High-quality manufacturing method of complicated castings based on multi-material hybrid moulding process

Injection moulding is an important manufacturing method for plastic parts. There are however many moulding quality defects caused by inappropriate setting of moulding process conditions, as well as the poorly designed plastic part geometry. Often, stiffeners are used in a plastic part to increase its strength. However, if the stiffeners are not designed properly, they will introduce one or more moulding quality problems, which in turn will worsen the part strength rather than increasing it. Although there have been quite a lot of researches on optimising moulding quality, it is often difficult to minimize multiple quality defects simultaneously. In this paper, we propose to employ flow uniformity as the optimisation objective to address this problem. A number of stiffener layout designs are evaluated in terms of this objective to determine the best design, where standard deviations of filling times and pressures at the extremities of the plastic part are used to measure the uniformity of flow. A simple case study is also presented to demonstrate the applicability of the proposed methodology.

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Modelling IR-Heating in Stretch-Blow Moulding and Thermoforming

Volume 2: Applied Fluid Mechanics; Electromechanical Systems and Mechatronics; Advanced Energy Systems; Thermal Engineering; Human Factors and Cognitive Engineering ◽

10.1115/esda2012-82590 ◽

2012 ◽

Cited By ~ 1

Author(s):

S. Rasche ◽

M. Begemann ◽

Ch. Hopmann

Keyword(s):

Temperature Profile ◽

Thickness Distribution ◽

Production Costs ◽

Energy Costs ◽

Total Production ◽

High Quality ◽

Moulding Process ◽

Blow Moulding ◽

Wall Thickness Distribution ◽

Ir Heating

The two-stage stretch-blow moulding process has been established for the large scale production of high quality PET containers with excellent mechanical and optical properties. Thermoforming is the process of choice for manufacturing thin-gauge or large-area parts for packaging or technical applications. Both processes allow lightweight thermoplastic parts to be produced rapidly and economically. In both processes thermoplastic semi-finished products are formed by pressurised air under the influence of heat. To enable forming of the thermoplastic materials, the semi-finished products need to be transferred into a thermoelastic state. IR-heating is widely used due to short heating times. From a cost perspective, about 7 % of the total production costs of a stretch-blow moulded bottle are spent for energy in order to heat and form the preform to the later bottle. Depending on machine, semi-finished product type and cycle time, energy costs in thermoforming account for around 1–5 % of the total production costs. Modern roll-fed automatic thermoforming machines use about 22 % of the energy consumption for the heating step and around 70 % for the production of pressurised air. Due to this significant share and due to increasing energy costs during recent years, the packaging industry is interested in increasing the energy efficiency of these processes. The most important quality criterion for both processes is a uniform wall thickness distribution. The production of high-quality parts requires optimised temperature profiles of the semi-finished product depending on the particular product geometry. Simulation is an approved tool for the prediction of the influence of the heater setting on the temperature profile. Over the last decade IKV has developed an integrative three-dimensional process simulation which models the complete path of a preform through a stretch-blow moulding machine. An essential first step is the heating simulation where the temperature profile of the preform is computed. Based on this data the temperature-dependent material behaviour of PET can be considered during the inflation simulation. This work shows the influence of a thoughtful temperature profile on the wall thickness distribution in stretch-blow moulding. The focus is on modelling the reheat phase of the stretch-blow moulding process in FEA. Beyond that, a purposeful heating offers the possibility to cut down energy waste.

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High Quality Flax Fibre Composites Manufactured by the Resin Transfer Moulding Process

Journal of Reinforced Plastics and Composites ◽

10.1177/073168401772678634 ◽

2001 ◽

Vol 20 (7) ◽

pp. 621-627 ◽

Cited By ~ 145

Author(s):

Kristiina Oksman

Keyword(s):

Flax Fibre ◽

Resin Transfer Moulding ◽

High Quality ◽

Moulding Process ◽

Fibre Composites ◽

Transfer Moulding

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Research on Fabrication Technology and Hydraulic Performance of Multi-Point Gear Flow Dividers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.188.376 ◽

2011 ◽

Vol 188 ◽

pp. 376-380

Author(s):

Xi Bing Li ◽

X.L. Liu ◽

Z.M. Shi ◽

Q.M. Hu ◽

S.G. Wang

Keyword(s):

Rapid Development ◽

Structural Features ◽

Supply System ◽

Experimental Results ◽

Group Method ◽

Manufacturing Cost ◽

Fabrication Technology ◽

High Quality ◽

Manufacturing Method ◽

Work Table

With the rapid development of static-press technique, multi-point constant oil supply system has been widely applied into bearing the work table of large CNC vertical turning machine. A group method has been proposed through the analysis of the operating principle, structural features and manufacturing method of multi-point gear flow dividers. Then the diversion characteristics of the twelve point gear flow dividers manufactured through this method are compared with those of the dividers alike both at home and abroad. The experimental results show that the multi-point gear flow dividers manufactured through this group method not only have good diversion accuracy , but reduce the manufacturing cost and assure workbench’s running stability as well as high quality and precision products.

