Great animation and excellent narration make this video of the vertical green sand foundry process easy to understand.
"Waupaca foundry has patented many improvements in the industry's vertical molding with regards to safety, quality, productivity, and reliability. Our innovative thinking is a large part of how we've lead the industry in delivering consistent, high-quality castings. The vertical green sand molding process begins with a silica sand, clay, and water mixture that is forced into the molding chamber with compressed air. The sand is squeezed under intense pressure, creating a mold with both the strength and hardness to retain its shape.
Navigate the differences in capabilities and cost factors between nobake and green sand metal casting molding processes to ease your sourcing decision.
Opting for a sand casting process over permanent mold, diecasting, or investment casting is step one in sourcing a casting. But sand casting encompasses several methods, each of which carries its own advantages and disadvantages. The two most common processes used are green sand and nobake molding, and sourcing between the two is not always cut and dry.
Forty-two precent of North American metalcasters employ the green sand molding process. Its popularity stems from its affordability, ability to be used for most metals and flexibility for low to high volume production.
Green sand molding does not hold the tightest tolerances or achieve the finest surface finish of all the casting processes; however, in general, it meets most of the qualifications desired to produce a high quality casting with a good finish.
Nobake sand casting, which is utilized by 40% of North American metalcasters, also is known for its versatility. Virtually all metals can be cast via nobake molding, a wide range of sizes can be produced, and the rigid mold walls provide good dimensional tolerances and control.
$125-million project will keep Michigan operation "competitive" for global supplier of municipal and infrastructure castings.
EJ —a global organization that produces and distributes ductile iron castings for municipal and infrastructure programs — staged a groundbreaking event for a greenfield foundry it is building in Elmira, MI, about 20 miles east of its current and original location in Warner Township, in northern Michigan. The $125-million project will result in a new foundry to be operating by the fall of 2018.
Michigan Lieutenant Governor Brian Calley and other elected officials, along with numerous members of the Malpass family, descendants of the founders and including current executives and directors of the company, joined in the groundbreaking event in late July.
Controlling the quality of raw materials, additives is critical to high-quality green sand system ferrous castings
Basic understanding of raw materials is equally important as good quality control measures and consistent operating practice.
Controlling raw materials is critical to the success of iron casting production. The base silica sand is often overlooked, with the main focus on bentonite additions. Carbonaceous additives can be considered a “necessary evil” to ensure a good surface finish and reduction in sand-related surface defects. Other additives are used when systems get out of balance, and these will further complicate the complexity of green sand systems.
For castings requiring cores this becomes a bigger issue, as many differing resin systems are employed for core production, and these must be taken into consideration when controlling both the carbonaceous levels and the overall grading of the sand system. The twin effects on additional carbon and loss-on-ignition, and overall sand grading, need careful understanding and control.
More than 60% of castings are made using the green sand metalcasting foundry molding process, but what is that? Green sand is a mixture of sand or aggregate, clay and water. In a green sand system, the clay and water combine to form a clay bridge that binds sand grains to one another. This bonding mechanism is a hydrated system that requires water, energy, time and technical expertise.
Two types of bentonite clay are typically used: calcium bentonite and sodium bentonite.
Sodium Bentonite (also known as Western Bentonite): Western bentonite is known for its ability to absorb and hold large amounts of water and for the resulting qualities of its high swell (bigger increase in volume) and high viscosity. It is good for green sand mixtures requiring high dry strength and hot strength, such as for iron and steel casting. It is more difficult to mull and help the clay to attach to the sand grains, so more mull energy is required.
This sodium-based clay is capable of swelling approximately 15 times its dry volume. In molding sand, it helps molding maintain its dimensional accuracy and provides a greater dry/hot strength.
Hill and Griffith’s Slagone is a perlite material used as a slag coagulant in a molten metal application. Slagone is typically used with Iron, Brass and Bronze metals.
Perlite is a generic term for a naturally occurring siliceous volcanic rock. The distinguishing feature of perlite is that when it is heated to its softening range, it expands 4 to 20 times its original volume. This expansion is due to a small amount of water contained in the crude perlite rock. As the ore heats, the water vaporizes and pops allowing the expansion. Any slag present on the molten metal will adhere to the expanded perlite and continue to float. The combined slag/perlite from the molten metal slag coagulant can then be removed from the molten metal in large pieces, resulting in clean molten metal for the casting process.
Video and images from, "BMW Engine Block Foundry" from Car TV.
The FOUNDRY Management & Technology Hall of Honor recognizes men and women whose technical and process innovations; organizational leadership; professional and industrial standards; and personal contributions and achievements have improved and enhanced metalcasting as a science, as an industry, and as a community.
Go to the form and provide the following:
Please respond by July 29, 2016, and help us to identify the next metalcaster to join the FM&T Hall of Honor.
The sustainability of the green sand metal casting industry depends on having capable leaders in positions of responsibility. Future Leaders in Metalcasting (FLM) is a key AFS program to develop the next generation of leaders in the evolving metalcasting industry as they make their journey through the early stages of management tracks.
Sixty up-and-coming leaders met during the 121st Metalcasting Congress this April 26 in Milwaukee for interaction, networking and discussion of topics relevant to young leaders who are maturing into our industry’s future class of leaders. The event was one of at least two FLM meetings per year the group conducts to encourage its members to discover together best practices in team building, decision-making, strategic planning and plant operations.