Proper handling of miniaturised machine parts

This article analyses the capacity of the industry in handling and fixturing at the micro scale. The material handling, which consists of manipulation and fixturing of miniaturised parts, on the micro/meso-scale machine tool is challenging and sets the limitations of accurately affecting dimensional change and phenomena measurement. To go beyond the limits, innovative work-holding approaches are necessary. Miniaturisation The rising trend towards miniaturisation has been widely used in most technologies in almost every field, from medicine to manufacturing. The on-going manufacturing paradigm is rapidly contributing to the development of complementary capabilities for producing miniaturised products. At the same time, most efforts are targeted on multi-scale levels, thinning the gap between micro and macro worlds while presenting the limitations of the micro-electro-mechanical systems (MEMS) and lithographic technologies. Recent micro/meso-scale machine tool (mMT) developments are seen to have higher potential in achieving tighter tolerances and finishes with lowered scrap (Fig.1). The new machine tools are generally more affordable and lighter than common precision machine tools. Despite the processes are being upgraded and carefully studied, micro- scale machining still encounters some problems in process monitoring caused by poor signal-to-noise ratios, adverse mechanical effects like distortion due to forces, tooling and machining variations, and whenever positioning and registering parts. Precision in minute tools At present, it is impractical to create mMT with inherent accuracy in the sub- micron range (e.g. 0.01μm accuracy for 1mm feature). When testing accuracies within sub-micron repeatability, researchers are looking into the effects of scale in different techniques for volumetric error estimation, part transfer errors and kinematic self- calibration, finding the workpiece and tool, and developing micro- and nano-positioners. Although physics promotes favourable scaling laws, lower machine costs, and machine portability, the effect of miniaturisation on the dynamic behaviour of the machine structure is seen to decrease the rigidity of the mMT structure. A significant reduction in rigidity also happens at the mMT structural joints because smaller bolts are employed to integrate the machine''s components. It is also noted among manufacturers that the workpiece-fixture interaction affects the machine performance, particularly in the workpiece''s accuracy of part registration, dynamic behaviour and resulting surface finish. Restrained by relative variability in tolerances, temperature variations affecting more than the tool-workpiece interface and unknown possibilities in the process and constraint loads, including limitations in geometry, materials, part weakness and part transfer across different machining operations, fixturing is a critical consideration impeding the integration and autonomous operation of micro/meso - scale anufacturing systems. Thus, the material handling of iniaturised parts on the mMT tool is challenging and sets the limitations of accurately affecting dimensional change and phenomena measurement. To go beyond the limits, innovative work - holding approaches are necessary. Effective solutions Today''s approaches that the industry looks into to mitigate the on-going issues largely fall within enhanced tooling (e.g. minimising tool run-out by introducing shrunk fit adapters), and lowering part re-registration errors through palletising parts and/or transferring the processes to the part by creating multi-functional machines. To reduce the necessity to re- register parts, many of the mMT builders have also combined their innovative design workpieces and spindle mounting systems to the automated tool changers and quick-mount fixturing strategies. These approaches, however, have only begun to respond to thNew Balance