A Cost Model for 3D Woven Preforms

Lack of cost information is a barrier to acceptance of 3D woven preforms as reinforcements for composite materials, compared with 2D preforms. A parametric, resource-based technical cost model (TCM) was developed for 3D woven preforms based on a novel relationship equating manufacturing time and 3D preform complexity. Manufacturing time, and therefore cost, was found to scale with complexity for seventeen bespoke manufactured 3D preforms. Two sub-models were derived for a Weavebird loom and a Jacquard loom. For each loom, there was a strong correlation between preform complexity and manufacturing time. For a large, highly complex preform, the Jacquard loom is more efficient, so preform cost will be much lower than for the Weavebird. Provided production is continuous, learning, either by human agency or an autonomous loom control algorithm, can reduce preform cost for one or both looms to a commercially acceptable level. The TCM cost model framework could incorporate appropriate learning curves with digital twin/multi-variate analysis so that cost per preform of bespoke 3D woven fabrics for customised products with low production rates may be predicted with greater accuracy. A more accurate model could highlight resources such as tooling, labour and material for targeted cost reduction.

Development of aerostatic porous bearings manufactured using metal 3D printing technology

Aerostatic porous bearings have been applied widely in precision devices to achieve higher accuracy of motion. Conventional aerostatic porous bearings are made of porous graphite, porous ceramics or sintered metal porous material, having a thickness of several millimetres and a surface-restricted layer. However, during mass production of porous bearings, the time required for the production of the porous materials and the surface restriction treatment leads to an increase in the manufacturing time and cost of the porous bearings. Accordingly, to overcome this problem, an aerostatic porous bearing with a layer thickness of several hundred µm and a support member, manufactured using metal 3D printing technology, is proposed. In this study, the optimum conditions for manufacturing the proposed aerostatic porous bearings with a direct metal laser sintering method 3D printer were investigated, and characteristics of the prototype of the proposed bearings were investigated experimentally.

DESIGN AND MANUFACTURING OF AN OPTIMIZED MOULD INSERT BY DMLS TECHNOLOGY

Utilization of the DMLS technology in manufacturing of tools and moulds designed for injection and casting ranks among significant possibilities of use. The main advantage in case of DMLS in comparison to conventional methods rests in the fact that manufacturing time does not depend on geometrical complexity of shaping part of the mould. In case of low volume or prototype moulds it is advantageous to use a concept of combination of shaping intermediate pieces inserted in universal frames and as material the DM 20 alloy on bronze basis the service life of which in case of such application is several thousand pieces.

Effect of infill density and pattern on the specific load capacity of FDM 3D-printed PLA multi-layer sandwich

Three-dimensional (3D) printing settings allow the existence of differently filled sections together within a piece. That means the use of inhomogeneous internal material structure. Knowing the load capacity that 3D printed plastic parts can withstand leads to the reduction of the filling degree, thus the amount of the used material in certain places. This approach has two advantages during production: (i) less material use and (ii) reduced manufacturing time, both being cost-reducing factors. The present research aims to find the optimal proportions for fabricating a bending test piece with varying filling degrees. To achieve this goal, experimental tests were performed for obtaining tensile strength and modulus of elasticity using different pairs of infill density and pattern. This provided a basis for creating a working mechanical model based on accurate and realistic material properties. Hence, a series of virtual bending test experiments were conducted on a sandwich structure specimen employing Ansys Workbench software. By doing so, the optimal thickness (of the sandwich’s inner layer) with the highest specific load capacity for the given filling patterns and densities were determined. To the best of our knowledge, the current procedure of experiments and method of settings optimization were not discussed elsewhere.

Konka Board: a cement-pumice-tow sheathing board

Konka board was a New Zealand invention which combined cement, pumice and flax fibre ("tow") into a fibre-cement board, replacing the imported asbestos-cement sheet. Sold soon after manufacture, Konka, it could be nailed or screwed, and over time it hardened. A waterproof plain or stucco plaster finish provided a resilient, borer proof, fireproof, low maintenance house. Three patents created the Konka system – 34,845 for the fibre-reinforced board, 37,354 for the stud and support system into which a concrete grout was poured to lock the panels in place, and finally 52,50 for metal strips to ensure a smooth final plaster surface. A waterproofing additive in the plaster provided the final part of the system.The company quickly setup a national series of agents, with manufacturing ultimately occurring in Wanganui, Gisborne, Christchurch and Timaru. Patent 34,845 was challenged in 1927, with the Privy Council finding in 1930 that it was invalid, opening the way for similar products to be made. The development in the 1930s of NZSS 95 Model Building By-law allowed Konka to be used nationally, without further evidence as to its performance. However, competitor other products were also included e.g. Excell, Rotorua, Thermax, Duro, Wangan, Walasco and the asbestos based Fibrolite.Konka survived until the 1960s, when flax production was in decline, the high labour costs and manufacturing time meant it was no longer competitive. Even so, in a twist of fate it was a Konka style approach which led to cellulose fibre replacing asbestos in fibre-cement sheeting. In the twenty-first century, Konka could even be considered a desirable product – a natural fibre reinforced, composite sheet.