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Transfer Moulding

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1947_156_013_02 ◽

1947 ◽

Vol 156 (1) ◽

pp. 43-55

Author(s):

M. Freund

Keyword(s):

Mass Production ◽

Injection Moulding ◽

Large Scale ◽

Compression Moulding ◽

Moulding Process ◽

Manufacturing Method ◽

Recent Developments ◽

Transfer Method ◽

Transfer Moulding

Since the early days of the commercial plastics moulding industry, injection moulding principles have been successfully applied. Compression moulding technique has achieved a high economic standard by the design of multiple-impression moulds, and when transfer moulding technique has been applied it has mainly been for technical reasons. Recent developments, however, make it possible to use transfer moulding on a large scale, and it can now compete with the orthodox compression moulding in economy and efficiency. Existing machines can be used for the transfer method, but special presses adapted or built for this purpose will give a better service. Consideration of the engineering fundamentals of the transfer moulding process will contribute to the economy of tooling; the tooling is influenced by the presses used, and the plastics moulding engineer will have to co-ordinate all production items for successful competition with compression moulding. The strength of the finished mouldings, too, is influenced by the manufacturing method. Further developments in machines, tooling, and methods are necessary if conventional moulding methods are to be replaced entirely in mass-production applications.

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Additive Manufacturing of Shape Memory Devices and Pseudoelastic Components

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Integrated System Design and Implementation ◽

10.1115/smasis2013-3070 ◽

2013 ◽

Cited By ~ 12

Author(s):

Christoph Haberland ◽

Mohammad Elahinia ◽

Jason Walker ◽

Horst Meier ◽

Jan Frenzel

Keyword(s):

Additive Manufacturing ◽

Shape Memory ◽

Raw Material ◽

Processing Route ◽

High Quality ◽

Manufacturing Method ◽

Structural And Functional Properties ◽

Shape Memory Effects ◽

Near Net Shaping ◽

Net Shaping

Processing of Nickel-Titanium shape memory alloys (NiTi) is by no means easy because all processing steps can strongly affect the properties of the material. Hence, near-net-shaping technologies are very attractive for processing NiTi due to reduction of the processing route. Additive Manufacturing (AM) provides especially promising alternatives to conventional processing because it offers unparalleled freedom of design. In the last 5 years AM of NiTi received little attention from academics and researchers and, therefore, is far from being established for processing NiTi today. This work is to highlight the current state of the art of using the AM technique Selective Laser Melting (SLM) for processing high quality NiTi parts. For this reason, fundamentals for SLM processing of NiTi are described. It is shown in detail that a careful control of process parameters is of great importance. Furthermore, this work characterizes structural and functional properties like shape recovery, referring to the shape memory effect in Ti-rich SLM NiTi, or pseudoelasticy in Ni-rich SLM NiTi. It is shown that both types of shape memory effects can be adjusted in SLM NiTi by the choice of the raw material and processing strategy. By comparing the properties of SLM NiTi to those of conventionally processed NiTi, this work clearly shows that SLM is an attractive manufacturing method for production of high quality NiTi parts.

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Evaluation of MoS2 Films Fabricated by Metal-Organic Chemical Vapor Deposition Using a Novel Mo Precursor i-Pr2DADMo(CO)3 Under Various Deposition Conditions

MRS Advances ◽

10.1557/adv.2020.187 ◽

2020 ◽

Vol 5 (31-32) ◽

pp. 1643-1652

Author(s):

K. Yamazaki ◽

Y. Hibino ◽

Y. Oyanagi ◽

Y. Hashimoto ◽

N. Sawamoto ◽

...

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Photoelectron Spectroscopy ◽

Chemical Vapor ◽

Organic Chemical ◽

High Quality ◽

Practical Applications ◽

Manufacturing Method ◽

Metal Organic ◽

Organic Chemical Vapor Deposition

ABSTRACTMolybdenum disulfide (MoS2) is expected to be applied for devices in various fields owing to its unique characteristics. Establishing a high-productivity manufacturing method which yields high quality films is an important and unresolved issue for the practical applications of MoS2. Among different techniques conducted by researchers all over the world, our approach is cold-wall metal-organic chemical vapor deposition, and we previously reported the deposition of MoS2 with i-Pr2DADMo(CO)3, a novel Mo precursor [S. Ishihara, et al., MRS Advances 3, 379-384 (2018).]. In this study, with the aim of further improving the quality of the MoS2 film using this new Mo precursor, various film formation conditions were controlled and the influence on the film quality was investigated. X-ray photoelectron spectroscopy, atomic force microscopy and Raman spectroscopy were used as evaluation techniques of the samples. As a result, mm-scale uniform film was formed with the deposition time less than 30 min. at temperature as low as 400 °C to 500 °C. It was revealed that maintaining low Mo/S supply ratio (SRMo/S) is crucial in fabricating high quality films.

