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The purpose of this paper is to present the advantages of computer-aided design/rapid prototyping (CAD/RP) usage in designing and manufacturing of the core models used for precise casting with direct and single solidification of aircraft engine turbine blade cores.

The process of modelling three-dimensional CAD geometry of research blade in relation to the model of the core was presented with different wax types used in the RP technique.

The geometry of the blade model has been designed in a way which allows making a silicon mould on the basis of a base prototype in the process of rapid tooling (RP/RT). Filing by different wax types was investigated in mean of the impact on filling accuracy of the mould cavity.

The resulting models were used to make ceramic moulds and carry further work on the development of casting technology in the process of directional solidification and single crystal solidification of core blades of aircraft engines.

Fixed structures in prosthetic dentistry are highly customized products, manufactured individually for patients who have missing teeth. When choosing the technology for fixed dental structure manufacturing, three viable options are available (precise casting, milling and selective laser melting [SLM]). All these technologies can be used to produce a dental structure from CoCr alloy. Besides materials and availability of technologies, economic efficiency is an important factor when choosing a production method. The purpose of this study is to develop an estimation model for achievable productivity of selective laser melting and compare the results with the productivity of conventional manufacturing.

Results presented in this paper are based on manufacturing time analysis of an individual case with each of the technologies mentioned above. Because of the efficiency of SLM is highly dependent on how efficiently the work space of the machine is used, this issue was also included in the research. Data used for research were acquired from practical use of each technology in dental applications.

Analysis of achievable SLM manufacturing speeds is based on the previous research into manufacturing speeds of additive manufacturing technologies. The presented results present a model that can be used to estimate the productivity of the SLM technology.

Research was limited to a specific SLM machine type with a fixed workspace volume. Nevertheless, the results show that any SLM machine has to be used as efficiently as possible to be able to be competitive regarding the conventional manufacturing technologies.

The presented results show clearly at least a rough estimation of what kind of parts and in what volume will be manufactured with an SLM machine prior to buying one.

Results can help to widen the economically efficient way of running SLM machines, replacing conventional manufacturing for medical applications especially with complicated cases.

A method is presented to adapt the estimation model to a particular real-life production scenario. This method can be used to establish how efficiently selective laser sintering can be used and if using SLM machine instead of conventional manufacturing would be economically viable.

(1) Casting technique comprises the methods of working in which liquid metal is poured into moulds.

The purpose of this paper is to review the various pre-processing and post-processing approaches used to ameliorate the surface characteristics of fused deposition modelling (FDM)-based acrylonitrile butadiene styrene (ABS) prototypes. FDM being simple and versatile additive manufacturing technique has a calibre to comply with present need of tailor-made and cost-effective products with low cycle time. But the poor surface finish and dimensional accuracy are the primary hurdles ahead the implementation of FDM for rapid casting and tooling applications.

The consequences and scope of FDM pre-processing and post-processing parameters have been studied independently. The comprehensive study includes dominance, limitations, validity and reach of various techniques embraced to improve surface characteristics of ABS parts. The replicas of hip implant are fabricated by maintaining the optimum pre-processing parameters as reviewed, and a case study has been executed to evaluate the capability of vapour smoothing process to enhance surface finish.

The pre-processing techniques are quite deficient when different geometries are required to be manufactured within limited time and required range of surface finish and accuracy. The post-processing techniques of surface finishing, being effective disturbs the dimensional stability and mechanical strength of parts thus incapacitates them for specific applications. The major challenge for FDM is the development of precise, automatic and controlled mass finishing techniques with low cost and time.

The research assessed the feasibility of vapour smoothing technique for surface finishing which can make consistent castings of customized implants at low cost and shorter lead times.

The extensive research regarding surface finish and dimensional accuracy of FDM parts has been collected, and inferences made by study have been used to fabricate replicas to further examine advanced finishing technique of vapour smoothing.

The purpose of this paper is to present a method of rapid prototyping (RP) used in the development of a regenerative pump impeller. RP technology was used to create complex impeller blade profiles for testing as part of a regenerative pump optimisation process. Regenerative pumps are the subject of increased interest in industry.

