Comparison of a bat and genetic algorithm generated sequence against lead through programming when assembling a PCB using a 6 axis robot with multiple motions and speeds

An optimal component feeder arrangement and robotic placement sequence are both important for improving assembly efficiency. Both problems are combinatorial in nature and known to be NP-hard. This paper presents a novel discrete hybrid bat-inspired algorithm for solving the feeder slot assignment and placement sequence problem encountered when planning robotic assembly of electronic components. In our method, we use the concepts of swap operators and swap sequence to redefine position, and velocity operators from the basic bat algorithm. Furthermore, we propose an improved local search method based on genetic operators of crossover and mutation enhanced by the 2-opt search procedure. The algorithm is formulated with the objective of minimizing the total traveling distance of the pick and place device. Through numerical experiments, using a real PCB assembly scenario, we demonstrate the considerable effectiveness of the proposed discrete Bat Algorithm (BA) to improve selection of feeder arrangement and placement sequence in PCB assembly operations and achieve high throughput production. The results also highlighted that the even though the algorithms out performed traditional lead through programming techniques, the programmer must consider the influence of different robot motions

Design and Implementation of an Automated Pick and Place System for Johanson Technology, Inc.

Johanson Technology, a capacitor and microelectronic part manufacturer, located in Camarillo, CA has forecasted a 50% increase in demand for single layer capacitors for the year 2011. Johanson chose to hire an intern to design and implement a robotic pick and place system to meet this demand. A complete automated system composed of a Stäubli RS20 robotic arm, CS8C-M Controller, and Electrosort Bowl Feeder needed to be integrated into an environment where no system currently existed. A bill of materials and parts list indicated that the entire system would be a fixed cost of $50,104. This proved to be the superior choice over the alternatives of hiring an outside consultant to design the system for$115,051 or hiring an additional employee to hand pick and place the parts for nearly $24,000 annually. Programs were written in VAL3, Stäubli’s own programming language, for the RS20 to pick and place parts in a grid formation onto Waffle, Gel, and Ring Packs. A custom tool composed of manufactured and purchased parts was made at Johanson Technology and held by the RS20 arm to handle the single layer capacitors. Performance of the system’s placement accuracy was analyzed by measuring correct placements on Waffle, Gel, and Ring Packs. Waffle Packs received a placement accuracy of 99.21%, missing around 10-20 parts out of 2,400. Gel Packs received 99.71% accuracy, and Ring Packs failed to place parts consistently within their 2-3⁰ rotation tolerance so their accuracy of placement could not be measured. The robotic pick and place system places single layer capacitors into Waffle, Gel, and Ring Packs at two to three times the speed of a human operator. At this rate, Johanson Technology will be able to meet their demand