Molding Operations at Spokane Steel Foundry

by Randy Mullins, Molding Supervisor

Spokane Industries Steel Castings Division boasts two varieties of molding lines in which to generate steel castings and meet our customers demand - Greensand and No-Bake lines. Our No-Bake line is an automated IMF conveyor system. It provides the ability 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 roll 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 proceeds down the conveyor line and reaches the coring line where the cores are fitted in place and prepped for closing. Once the mold is cleaned out and cored up 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 steel casting molds depending on the size of the molds. Once the molds are poured off, they are transferred 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 mixed and monitered with a Hartley automated system that controls the mixture of reclaimed sand, Gilsonite, Bentonite, water and cereal flour which comprises our facing and backing sand. It is then transported 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 and compacted 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 Castings Division 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 reclaimed in the sand recycling system.

Billy Newman, Production Manager at Spokane Steel Castings 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."

Palmer Mixer

Palmer Mixer

Spokane Industries has replaced an Omco batch mixer (50# batches) with a new continuous mixer that will enhance our coring abilities.  In light of the size of the castings we are making currently, the quality of the cores will improve dramatically.  With our previous sand system, we had to mix in 50# batches at a time, which can potentially create layers of sand that have subtle variations in strength.  With our new core system, we will have continuous feed and consistent sand pours that will eliminate this variable.

The new Palmer Mixer allows us to move more efficiently into the realm of a 2 sand feeding system that allows either silica sand or specialty sand.

Additionally, we are moving away from spraying the cores – which lacks consistency from operator to operator – to “flow coating” - which creates a more consistent wash coating and allows for greater material penetration.  These 2 processes are expected to greatly enhance our efficiencies and minimize scrap and waste.

With this new addition we are taking the opportunity to redesign the floor plan of the coring department, which will allow for less material handling, less wasted movement and greater productivity.

New Palmer Mixer Installation

Quench Filtration

Quench Filtration

Our engineering staff has conducted an in-house research project to ascertain the efficiency of filtered water in our quench tanks as opposed to the current quench tank usage, which recycled the same water repeatedly.  The results were quite compelling.  It was discovered that the cleaner the water, the better the properties attained in the quenching process.  Cleaner water creates a “more severe” quench – facilitating more consistent and predictable results, allowing for a tighter tolerance band for our mechanical testing. 

This filtration system with it’s $18K price tag more than pays for itself by eliminating the need to test and dispose of quench water on an annual basis while at the same time delivering more consistent and reproducible results. 

New Quench Filtration System

New Air Compressor Installation

Bldg. #4 air compressor

Consistent air pressure is a constant need in a foundry, and we struggle with a shortage of air from time to time.   The need for compressed air is driven by several departments, most notably the molding and finishing departments.  A shortage of air can affect mold quality, productivity, and efficiency throughout the production process. 

While we recognize that sales orders are below capacity, we are taking a pro-active approach to building infrastructure for future potential, understanding that we want to be prepared for the next wave of opportunity.

Adding a new air compressor serves this philosophy in 2 ways.  First, we are able to maintain consistent air pressure throughout the plant at all times; second, this gives us the opportunity to improve our finishing capabilities by 30%.

New Ingersoll Rand Compressor

Digital Controls

Reconfiguring Finishing Cells

Finishing Cells

In everything we do, we try to increase efficiencies, improve processes, and reduce waste.  There are 7 forms of waste; the 2 main forms of waste that most significantly affect our finishing department are over processing and wasted motion. In theory, just by moving operations into a certain area, you’re not really eliminating a lot of waste.  Effective cells are designed to eliminate those wastes.  We want to take “families” of parts and run them through a condensed work area designed for those castings. 

The introduction of finishing cells will also assist as we train new employees.  When we bring people onto the work force, they are somewhat isolated.  Being new, they wade into the unknown.  With finishing cells, you have teams.  The newcomer not only gets training but they become part of something.  They’re part of a team - part of something bigger than themselves.  They experience camaraderie that allows an outsider to become an insider very quickly. 

As a job shop, we have a wide variety of products that we process through the finishing department that would need to be identified and classified.  If we can identify similarities – alloy, size range, processing steps, etc.  We can process those in the same area and have the same people working on them that know exactly what work content is needed – no more and no less – to get that product out the door.  This would greatly enhance workflow and minimize waste.

At this time, the reconfiguration of the finishing cells is underway and the first iteration should be complete by mid-august. 

More than 60 years of experience...

INNOVATION

SPOKANE INDUSTRIES, the industry leader in high quality, high chrome iron impact crusher wear parts, has developed a line of wear parts for use in material handling applications using Si-Tec®, their patented Ceramic Composite Technology.

Si-Tec® ceramic composites provide twice the wear life of standard parts in most applications which means:

·       Reduced liner costs per ton of rock processed

·       Fewer liner change-outs and interruptions

·       Quicker replacement

·       Safety - Reduced exposure to injuries associated with liner replacements

Spokane Industries has been an integral player in the crushed rock industry with their Spokane Crusher line, their extensive crusher wear parts line and their innovations in ceramic composite technology. With more than a decade of successful ceramic composite integration in impact crusher wear parts, Spokane Industries is leveraging this success with a burgeoning line of material handling wear parts.

ULTRA WEAR-RESISTANCE

One such success story involves their large Si-Tec® chute liners which are utilized in the world’s largest gold mine. These large liners are specifically designed for a snug fit in curved chutes. The dense copper/gold ore flowing across their liners is 8 inch minus and moves at a rate of 80,000 tpd. As this river of rock enters the transfer point, it slams into a rock box and then drops down into the chute which redirects the flow onto the next conveyor. Unlike the previously utilized high chrome iron liners, the Si-Tec® liners are fortified with highly abrasion resistant ceramic to better resist wear. Initial trials yielded relative wear life of 1.9x that of the high chrome iron liners. As high chrome iron liners are replaced, Si-Tec® liners are installed.

Mine maintenance personnel were so impressed with the longevity of Si-Tec® liners that they requested designs to address both high and medium wear areas of the chutes. Although the liners were designed and manufactured halfway around the world, Spokane Industries' Engineering and Development teams replicated the actual chute to verify and ensure a close fit of the liners within the fabricated chute (see image above). This proactive effort is typical of Spokane Industries’ approach to solving problems with cast composite technology.

WEAR-RESISTANT SOLUTIONS

Spokane Industries solves severe wear problems with their burgeoning line of material handling wear parts. Visit their site to download a brochure which depicts wear solutions to suit a variety of applications.

http://www.spokaneindustries.com/PDF/MiningWearPartApplications.pdf

If you need a custom shape, Spokane Industries' experienced engineering team will work with you to assess wear in existing parts and high wear problems in your plant. They will recommend and design solutions for your application that optimize wear life, simplify installation while effectively managing costs.

Spokane Industries is a world-class designer and manufacturer of cast and fabricated metal products. It is the parent corporation of three thriving companies, Spokane Steel Castings, Spokane Precision Castings and Spokane Metal Products.

Si-Tec® is registered in the U.S. Patent and Trademark Office

Use Si-Tec® Ceramic Composite wear liners to protect your material handling systems from the abrasion of ore and overburden high in silicates and quartz.

Their composites can be applied as large chute liners, skirt boards or wear plates.