A finned-riser design to avoid the capillarity effect in multi-jet fusion technology

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mattia Mele ◽  
Giampaolo Campana ◽  
Gian Luca Monti
Keyword(s):  
Analytical Model ◽  
Dimensional Accuracy ◽  
Measuring System ◽  
Original Design ◽  
Heat Management ◽  
Convex Shape ◽  
Content Type ◽  
Riser Design ◽  
Under Construction

Purpose Multi-jet fusion (MJF) process is based on a polymeric powder bed that is heated and irradiated by infra-red lamps. The layer under construction is jetted with inks to provide the desired heat management conditions for selective melting. Depending on several process variables, manufactured parts can exhibit lifting of the borders of the top surface of the shape under construction. This phenomenon is related to the capillarity effect. As a result, the top surface of MJF-manufactured parts can present a peculiar convex shape. This study aims to propose a solution that instead induces the capillarity effect outside of the part under construction. Design/methodology/approach A specific design is developed to avoid the capillarity effect in MJF. It is based on an analytical model that was previously developed by the authors to estimate the shape and extent of the capillary on top surfaces of benchmark components. The proposed methodology is established by the predicted calculation of maximum values of capillarity rise and length, and safety factors. A fin-shaped geometry is designed to avoid the capillarity effect. An experimental campaign is implemented to verify the effectiveness of the proposed solution. Prototypes are manufactured by an HP MultiJet 4200 in the original design and the so-called finned-riser design, by adding a well-dimensioned appendage on the top surface to shift the capillarity effect outside the border of the part under construction. Measurements are done by a CAM2 ScanArm contactless measuring system to achieve the real shape of top surfaces. Geomagic Control X software by 3D systems is used to evaluate the quality of measured surfaces in comparison with the expected geometry of the top plane of the benchmark. Findings The investigated approach involves adding an auxiliary finned-shape appendage, which acts similarly to the risers in foundry technology, to the top surface of the part that is being produced by MJF technology. The procedure and rules for determining the dimensions of the fin are established based on physical considerations and process modelling. The method is then applied to a prototype part, which is designed to highlight the effectiveness of the finned-riser design for improving the dimensional accuracy of the top surfaces of products manufactured by the MJF process. Experimental measurements of top surfaces of the original benchmark are compared to the same ones in the case of the finned-riser benchmark. Reported results are satisfactory, and the capillary effect occurred in the fins outside the border edges of the part. Further developments are planned to extend the proposed design. Originality/value MJF technology is attracting large interest from manufacturers to produce mass customised products. The quality of manufactured parts could be affected by peculiar defects related to process parameters. The present work aims to show a method to avoid the capillarity effect. It is based on an original analytical model developed by the authors and implemented successfully in the case of a benchmark geometry.

scholarly journals Developing a Measuring System for Monitoring the Thickness of the 6 m Wide HDPE/LDPE Polymer Geomembrane with Its Continuous Flow Using Automation Equipment

2021 ◽  
Vol 11 (21) ◽  
pp. 10045
Author(s):  
Tatyana Nikonova ◽  
Olga Zharkevich ◽  
Essim Dandybaev ◽  
Murat Baimuldin ◽  
Leonid Daich ◽  
...  
Keyword(s):  
Continuous Flow ◽  
High Density Polyethylene ◽  
Foreign Bodies ◽  
Automated System ◽  
Measuring System ◽  
Original Design ◽  
Software Complex ◽  
Automation Equipment ◽  
Production Conditions

As a result of R&D, a measuring system for controlling the thickness of the HDPE/LDPE (high-density polyethylene/low-density polyethylene) polymer geomembrane was developed using automation equipment. The relevance of this work consists of the development of a domestic, relatively inexpensive system for controlling the thickness of the HDPE/LDPE polymer geomembrane in production conditions based on modern equipment for enterprise automation. The scientific novelty consists of the use of original design solutions in the development of hardware and software complex mechanisms that allow controlling the thickness of the HDPE/LDPE polymer geomembrane layers along the entire width of the shaft, excluding deformation of the film as a result of foreign bodies entering during extrusion, cuts, monitoring the quality of the film in real time, as well as the possibility of analyzing the measured parameters in the database of the automated system.

