Ten Million Units

Story by Nicole McKay | September 28, 2010

Hamilton Drywall Products, based in Woodland, Wash., specializes in the production of drywall finishing compound, which the company supplies to regional markets as well as some international exports.

At the startup of the company in 1999, Hamilton made the decision to integrate a fully automatic in-motion checkweigher and semi-automatic checkweigh scale into its production line. With the assistance of Mark Hudzinski, territory manager at the Avery Weigh-Tronix facility in Portland, Hamilton found a solution.

"Weighing product before it leaves the facility is important to guarantee customers get what they pay for," said Ted Buker, Hamilton plant engineer. "At Hamilton, we stand by our commitment to 'Quality, Integrity & Service.' This is one way we can honor that."

Hamilton decided to purchase both checkweighers from Avery Weigh-Tronix after a recommendation from a packaging equipment vendor. According to Buker's calculations, weight records over the last several years indicate that over 10 million units of product have been weighed using the equipment, with minimal maintenance.

Hamilton's finishing product is offered in cardboard boxes ranging from 25 pounds to 65 pounds, and plastic buckets from 1-gallon up to 5-gallon sizes. Production begins at the filling stage where boxes or buckets are filled using a semi-automatic filling and weighing process. An operator places a container on an Avery Weigh-Tronix Diamond Series checkweigh scale, directly underneath a filling head, and presses a button to initiate filling. The checkweigher weighs the container until the appropriate weight has been reached and communicates with the filler to stop filling.

Filled containers are conveyed to an Avery Weigh-Tronix CVC conveyor scale where their weights are verified. Depending on the type of container being weighed, the CVC determines whether each individual container passes minimum weight requirements. An on-board display allows the operator to see pass/fail inspections in real time. Weight information is also transmitted to a PC, which communicates to other equipment on the line. Containers that pass inspection continue down the line for further packaging and palletization. Containers that fail minimum weight requirements are pushed off the line with a mechanical reject mechanism so they can be refilled.

Rejects Are Rare

One-hundred percent of product output is weighed. Buker said that due to the high-accuracy equipment, Hamilton almost never sees rejected containers.

"We might see a couple of rejects at the very beginning of a new batch, but it's very rare we would ever see more than that," Buker said.

Changeover between containers and sizes is made easy due to the CVC's dual photoelectric cell, which allows maximum accuracy even for randomly sized products.

In addition, the CVC's self-contained, freestanding design allowed Hamilton to integrate it directly in line with other manufacturing equipment.

Also in use at the plant are Avery Weigh-Tronix 5-foot-by-5-foot and 4-foot-by-4-foot deck scales with a 5,000-pound capacity for weighing incoming inventory and outgoing shipments.

All of the Avery Weigh-Tronix equipment that Hamilton uses at its plant features patented WeighBar weighing technology for repeatability and durability. Buker estimated that Hamilton Drywall runs the equipment on average 14 to 17 hours a day, five days a week. Sometimes production increases to 24 hours a day, depending on output needs.

"We are incredibly happy with the equipment's cycle performance and consistency," Buker said, "considering we run multiple shifts a day and haven't had any major setbacks."

Author Information
Nicole McKay is a writer/publicist at Next Communications Inc.