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Optical tweezers are designed to trap nano- and micro-scale particles. Once trapped, it is possible to move the particles but this requires complex mechanical adjustments to the optical system. In this paper, an easier way to trap and move multiple particles simultaneously is proposed, that uses a digital mirror-array and freeform micro-lens-array to generate several steerable optical traps inside a light-field.

Increasing productivity and surface quality in manufacturing is inevitable for the efficient use of resources. Precision smooth surfaces are generally achieved through sequential milling, grinding, fine-grinding, and polishing. This research aims to increase productivity through a shorter process chain. Hybrid tooling technology is presented where an elastic fine grinding tool is integrated with a conventional milling cutter or a grinding tool, in order to produce smooth surfaces on metal and non-metals. A hybrid milling cutter with an elastic tool could produce a low-waviness surface as compared to that of a milled-only surface. Surface roughness could be reduced by almost 50% using the hybrid milling tool on a steel workpiece. A monocrystalline silicon surface was machined with a hybrid grinding tool. Surface roughness of Ra ~ 100 nm could be obtained for hybrid tool in comparison to Ra ~ 200 nm with grinding only tool. The surface machined with a hybrid tool showed ductile mode cutting streaks, whereas, the ground surface was observed to be completely in brittle mode. Additionally, the hybrid tools also showed reduced machining vibrations due to the damping effect induced by the elastic tool member. [ABSTRACT FROM AUTHOR]

Compliant machining processes, such as bonnet polishing, can be used on hard and brittle ceramic materials such as alumina and silicon carbide, to produce ultra-precise surfaces with sub-micron form accuracy and nanometric surface roughness. However, a comprehensive understanding of the removal mechanism in such process is lacking. In this paper, an analytical model is proposed that is based on the existence of “three zones” in compliant machining process, namely elastic recovery, plastic removal and brittle fracture. The inherent relationships of the three critical pressures with actual pressure, due to compression of the elastic bonnet tool and asperity effect, are established and analyzed in association with different material removal behaviors. Analysis indicates that pad asperity plays an important role in material removal and that lower material hardness combined with higher tensile strength contributes to enlarged plastic removal zone, and thus higher manufacturability. Removal footprints and polishing tests were then generated to verify accurate prediction of the material removal rate under different conditions and demonstrate effectiveness of the proposed model. Keywords: Ultra-precision, Elastic/plastic transition, Brittle fracture, Material removal, Ceramics

Abrasive wire cutting (AWC) and wire electric discharge machining (WEDM) are efficient and economical processes for the fabrication of precision parts from bulk material. Operating costs and manufacturing lead times are low compared to more general methods such as 5-axis CNC milling, turning, or electro-discharge machining. In this paper, an algorithm based on differential geometry in Euclidean space is proposed for reverse engineering of ruled geometries. The algorithm can determine whether a given geometry is producible by wire cutting, and can also derive the associated wire trajectories. Implementation is demonstrated by producing complex turbine blade geometries on 4-axis wire cutting machines with an overall shape accuracy of 20–40 μm peak-to-valley. [ABSTRACT FROM AUTHOR]