Experimental study on the accuracy and surface quality of printed versus machined holes in PEI Ultem 9085 FDM specimens

2021 ◽  
Vol 27 (11) ◽  
pp. 1-12
Author(s):  
Giovanni Gómez-Gras ◽  
Marco A. Pérez ◽  
Jorge Fábregas-Moreno ◽  
Guillermo Reyes-Pozo
Keyword(s):  
Surface Quality ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Technological Parameters ◽  
Content Type ◽  
Fused Deposition ◽  
Comparison Of The Results ◽  
Through Hole

Purpose This paper aims to investigate the quality of printed surfaces and manufacturing tolerances by comparing the cylindrical cavities machined in parts obtained by fused deposition modeling (FDM) with the holes manufactured during the printing process itself. The comparison focuses on the results of roughness and tolerances, intending to obtain practical references when making assemblies. Design/methodology/approach The experimental approach focuses on the comparison of the results of roughness and tolerances of two manufacturing strategies: geometric volumes with a through-hole and the through-hole machined in volumes that were initially printed without the hole. Throughout the study, both alternates are explained to make appropriate recommendations. Findings The study shows the best combinations of technological parameters, both machining and three-dimensional printing, which have been decisive for obtaining successful results. These conclusive results allow enunciating recommendations for use in the industrial environment. Originality/value This paper fulfills an identified need to study the dimensional accuracy of the geometries obtained by additive manufacturing, as no experimental evidence has been found of studies that directly address the problem of the FDM-printed part with geometric and dimensional tolerances and desirable surface quality for assembly.

Benchmarking the complex geometric profiles, dimensional accuracy and surface analysis of printed parts

2019 ◽  
Vol 26 (2) ◽  
pp. 319-329 ◽  
Author(s):  
Paridhi Subbaian Kaliamoorthy ◽  
Rajkumar Subbiah ◽  
Joseph Bensingh ◽  
Abdul Kader ◽  
Sanjay Nayak
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Measuring System ◽  
Experimental Result ◽  
Complex Geometries ◽  
Thin Wall ◽  
Content Type ◽  
Metal Parts ◽  
Cooling Channels

Purpose Additive manufacturing has paved a way for geometrical freedom and mass customization of new and innovative products. However, it has a few limitations in printing complex geometries and sizes. The purpose of this paper is three-dimensional printing of metal parts using selective laser melting (SLM) has several intricacies. Design/methodology/approach To test the capabilities of SLM, the complex geometries of varying sizes, orientations, shapes such as square and cylindrical features, thin wall structures and holes were checked for dimensional accuracy and surface roughness. Findings The outcome of the study represents the capabilities of SLM and provide insight for solving the technological issues and processing constraint in the manufacture of metal parts from aluminum alloy. The analysis has proven that there is significant accuracy in dimension for large features in comparison with smaller one. The dimensional reproducibility was determined with the aid of an optical measuring system and the range of errors were calculated. These results show that the dimensional accuracy of the features in the printed part was within acceptable tolerance limits. This paper also investigated the significant contributing factors influencing printing of two and three-dimensional surface roughness based on the result of surface profilometer and it was observed that the surface was smoothened with the presence of overhangs and supports. Originality/value The ability of SLM to fabricate conformer cooling channels to support mould fabrication was tested. From the experimental result, it was observed that the quality of printing of conformal cooling channels depended on the diameter of channels with larger distortions in the channel having smaller diameter. The innovative aspect of the work was the study of build orientation combined with the investigated material.

An investigation on energy consumption and part quality of stereolithography apparatus manufactured parts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jizhuang Hui ◽  
Zhiqiang Yan ◽  
Jingxiang Lv ◽  
Yongsheng Liu ◽  
Kai Ding ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Energy Consumption ◽  
Layer Thickness ◽  
Laser Power ◽  
Dimensional Accuracy ◽  
Electrical Energy ◽  
Design Stage ◽  
Content Type ◽  
Part Quality

Purpose This paper aims to investigate the influences of process parameters on part quality, electrical energy consumption. Moreover, the relationship between part quality and energy consumption of UTR9000 photosensitive resin fabricated by stereolithography apparatus (SLA) was also assessed. Design/methodology/approach Main effect plots and contour maps were used to analyze the interactions and effects of various parameters on energy consumption and part quality, respectively. Then, a growth rate was used defined as the percentage of the value of energy consumption (or the part quality) of the sample compared to the minimum value of the energy consumption (or the same part quality), to jointly analyze relationships between part quality and energy consumption on a specific process parameter. Findings The part qualities can be improved with increased energy consumption via adjusting layer thickness, without further increasing energy consumption through adjusting laser power, over-cure and scanning distance. Energy consumption can be highly saved while slightly decreasing the tensile strength by increasing layer thickness from 0.09 mm to 0.12 mm. Energy consumption and surface roughness can be decreased when setting laser power near 290 mW. Setting an appropriate over-cure of about 0.23 mm will improve tensile strength and dimensional accuracy with a little bit more energy consumption. The tensile strength increases nearby 5% at a scanning distance of 0.07 mm compared to that at a scanning distance of 0.1 mm while the energy consumption only increases by 1%. Originality/value In this research, energy consumption and multiple part quality for SLA are jointly analyzed first to accelerate the development of sustainable additive manufacturing. This can be used to assist designers to achieve energy-effective fabrication in the process design stage.

