Three-Dimensional Curved Profile Extrusion – First Results on the Influence of Gravity

2006 ◽  
Vol 10 ◽  
pp. 5-12 ◽  
Author(s):  
Alexander Klaus ◽  
Dirk Becker ◽  
Matthias Kleiner

This paper presents and discusses the latest achievements in the manufacture of threedimensionally curved aluminum profiles using an integrated bar extrusion process. While the conventional process chain lacks applicability and quality especially in low volume production, the new technology is promising, but still needs research to understand the correlation between the product to be manufactured and the contour accuracy to be achieved. This paper shows first results on the manufacture using a robot-guided second guiding tool and direct air quenching. The results will have an impact on further processing steps

2020 ◽  
Vol 26 (6) ◽  
pp. 1145-1154 ◽  
Author(s):  
Paul Lynch ◽  
C.R. Hasbrouck ◽  
Joseph Wilck ◽  
Michael Kay ◽  
Guha Manogharan

Purpose This paper aims to investigate the current state, technological challenges, economic opportunities and future directions in the growing “indirect” hybrid manufacturing ecosystem, which integrates traditional metal casting with the production of tooling via additive manufacturing (AM) process including three-dimensional sand printing (3DSP) and printed wax patterns. Design/methodology/approach A survey was conducted among 100 participants from foundries and AM service providers across the USA to understand the current adoption of AM in metal casting as a function of engineering specifications, production demand, volume and cost metrics. In addition, current technological and logistical challenges that are encountered by the foundries are identified to gather insight into the future direction of this evolving supply chain. Findings One of the major findings from this study is that hard tooling costs (i.e. patterns/core boxes) are the greatest challenge in low volume production for foundries. Hence, AM and 3DSP offer the greatest cost-benefit for these low volume production runs as it does not require the need for hard tooling to produce much higher profit premium castings. It is evident that there are major opportunities for the casting supply chain to benefit from an advanced digital ecosystem that seamlessly integrates AM and 3DSP into foundry operations. The critical challenges for adoption of 3DSP in current foundry operations are categorized into as follows: capital cost of the equipment, which cannot be justified due to limited demand for 3DSP molds/cores by casting buyers, transportation of 3DSP molds and cores, access to 3DSP, limited knowledge of 3DSP, limitations in current design tools to integrate 3DSP design principles and long lead times to acquire 3DSP molds/cores. Practical implications Based on the findings of this study, indirect hybrid metal AM supply chains, i.e. 3DSP metal casting supply chains is proposed, as 3DSP replaces traditional mold-making in the sand casting process flow, no/limited additional costs and resources would be required for qualification and certification of the cast parts made from three-dimensional printed sand molds. Access to 3DSP resources can be addressed by establishing a robust 3DSP metal casting supply chain, which will also enable existing foundries to rapidly acquire new 3DSP-related knowledge. Originality/value This original survey from 100 small and medium enterprises including foundries and AM service providers suggests that establishing 3DSP hubs around original equipment manufacturers as a shared resource to produce molds and cores would be beneficial. This provides traditional foundries means to continue mass production of castings using existing hard tooling while integrating 3DSP for new complex low volume parts, replacement parts, legacy parts and prototyping.


2008 ◽  
Vol 43 ◽  
pp. 1-8 ◽  
Author(s):  
Dirk Becker ◽  
Marco Schikorra ◽  
A. Erman Tekkaya

Curved Profile Extrusion (CPE) is an extension of the common extrusion process and offers the possibility to manufacture three-dimensionally curved profiles. Due to the flexibility of the process different curvatures can be produced with the same setup, which makes this technique efficient especially for low volume production. The process is characterized by a controlled lateral deflection of the strand which influences the material flow in the die and causes the profile curvature. In this paper, a direct comparison of the power rating between warm bending and CPE is presented. Furthermore, the investigations concerning the choice of support strategy of the surmounting profile by a robot to increase the curvature accuracy are continued. Finally, some extensions of the equipment are explained to increase the level of process integration.


