Search results

This paper proposes the combination of rapid prototyping and physical modelling as a set-based concept evaluation method in the early stage of new product development.

The concept evaluation method is applied in a case study of a new metal additive manufacturing process for aluminium, where a set of four extruder concepts has been modelled and evaluated. Rapid prototyping was used to produce plastic models of the different designs, and plasticine feedstock material was used to physically model the metal flow during operation. Finally, the selected concept has been verified in full-scale for processing of aluminium feedstock material.

The proposed method led to several valuable insights on critical factors that were unknown at the outset of the development project. Overall, these insights enabled concept exploration and concept selection that led to a substantially better solution than the original design.

This method can be applied for other projects where numerical approaches are not applicable or capable, and where the costs or time required for producing full-scale prototypes are high.

Employing this method can enable a more thorough exploration of the design space, allowing new solutions to be discovered.

The proposed method allows a design team to test and evaluate multiple concepts at lower cost and time than what is usually required to produce full-scale prototypes. It is, therefore, concluded to be a valuable design strategy for the early development stages of complex products or technologies.

In School Science 2, in our November 1967 issue, Russell Edwards discussed building a home‐made back‐projector. This month he deals with molecular models in plasticine.

A finite element model for multimaterial configurations is presented. The material behavior of each body within a composite material is given by an elastic‐viscoplastic constitutive law. Automatic remeshing techniques which preserve the topology of the different bodies of material are used to simulate large deformations of the multiphasic system. An experimental set‐up has been designed in order to simulate the compaction of multilayer composite materials. Plasticine was chosen as a model material. Experimental results are used to validate the finite element model for consolidation of multilayer composites.

The Equal Pay Act 1970 (which came into operation on 29 December 1975) provides for an “equality clause” to be written into all contracts of employment. S.1(2) (a) of the 1970 Act (which has been amended by the Sex Discrimination Act 1975) provides:

Last month Russell Edwards dealt with molecular models in plasticine. In School Science 4 he considers a first lesson in crystallography.

Describes an elastic visco‐plastic finite element formulation that is applied to the modelling of pastes. Comparisons are made with experimental results obtained for a particular paste, plasticine. Special attention is applied to the frictional boundary conditions, for which the usual Coulombic procedure is augmented by a “cohesive” wall friction component. Viscous effects also are considered.

The investigations have been primarily concerned with some of the practical problems associated with the metoplastic technique, they have in this respect attempted to solve some of these problems with the best means available at the time.

IT WAS THE then Duke of Gloucester who, observing the said Mr Gibbon (of Roman Empire fame) writing, said, to quote as accurately as my reference source will allow, ‘Another damned thick square book! Always scribble, scribble, scribble, scribble! Eh! Mr Gibbon!’

As the design of mechanisms, structures and so on increases in complexity, and manufacturing processes become more complicated, the need for set courses on drawing reading as a classroom subject for student and craft apprentices becomes more evident. Among the many maxims of good design are ‘Foolproof Assembly’ and ‘Minimum Number of Parts’. Although the application of these maxims is usually reasonably simple, it does make for more complex parts and, consequently, more complex detail drawings. Some of these drawings are really difficult to interpret correctly — particularly for apprentices in the early years of their training before they have received any full‐time instruction in drawing and design.

ALL COURSES on strength of materials and theory of structures deal in detail with the methods of finding slopes and deflections for beams carrying a wide variety of forms of loading. Yet frequently in experimental work the subject is unnecessarily restricted to verification of deflections caused by some relatively simple system of concentrated loading.