strength reach 93.16 %, 181.92 MPa and 91.20 MPa respectively. Further, the grain size grows from 38.03 μm at 600 °C to 45.09 μm at 640 °C, a size increase of 18.56 %. Additionally, the material phase composition is consistent at different temperatures, but the α-Mg peak shows a small shift to the left as the temperature increases. The sample morphology shrinks and swells significantly at sintering temperatures above 630 °C, where grain coarsening and larger holes appear in the microstructure, resulting in reduced properties. In summary, the full liquid phase sintering method offers significant advantages in optimizing the sintering process for binder jetting of magnesium alloys.

Robust topology optimization considering part distortion and process variability in additive manufacturing

This paper presents a method to consider uncertainties in the distortion prediction of additive manufacturing processes within robust topology optimization. The random variable of the stochastic additive manufacturing process is the inherent thermomechanical strain, typically determined by process characterization experiments. The value of the inherent strain per se encompasses uncertainty due to differences between characterization and production geometries, uncontrolled process variations, hatching pattern choices, and other effects not captured in layer-by-layer part-scale additive manufacturing simulation. These effects can be represented by different inherent strains for each realized layer, therefore, model the variability in part distortion. Instead of employing a more detailed simulation approach, requiring significantly more process data and computation time, our method aims at generating a robust design in this setting, to obtain parts exhibiting reduced distortion regardless of uncertainties in distortion prediction. The formulation benefits from the superposition potential within the employed process simulation. For robust optimization, the expected part distortion and its estimated variance are included in the standard density-based topology optimization algorithm’s objective function. The effectiveness of the approach is demonstrated by simultaneously optimizing structural performance combined with a minimized additive manufacturing part distortion under uncertain process conditions.

Mechanical property estimation for additive manufacturing parts with supports

Mechanical property estimation for additive manufacturing parts with supports

Study on surface quality of ultrasonic assisted underwater laser polishing

Surface polishing is a critical factor in optimizing the practical utility of laser additive manufacturing (LAM) parts. This study explores the use of nanosecond pulsed lasers for polishing the surface of laser-directed energy deposition (LDED) TA15 titanium alloy. Various polished surfaces are achieved by adjusting laser processing parameters. Analytical techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), laser confocal microscopy, and ultra-depth of field microscopy, are employed to assess phase composition, oxidation levels, and surface roughness under different laser polishing conditions. The study also investigates changes in surface properties and the underlying mechanisms that occur during laser polishing. Microhardness tests and room temperature tensile tests are conducted to evaluate the compressive strength and tensile strength of the TA15 alloy's surface after laser polishing. The results demonstrate that different laser polishing methods yield varying surface quality and mechanical properties. Notably, ultrasonic assisted underwater laser polishing (UWP) exhibits significantly lower surface roughness Ra (3.035 μm) and Sa (3.172 μm) compared to air laser polishing (AP) and underwater laser polishing (WP), indicating improved surface quality and enhanced surface strength and plasticity.

Design of Horizontal Shell Core Casting Machine for Small and Medium Enterprise in the Automotive Sector

The manufacturing industry plays an important role in a country's economy because it can produce high-value products and has the opportunity to create jobs for local communities. In this study, the authors designed a horizontal shell core casting machine for small and medium enterprises in the automotive sector with a productivity of 60 seconds per cycle of products is designed based on requirements needed. This shell core casting machine is a device to produce shell core molds used to manufacture automotive components and parts. The design of this device was focused on engineering design in the form of 2-dimensional drawings and computer aided design models in 3-dimensional form. This study was done in collaboration with a local machinery manufacturer in Karawang district in Indonesia. It is expected from these designs will become a reference to manufacture shell core casting machines to support national industrialization impacted on improving the local community's economy.

