Packaging costs (direct labor and material) account for a substantial portion of a product's manufactured cost and so it is desirable to minimize these costs. And since major productivity gains have already been realised in manufacturing operations, the last frontier for productivity improvements appears to be in logistics. A formal methodology is therefore proposed to assess the efficiency of manual insertion and packing operations such as folding, insertion, labeling, sealing and scanning. Through this methodology, inefficient packaging operations can be identified and improved upon. This paper also discusses how standard manual handling and insertion times can be computed from raw data collected from industry. These standard manual handling and insertion times form the basis for the computation of the manual packaging efficiency expressed as a packaging index. The closer the index is to 1, the more efficient are the packaging operations. Tables of standard times for labelling, scanning barcodes, sealing with adhesive tape, and insertion into Zip‐Lock™ bags and cardboard boxes with two, three and four flaps are presented. A simple five‐step procedure records the ideal and actual packaging times in a worksheet, from which the packaging efficiency may be computed. The methodology was applied to the packaging of mobile phones, hard disk drives, a desk‐jet printer, a notebook computer, a video cassette recorder and a microwave oven. The packaging efficiencies of the three popular mobile phone models were computed to be 81.5 percent, 76 percent and 74.4 percent. By adopting the best packaging features of two competitor models, it was found that the packaging efficiency of one model of mobile phone could be improved by 13.7 percent. Arising from the research, the authors postulated a general manual packaging line consisting of all conceivable manual packaging operations. This generic manual packaging line is significant in a specific line for a specific product may be quickly configured from it. Finally, arising from the experience of the authors in this research, guidelines for the design of efficient packaging lines are proposed.
In this paper, a vibration-based MEMS electromagnetic energy harvester (EM-EH) device with two-degree-of-freedom (2DOF) configuration has been presented, modeled and characterized. The proposed 2DOF system comprises a primary subsystem for power generation, and an accessory subsystem for frequency tuning. A lumped parametric 2DOF model is built and examined in respect of energy harvesting capabilities. By controlling the mass ratio and frequency ratio, the first two resonances of primary mass can be tuned close to each other while maintaining comparable magnitudes. The 2DOF configuration is expected to be more adaptive and efficient than the conventional 1DOF structure, which could only operate near its sole resonance. The 2DOF EM-EH chip is fabricated on silicon-on-insulator (SOI) wafer through double-sided deep reactive-ion etching (DRIE). Induction coil is only patterned on the primary mass for energy conversion. With current prototype at an acceleration of 0.12 g, two resonances of 326 and 391 Hz with output voltages of 3.6 and 6.5 mV are obtained respectively, providing good validation for the modeling results. This paper offers new insights of implementing a multimodal MEMS EM-EH device.
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