Entrepreneurship and innovation in informal productive enterprises: Development of process innovation in a floral arrangement company

Purpose: reporting a process innovation in an informal productive enterprise, inserted in the field of parties, ceremonies and events décor, involving floral arrangements. Methodology: qualitative-descriptive study, with information being obtained through documentary research and case study. Originality/Relevance: this study analyzes an informal productive business, whose practice improvement was conducted based on technological resources. It is relevant because there are only few studies dedicated to technological development, and that thematize the most frequent type of productive enterprise in Brazil. Findings: the process innovation that was conducted has enabled a greater productive efficiency, as well as health, safety and hygiene in the workplace, since it has reduced costs and manufacturing time; and it has eliminated unnecessary procedures that result from the manual method. Theoretical/Methodological Implications: the innovation, developed and described heading from the theories and methodological approach used, in addition to promoting improvement in the ability of adapting to different customer demands, has added an element to the process innovation effects foreseen by Oslo Manual. Social Implications: in parallel to the operational results pointed out, the academic activity has enabled the improvement of economic enterprise that belong to settings and groups in social disadvantage.

A Review on: 3D Printed Orthopaedic Cast for Improved Forearm Fracture Rehabilitation

Forearm fracture has many management related problems. In order to regain its function anatomical reduction and immobility is very necessary. Traditional cast is not a satisfactory cast as it is heavy, poorly ventilated and often causes fracture related complications. The paper deals with application of 3D printing technique for suitable cast for forearm rehabilitation. Novel 3D printed cast is light weighted, ventilated, custom fit, strong and waterproof and substantial improvement over conventional orthopaedic cast. With the development in technology, it is expected that the cost of fabrication and its manufacturing time will be greatly reduced in the coming future. Keywords: bone fracture, immobility, rehabilitation, 3D printing, orthopaedic cast

Mechanical Performance of 3D-Printed Biocompatible Polycarbonate for Biomechanical Applications

Additive manufacturing has experienced remarkable growth in recent years due to the customisation, precision, and cost savings compared to conventional manufacturing techniques. In parallel, materials with great potential have been developed, such as PC-ISO polycarbonate, which has biocompatibility certifications for use in the biomedical industry. However, many of these synthetic materials are not capable of meeting the mechanical stresses to which the biological structure of the human body is naturally subjected. In this study, an exhaustive characterisation of the PC-ISO was carried out, including an investigation on the influence of the printing parameters by fused filament fabrication on its mechanical behaviour. It was found that the effect of the combination of the printing parameters does not have a notable impact on the mass, cost, and manufacturing time of the specimens; however, it is relevant when determining the tensile, bending, shear, impact, and fatigue strengths. The best combinations for its application in biomechanics are proposed, and the need to combine PC-ISO with other materials to achieve the necessary strengths for functioning as a bone scaffold is demonstrated.

Metaheuristics for the Minimum Time Cut Path Problem with Different Cutting and Sliding Speeds

The problem of efficiently cutting smaller two-dimensional pieces from a larger surface is recurrent in several manufacturing settings. This problem belongs to the domain of cutting and packing (C&P) problems. This study approached a category of C&P problems called the minimum time cut path (MTCP) problem, which aims to identify a sequence of cutting and sliding movements for the head device to minimize manufacturing time. Both cutting and slide speeds (just moving the head) vary according to equipment, despite their relevance in real-world scenarios. This study applied the MTCP problem on the practical scope and presents two metaheuristics for tackling more significant instances that resemble real-world requirements. The experiments presented in this study utilized parameter values from typical laser cutting machines to assess the feasibility of the proposed methods compared to existing commercial software. The results show that metaheuristic-based solutions are competitive when addressing practical problems, achieving increased performance regarding the processing time for 94% of the instances.