Computational and experimental study of lattice structured patterns for casting process

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ablyaz Timur Rizovich ◽  
Muratov Karim Ravilevich ◽  
Алексей Aleksey Шумков ◽  
Evgeniy Shlykov ◽  
Sahil Dhiman ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Dimensional Accuracy ◽  
Casting Process ◽  
Content Type ◽  
Cell Parameters ◽  
Alloy Casting ◽  
Ni Alloy ◽  
Porosity Coefficient ◽  
Ceramic Shell Mold

Purpose The quality of lost foam casted engineering components is directly influenced by the characteristics of the respective ceramic shell mold (CSM) and hence casting pattern. In this present work, rapid prototyping (RP) was used to fabricate the lattice structured patterns (LSPs) to reduce the defects and cracks in CSM during the heating stage. Design/methodology/approach The quality of the LSPs was accessed by measuring the dimensional accuracy. Further, the thermal stress in the CSM during the heating of porosity varied LSPs was analyzed using ANSYS software package 16.0. The Ni-alloy casting was fabricated by using the designed LSP and compared with its respective CAD model to access its quality. Findings The obtained results revealed that the Wigner–Seitz LSPs retained high accuracy and minimized the stress for defect-free CSM. Also, the thermal stress generated in the CSM depends upon the porosity coefficient of the LSP. Hence the interplay with porosity coefficient of LSPs leads to the formation of defect free CSM and hence high quality casting. Originality/value RP was used to develop LSPs and investigated the dependency of unit cell parameters on the accuracy of the final casting.

Case study of the additive manufacturing application in the supersonic flow researches

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jefte da Silva Guimarães ◽  
Valéria Serrano Faillace Oliveira Leite ◽  
Marco Antonio Sala Minucci ◽  
Dermeval Carinhana
Keyword(s):  
Additive Manufacturing ◽  
Supersonic Flow ◽  
3D Printing ◽  
Dimensional Change ◽  
Supersonic Combustion ◽  
Measuring System ◽  
Content Type ◽  
Before And After ◽  
New Perspective

Purpose The purpose of this paper is to demonstrate the aerodynamic behavior of a supersonic combustion test bench (SCTB) components, as the transition piece and the combustor of a scramjet (supersonic combustion ramjet), manufactured by 3D printing or additive manufacturing (AM). Design/methodology/approach For the dimensional and structural analysis of the manufactured models, a portable 3D scanner was used to generate the mesh of its dimensions, and to compare them before and after the experiments, a roughness measuring system was also used to verify the roughness inside the models before and after the tests, as roughness is an important parameter because it directly affects the boundary layer. For the visualization of the flow, the non-intrusive schlieren optical technique was used. Findings The experiments were carried out on the SCBT for Mach 2 flows, using the manufactured prototypes and showed that there was no structural and dimensional change of the model after the test batteries. It was found that the roughness presented by the material did not affect the quality of the flow generated. This shows that the investigated material can also be applied in experiments with supersonic flow. Originality/value This paper presents that it is possible to use in ground test facilities, for the studies of supersonic flow (in cold condition), pieces and models manufactured by 3D printing without affecting the quality of the flow generated during the experiments. This study presents a new perspective to approach AM applied in the studies of supersonic flows.

The influence of support base on FDM accuracy in Z

2014 ◽  
Vol 20 (3) ◽  
pp. 182-191 ◽  
Author(s):  
Neri Volpato ◽  
José Aguiomar Foggiatto ◽  
Daniel Coradini Schwarz
Keyword(s):  
Fused Deposition Modeling ◽  
Surface Profile ◽  
Dimensional Accuracy ◽  
Contact Method ◽  
Content Type ◽  
Fused Deposition ◽  
Support Strategy ◽  
Deposition Modeling ◽  
Quality Surface

