A parametric study of friction stir spot welding (FSSW) using pinless tool with a scrolled shoulder ofaluminium alloy 5754 in a lap joint is presented. Experimental plan was done according to theresponse surface methodology (RSM), where tool rotation speed varied between 988 and 3511 revmin-1, plunge rate between 24.4 and 150 mm min-1 and dwell time between 1 and 3.5 s. The plungedepth was constantly 0.4 mm. During the welding an axial force and torque were monitored usingdynamometer. The welds were tensile-shear tested and the broken samples were visually examined.The weld bond line and microstructure was analysed using light optic microscope under polarisedlight. Mathematical models describing the relationship between welding parameters and spot strength,axial force and rotational moment were developed. Optimal FSSW parameters were found at whichmaximal joint strength was obtained. At these welding parameters the axial force and torque were inthe lower range among tested parameters.
F.13 Development of new production methods and tools or processes
COBISS.SI-ID: 13240859The aim of this work was to investigate the influence of six injection moulding process parameters on the post-moulding shrinkage and warping of parts made from polypropylene filled with calcium carbonate, as used in large quantities throughout the automotive industry. For experimental purposes, standard test specimens were used for the determination of post-moulding shrinkage and warping. Each experiment was observed precisely through the measurement of acoustic emission (AE) signals and in-cavity pressure. We scanned each test specimen using an optical 3D scanner for accurate measurement of post-moulding shrinkage and warping. The optimal set of parameters that provides minimal post-moulding shrinkage and warping, was determined by the Taguchi method, together with nominally-the-best (type II) quality characteristic. The most influential parameter was statistically obtained through analysis of variance, which showed that packing pressure had the largest impact. The results from the measured AE signals showed clear correlation with the post-moulding shrinkage and warping, indicating the possibility of on-line monitoring the adequacy of the process by capturing AE signals.
F.13 Development of new production methods and tools or processes
COBISS.SI-ID: 16720150Project management of product/service orders has become a mode of operation in many companies. Although these are mostly cyclically recurring projects, risk management is very important for them. An extended risk-analysis model for new product/service projects is presented in this paper. Emphasis is on a solution developed in the Faculty of Mechanical Engineering in Ljubljana, Slovenia. The usual project activities risk analysis is based on evaluation of the probability that risk events occur and on evaluation of their consequences. A third parameter has been added in our model: an estimate of the incidence of risk events. On the basis of the calculated activity risk level, a project team prepares preventive and corrective measures that should be taken according to the status indicators. An important advantage of the proposed solution is that the project manager and his team members are timely warned of risk events and they can thus activate the envisaged preventive and corrective measures as necessary.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 12916251Concept has been developed for a novel apparatus, which allows the simulation of the peristaltic movements of the human small intestine. The device is intended for use in the development of pharmaceutical dosage forms. Application for an international patent has been filed.
F.06 Development of a new product
COBISS.SI-ID: 13155611The paper covers the main design, management and operational aspects of scalability in manufacturing systems (MS). It promotes scalability as an area of research of MS theory and practice in order to enhance techniques and methodologies in existing MS paradigms using advanced and emerging design and management approaches and ICT, and meet challenges of emerging MS paradigms and support their promotion and effective and efficient deployment in practice. The paper presents an introduction to scalability, state-of-the art in manufacturing and computer science, and related applications including manufacturing and education and a roadmap for future research and developments.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 13038107