8.17 When checked against actual machines, these values give agreement within about 30% of the real values of power, mass, and volume. The design procedure at this preliminary stage is very simple. One must simply size the machine tool to the largest work piece it must ever handle. Having sized it, one uses the mean density to approximate its mass, and then the power to mass ratio to estimate its power consumption. This is the procedure which will be used here. VIII.4.4.2: Plate Finishing Milling Machine: The plate finishing mill is a vertical lead milling machine which takes the rough plate produced by the plate mill and cut to rough shape by the shear, and mills its edges to the exact shape required. The edges are e~ther square butt or beveled, and square or tapered depending on the exact final position of the plate in the final structure. The milling machine, like all machines in the manufacutring shacks, is controlled by a central automated control unit. Since one plate is needed about every 3.5 minutes, it is estimated that three plate milling machines are required: Dimension Mass Power Output Each Hill 3m x 2m x 2m 6 T 18 kW 1 plate per 10 min Total (3) 3m x 6m x 2m 18 T 54 kW 1 per 3.5 min VIII.4.4.3: Fastener and Nut Machine: It is assumed that aircrafttype fasteners are used with a diameter of 10-20 mm. The exact details of a high-speed fastener manufacturing machine are not known at this time so the following rough approximations have been made: Dimensions Mass Power Output Total of both Each Machine Fastener and Nut Maker 2m x 2m x 2m 4 T 12 kW 1 item per .63 min 2m x 4m x 2m 8 T 24 kW 1 nut and 1 fastener per .63 min
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