The effect of scanning strategies on the microstructure and mechanical properties of M2052 alloy manufactured by selective laser melting

To control the microstructure and improve the mechanical properties of Mn–Cu alloy additive manufacturing components, this work adopts various scanning strategies (rotations of 0°, 45°, 67°, and 90° between successive layers) to change the heat input distribution and heat dissipation. The results show that the scanning strategies can impact the porosity, cracks, grain size, and grain growth direction of Mn–Cu alloy additive manufacturing parts. By adjusting scanning strategies to change the heat flow direction the columnar-to-equiaxed transition can be achieved. The samples exhibit minimal cracks and pores (porosity of 0.0006 %). Using a scanning rotation angle of 67° during processing, the maximum tensile strength can reach 510 MPa with a 29 % elongation, attributed to effective grain refinement and a high dislocation density. This study demonstrates the feasibility of grain refinement and improved mechanical properties for the Mn–Cu alloys by changing the scanning strategies.

Optimisation of Process Parameters on Compressive Strength of 3D-Printed Polylactic Acid Parts

Purpose: The purpose of this work is to optimise the influence of 3D printing processing parameters on the ultimate compressive strength of 3D-printed polylactic acid (PLA) parts. The objective is to develop the predictive models to help predict and attain optimized compressive strength integrity of 3D printed parts.
 Design/Methodology/Approach: In the present study, 3D printed PLA samples were modelled and fabricated using carefully selected processing parameters-processing speed, processing temperature and nozzle diameter. Compressive tests were performed by ASTM D695-15 standard. Two characteristics response optimisation models based on the Taguchi Technique and multi-linear regression models were developed to optimize the process parameters and the ultimate compressive strength of the 3D printed samples.
 Findings: Results of this study reveal that ultimate compressive strength is significantly affected by the Nozzle diameter. The ultimate compressive strength of the 3D-printed PLA sample was found to be significantly higher than the strength of the original PLA filament printed.
 Research Implications/Limitations: In this study, only three critical 3D printing processing parameters including, processing speed; processing temperature and nozzle diameter were implemented concurrently.
 Practical implication: By optimising process parameters, such as layer thickness, infill density, printing speed, and processing temperature, manufacturers can produce 3D-printed PLA parts with higher compressive strength. This leads to higher product quality and reliability.
 Social implication: It can empower local communities and small businesses to manufacture parts and products that meet their specific needs. This can reduce dependence on centralized manufacturing and promote economic self-sufficiency.
 Originality / Value: In this work, Nozzle diameter, which is a not too much studied 3D printing processing parameter, is implemented simultaneously with processing speed, and processing temperature to 3D print PLA filament to achieve an ultimate compressive strength value significantly higher than the strength of the original filament.

Dynamical model and numerical study of cavitation bubble in ultrasonic assisted electrochemical polishing solution of selective laser melting NiTi alloy

In the process of ultrasound assisted electrochemical polishing of selective laser melting (SLM) NiTi alloy, a large number of cavitation bubbles will be generated in the anode and cathode, and these cavitation bubbles will expand and compress rapidly until finally collapse. At the moment of collapse, high temperature and high pressure will occur, and at the same time, pressure shock wave and micro-jet will be produced, which will have a certain impact on material removal during polishing. In order to explore the mechanism of ultrasonic assisted electrochemical polishing, in this paper, the dynamics of cavitation bubbles with free interface and rigid interface are analyzed by ultrasonic assisted electrochemical polishing. The dynamics models of single cavitation bubble and two cavitation bubbles are established. The fourth order Runge–Kutta method was used to solve the model numerically, and the influence of electric field intensity, initial bubble radius, sound pressure amplitude and ultrasonic frequency on the dynamics of cavitation bubble was analyzed. The results show that in the range of f = 1–10 KHz, the initial radius of bubble is 0.01–0.05 micron, the sound pressure amplitude is 103 Pa, and the electric field intensity is 104 V m−1, the cavitation movement gradually becomes regular, and it goes through a complete process of expansion, contraction and then collapse, which is beneficial to the cavitation effect. This provides a theoretical basis for further research on the mechanism of ultrasonic assisted electrochemical polishing of SLM-NiTi alloy, which is of great significance for broadening the processing of additive manufacturing parts with low cost, high efficiency, and consistent quality.

