If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -To provide a systematic framework for mold designers, that can be used for rapid tooling (RT) process selection and prioritization of process parameters. Design/methodology/approach -This paper presents a QFD-AHP methodology which has three phases. The first phase involves prioritizing the tooling requirements (driven by customer preferences) against a set of die/mold development attributes (such as product material, geometry, and die material and production order) through pair-wise comparison using analytical hierarchal process (AHP). These priority ratings are used for selecting the most appropriate tooling process using quality function deployment (QFD) in the second phase. Finally, QFD is used again for identifying critical process parameters (such as layer thickness, scan pitch and laser power) for the selected RT process. Findings -The QFD-AHP methodology has been illustrated with industrial examples on RT for molded parts. The molds were fabricated using direct metal laser sintering and spray metal tooling processes, for example, 1 and 2, respectively, to prove that the methodology can be easily implemented in tool rooms. The issues noted in these experimental studies are also discussed for the benefit of researchers.Research limitations/implications -The capabilities of the RT processes presented in the paper reflect the experience of the research team in RT development. The QFD-AHP methodology will give progressively better results with a growing body of RT process knowledge. Practical implications -This investigation is a key step towards the goal of developing a comprehensive system for RT process selection and manufacturability evaluation. The mold designer can use this QFD-AHP process selection methodology, prior to detailed manufacturability analysis, to better realize the benefits of RT technologies. Originality/value -The proposed QFD-AHP methodology is a new approach for the tooling process selection domain, and has not been reported earlier; this can be easily used for similar applications for any manufacturing domain.
Purpose -The purpose of this paper is to present the results of an investigation on the straightness, flatness and circularity achievable on two direct RT methods: direct metal laser sintering (DMLS) and stereolithography (SLA). Design/methodology/approach -The steps included manufacturing of samples in eight custom designs with widely used geometric features, intelligent sampling of measurement data, and estimation of corresponding form tolerance by the least square method (LSM). The region elimination adaptive search-based sampling method involved selecting additional sampling points around the maximum deviation in both positive and negative directions from the corresponding reference feature. The LSM solutions, which are commonly used in metrology, are used to estimate the form tolerances considering the best points along with initial measurement data points. Findings -Application of the region elimination search-based sampling method enables form tolerance estimation from a limited number of sample measurements. The study of the DMLS and SLA processes suggested that form accuracy of SLA samples are relatively poor, though their dimensional accuracy is much better than DMLS. Research limitations/implications -This paper was focused on estimating the form tolerances based on limited number of measurement data using region elimination search-based sampling technique. It was assumed that build process parameters suggested by the material and RP systems vendors gives optimum results, presently it does not cover the effect of geometry and other causes of errors on form accuracy. Practical implications -There are two major applications of this investigation and the corresponding knowledge base: evaluating the process capabilities of different rapid tooling processes for comparison and for selecting an appropriate process; and allocating tolerance based on manufacturability considerations, so that the designs are compatible with the process, leading to fewer iterations. A similar approach can be used for updating the capabilities of an improved process as well as include newer processes to develop a comprehensive database of RT process capabilities. Originality/value -In most of the previous benchmarking studies, a given RT process is compared with conventional practice or a limited number of other RT processes, the capabilities in terms of dimensional accuracy, form tolerance, and surface properties (surface finish, wear, and scratch resistance) have not been studied very well. To the best of authors' knowledge, no efforts have been made to estimate form tolerances of the parts or tooling produced by rapid prototyping and tooling processes. Application of the region elimination search-based sampling technique enables estimation of form tolerances that saves costly experimentations. It appears to be completely new in the rapid prototyping and tooling domain.
Application of Micro-Nano scale Electrical Discharge Machining is rapidly growing in manufacturing of metal products irrespective of its hardness having geometric features in range of micrometer to nanometer scale. To achieve such small geometrical features, smaller dimensional tool electrode is required. However fabrication of this tiny electrode with desired dimension and also handling of such tiny electrodes is a primary aspect that needs to be investigated systematically to use the Micro-Nano scale EDM in batch production of micro parts. In this work authors investigate the application of electrochemical etching process for fabricating EDM electrodes smaller than 10 µm. While the smallest electrode fabricated with the optimized parameter is 3.33 µm, their performance as electrode in micro-EDM has been studied systematically. To the best of authors’ knowledge such studies are not reported in the published literatures. However, the fabrication of such smaller size features by applying alternating current in ECE has been attempted previously but not for micro-EDM applications.
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