A checkweigher is a device which is designed for the purpose of checking the weight of finished packaged products. These devices are part of the quality control system used to ensure that the products rolling off an assembly line are consistent. Consistency is key for the company, ensuring that it operates efficiently, and for customers, who come to rely on consistency in the products they buy. Checking weights in particular is important as if the weight is off, it can cause problems for the consumer, and selling products at the wrong weight can expose a company to fines and other penalties.
There are several different checkweigher designs in use. Some are integrated right into the production line, while others are designed to be moved into place as needed. Many are automated, allowing products to move across the scales automatically and taking any actions needed, such as pulling something off the line because it fails to weigh out properly, with automated devices. For example, a checkweigher might use a blast of air or a hydraulic arm to push packages off the belt if they are too light or too heavy.
It is also possible to integrate other quality control features into a checkweigher. For example, the device may x-ray products which move across the conveyer, or use a magnet to identify ferrous materials in products. Packages which do not pass these tests can also be set aside by the machine for disposal or manual inspection. These safety measures are especially important with packaged foods, ensuring that obvious health risks are not accidentally packaged into products sold to the public.
Like other scales, a checkweigher needs to be periodically recalibrated. These devices also tend to have an averager system which is designed to compensate for movement and other environmental factors which could cause the weight of an item on the scales to vary. Instead of taking one reading and reporting it, in other words, the checkweigher takes several readings and picks the average of the readings to determine the weight of the package. This system may need to be periodically checked to confirm that it is working properly.
Speed checkweighers can handle hundreds of items a minute. Other devices may be slower. In many cases, a computer keeps a log of what happens during the day. This is designed to allow people to check on things like the efficiency of the packaging line, and to generate a list of how many products made it all the way through production. If a checkweigher starts discarding large numbers of packages, it can indicate that there is a problem with production or with the checkweigher.