Enhanced continuous liquid interface production with track-etched membrane

2019 ◽  
Vol 25 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Wenxiong Lin ◽  
Huagang Liu ◽  
Haizhou Huang ◽  
Jianhong Huang ◽  
Kaiming Ruan ◽  
...  

PurposeThe purpose of this paper is to explore the possibility of an enhanced continuous liquid interface production (CLIP) with a porous track-etched membrane as the oxygen-permeable window, which is prepared by irradiating polyethylene terephthalate membranes with accelerated heavy ions. Design/methodology/approachExperimental approaches are carried out to characterize printing parameters of resins with different photo-initiator concentrations by a photo-polymerization matrix, to experimentally observe and theoretically fit the oxygen inhibition layer thickness during printing under conditions of pure oxygen and air, respectively, and to demonstrate the enhanced CLIP processes by using pure oxygen and air, respectively. FindingsOwing to the high permeability of track-etched membrane, CLIP process is demonstrated with printing speed up to 800 mm/h in the condition of pure oxygen, which matches well with the theoretically predicted maximum printing speed at difference light expose. Making a trade-off between printing speed and surface quality, maximum printing speed of 470 mm/h is also obtained even using air. As the oxygen inhibition layer created by air is thinner than that by pure oxygen, maximum speed cannot be simply increased by intensifying the light exposure as the case with pure oxygen. Originality/valueCLIP process is capable of building objects continuously instead of the traditional layer-by-layer manner, which enables tens of times improvement in printing speed. This work presents an enhanced CLIP process by first using a porous track-etched membrane to serve as the oxygen permeable window, in which a record printing speed up to 800 mm/h using pure oxygen is demonstrated. Owing to the high permeability of track-etched membrane, continuous process at a speed of 470 mm/h is also achieved even using air instead of pure oxygen, which is of significance for a compact robust high-speed 3D printer.

2017 ◽  
Vol 23 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Yayue Pan ◽  
Haiyang He ◽  
Jie Xu ◽  
Alan Feinerman

Purpose Recently, the constrained surface projection stereolithography (SL) technology is gaining wider attention and has been widely used in the 3D printing industry. In constrained surface projection SL systems, the separation of a newly cured layer from the constrained surface is a historical technical barrier. It greatly limits printable size, process reliability and print speed. Moreover, over-large separation force leads to adhesion failures in manufacturing processes, causing broken constrained surface and part defects. Against this background, this paper investigates the formation of separation forces and various factors that affect the separation process in constrained surface projection SL systems. Design/methodology/approach A bottom-up projection SL testbed, integrated with an in-situ separation force measurement unit, is developed for experimental study. Separation forces under various manufacturing process settings and constrained surface conditions are measured in situ. Additionally, physical models are constructed by considering the liquid resin filling process. Experiments are conducted to investigate influences of manufacturing process settings, constrained surface condition and print geometry on separation forces. Findings Separation forces increase linearly with the separation speed. The deformation and the oxygen inhibition layer near the constrained surface greatly reduce separation forces. The printing area, area/perimeter ratio and the degree of porousness of print geometries have a combined effect on determining separation forces. Originality/value This paper studied factors that influence separation force in constrained surface SL processes. Constrained surface conditions including oxygen inhibition layer thickness, deformation and oxygen permeation capability were investigated, and their influences on separation forces were revealed. Moreover, geometric factors of printing layers that are significant on determining separation forces have been identified and quantified. This study on separation forces provides a solid base for future work on adaptive control of constrained surface projection SL processes.


Significance The government hopes greater domestic and foreign investment can help turn around the pandemic-hit economy. The governor of Bank Indonesia (BI), the central bank, last week said GDP should grow by 4.6% in 2021, compared with last year’s 2.1% contraction. Impacts Indonesia will count on private vaccination, whereby companies buy state-procured jabs for their staff, to help speed up its roll-out. The Indonesia Investment Authority, a new sovereign wealth fund, will prioritise attracting more investment into the infrastructure sector. Singapore will continue to be Indonesia’s largest source of FDI in the short term.