Purpose – The aim of this work is to study the influence of the quality (surface profile) of the support base on dimensional accuracy in the Z-axis in fused deposition modeling (FDM). Design/methodology/approach – The surface profile of a support base produced using a standard (default) FDM configuration is analyzed experimentally, and two new deposition configurations are proposed. Some parts are built using these approaches, and the influence of the profile on Z accuracy is investigated. The parts are examined using a contact method and measured using a caliper. Findings – The surface profile of the support base has a direct influence on FDM part accuracy in Z. The results show that the accuracy in the Z dimension of an FDM prototype can be increased by improving the surface quality of the support base. In cases where accuracy is paramount, this can be achieved by better planning (tuning) of the support strategy. Originality/value – A significant component of the Z error in FDM has been identified and studied.

scholarly journals Chazuta: subnational governments and internationalization of the agro-industrial value chain

2019 ◽  
Vol 26 (4) ◽  
pp. 340-351
Author(s):  
Alberto Carlo Cajavilca ◽  
Marta Tostes
Keyword(s):  
Value Chain ◽  
Qualitative Approach ◽  
Value Chains ◽  
Public Officials ◽  
Extension Services ◽  
Content Type ◽  
Alternative Crop ◽  
San Martín ◽  
Subnational Governments

Purpose The purpose of this paper is to examine the role and contribution of San Martin and Chazuta subnational governments in promoting development and internationalization of the cocoa and chocolate value chain from the stakeholders’ perceptions. This work was based on a qualitative approach in which information triangulation method, information processing with evaluation rubric and WebQDA software were used. The results showed that stakeholders of both value chains perceive that the subnational government’s actions taken to develop and internationalize these value chains are poorly valued and insufficient. Likewise, six internationalization barriers were identified in which two are perceived as the main limitations: low productivity levels and access to innovations and technology. These results contribute to enrich the decision-making process of political authorities and public officials from the San Martin subnational governments. Moreover, they provide information, according to the Peruvian national requirements, on the perceptions needed to rethink and improve the governmental services available, especially productive activities in the rainforest area (Presidencia del Consejo de Ministros, 2015; Wiener Fresco, 2010). This can improve or create new extension services to increase the quality of the Chazuta’s cocoa and chocolate products and to facilitate their entry into more demanding and profitable markets (Shapira, y otros, 2015). Design/methodology/approach This paper has been developed by using a qualitative approach with an exploratory and descriptive scope. The objective was to examine a study case of how subnational governments contribute in the promotion of development and internationalization of agro-industrial value chains as alternatives to illicit crops (Hernandez, Fernandez, & Baptista, 2010). The Chazuta case was selected because it is representative of the region in terms of coca eradication and is located between two regions of high biodiversity – Cordillera Escalera Regional Conservation Area and Cordillera Azul National Park. Findings One of the issues hindering the ability of the Chazuta cocoa and chocolate producers is based on their perception that the subnational governments’ efforts are focused on meeting already-established goals and little emphasis is placed on solving productive problems. On the other hand, at an articulation level, the most relevant efforts have been connecting the cocoa and chocolate customers to Chazuta producers through events. In spite of this, such events are not considered a permanent activity and the producers do not perceive that these mechanisms enable them to maintain these long-term trade relationships. This can be explained by the fact that Chazuta cocoa and chocolate organizations recognize that they still have incipient productive capacities to meet the foreign market’s demand. Furthermore, associations, cooperatives and SMEs are not able to maintain constant levels of production quality, except the family-based business. Knowledge and techniques provided by subnational governments and private organizations are not fully used or implemented by the associations’ members. This low level of knowledge application can be explained by cultural factors and also because the producers receive multiple and sometimes contradictory information from various providers of technology extension services. This leads to inadequate use or non-implementation of productivity improvements, thus generating a virtuous circle in which production and quality of the goods remain at low levels, which hinders their entry into demanding and profitable markets. Research limitations/implications This paper has been developed with a qualitative approach considering an exploratory and descriptive scope. Chazuta case was selected because it is representative of the region in terms of eradication achievements and it is located between two regions of high biodiversity. A rubric is an evaluation method of individuals or organizations performance, taking into consideration the evaluator’s pre-established criteria to determine if the objectives and goals are being met. Based on these criteria, evidence and performance information is collected. Following, performance is graded based on the researcher’s predetermined criteria and finally a merit-based judgment is made on the performance. Practical implications The results contribute to enrich decision making of political authorities and public officials from San Martin subnational governments. They provide information, according to Peruvian national requirements, on the perceptions needed to rethink and improve provided government services, especially in rainforest area productive activities. This adds up to improvement or creation of new extension services to increase the quality of Chazuta’s cocoa and chocolate products, and to facilitate their entry into more demanding and profitable markets. Social implications The situation of San Martín region and Chazuta district is contextualized and emphasis is given to socioeconomic conditions and the value of cocoa as an alternative crop to coca. From 1980 to early 2000, Peru lived a period of generalized violence due to narcoterrorism, which had large-scale outreach in southern highland and rainforest areas. To deal with this situation, subnational governments in collaboration with international cooperation decided to consolidate agro-industrial value chains in order to generate legal income for rural populations. For this purpose, alternative crop policies were implemented and San Martin region achieved the best results. Originality/value This fieldwork was carried out as part of the undergraduate thesis but after fieldwork, with the use of online software tool WebQDA, codes were created to systematize and quantify the collected information in the content manager. The codes were created taking into account assessment and evaluation variables. Each value represented a code referred to a performance level as perceived by Chazuta cocoa and chocolate value chains stakeholders.

