As a way of enhancing the mechanical properties of photopolymer-based parts produced by layered manufacturing (LM) techniques, the use of short glassfibre reinforcements has been recently explored in the literature. This paper proposes a novel methodology that utilizes a modified rule-of-mixtures model for the prediction of the mechanical properties of such layered composites. The prediction process employs empirical data on (i) the fibre-matrix interface, (ii) the fibres' geometrical arrangement within the specimens (i.e. fibreorientation distribution), and (iii) the fibre-length distribution. The effects of the fibre-orientation and fibrelength distributions are accounted for in the prediction model by the fibre-length-correction and orientationefficiency factors. Comparison of extensive experimental results and model-based predictions of mechanical properties of layered composites demonstrated the effectiveness of the proposed estimation methodology.

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This paper addresses the reinforcement of photopolymers, through the addition of short glass fibers, for Rapid Layered Composite parts Manufacturing (RLCM). Novel designs for an (external) fiber-resin-mixing subsystem and a (slot-coating-based) liquid-layer-formation subsystem are presented. These subsystems, when used as integral parts of a lithography-based RLCM system, successfully cope with typical difficulties encountered in the formation of thin layers from a highly viscous fiber-photopolymer composite liquid. Axiomatic Design theory was utilized for the analysis of both subsystem designs. Verification experiments run on an RLCM system confirmed (i) the ability of the fiber-resin-mixing subsystem to supply liquid composite with specified fiber content and to avoid fiber degradation through breakage, as well as (ii) the ability of the liquid-layer-formation subsystem to form solid layers with high fiber content and of uniform thickness.

This paper describes the uid mechanics of the slot-coating process in the context of rapid layered manufacturing. It has been conjectured that slot-coating would successfully address a number of common dif culties encountered in the formation of thin layers from a highly viscous brephotopolymer composite liquid. The objective of the present study was therefore the development of an engineering analysis tool to assist with the design of a slot-coating-based liquid layer formation mechanism for use as an integral part of a lithography-based rapid layered composite parts manufacturing (R LCM) system.In addition to an analytical model, the paper presents a numerical model based on a volume-ofuid (VOF ) algorithm. This algorithm allows (a) solution of non-steady-state problems, (b) tracking of the free surface of the uid undergoing large deformations and (c) easy modi cation of the model's domain to facilitate experimentation with coater geometry. R esults from a set of simulated experiments establish a relationship between the liquid-coat height and several design and process parameters.Physical examination of cross-sections of several test parts built on an R LCM prototype system in the authors' laboratory con rmed the ability of the new coater design to form solid layers of good quality, as predicted by the numerical simulations.