The demand for products made of fiber‐reinforced polymer composites (FRPC) is constantly growing. These lightweight products are characterized by high stiffness, high tensile strength, and high service life. FRPC processes that employ thermoset‐impregnated continuous rovings are easily automated and provide the products with the highest unidirectional tensile strength. A critical disadvantage of continuous fiber‐reinforced polymers is caused by relatively high production costs. Among others, three main factors contribute to these production costs: (1) material costs, especially when carbon fibers are used, (2) costs for manufacturing semi‐finished products, such as textiles or preimpregnated fabrics, and (3) costs for waste occurring along the entire chain of process steps. In this context, one group of processes shows outstanding characteristics: processes in which rovings are in situ impregnated with a thermoset resin and then directly processed. Wet filament winding and pultrusion are the most popular but not the only representatives of this group. For all these processes, in situ impregnation is the key element, and various technologies have been developed for this purpose, each with its own unique fluid‐mechanical effects on rovings. A fundamental understanding of these effects is crucial to achieve products of the utmost quality. The paper at hand provides an overview of manufacturing processes that employ in situ impregnation of continuous rovings, specifically focusing on impregnation technologies. On this basis, phenomenological models describing the effects on the rovings during processing (impregnation, tension, and spreading) are reviewed.

Current demands for flexible, individual microstructures in high quality result in high requirements for micro tools. As the tool size defines the minimum structure size, ultra-small tools are needed. To achieve tool diameters of 50 µm and lower, we investigate the complete manufacturing chain of micro machining. From the development of the machine tools and components needed to produce and apply the micro tools, the micro tools themselves, as well as the micro machining processes. Machine tools are developed with the possibility of producing the micro geometry (cutting edge design) of micro tools as well as plating processes to produce super abrasive micro grinding tools. Applying these setups, we are able to produce ultra-small micro grinding and micro milling tools with typical diameters of 50 µm and down to 4 µm. However, the application of such tools is very challenging. The article presents possibilities and limitations in manufacturing the micro tools themselves as well as microstructures made with these tools. A special emphasis will be on the influence of the tool substrate in micro milling and grain sizes in micro grinding.

This paper presents the development process of a new coating method for micro pencil grinding tools (MPGTs). MPGTs, applied for microgrinding, consist of a base body, abrasives, and a metallic bond. The manufacturing process of these microtools presents two challenges. The first being in finding a method to embed the abrasives with a uniform grit distribution and the second finding the correct parameters, required for a bond with adequate grit retention forces. In this research, an electroless plating process is presented. Both the abrasive grit distribution method and the plating parameters will be presented in this paper.

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Milling of ferrous metals is usually performed by applying cemented carbide tools due to their high hardness, temperature and wear resistance. Recently, ceramic tool materials have been on the rise and enhanced the efficiency in machining. As ceramics are brittle-hard materials, tool manufacturing requires a sound knowledge in order to meet the tool requirements such as sharp cutting edges and wear resistance. In this study, milling tools made of the high performance ceramic SiAlON were compared to tools made from cemented carbide. For both tool materials, the influence of a prepared cutting edge was investigated. Both the tool manufacturing process and the cutting edge preparation processes are presented, followed by the application of those tools within milling experiments. In order to evaluate the efficiency of both tool types, the cutting forces and the cumulative process energy demand were analyzed. Additionally, surface roughness of the machined workpieces and tool wear were examined. It was found that the ceramic tools, although process forces were higher than for cemented carbide tools, exhibited by far lower energy consumption, less tool wear and finally generated lower surface roughness.

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Abstract:Microgrinding with micropencil grinding tools (MPGTs) is a flexible and economic process to machine microstructures in hard and brittle materials. In macrogrinding, cooling and lubrication are done with metal cutting fluids; their application and influence is well researched. Although it can be expected that metal cutting fluids also play a decisive role in microgrinding, systematic investigations can hardly be found. A metal cutting fluid capable of wetting the machining process, containing quantities as small as 0.02% of the water-soluble fluid sodium dodecyl sulfate was tested in microgrinding experiments with MPGTs (diameter~50 µm; abrasive grit size 2-4 µm). The workpiece material was hardened 16MnCr5.

Due to the constant need for better functionalized surfaces or smaller, function integrated components, precise and efficient manufacturing processes have to be established. Micro milling with micro end mills is one of the most promising processes for this task as it combines a high geometric flexibility in a wide range of machinable materials with low set-up costs. A downside of this process is the wear of the micro end mills. Due to size effects and the relatively low cutting speed, the cutting edge is especially subjected to massive abrasive wear. One possibility to minimize this wear is coating of micro end mills. This research paper describes the performance of eight different hard coatings for micro end mills with a diameter <40 µm and discusses some properties for the best performing coating type. With this research, it is therefore possible to boost the possibilities of micro milling for the manufacture of next generation products.