Tuesday, March 3, 2009

Spokane Steel Foundry Molding Operations

By Randy Mullins, Molding Supervisor

Spokane Industries Steel Foundry Division boasts two varieties of molding lines in which to generate steel castings and meet our customers demand - No-Bake and Green Sand lines. Our No-Bake line is a fully automated IMF conveyor system. It provides the flexibility to make larger steel castings and more steel castings per mold. We have the capability of running four to eight patterns at the mixer head with two to four patterns on our backup line depending on the size of the pattern.

As the loop begins each pattern is filled at the mixer station, compacted and sent to get strike off where an automated arm removes the excessive sand from the pattern. The mold is then sent to the roller over machine where the mold is prepped and stripped from the pattern. The empty pattern is looped back around to the mixer head to be set up and filled again.

The mold is then transported to a curing oven where it finishes curing. It then is prepped and cleaned out and sent to the flow coating station where we permeate the mold with a water base coating to give it a good penetration of coating to protect the metal from burn in and to give the casting a smooth finish. Its then sent through a drying oven to cure. This creates a strong barrier between the coating and the molded sand.

The mold continues down the conveyor line and reaches the coring line where the cores are fitted in place and prepped for closing. Once the mold is cored up and cleaned out it is sent to the closer which is an automated manipulator that picks up the drag half of the mold and places it on a plate then returns and picks up the cope half, rotates and places it on the drag half, then sent out to be placed on the pouring floor.

The Steel Foundry pouring floor has forty-eight plates that are divided into four rows of twelve plates which can have from forty-eight to ninety-six molds depending on the size of the molds. Once the molds are poured off, they are transfered to be cooled. When the steel casting reaches its cooling time it is sent to a shaker where the steel casting is separated from the mold and the sand is reclaimed back into the sand system to be reused at the mixing station.

Our Greensand line is where we make our smaller steel castings. We have two lines of greensand molding, an EMI line that makes 30x36 molds and a larger EMI 36x64 molding line. These molding lines are made with a clay bonding system. The clay bonding sand is made and monitored with a Hartley automated system that controls the mixture of reclaimed sand, Bentonite, Gilsonite, water and cereal flour which comprises our facing and backing sand. It is then sent to a holding bin for each cope and drag side of the molding lines.

Once a pattern is mounted to a mounting plate on each side of the machines, a flask is placed over the pattern where sand is released and fills the flask. The sand is then tamped down to form a mold. The mold is stripped from the pattern and sent to the closing station where the molds are cleaned out and cores are placed. When the mold is ready to be closed the cope is brought over and placed over the drag, clamped up and sent to the pouring floor.

Spokane Industries Steel Foundry can place up to seventy steel casting molds out on the floor to be poured off. When the steel casting has cooled, the mold is sent to our punch out machine where the steel castings are separated and sand returned to be recycled in the sand reclaiming system.

Billy Newman, Production Manager at Spokane Steel Foundry states "Our processes and procedures have vastly improved over the last few years as we strive to augment our recycling programs, reduce waste, and reclaim as much of the process as possible which minimizes our carbon footprint. Our goal is to lead by example in the Steel Casting Industry and maximize our efficiencies. - 16651

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