Crc Press - Mechanical Engineering Handbook - Robotics 1 Part 9 pot

14-80 Section 14 © 1999 by CRC Press LLC with the right side up, and placed on a flat board. Standard machine vision was used to detect the orientation of the parts. Kitting Cell for Large-Scale Manufacturing. In the field of large-scale manufacturing such as automo- bile manufacturing, engine assembly, and machining processes, where the setup time of specialized tools for each task is excessive, the work is generally distributed into several cycle zones. As an example, actual cutting time (production time) represents a value between 5 and 20% of average machine utilization time that includes nonproductive time accountable by workpiece load/unload, too) change/setting, and workpiece inspect. To avoid a high level of wear and tear on tools due to constant conversion, the cycle zone is commonly divided into individual operating cells which may be interconnected in series, parallel, or a combination of series and parallel. A typical workcell (Figure 14.9.3) consists of a robot, a part-feeder, an end-of- arm tooling section, and the manufacturing process. The parts are contained in a regularly spaced pallet, which are transported by means of an automated guided vehicle (AGV) or a conveyor to the loading tables and are fed to process by the robot. The most common approach in automated part presentation for machine loading is the use of specially designed pallets for each part family to maintain sufficient position accuracy for a completely preprogrammed robot picking. In the case of assembly, purchased parts or parts to be processed are kitted onto one kit tray in a single location. Kitting is the process of taking parts from bulk and placing them on a kit tray, which is an organized group of parts. Concentrating the material delivery system and its control to one area is the main benefit of the kitting cell. In addition to efficient use of floor space by eliminating duplicate equipment at each assembly cell, the feeders and tooling are universal — the same equipment is being used all the time for all parts, thus maximizing utilization while minimizing capital expense. The material delivery equipment is eliminated at the assembly cycle times. Also, having all the parts for an assembly on a carrier permits changes in the process route during machine downtime or blockages. Figure 14.9.4 shows a layout of the kitting cell. An overhead gantry takes bins of parts and dumps them in the appropriate feeders (indicated in Figure 14.9.4 as F1, … F7). The feeders fill the lanes with an initial quantity and replenish them as parts are kitted. The parts come to rest in nests at the end of the feeder lanes. Here the vision system verifies the correct part family, performs some quality checks, and determines the position and orientation for the robot to pick the parts. Should the vision reject the part, the nest will dump the part and a new part will be fed in for an inspection. Using a quick changeover gripper, multiple parts are kitted onto a tray. Once all the parts are on the kit tray, the tray is indexed to the inspection station for verification that all parts are placed. The robot takes the completed kit tray and places it on the assembly conveyor to an idle station, ready to be picked up by an AGV. Part-Feeding and Transfers The term “part-feeding” refers here to feeding workpieces from pallets using a preprogrammed robot for subsequent processes such as machining or assembly. The cost to feed parts to a robot for either FIGURE 14.9.3Typical single-purpose workcell. . 1 4-8 0 Section 14 © 19 99 by CRC Press LLC with the right side up, and placed on a flat board. Standard machine vision was used to detect the orientation of the parts. Kitting Cell for Large-Scale. and parallel. A typical workcell (Figure 14 .9. 3) consists of a robot, a part- feeder, an end-of- arm tooling section, and the manufacturing process. The parts are contained in a regularly spaced. blockages. Figure 14 .9. 4 shows a layout of the kitting cell. An overhead gantry takes bins of parts and dumps them in the appropriate feeders (indicated in Figure 14 .9. 4 as F1, … F7). The feeders