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21st Century Manufacturing Episode 1 Part 6

Tham khảo tài liệu '21st century manufacturing episode 1 part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 94 Product Design Computer Aided Design CAD and Solid Modeling Chap. 3 Figure 3.9 Outline of the base exterior before the ưimming process. Figure 3.10 Outline of the base exterior after the trimming process. A good place to start is the shallow rounded pocket in the bottom face because many consumer electronics products including telephones have a cover plate on the bottom. This is more like a shallow recess that the cover plate will eventually nestle into. The cover plate will close over the larger internal cavity that houses the printed circuit boards and wires. The plate generally follows the contour of the bottom surface of the object. For the joystick the base plate itself is a flat trapezoid with rounded corners. A shallow rounded pocket will thus be drawn in the next few images to accommodate the plate. This task begins in Figure 3.11. First the straight lines of a trapezoid are drawn that remain equidistant from the outside edges of the bottom. These will then be connected next rounded and then copied and repeated for the depth of the cavity. In the fust construction step the line i is drawn parallel to the base at a small distance w in the y direction from a. This line travels some distance past the outline 3.8 First Tutorial Wire Frame Construction 95 Figure 3.11 Initial formation of the cavity in the base exterior. of the object on each side. Line ii begins by placing a tiny line of length w perpendicular to the other edge. The full extent of line ii is then constructed from the end point of this short construction line w. It goes past the front of the object parallel to the angled bottom edge. The line is completed by extending it with the extend command such that it intersects line i. The extend command finds the intersection automatically. Line ill is constructed in a similar manner from the short construction line w2 from the front face. Once one of the lines marked ii is constructed on the right side of the object it is mirrored to the left across .