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Playback Robot

An operator leads or walks the playback robot and its end effectors through the desired path; in other words, the operator teaches the robot by showing it what to do. The robot records the path and sequence of motions and can repeat them continually without any further action or guidance by the operator.

Another type is the teach pendant, which utilizes hand-held button boxes that are connected to the control panel; they are used to control and guide the robot and its tooling through the work to be performed. These movements then are registered in the memory of the controller and are reenacted automatically by the robot whenever needed.

(Kalpakjian S., Schmid S.R., Manufacturing engineering and technology, p. 1169)

Smart Sensors These sensors have the capability to perform a logic function, to conduct two-way communication, and to make decisions and take appropriate actions. The necessary input and the knowledge required to make a decision can be built into a smart sensor. For example a computer chip with sensors can be programmed to turn a machine tool off when a cutting tool fails. Likewise, a smart sensor can stop a mobile robot or a robot arm from accidentally coming in contact with an object or people by sensing quantities such as distance, heat, and noise.

(Kalpakjian S., Schmid S.R., Manufacturing engineering and technology, p. 1175)

Kanban

The implementation of JIT in Japan involved kanban, meaning visible record. These records originally consisted of two types of cards (called kanbans- now replaced by bar-coded plastic tags and other devices):

The production card which authorizes the production of one container or cart of identical, specified parts at workstation. The conveyance or move card, which authorizes the transfer of one container or cart of parts from that particular workstation to the workstation where the parts will be used.

The cards contain information on the type of part, the location where issued the part number of items in the container. The number of containers in circulation at any time is controlled completely and can be scheduled as desired for maximum production efficiency.

(Kalpakjian S., Schmid S.R., Manufacturing engineering and technology, p. 1226)

Open-Loop Control

Every control system, including CNC systems, may be designed as either an open or a closed loop control system. Open-loop systems provide no check or measurement to modify orthat a specific position has actually been reached. No feed back information is passed from the machine tool back to the controller. Stepping motor-driven systems are examples of open-loop NC control. Open loop control provides relatively cheap solution to NC control systems, while closed-loop control is especially suited for varying load conditions and contouring control systems.

(Niebel B., Draper A., Wysk R., Modern Manufacturing Process Engineering,1989 ,p. 860)