Check Weighing Systems

Equipment
Hardy Process Solutions weight controllers are used to check weigh static or in-motion parts, products and packages. Simple platform scales are used for static check weighing. Load points (load cells and mounting hardware) or platform scales are incorporated with conveyors to provide in-motion check weighing. In-motion check weighing is made possible with Hardy`s WAVERSAVER technology, which ignores plant and process mechanical vibrations such as those created by the conveyor belts. Hardy`s instruments can be configured to sequence items on and off the scale, divert out-of-tolerance material, or separate classified product. Under/Accept/Over lights can be used to notify the operator of the weight status.

Controls
Check weighing system controls range from manual to fully automatic. A manual (static) check weighing operation requires an operator to place the item on the scale and observe Under/Accept/Over lights. A fully automated system is where the item is automatically weighed in-motion. The check weight controller then directs downstream diverter gates to route product based on weight. Automated control is done by a Hardy Instruments weight controller, a host computer or a PLC program communicating with a Hardy Instruments front-end.

Data Collection
In addition to verifying the weight and directing product flow, a check weighing system also provides valuable statistical information. This information can be used for SPC (Statistical Process Control) to support the requirement for quality records.

Usually the check weighing station is an inspection station after the manufacturing or packaging process. By analyzing and feeding back the results of the check weighing operation, the source process can be adjusted to optimize quality and lower costs. Automatic or manual feedback or information is downloaded to a printer, computer or PLC.

Verify Package Contents
Hardy weight controllers and load point(s)/platform scales are used to weigh packages to confirm that they have been filled to the proper level or that they contain the correct number of parts. A wide variety of products ranging frm boxed food, bagged grain and glass bottles to gas cylinders can be weighed to verify the contents. Check weighing can determine whether or not the correct number of items are in a box, the right number of boxes are in a carton, and the correct number of cartons are on a pallet. For example, the beverage industry weighs kegs and canisters to make sure they are empty prior to filling and full within tolerance after filling.

Check Product Tolerance
Check in a manufactured product`s weight verifies if it is within design tolerances. For example, an injection molding company can detect improperly produced product by using a Hardy Process Solutions weight controller and load point(s)/platform scale to check weigh each part as it falls out of the mold. In a coating process, the quality and thickness of the coating can be verified by the additional weight.

Classify Product
A mix of different items can be sorted by weight and diverted to the proper packaging station for classifying or grading purposes. For example, variable weight products such as fruit and vegetables can be classified or graded by their weight class using a Hardy weight controller and load point(s)/platform scale. If the check weighing process is in-motion, relays from a Hardy weight controller can be set to divert the product to the proper station.

Identify Parts
Items with different weights can be identified automatically by a check weighing system. For example, assembly processes use Hardy Instruments weight controllers and load point(s)/platform scales to verify the correct parts have been delivered.

Overload Safety Check
Items are often weighed to ensure they do not violate safety limits. For example, a train car is weighed with a Hardy weight controller and load point(s)/platform scale to make sure it doesn`t exceed the weight tolerance of an upcoming bridge.