Some new inventions change the way we do things, when Ishida launched world’s first multihead weigher in 1972, it was destined to be a game changer. It proved to be one of the best filling machine in snacks and confectionary industry. The packaging machines of that time were in the dire need of an accurate and reliable filling system in the food industry. Multihead weigher was a great concept put into reality by utilizing the available technology of that time.
Today, combination / multi-head weighers, because of their high speeds, accuracy and capability to handle various products are wide spread in the packaging industry. These machines are produced worldwide by a number of leading manufacturers. These machines are mostly circular-designed (there are also versions of linear design) basically work in following way.
(1) Product is fed from a vibratory feeder / metering conveyor to the top of the weigher.
(2) Using vibration OR product transfer screws, the product is evenly distributed across the top of the weigher to a set of pool hoppers where the product is held for some time.
(3) The content of each pool hopper is discharged to a corresponding weigh hopper directly underneath. The hoppers on a multi-head weigher can vary from 8 to 36, the increase in number of hoppers increases the speed and accuracy as the number of permutations and combinations for filling increase.
(4) A built-in computer instantaneously calculates all possible weight combinations and selects the one that comes closest to the target weight.
(5) The selected weigh hoppers discharge their contents into a packaging machine.
Many manufacturers offer complete packaging lines involving multihead weighers with other packaging machines ranging from bagmakers (VFFS, HFFS, Pouch machines) to tray-sealers, thermoformers, Can lines, inspection systems and so on.
Multihead weigher manufacturers have worked closely with the users for developing these machines further to meet the ever-changing demands of the food and FMCG industries. Over the years, multihead weighers have constantly improved in terms of even faster speeds and greater weighing accuracies. The original multihead weighing concept was ideal for easy-to-handle dry and frozen products such as snacks, confectionery, cereals and vegetables. Over the years, there have been tremendous improvement of features and application-specific multi-head weighers that can deal with more difficult products. Special raised surfaces, for example, have been developed for sticky products such as prepared fruit, jellies and gums; reduced angles and drop distances throughout certain models protect fragile or brittle products from breakages. Few years ago, screw feeding multi-head weighers were launched and these are especially designed to handle sticky and wet products such as fresh poultry, beef, pork or lamb chops, meat cubes, with or without marinade, etc.
For ready meals, mixed snacks and cereals, one of the multihead weigher’s major strengths has been its ability to handle the mix weighing of different products. This ensures the pack receives identical weights and that all the ingredients are always present in the mix in the same proportion (thus creating overall product consistency and reducing customer complaints).
All these developments in multi-head weigher technology, capabilities and integration have helped food manufacturers keep pace with market demands and consumer and retailer requirements. The multihead weigher may be well established, but its relevance shows no sign of diminishing and it is clearly more than capable of dealing with any further challenges that may arise. Thus, for all its achievements to date, the technology is still work in progress and improving every day.
Along with the weigher, equipment such as tray denesters, tray fillers and sealers, bag makers, Inspection systems, check-weighers, seal testers, label inspection and end-of-line packing equipment can be linked together to ensure maximum throughput and efficiency. Find and shortlist various machines here.