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Green Sand Metalcasting Foundry News

Straight to Sand

Posted by Hill and Griffith Company on Mar 23, 2021 8:18:29 PM

Excerpt from the Modern Machine Shop October 2009 article by Peter Zelinski

Through direct CNC machining of molds and cores, this supplier of cast and machined parts skips the pattern-making step that would otherwise be fundamental to casting. The result is weeks of lead-time savings for complex parts that are needed in a hurry.

CNC machining is a proven technology for holding tight tolerances. Reg Gustafson of Clinkenbeard knows this. Clinkenbeard is a supplier of short-lead-time castings in Rockford, Illinois. Mr. Gustafson says the company's recognition of the basic effectiveness of machining ultimately showed it the way to respond, back when additive technologies for making molds and cores first began to succeed.

 

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Modern Machine Shop

Formwork for Visual In-Situ Concrete

Posted by Hill and Griffith Company on Mar 18, 2021 9:00:48 PM

Excerpt from the Concrete Quarterly by the Mineral Products Association (MPA) website

The texture of cast in-situ concrete is typically dictated by the formwork facing material providing an as-struck finish. The selection and construction of appropriate, good quality formwork is fundamental to achieving a good finish. Impermeable linings such as steel, polypropylene, glass reinforced plastic (GRP) and high density overlay (HDO) board produce a smooth, shiny surface whereas timber, unsealed plywood, paper-faced or medium density overlay (MDO) boards give a matte finish. Pattern or texture can be created by lining the formwork with a material to create the desired finish. Proprietary form liners are available with either established or bespoke textures or patterns. Timber boards are commonly used as a form liner to create a board-marked finish

 

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Tags: Concrete, Casting Solutions, Concrete Casting Products, Concrete Casting Supplies, Concrete Casting, Precast Concrete, Concrete Form Release Agent, American Concrete Pipe Association

Advances in Green Sand Reclamation

Posted by Hill and Griffith Company on Mar 16, 2021 5:15:34 PM

Excerpt from the Foundry Management & Technology January 2021 article by Jack Palmer

Now is the time to be look at newer sand reclamation technologies, to reduce cost and environmental impacts, and to enhance casting quality.

Most everyone realizes that sand reclamation is necessary for cost reducing and environmental requirements. While the popularity of sand reclamation certainly resulted from increasing sand prices (caused primarily by the demand for fracking), there are few processes that provide as many immediate benefits as sand reclamation.

Reducing the cost of sand is by far the most attractive consideration for sand reclamation, though lowering disposal and transportation costs are equally attractive. Couple these with reducing your environmental footprint and you realize that reclaiming sand is just good business.

One of the most overlooked benefits from sand reclamation is quality assurance. Controlling your materials through an in-house system will enhance the quality of your castings; because better sand makes better castings.

 

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Foundry Management & Technology magazine

Eliminating Green-Sand Variation at the Molding Location

Posted by Hill and Griffith Company on Mar 9, 2021 5:05:04 PM

Excerpt from the Foundry Management & Technology January 2021 article

Proactively monitoring sand temperature, compactability, moisture content, green compressive strength, and permeability will eliminate green sand variation at the molding location.

A common problem for metalcasters is proper green sand preparation. Even when the sand is prepared correctly, how can the foundry operators determine the accuracy of the formulation? How are the results recorded for repeatability purposes? How are changes implemented at the muller? Many foundries monitor sand by how the molding is performing. Proactive preparation of the green sand, accurately and consistently, will eliminate green-sand variation at the molding location.

Removing unwanted variations from the green sand properties is critical to producing consistent castings and running a successful foundry. Many factors contribute to variations in the way that green sand is prepared and delivered. Foundries usually have equipment from different manufacturers and perform different types of molding processes, which means they prepare the green sand from various recipes. It's important to determine what type of sand works best for each molding system.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products

Entrainment: Inclusions of Green Sand in Casting Molds

Posted by Hill and Griffith Company on Mar 2, 2021 9:48:35 PM

Sand Inclusions

Excerpt from the Complete Casting Handbook, Second Edition by John Campbell

Inclusions of molding sand are perhaps the most common extrinsic inclusion, but whose mechanism of entrainment is probably rather complicated. It is not easy to envisage how minute sand grains could penetrate the surface of a liquid metal against the repulsive action of surface tension and the presence of an oxide film acting as a mechanical barrier. The penetration of the liquid surface would require the grain to be fired at the surface at high velocity, like a bullet. However, such a dramatic mechanism is unlikely to occur in reality. Although the following description appears complicated at first sight, a sand entrainment mechanism can occur easily, involving little energy, as described next.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products

Elimination of Pinhole Porosity in Alloy Steels

Posted by Hill and Griffith Company on Feb 23, 2021 4:50:06 PM

Adding small amounts of ferroselenium and keeping charged nitrogen volumes low is effective in preventing subsurface porosity.