Predicting Sintering Window of Binder Jet Additively Manufactured Parts Using a Coupled Data Analytics and CALPHAD Approach

Predicting Sintering Window of Binder Jet Additively Manufactured Parts Using a Coupled Data Analytics and CALPHAD Approach

On the Influence of Scattered Errors over Full-Field Receptances in the Rayleigh Integral Approximation of Sound Radiation from a Vibrating Plate

Spatially dense operative deflection shapes and receptances, acquired in broad frequency bands, increase the detail in the spatial and frequency domains of the responses of parts in actual dynamic loading, manufacturing and mounting conditions. This work remarks the potential benefits of greater spatial resolution in the Rayleigh integral approximation of sound pressure—here reformulated to exploit the increased quality output from experiment-based optical full-field technologies in contactless structural dynamics—radiated by a vibrating surface in a broad frequency band. But in some cases the noise that is scattered over the estimated receptance maps might be heavier, or with different patterns, than expected, with potential repercussions on the sound pressure simulations that come thereof. This work covers this specific latter issue with insight over examples from experiment-based receptances of a lightweight vibrating plate. The effects of error spreading are analysed in the space and frequency domains, with special attention to the contribution of the experiment-based full-field receptance maps to the accuracy of the vibro-acoustic frequency response function maps.

Review on Laser Shock Peening Effect on Fatigue of Powder Bed Fusion Materials

The ability to manufacture parts with complex geometry by sending a model from CAD directly to the manufacturing machine has attracted much attention in the industry, driving the development of additive manufacturing technology. However, studies have shown that components manufactured using additive manufacturing technology have several problems, namely high tensile residual stresses, cracks, and voids, which are known to have a major impact on material performance (in service). Therefore, various post-treatment methods have been developed to address these drawbacks. Among the post-treatment techniques, laser shock peening (LSP) is currently considered one of the most efficient post-treatment technologies for improving the mechanical properties of materials. In practice, LSP is responsible for eliminating unfavorable tensile residual stresses and generating compressive residual stresses (CRS), which result in higher resistance to crack initiation and propagation, thus increasing component life. However, since CRS depends on many parameters, the optimization of LSP parameters remains a challenge. In this paper, a general overview of AM and LSP technology is first provided. It then describes which parameters have a greater influence during powder bed melting and LSP processing and how they affect the microstructure and mechanical properties of the material. Experimental, numerical, and analytical optimization approaches are also presented, and their results are discussed. Finally, a performance evaluation of the LSP technique in powder bed melting of metallic materials is presented. It is expected that the analysis presented in this review will stimulate further studies on the optimization of parameters via experimental, numerical, and perhaps analytical approaches that have not been well studied so far.

Computational Model for Tree-like Fractals Used as Internal Structures for Additive Manufacturing Parts

It is well established that the introduction of additive manufacturing in various domains has produced significant technological leaps due to the advantages over other manufacturing techniques. Furthermore, additive manufacturing allows the design of parts with complex internal structures (e.g., lattice, honeycomb) to achieve lightweight or other mechanical properties. This paper presents a computational model (integrated into a programable algorithm) designed to generate complex internal structures, using tree-like fractals, for components (mechanical parts) whose designs are achievable by additive manufacturing. The computational model is presented in detail, starting from the mathematical definition and the properties of the proposed tree-like fractals. The fractal data are computed and arranged unequivocally using table representations. Based on the fractal data, the structures are generated inside CAD parts (which are given as inputs in the algorithm). The proposed computational method is applied in different case studies to illustrate their functionality. The generated CAD components (with fractal internal structures) are intended for manufacturing (using selective laser melting) and laboratory (mechanical) testing and for finite element analysis, which in turn can validate the use of tree-like fractals as interior structures for mechanical components.

CT-Based Dimensional Metrology for Quality Assessment of the Internal Structure of Additive Manufactured Aluminum Parts

Two common types of internal defects of additively manufactured (AM) samples are lack-of-fusion and gas-entrapped porosities. These internal defects can have different physical origins and particular local characteristics (e.g., different shape, size). Thus, the use of reliable non-destructive inspection techniques is essential for the accurate assessment of integrity, allowing the applicable AM processing parameters correction. To overcome this challenge, this work aims to evaluate the accuracy of volumetric characteristics measured by computed tomography for porosity evaluations in AM samples, including assessment of measurement uncertainty. The effect of different cumulative thickness on the evaluated measurements accuracy is also assessed. The results show that deviations of defect size measurements can be below 2% if the proposed procedure is followed. In addition, the expanded uncertainty can be up to 10% of the measured magnitude when the cumulative thickness is increased to 70 mm. The physical relationships obtained between the cumulative thickness and the individual measurements are also presented.