2013 ◽  
Vol 2013 (1) ◽  
pp. 000641-000646
Author(s):  
Jorge Teixeira ◽  
Mário Ribeiro ◽  
Nélson Pinho

Current standards for silicon wafers shape characterization use simple metrics. Warpage and bow are computed as the mean surface wafer height range or the mean surface wafer center height, respectively [1]. These metrics are valid for silicon wafers because of their homogenous and linear thermomechanical properties [2]. In fan-out wafer level package (FO-WLP), embedded Wafer Level Ball Grid Array in specific (eWLB), the use of epoxy mold compound that works both as the physical carrier of the dies and as the base of second level connections has a major impact on the overall macroscopic behavior of the wafer, inducing shapes that do not follow a simple bended or bowed wafer, impacting wafer processability [3]. Warped wafers can affect device performance, reliability, and linewidth control in various processing steps [3]. Early detection will minimize cost and processing time. In our research, we present a solution for wafer characterization in FO-WLP by increasing the information vector that one obtains from standard automated non-contact scanning equipment. For this, we defined wafer shape and wafer ratio as the two new metrics besides warpage, creating a three dimensional vector that can be used to compare and evaluate wafers in high volume production or even single wafer analysis. This is a major improvement over previously used approaches, in which only the average warpage is considered. These metrics were determined by the developed numeric algorithm and their validity was demonstrated through the use of different production conditions, wafer constructions and production monitoring. The proposed approach requires no extra processing steps and time, as compared to conventional off-line methods. Experimental results demonstrate its feasibility and repeatability. This methodology was successfully used in the field and proved to be of high value when evaluating wafer geometrical requirements for both product development and process monitoring.


2020 ◽  
Author(s):  
Hongfeng Sheng ◽  
Weixing Xu ◽  
Bin Xu ◽  
Hongpu Song ◽  
Di Lu ◽  
...  

UNSTRUCTURED The retrospective study of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures provides a theoretical basis for the application of this technology. The paper collected 28 patients with tibiofibular fractures from the Department of Orthopaedics in our hospital from March 2015 to June 2018. After the treatment, the follow-up evaluation of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures and concurrency the incidence of the disease, as well as the efficacy and occurrence of the internal fixation of the treatment of tibial fractures in our hospital. The results showed that Taylor's three-dimensional external fixator was superior to orthopaedics in the treatment of tibiofibular fractures in terms of efficacy and complications. To this end, the thesis research can be concluded as follows: Taylor three-dimensional external fixation in the treatment of tibiofibular fractures is more effective, and the incidence of occurrence is low, is a new technology for the treatment of tibiofibular fractures, it is worthy of clinical promotion.


2020 ◽  
pp. 61-73
Author(s):  
Yu. M. Tsygalov

The forced work of Russian universities remotely in the context of the pandemic (COVID-19) has generated a lot of discussion about the benefits of the new form of education. The first results were summed up and reports were presented, the materials of which showed that the main goal of online education — the prevention of the spread of infection, - has been achieved. Against this background, proposals and publications have appeared substantiating the effectiveness of the massive introduction of distance learning in Russia, including in higher education. However, the assessment of such training by the population and students in publications and in social networks was predominantly negative and showed that the number of emerging problems exceeds the possible benefits of the new educational technology. Based on the analysis of the materials of publications and personal experience of teaching online, the potential benefits and problems of distance learning in higher education in Russia are considered. It is proposed to consider the effects separately for the suppliers of new technology (government, universities) and consumers (students, teachers, society). It is substantiated that the massive introduction of online education allows not only to reduce the negative consequences of epidemics, but also to reduce budgetary funding for universities, optimize the age composition of teachers, and reduce the cost of maintaining educational buildings. However, there will be a leveling / averaging of the quality of education, and responsibility for the quality of training will shift from the state/universities to students. The critical shortcomings of online education are the low degree of readiness of the digital infrastructure, the lack of a mechanism for identifying and monitoring the work of students, information security problems, and the lack of trust in such training of the population. The massive use of online education creates a number of risks for the country, the most critical of which is the destruction of the higher education system and a drop in the effectiveness of personnel training. The consequences of this risk realization are not compensated by any possible budget savings.


2021 ◽  
Vol 15 (2) ◽  
pp. 137-150
Author(s):  
Susanne Elisabeth Thürer ◽  
Anna Chugreeva ◽  
Norman Heimes ◽  
Johanna Uhe ◽  
Bernd-Arno Behrens ◽  
...  

AbstractThe current study presents a novel Tailored Forming process chain developed for the production of hybrid bearing bushings. In a first step, semi-finished products in the form of locally reinforced hollow profiles were produced using a new co-extrusion process. For this purpose, a modular tool concept was developed in which a steel tube made of a case-hardening steel, either C15 (AISI 1015) or 20MnCr5 (AISI 5120), is fed laterally into the tool. Inside the welding chamber, the steel tube is joined with the extruded aluminum alloy EN AW-6082. In the second step, sections from the compound profiles were formed into hybrid bearing bushings by die forging. In order to set the required forming temperatures for each material—aluminum and steel—simultaneously, a tailored heating strategy was developed, which enabled successful die forging of the hybrid workpiece to the desired bearing bushing geometry. Using either of the case-hardening steels in combination with aluminum, this novel process chain made it possible to produce intact hybrid bearing bushings, which showed both macroscopically and microscopically intimate material contact inside the compound zone.


Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 3
Author(s):  
Kyo-in Koo ◽  
Andreas Lenshof ◽  
Le Thi Huong ◽  
Thomas Laurell

In the field of engineered organ and drug development, three-dimensional network-structured tissue has been a long-sought goal. This paper presents a direct hydrogel extrusion process exposed to an ultrasound standing wave that aligns fibroblast cells to form a network structure. The frequency-shifted (2 MHz to 4 MHz) ultrasound actuation of a 400-micrometer square-shaped glass capillary that was continuously perfused by fibroblast cells suspended in sodium alginate generated a hydrogel string, with the fibroblasts aligned in single or quadruple streams. In the transition from the one-cell stream to the four-cell streams, the aligned fibroblast cells were continuously interconnected in the form of a branch and a junction. The ultrasound-exposed fibroblast cells displayed over 95% viability up to day 10 in culture medium without any significant difference from the unexposed fibroblast cells. This acoustofluidic method will be further applied to create a vascularized network by replacing fibroblast cells with human umbilical vein endothelial cells.


2021 ◽  
Vol 11 (8) ◽  
pp. 3635
Author(s):  
Ioannis Liritzis ◽  
Pantelis Volonakis ◽  
Spyros Vosinakis

In the field of cultural heritage, three-dimensional (3D) reconstruction of monuments is a usual activity for many professionals. The aim in this paper focuses on the new technology educational application combining science, history, and archaeology. Being involved in almost all stages of implementation steps and assessing the level of participation, university students use tools of computer gaming platform and participate in ways of planning the virtual environment which improves their education through e-Learning. The virtual 3D environment is made with different imaging methods (helium-filled balloon, Structure for motion, 3D repository models) and a developmental plan has been designed for use in many future applications. Digital tools were used with 3D reconstructed buildings from the museum archive to Unity 3D for the design. The pilot study of Information Technology work has been employed to introduce cultural heritage and archaeology to university syllabuses. It included students with a questionnaire which has been evaluated accordingly. As a result, the university students were inspired to immerse themselves into the virtual lab, aiming to increasing the level of interaction. The results show a satisfactory learning outcome by an easy to use and real 3D environment, a step forward to fill in needs of contemporary online sustainable learning demands.


2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Maria Jose Segovia ◽  
Daniel Diaz ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga

AbstractTo analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data-processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1 s and two-dimensional for periods greater than 10 s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80–100 km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 358 ◽  
Author(s):  
Chiara R. M. Brambilla ◽  
Ogochukwu Lilian Okafor-Muo ◽  
Hany Hassanin ◽  
Amr ElShaer

Three-dimensional (3D) printing is a recent technology, which gives the possibility to manufacture personalised dosage forms and it has a broad range of applications. One of the most developed, it is the manufacture of oral solid dosage and the four 3DP techniques which have been more used for their manufacture are FDM, inkjet 3DP, SLA and SLS. This systematic review is carried out to statistically analyze the current 3DP techniques employed in manufacturing oral solid formulations and assess the recent trends of this new technology. The work has been organised into four steps, (1) screening of the articles, definition of the inclusion and exclusion criteria and classification of the articles in the two main groups (included/excluded); (2) quantification and characterisation of the included articles; (3) evaluation of the validity of data and data extraction process; (4) data analysis, discussion, and conclusion to define which technique offers the best properties to be applied in the manufacture of oral solid formulations. It has been observed that with SLS 3DP technique, all the characterisation tests required by the BP (drug content, drug dissolution profile, hardness, friability, disintegration time and uniformity of weight) have been performed in the majority of articles, except for the friability test. However, it is not possible to define which of the four 3DP techniques is the most suitable for the manufacture of oral solid formulations, because the selection is affected by different parameters, such as the type of formulation, the physical-mechanical properties to achieve. Moreover, each technique has its specific advantages and disadvantages, such as for FDM the biggest challenge is the degradation of the drug, due to high printing temperature process or for SLA is the toxicity of the carcinogenic risk of the photopolymerising material.


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