Excerpt from Foundry Management & Technology's February 2020 issue by Dr. R. L. (Rod) Naro and D. C. Williams

Nothing is more frustrating in foundry operations than finding an outbreak of subsurface porosity after costly machining operations. Outbreaks of subsurface porosity always seem to occur during high humidity seasons, especially during the rainy spring. The prime culprit universally blamed is hydrogen absorption into molten steels.

The hydrogen atom is the smallest and simplest of all the elements. Hydrogen can be absorbed only in its mono-atomic state. Nitrogen also can play a significant role in the development of porosity, especially in the production of high-alloy steel castings.

Hydrogen and nitrogen absorption in steel casting may result from alloy additions and reactions at the mold-metal interface. The ability of molten steel to absorb large amounts of hydrogen and nitrogen is shown in Figure 1.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Foundry Management & Technology magazine, Shakeout

Manufacturing Processes for Light Alloys

Posted by Hill and Griffith Company on Feb 16, 2021 8:53:03 PM

7.6.2 Selected expendable mold processes

Excerpt from the publication, Materials, Design and Manufacturing for Lightweight Vehicles by G.T. Kridli, et. al.

Sand casting is the most commonly used expendable mold process. In this process, sand is bound together (as detailed in  Table 7.8 ) and shaped to conform to the negative impression of the desired component. Molten metal is then poured into the sand mold; upon solidification, the metal has the geometry of the desired component.
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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Shakeout

High-Speed, High-Efficiency Core Box and Mold Cleaning

Posted by Hill and Griffith Company on Feb 9, 2021 5:36:28 PM

Progress Casting's dry-ice blasting operation cuts cleaning time by 86% and saves operating costs.

Excerpt from the October 2019 Foundry Management & Technology article

Metalcasters' product quality and performance results are under constant review, and new technologies and techniques are always being tested, or considered. But how often are maintenance methods reconsidered? Progress Casting Group in Plymouth, MN, produces precision die castings and sand castings it supplies to automotive, aerospace, and defense industry customers. It had a fairly standard problem — cleaning core boxes and low-pressure die casting molds — and a fairly standard approach to addressing it.

Core boxes and casting molds are meant to be used over and over again. So, they must be cleaned frequently and effectively in order to maintain dimensional accuracy and process reliability. The refractory coatings (i.e., release agent) and resin spray buildup on the mold faces, as well as sand and binder residue on the core boxes, had been removed by sand blasting and manual brushes. Both processes are slow and not fully effective. Sand blasting degrades the urethane on the molds and both methods routinely destroy the vents on the core boxes. More than this, the cleaning can damage machinery and workers' safety may be at risk in the process.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Foundry Management & Technology magazine, Shakeout

Reexamining Shakeout to Control Time, Temperature

Posted by Hill and Griffith Company on Feb 2, 2021 3:44:11 PM

What happens to castings during shakeout may be instructive to foundries seeking to optimize production costs and process quality.

Excerpt from the March 2016 Foundry Management & Technology article by G.D. Henderieckx.

Shaking out castings is done in different ways, according to a foundry’s specific molding operation, and mold cooling may require hours or even days for batch production and larger castings. There is much to be learned about the process: In general, shakeout timing is not calculated, and it is determined mainly by older, experienced employees using very safe operating practices (i.e., a long time).

What happens during the shakeout? First, the cast iron in the mold will transform its structure from austenite to ferrite (or pearlite, bainite or martensite). This initiates a transformation stress. The amount of stress depends on the final structure: transforming to martensite leads to the highest stress; transforming to ferrite to the lowest stress level. Austenitic materials have no transformation and will not suffer from transformation stress.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Foundry Management & Technology magazine, Shakeout

3D Printing As an Alternative to Pattern Making

Posted by Hill and Griffith Company on Jan 26, 2021 9:16:21 PM

3D printing has eliminated much of the tedium of the 3,000-year-old sand casting process

Excerpt from the January 2014 Additive Manufacturing article by Peter Zelinski.

Hoosier Pattern has changed its business in a way that dramatically expands the design freedom available to its customers. Historically, the company has machined foundry patterns. Today, it uses 3D printing to create molds and cores directly from sand.

That's sand casting in a nutshell, although journeyman pattern maker Dave Rittmeyer will tell you there's far more to it than that. Rittmeyer, the customer care and additive manufacturing manager at Hoosier Pattern Inc., Decatur, Ind., also will tell you the industry has undergone a dramatic shift over the past decade or so, thanks in part to AM.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metal Casting, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Additive Manufacturing Magazine

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