Produksi Pemindangan Ikan Tongkol Variasi Konsumsi Olahan untuk Meningkatkan pendapatan Masyarakat Gampong Aceh Kabupaten Aceh Timur

The aim of this program is to empower the community to make tuna pindang products, provide motivation to produce tuna pindang to help increase people's income and contribute to the development of tuna tuna business in Gampong Aceh. The methods to be used in Community Service activities are the observation method, practice method and lecture method. Community participation is very important in the success of this PKM program. It is hoped that the community will be able to take part in this activity starting with the desire to empower active and sustainable working groups of housewives, the community taking part in product manufacturing and packaging counseling, the community jointly making pindang cob products which will become their trademark from Gampong Aceh, Kabupaten Aceh Timur, and the community can market their products which extend to other areas. Problems in empowering the Gampong Aceh community to become a productive community in processing the available natural resources into superior products and are the hallmark of Gampong Aceh. The abundance of tuna has not yet been produced by doing pemindangan, by assisting the people of Gampong Aceh to make tuna processing into a savory variation of processed tuna fish, hopefully it will be in great demand by the community. After the cob fish processing is done, it will be packaged in attractive and hygienic packaging so that it becomes an attraction for the market share.

Study of Improvement of the Build Rate of Ti-6Al-4V Alloy by Laser Beam Powder Bed Fusion Technology

Metal powder bed fusion additive manufacturing technologies are increasingly being adopted in industrial applications, but their widespread implementation on an industrial scale is hindered by the high manufacturing cost. This study investigates two strategies to improve the build rate of Ti-6Al-4V alloy processed by powder bed fusion using a laser beam (PBF-LB/Ti6Al4V), which is a critical factor that affects the cost of an additive manufacturing part. The first strategy involves increasing the layer thickness from 30 µm to 60 µm, while the second strategy entails increasing the particle size of the raw material from 25-45 µm to 45-106 µm while maintaining a layer thickness of 60 µm.The experiment involved modifying the process parameters based on the energy density (J/mm2), combining laser powers between 180-470 W, scanning speeds between 600-2611 mm/s, and distance between passes from 0.12 to 0.21 mm. With the highest density level process parameter combinations, a comparative study of manufacturing times for a given geometry showed a productivity improvement of up to 50%. The static mechanical properties of the specimens were evaluated by performing tensile tests. The roughness of the melt was determined for each strategy. The study concludes that modification of process parameters can reduce the build rate of PBF-LB/Ti6Al4V while maintaining its tensile strength and surface roughness.

The Influence of Halal Certification and Religiosity on Interest in Buying Mixue Products Through Attitude as an Intervening Variable (Study of Communities in Madiun City)

The processed food industry is one of the industries that has been able to survive and grow positively, even including the one with the highest growth. The processed food industry as part of manufacturing has very promising prospects, both globally and domestically. Several factors determine interest in purchasing food products, including halal certification and religiosity. This study aims to empirically prove the effect of halal certification and religiosity on purchasing interest in mix products through attitude as an intervening variable.This type of research is descriptive quantitative. Data collection was carried out by distributing questionnaires. The sampling method used is purposive sampling method. The sample in this study is the community in Madiun City. The data used in this research is primary data. Regarding data analysis using multiple linear regression analysis with the help of the SPSS version 19 program. The results of this study prove that the variables of halal certification and religiosity have a positive and significant effect on the intention to buy mixed products. The results of this study also show that the variables of halal certification and religiosity affect consumer attitudes.