Ten modified impeller blade profiles, relative to the standard radial configuration, were evaluated with the use of computational fluid dynamics (CFD) and experimental testing. Prototype impellers were needed for experimental validation of the CFD results. The manufacture of the complex blade profiles using conventional milling techniques is a considerable challenge for skilled machinists.

The complexity of the modified blade profiles would normally necessitate the use of expensive computer numerically controlled machining with five‐axis capability. With an impeller less than 75 mm in diameter with a maximum blade thickness of 1.3 mm, a rapid manufacturing technique enabled production of complex blade profiles that are dimensionally accurate and structurally robust enough for testing.

As more advanced RP machines become available in the study in the coming months, e.g. selective laser sintering, the strength of the parts particularly for higher speed testing will improve and the amount of post processing operations will reduce.

This technique offers the possibility to produce components of increased complexity whilst ensuring quality, strength, performance and speed of manufacture.

The ability to manufacture complex blade profiles that are robust enough for testing, in a rapid and cost effective manner is proving essential in the overall design optimisation process for the regenerative pump.

A Selection of Equipment of Use in the Production and Maintenance of Aircraft, Missiles, Space Vehicles and Components. A new industrial stethoscope has been produced by Airflow Developments Ltd., High Wycombe, Bucks., called the Sensitone. This new industrial stethoscope has its uses in a wide range of industries. Very simply, the engineer can detect, locate and often diagnose faults which, without an industrial stethoscope, could take hours to trace, thereby losing valuable production time. In the field of preventive maintenance, the Sensitone can often detect faults before they become apparent.

In the never‐ending quest for speed, designers are now turning to digital GaAs integrated circuits both to extend the bandwidth of current designs and in some cases to generate a whole new class of products never before possible. The engineer well versed in high speed ECL design techniques generally understands the problems associated with this transfer to GaAs logic. However, even with the design task well defined, the exact solution for interconnecting devices is often difficult and stresses the capabilities of existing multilayer printed circuit techniques using conventional dielectric materials and processing. This paper examines the design task in detail, and will present recent developments in shielded discrete wiring techniques as a possible solution for GaAs packaging.

In future generations, electronic systems will rely extensively on advanced IC technology to achieve higher performance levels. However, with limits placed on the level of integration that can be obtained on a single IC, a need still exists for an interconnection hierarchy to provide the necessary density transform between system components. A recent addition to many high performance interconnection structures has been the Multichip Module. By eliminating the conventional IC package, MCMs have dramatically reduced the electrical length between devices, thereby minimising propagation delay, crosstalk, and attenuation. Although MCM techniques will offer many performance advantages, they also present many design challenges at subsequent levels of interconnection. This paper will focus on the requirements of MCM backplanes interconnecting several modules and, as a solution, will present recent work on advanced metal core substrates. MCM substrates provide a tremendous density advantage, however, the interconnection between modules is still a formidable task. Modules often have I/O densities of 300 to 500 leads per square inch and typically dissipate 10 to 50 watts per square inch. In addition, with sub‐nanosecond rise times, the distance between modules is often sufficient for signal paths to be treated as transmission lines. In an effort to meet these requirements, metal core circuits based on copper, copper Invar, and copper molybdenum have been fabricated using 0·0025 in. diameter embedded discrete wiring technology. Combined with a Kevlar surface layer suitable for wire bonding and blind laser drilled vias to access the internal wires, this technique offers many benefits. As many as 4 conductors can pass between holes on 0·050 in. centres in a single wiring layer only 0·018 in. thick. With the absence of interstitial vias, additional substrate area can be dedicated to create a sizeable thermal path, essential to conduct the heat from the MCM to an internal metal core. Together, these features have made this an attractive approach for interconnecting multichip modules.

Westland Aerospace Division has delivered its first orders for the laser cable marking system, developed by Westland. The orders, worth about £350,000, include one for Boeing Corporation.