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The Development of Lead-Free Sliding Contacts Based on Bronze-Graphite Composites through Powder Injection Moulding

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.742.205 ◽

2017 ◽

Vol 742 ◽

pp. 205-212

Author(s):

Husam Ahmad ◽

Robert Stelzer ◽

Daisy Nestler ◽

Wolfgang Nendel ◽

Lothar Kroll ◽

...

Keyword(s):

Injection Moulding ◽

Powder Processing ◽

Electrical Contacts ◽

Powder Injection ◽

Sliding Contacts ◽

Moulding Process ◽

Manufacturing Method ◽

Powder Injection Moulding ◽

Process Route ◽

Injection Moulding Process

Sliding electrical contacts are traditionally produced by conventional compacting technologies. Employing the powder injection moulding process (PIM) as a new manufacturing method can offer several advantages such as the fabrication of complex net-shaped parts, cost-effectiveness and high volume productions. The PIM process route consists of the following steps: powder processing, compounding, injection molding, debinding and sintering. A two-stage process consisting of solvent debinding and thermal debinding is often used to remove the moulding binder. In the present paper, the suitability of the powder metallurgical processes: mechanical alloying and powder mixing for the preparation of bronze-graphite powder mixtures for the compounding and injection moulding of sliding contacts is discussed. The use of a suitable binder is of central importance for the preparation of injection-moldable feedstocks. For this purpose, two commercial ready-to-use binder systems were utilized and evaluated. The essential challenge of the process route is to optimize all parameters of the subprocesses to achieve a damage-free debinding and sintering of the injection-moulded parts. First results on the influence of the graphite content, the binder fraction, the debinding and sintering parameters are presented and discussed.

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Fabrication of a novel liquid metal microelectrode in microfluidic chip

Modern Physics Letters B ◽

10.1142/s0217984921400054 ◽

2021 ◽

pp. 2140005

Author(s):

Yanli Gong ◽

Bei Peng ◽

Xuan Weng ◽

Hai Jiang

Keyword(s):

Liquid Metal ◽

Electric Field ◽

Microfluidic Chip ◽

Three Dimensional ◽

Uniform Electric Field ◽

High Quality ◽

Manufacturing Method ◽

Injection Process ◽

Metal Microelectrode ◽

Good Material

Electrokinetics is a good fluid control tool in microfluidics and usually microelectrodes play important roles in such approach such as generating a desired electric field. Though the fabrication of two-dimensional (2D) microelectrodes has been relatively mature, they cannot generate uniform electric field in space. Three-dimensional (3D) microelectrodes developed more recently may solve the problem, however the fabrication process is usually complicated and requires micro-alignment platform. Non-toxic liquid metal is a good material for making electrodes that has been introduced into microfluidics. It can be injected directly into a microchannel to form an electrode, but its special physical properties make the injection process complex and difficult to control. In this study, we investigated an optimized manufacturing method of liquid metal microelectrode in a microchip by numerical analysis and experimental study. High quality microelectrodes on morphology and stability were successfully fabricated. A fluorescent enrichment experiment was performed using the developed microelectrode in a microfluidic chip. The result shows that the optimized fabrication method of microelectrode in this study provides a promising way for high quality and good performance liquid metal microelectrode formation, and paves the way for its versatile applications.

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Some problems of objective-prism spectra classification

Symposium - International Astronomical Union ◽

10.1017/s0074180900053183 ◽

1966 ◽

Vol 24 ◽

pp. 51-52

Author(s):

E. K. Kharadze ◽

R. A. Bartaya

Keyword(s):

Short Wave ◽

High Quality ◽

Stellar Spectra ◽

Objective Prism

The unique 70-cm meniscus-type telescope of the Abastumani Astrophysical Observatory supplied with two objective prisms and the seeing conditions characteristic at Mount Kanobili (Abastumani) permit us to obtain stellar spectra of a high quality. No additional design to improve the “climate” immediately around the telescope itself is being applied. The dispersions and photographic magnitude limits are 160 and 660Å/mm, and 12–13, respectively. The short-wave end of spectra reaches 3500–3400Å.

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