2018 ◽  
Vol 24 (3) ◽  
pp. 532-538 ◽  
Author(s):  
Maria Luiza Seixas ◽  
Paulo Santos Assis ◽  
João Cura D’Ars Figueiredo ◽  
Maria Aparecida Pinto ◽  
Daniella Gualberto Caldeira Paula

Purpose This paper aims to present a proposal for the restoration of a silver crown by means of fitting pieces produced by the process of 3D modelling and rapid prototyping. It also analyses the benefits of this procedure in restoration of objects weakened by corrosive processes. Design/methodology/approach Elemental chemical analysis was carried out in the alloy used in the manufacture of the crown and the constructive and corrosive processes present were studied. Three fitting pieces were modelled and prototyped in wax casting by the stereolithography apparatus system aiming to restore the part and protect the original metal against impacts and external tensions which could speed up some deterioration processes. Findings The procedure presented in this paper has shown that formal and dimensional accuracy, only achieved by means of 3D technologies, made the restoration and mechanical stability of the crown possible without the use of adhesives or welding. Originality/value The proposed procedure is a new restoration alternative which causes minimal impact to the object and abides by the main standards for modern conservation. It is made with metal which is compatible with the original piece, retractable and easily identifiable.


2019 ◽  
Vol 18 (4) ◽  
pp. 150-154
Author(s):  
Charles Hipps

Purpose Change is no longer an event in HR. Competition is tougher than ever, and this battle for top talent is a vicious cycle that doesn't stop but reinvents itself all the time. The recruitment market needs to be more responsive to the continuous cycle of innovation and recognise the increasingly competitive marketplace that is rapidity getting tighter. Design/methodology/approach With more than 20 years as the founder of a leading recruitment technology vendor, the detail and content supplied in the feature are all of the author’s own thoughts and experiences, drawn from his own expertise and learning from others he has met en route. Findings More often than not, recruitment teams are doing what they have always done – seeing the same candidates and visiting the same events. Change, or more specifically in this case, technology, actually has the ability to speed up the process, enhance the candidate experience and give time back to recruiters to spend with the candidates. Originality/value It is widely known that talented people have higher expectations and opportunities than ever before. That makes it crucial for companies to reach them, deliver a highly engaging candidate experience and nurture a relationship well ahead of open opportunities.


2019 ◽  
Vol 488 (1) ◽  
pp. 117-119
Author(s):  
S. L. Bazhenov ◽  
I. V. Razumovskaya ◽  
N. P. Kovalets ◽  
S. A. Bedin

2009 ◽  
Vol 330 (1-2) ◽  
pp. 145-155 ◽  
Author(s):  
A.A. Belkova ◽  
A.I. Sergeeva ◽  
P.Y. Apel ◽  
M.K. Beklemishev

2016 ◽  
Vol 35 (3) ◽  
pp. 304-325 ◽  
Author(s):  
Charttirot Karaveg ◽  
Natcha Thawesaengskulthai ◽  
Achara Chandrachai

Purpose – The purpose of this paper is to study the criteria of R & D commercialization capability by using the successful cases from government research institutes. Design/methodology/approach – The data were collected from 272 entrepreneurs and researchers with a structured questionnaire. The data analysis was carried out by the structural equation modeling (SEM). Findings – The research results revealed that there are six criteria for R & D project commercialization capability, these are arranged according to the significance; marketing, technology, finance, non-financial impact, intellectual property, and human resource. Moreover, the evaluator’s roles, both researchers and entrepreneurs, effect the level of criteria for consideration. Research limitations/implications – This research is derived from samples form voluntary participants from the disclosed lists in the governmental research institutes. Although SEM results provide weight for each R & D commercialization capability that would be the first step for developing the R & D evaluation instrument and the longitudinal will need to investigate. Practical implications – This study provides the holistic R & D commercialization capability criteria to assist entrepreneurs and researchers when faced with R & D commercialization decision. The criteria was developed from successful innovation cases; hence they enhance decision-making potential, provide a guideline of R & D commercialization evaluation process, speed up the decision-making process, and prevent risk of a resource meltdown and increase innovation exploitation. Social implications – The roles of the evaluators are important when considering R & D, hence, to use the same criteria for evaluating the researchers and entrepreneurs seems inappropriate since naturally, the researchers usually lack marketing and financial skills while the entrepreneurs usually lack technological skills and human resources. The answer may be in the form of providing specifics about project requirement, establishment of marketing and financial consultants in research institutes, enhancement of research and development division, or doing the business matching before doing the agreement in order to encourage co-research and increase the technology transfer level. Originality/value – This paper proposes the holistic criteria in order to decrease the ambiguous subjectivity of fuzzy-expert system and to help with effectively funding R & D and to prevent a resource meltdown.


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