scholarly journals Geometric Measurements on a CNC Machining Device as an Element of Closed Door Technology

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4852
Author(s):  
Grzegorz Bomba ◽  
Artur Ornat ◽  
Piotr Gierlak
Keyword(s):  
Measurement System ◽  
Measurement Process ◽  
Cnc Machining ◽  
Measuring System ◽  
Cnc Machine ◽  
Statistical Process ◽  
Working Space ◽  
Closed Door ◽  
Accuracy And Repeatability

The article discusses the quality testing of a measuring system consisting of a CNC machine with measuring probes. The research was conducted in a broader context regarding the implementation of the closed door technology, i.e., production without human intervention, in an aviation plant manufacturing aircraft gearbox systems. This technology may involve automated measuring operations performed in machining centers, and not in measuring laboratories, provided that the quality of the measurements is appropriate. The aim of the study was to investigate whether the CNC machining device can be used to measure the geometric features of aircraft gearbox housing. For this purpose, measurement experiments were carried out with the use of three different probes. Measurements were carried out using four sequences of increasing complexity, so that, after error analysis, it was possible to find the causes of possible irregularities. A reference ring with known dimensions and position in the working space of the machine was used for the measurements performed as part of the assessment of the measurement system. The quality of the measurements was evaluated with the use of repeatability and reproducibility testing and statistical process control. The analysis results showed that the tested measurement system ensures adequate accuracy and repeatability, and the measurement process is characterized with adequate efficiency in relation to the manufacturing tolerance of the components produced using the machine. Thus, it was proven that the measurement process can be carried out on a machining device, which enables its integration into the closed door technology.

Do disclosure and transparency affect bank’s financial performance?

2019 ◽  
Vol 19 (6) ◽  
pp. 1344-1361
Author(s):  
Isaiah Oino
Keyword(s):  
Risk Management ◽  
Corporate Governance ◽  
Financial Performance ◽  
Financial Institutions ◽  
Content Type ◽  
Loan Portfolios ◽  
Cent Level ◽  
Transparency And Disclosure ◽  
The Impact

Purpose The purpose of this paper is to examine the impact of transparency and disclosure on the financial performance of financial institutions. The emphasis is on assessing transparency and disclosure; auditing and compliance; risk management as indicators of corporate governance; and understanding how these parameters affect bank profitability, liquidity and the quality of loan portfolios. Design/methodology/approach A sample of 20 financial institutions was selected, with ten respondents from each, yielding a total sample size of 200. Principal component analysis (PCA), with inbuilt ability to check for composite reliability, was used to obtain composite indices for the corporate governance indicators as well as the indicators of financial performance, based on a set of questions framed for each institution. Findings The analysis demonstrates that greater disclosure and transparency, improved auditing and compliance and better risk management positively affect the financial performance of financial institutions. In terms of significance, the results show that as the level of disclosure and transparency in managerial affairs increases, the performance of financial institutions – as measured in terms of the quality of loan portfolios, liquidity and profitability – increases by 0.3046, with the effect being statistically significant at the 1 per cent level. Furthermore, as the level of auditing and the degree of compliance with banking regulations increases, the financial performance of banks improves by 0.3309. Research limitations/implications This paper did not consider time series because corporate governance does not change periodically. Practical implications This paper demonstrates the importance of disclosure and transparency in managerial affairs because the performance of financial institutions, as measured in terms of loan portfolios, liquidity and profitability, increases by 0.4 when transparency and disclosure improve, with this effect being statistically significant at the 1 per cent level. Originality/value The use of primary data in assessing the impact of corporate governance on financial performance, instead of secondary data, is the primary novelty of this study. Moreover, PCA is used to assess the weight of the various parameters.

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