Systematic knowledge modeling and extraction methods for manufacturing process planning based on knowledge graph

Process knowledge is an important part of intelligent manufacturing, which has become the trend of global manufacturing industry. However, process planning in manufacturing heavily relies on experience and historical knowledge that cannot be effectively reused. Also, process knowledge is complicatedly structured, widely distributed, and weakly associated, which makes it more difficult to be shared and reused. Moreover, existing methods of organizing process knowledge are labor-intensive, inefficient and inevitable to extensive manual annotation. To overcome the above problems, a systematic method of knowledge graph construction for process knowledge is presented. First, through key concepts and relationships analysis, a domain ontology for process knowledge is proposed. Second, a pattern-based bootstrapping framework with a 2-level masking technique is established to perform process knowledge extraction, which does not require manual annotation and avoids overfitting issues. Third, a meta path-based question answering over knowledge graph approach is presented to support process planning, which can effectively capture keywords of the input question, present the intention and match the designed path. Finally, taking the production process of radiator as a research object, a corresponding manufacturing process knowledge graph is constructed and applied to process planning scenario, and experiments validate the feasibility of the proposed methods.

Environmental drawbacks of lightweight design algorithms in material extrusion additive manufacturing: a case study

Lightweight design is often assumed to be the leading strategy to improve the sustainability of parts produced by additive manufacturing. The present study confutes such an assumption by a cradle-to-gate life cycle assessment of different lightweight strategies applied to a specific case study in the medical field. In particular, a patient-specific finger splint made of polyamide is redesigned by means of generative design, topology optimization and lattice structures. The analysis investigates two markedly different deposition processes, namely Arburg plastic freeforming and fused filament fabrication. The former is carried out on an industrial-grade machine, while a desktop printer is used for the latter. This allows for observing the impact of the redesign in two quite distinct scenarios. Findings demonstrate that, since environmental impacts are mainly driven by building time, the adoption of automated design algorithms can be detrimental to the sustainability of the process. On the other hand, relevant benefits on environmental impacts were achieved by reducing the infill percentage of parts. The results of this work highlight the most relevant aspects which must be considered to limit environmental impacts when designing parts for deposition-based additive manufacturing. This information can be used by designers to drive weight reduction towards sustainability.

Research Regarding the Dimensional Precision of Electrical Steel Strips Machined by Waterjet Cutting in Multilayer Packages

Manufacturing parts made of thin steel in small batches is a challenging task in terms of reaching the proper balance between the productivity, the cost, and the dimensional precision. This paper presents the results of experimental research about manufacturing electrical steel thin parts using abrasive waterjet cutting. For a certain increase of productivity and a more efficient process, the parts were cut using multilayer packages of steel strips. The main objective was to analyze the influence of the number of layers on the dimensional precision of parts. Preliminary tests were performed, followed by a full factorial experiment using two independent parameters, the number of layers and the traverse speed. The parts were measured on a noncontact vision measurement machine and mathematical models were determined to predict the parts deviations depending on the independent parameters used. A practical validation of the models was performed. The main conclusion is that the number of layers has a certain influence on the accuracy of dimensions, but this influence can be predicted with a satisfactory level of confidence using mathematical models.

Enhanced performance of mixed HWMA-CUSUM charts using auxiliary information.

Quality control (QC) is a systematic approach to ensuring that products and services meet customer requirements. It is an essential part of manufacturing and industry, as it helps to improve product quality, customer satisfaction, and profitability. Quality practitioners generally apply control charts to monitor the industrial process, among many other statistical process control tools, and to detect changes. New developments in control charting schemes for high-quality monitoring are the need of the hour. In this paper, we have enhanced the performance of the mixed homogeneously weighted moving average (HWMA)-cumulative sum (CUSUM) control chart by using the auxiliary information-based (AIB) regression estimator and named it MHCAIB. The proposed MHCAIB chart provided an unbiased and more efficient estimator of the process location. The various measures of the run length are used to judge the performance of the proposed MHCAIB and to compare it with existing AIB charts like CUSUMAIB, EWMAAIB, MECAIB (mixed AIB EWMA-CUSUM), and HWMAAIB. The Run length (RL) based performance comparisons indicate that the MHCAIB chart performs relatively better in monitoring small to moderate shifts over its competitor's charts. It is shown that the chart's performance improves with the increase in correlation between the study variable and the auxiliary variable. An illustrative application of the proposed MHCAIB chart is also provided to show its implementation in practical situations.