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Error Recovery for Robotic Component Insertion

IP.com Disclosure Number: IPCOM000041953D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Harris, EW: AUTHOR

Abstract

The method sets forth searching and finding insertion locations, thereby increasing the reliability of robot assembly of PC (printed circuit) cards. The tolerances involved in the process of inserting components into PC cards are often close to the combined repeatability of the robot, feeders and fixturing. Hence, it is not surprising that a robot often misses the insertion on the first attempt. The following describes one solution to this situation which has been successfully implemented on a robot. Three pieces of hardware are required for this method. First, the vacuum chuck, which serves as the end of arm tooling, is spring-loaded so that it has about 0.1 inch of free travel.

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Error Recovery for Robotic Component Insertion

The method sets forth searching and finding insertion locations, thereby increasing the reliability of robot assembly of PC (printed circuit) cards. The tolerances involved in the process of inserting components into PC cards are often close to the combined repeatability of the robot, feeders and fixturing. Hence, it is not surprising that a robot often misses the insertion on the first attempt. The following describes one solution to this situation which has been successfully implemented on a robot. Three pieces of hardware are required for this method. First, the vacuum chuck, which serves as the end of arm tooling, is spring-loaded so that it has about 0.1 inch of free travel. The position of the shaft with respect to this travel is monitored by a binary sensor so that, when the shaft is compressed (pushed up), the sensor trips. If the sensor is tripped at an insertion point, the controlling program assumes that the insertion attempt missed the target holes. This hardware feature is occasionally referred to as the "height sensor" or the "height trip". The second hardware system is a binary vacuum sensor in the vacuum line to the pickup chuck. If a vacuum is detected, the robot assumes that a part is in the chuck. This feature is also referred to as the "presence sensor" because it senses part presence in the robot hand. The third piece of hardware is a block of steel in which chamfered holes have been drilled to receive and straighten component leads. The block is called the "registration" block or a "straightner". This block is mounted directly in front of the feeder bank so that the direction of movement to the PC card is approximately the same whether coming from the feeder bank or the registration block. When a missed insertion is detected, the following steps are taken: 1.

First, the robot carries the component back up off the PC card. The presence sensor has to be checked because the component could occasionally be knocked off the vacuum chuck when the insertion misses. If the c...