Terry Mackin, a process-product manager for Columbus, Ohio-based Mettler-Toledo Inc. (www.mt.com), says manufacturing use of scales essentially starts at a factory’s front door. In receiving, weighing technology finds weight or count for direct inputs into inventory. The technology can also help continuously maintain that inventory, by automatically transferring data to business systems that issue raw materials into production lines.
If there are processes, he says, scales help maintain formulation and recipes through weighing of ingredients. Quality assurance is another area for the use of scales in both discrete manufacturing and batch/continuous processes. Additionally, there’s filling and dispensing of final products into containers, and then weighing of materials in trucks or other containers before off-site shipment. Weighing product containers is very critical, Mackin notes, “to make sure that too much isn’t given away or that the containers don’t go out the door underfilled.”
Dimensional weighing key
But Herman Blanton, a Mettler-Toledo industry specialist, adds that dimensional weighing, which characterizes weight and space, is also very important. That’s because count may be more important than weight for some consumers, explains Mackin. “We do have examples where the customer will reject an entire truckload of a product (some parts, for example, in automotive parts manufacturing), if the count per container is not correct.” Blanton adds, “It’s common that a shipment will be rejected if the count is wrong. Because of their quality standards, end-users don’t want to second-handle materials if there’s anything that’s left over.”
How, though, does weighing provide part counts? In a counting application, each part will have a specification, but that may not be good enough to get gross weight, says Blanton. Sampling determines average part weight; net weight of a container then gives total parts.
Combined weighing-and-communication processes may be manual, semi-automated or automated, or some combination thereof. “A measurement could be done manually by a person. But the measurement could be automated from point of measurement up to and through the enterprise-resource-planning (ERP) system,” Blanton states. Alternatively, adds Mackin, measurement could be completely automated, “and then a hard-copy ticket is printed and the information would have to be manually entered into some record.”
Fully automated weighing and communications could occur in a packing line, with packages rolling over an in-line scale. “The measurements are made according to some logic and then data are transmitted automatically into the ERP,” says Mackin. This automated weighing is prevalent in warehousing, he adds, and generally in non-regulated industries.
When raw materials—such as gold—are very valuable, higher resolution is needed, and that demands high-precision weighing, says Blanton. Modulo, a Mettler-Toledo technology, is used at an industrial facility in the South, in which the manufacturer weighs very small PCBs, says Mettler-Toledo’s Frank Cava. “What they’re trying to do is determine how much content of a particularly valuable material they’re using on that board.” This quality-assurance check has a two-fold payoff: “It was costly if you had too much on the PCB and the board also wouldn’t work,” he adds.
Scales find equally unique applications by retail and non-manufacturing users. One is a bagel manufacturer who was making a dispensing machine, Blanton recalls, and wanted to determine both weight and count dispensed. To monitor the health of penguins as they go in and out of their homes, two zoos are buying the high-precision technology, he adds. Also, NASA has contacted Mettler-Toledo to purchase a scale to measure moisture loss of astronauts as they exercise.
Kenna Amos, ckamosjr@earthlink.net, is an Automation World contributing editor.
