Since implementing off-line programming in 1997 and then refining the process, Johnson Controls, Inc. has dramatically reduced programming costs while improving production uptime in its robotic waterjet-cutting cells. To date, JCI has reduced line utilization for programming purposes by 96 percent, from 50 hours to two hours, with an 82 percent reduction in cost per new robot program.
JCI is a major supplier of automotive interiors, with more than 200 robots in 19 North American facilities. These robots require creation of approximately 300 robot programs each year. About 75 of these robot programs are then cloned and shared by multiple robot cells.
This year JCI implemented an initiative to reduce production downtime costs related to robot programming. Goals were to maximize equipment use by eliminating downtime required for program touch-up, meet production requirements by launching new programs aster and reduce overall cost by minimizing both programming time and scrap parts.
Off-line programming initially reduced the cost per robot program by 25 percent and resulted in a 40-50 percent reduction of off-line program teaching time at JCI, but these programs still require considerable touch-up. While the computer simulations used to generate the OPL programs created fairly accurate program paths, the lack of calibration often meant the start and end points were not in the correct position, so the program would have to be touched up.
JCI determined that calibration of the robot, fixtures and tool centerpoint would lead to more accurate OLP program development and downloads. Proper robot calibration is essential for online programming and path accuracy in high precision applications.. Like any other mechanical system, robotic cells are built within manufacturing tolerances, resulting in slight differenced between robot cells. These minute differences affect the accuracy during off-line programming, robot cloning and recovery of robot programs after maintenance of a robot system.