• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.21-26
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• 2007

In industry, multihead automatic combination weighers are used to provide accurate weights at high speed. To minimize giveaway, greater accuracy is desired, especially for valuable products. This paper describes a combination algorithm based on bit operation. The combination method is simple and saves time, since only the elements to be considered for combination are generated. The total number of combinations from which the desired output weight is chosen can be increased by extending the combination from memory hoppers to include some weighing hoppers. For an eight-channel weigher, three or four combination elements are best. In addition to targeting approximately equal amounts of products in each channel, this study investigated other schemes. Simulation results show that schemes targeting combination elements with an unequal distribution of the output weight are more accurate. The most accurate scheme involves supplying products to all memory and weighing hoppers before commencing the combination operation. However, this scheme takes more time.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1567-1575
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• 2006

In an automatic combination weigher, the line feeders distribute the product to several weighing hoppers. The ability to supply appropriate amount of product to the weighing hoppers for each combination operation is crucial for the overall performance. Determining the right duration of operating a line feeder to supply a given amount of product becomes very challenging in case of products which are irregular in volume or specific gravity such as granular secondary processed foods. In this research, several schemes were investigated to determine the best way for a line feeder to approximate the next operating time in order to supply a set amount of irregular goods to the corresponding weighing hopper. Results obtained show that a weighted least squares method (WLS) employing 10 data points is the most effective in determining the operating times of line feeders.