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Green Sand Metalcasting Foundry News

Optimizing New Sand and Core Sand Additions in Foundry Green Sand Systems

Posted by Hill and Griffith Company on Jan 14, 2020 8:00:00 AM

The old rule for new/core sand additions is 300 lbs. per ton of metal poured, but that approach needs to be re-evaluated (and made more exact) for current molding methods and materials.

Article from the Foundry Management & Technology August 2005 issue by Mark Ziegler.

In order to understand the effect of core sand and the various binder systems on green sand properties and castings, the new sand's contribution to the dilution must be established. The objective of this research is to create a model where different amounts of new sand and core sand are added to system sand so that the green sand's properties and casting results can be evaluated. Initial work by the Green Sand Committee of CISA has shown that certain levels of new sand can be added, along with new clay/additives, to maintain consistent green sand properties. The study also found that there are critical levels where major changes in the green sand properties occur.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metal Casting Design & Purchasing

Nobake: The Basics

Posted by Hill and Griffith Company on Jan 7, 2020 8:00:00 AM

Dozens of chemically bonded sand molding methods exist, but they can be divided into three main categories: coldbox, heat-activated and nobake.

Excerpt from the Metal Casting Design & Purchasing January/February 2018 issue.

The basic principle is that a binder and catalyst are mixed with the sand to help form the mold into a “brick-like” product when cured. The differences in the process focus on the sand resin binder and catalyst used and how the mold or core is cured.

Coldbox—with this method, sand is coated with one of several binders, such as liquid sodium silicate or phenolic urethane, and catalyzed by a gas (such as carbon dioxide or sulfur dioxide) passing through the sand. This causes the resin binder to harden (cure) and lock the sand grains in place to maintain a solid mold wall.

Heat-Activated/Shell (also called hotbox and warmbox)—heat is used as the curing means in shell molding. Plastic resin-coated sand is compacted around a pattern and allowed to rest until a “shell” forms. The mold then is heated to temperatures higher than 500F (260C) to cure the mold.    

Nobake (also called airset, dry sand and precision sand)—like coldbox, several binders are optional. However, a liquid catalyst is used. The sand is processed in a continuous mixer and then formed around the pattern until it is fully cured.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metal Casting Design & Purchasing

Selecting the Right Green Sand Heater

Posted by Hill and Griffith Company on Dec 31, 2019 11:28:39 AM

For foundries that prepare chemically bonded sand for molds and cores, optimizing the process means understanding and evaluating the primary features and options for water-based and electric-resistance systems.

Excerpt from the Foundry Management & Technology Magazine February 2019 issue by Jack Palmer

In general, there are two types of sand heaters used to prepare chemically bonded sand for molding and coremaking, and both are designed as fluid bed processes — meaning the sand is moved around the heating/cooling elements with compressed air or blower air. The more popular style is the electric-resistance fluid bed with compressed air fluidization, followed by water-pipe units in which hot or cold water is passed through piping, with fluidized sand moving around them with blower air.

The popularity of the electric-resistance type heater is due primarily to cost (compared with water-pipe designs) and size. The electric-resistance units are much smaller than the water pipe-based designs, though both offer advantages.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Foundry Management & Technology magazine

Smooth Moves: Sand's Impact on Surface Finish

Posted by Hill and Griffith Company on Dec 24, 2019 8:00:00 AM

Different Types of Sand Molds and Cores Used by Your Supplier Will Impact the Surface Finish of Your Castings.

Excerpt from Casting Source Magazine Jan/Feb 2016 issue

For many casting buyers, a smooth, uniform surface finish is more than a visually appealing bonus. It can be a sign that the casting supplier has produced a high-quality component. Perhaps more importantly for the casting buyer, a proper surface finish can lead to eventual cost savings in the cleaning, finishing and machining of the part.

Castings produced in sand molds can have relatively smooth surfaces, but if need be, the baseline surface finish can be improved through various means, though such gains will come with additional costs. Discussions with casting suppliers can help buyers understand potential solutions and associated costs.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Casting Source Magazine

Semi-Permanent Release Agents for Cold Box Core Production

Posted by Hill and Griffith Company on Dec 17, 2019 4:42:37 PM

Posted to Metalworking World Magazine Jan. 16, 2017

There are several different types and formulations for release agents used in the cold box process. In highly stressed areas of the core box, traditional release agents do not function well. A new resistant release coating based on novel technology that adheres to the core box has been developed and introduced into foundry production to combat resin wipe-off. Trials were run, monitoring the number of cycles before the release coating needed to be re-applied. Data is presented from the trials. The testing shows the coating to be effective up to several hundred or even thousands of cycles between applications.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metalworking World Magazine

"No-Bake" Green Sand Castings

Posted by Hill and Griffith Company on Dec 13, 2019 9:00:24 AM

Excerpt from the March 2016 issue of Metalworking World Magazine

Sometimes, we believe foundries are similar. However, there are dozens of technical distinctions that differentiate green sand casting plants. Due to these large or small differences, we should define the technological advantages that transform a process from inefficient to concise. From this observation, foundry customers should know the productive processes in more depth to choose the most suitable one for producing the most competitive casting products.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metalworking World Magazine

Bringing Big Data to Green-Sand Processing and Control

Posted by Hill and Griffith Company on Nov 19, 2019 5:19:18 PM

Cloud-based software promises to reduce green sand casting rejects and optimize additive consumption by applying predictive and prescriptive data analytics, machine learning and IoT functions to green-sand molding

Excerpt from the March 2019 issue of Foundry Management & Technology

The Smart factory "vision" is gaining global acceptance. It involves integrating data analytics, machine learning and IoT by incorporating sensors, SCADA and line-speed or near-real-time data-based analytics for process optimization. Predictive and prescriptive data decision-support, predicting highly accurate outcome has shifted the paradigm in manufacturing and many other industrial and consumer sectors. For manufacturers, rapid proliferation and advancement of information technologies, such as cloud computing, allows them to generate and store huge volumes of data.

In addition, the digitalization of the green sand casting process automation has empowered industries to collect and transmit near-real-time data. Cloud computing ensures data availability without geographic or physical limitations. By leveraging the power of data-based analytics and machine learning, industries are generating significant tangible and intangible profits.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Foundry Management & Technology magazine

Solving Hot-Sand Problems: A guide, and a solution

Posted by Hill and Griffith Company on Nov 5, 2019 9:03:10 PM

Todays foundries cannot afford to sacrifice the efficiency and profits that are the consequences of poorly controlled hot molding sand.

Excerpt from the June 2003 issue of Foundry Management & Technology

Metalcasting researchers say hot sand is the leading sand-related problem for today’s foundries. Most metalcasters recognize a relationship between reduced casting quality, increased process variation, and other molding inefficiencies that result from using hot molding sands. Studies show that hot sand affects virtually every operation in the production line.

System sand returned to the muller for reconditioning with a temperature of 160°F (approximately 70°C) or greater is considered to be excessively hot. Return sand ranging from 120° to 160°F (approx. 49°-70°C) is hot enough to demonstrate inconsistent properties during mixing and to be very difficult to control.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Foundry Management & Technology magazine

Robotic Green Sand Printing a "Game Changer"

Posted by Hill and Griffith Company on Oct 29, 2019 5:43:00 PM

Excerpt from the November 2017 issue of Additive Manufacturing by Brent Donaldson

Atop a high plateau between the Susquehanna and Delaware Rivers, American manufacturing used to run through the heart of Hazleton, Pennsylvania. Or at least large deposits of high-carbon anthracite coal, the discovery of which helped launch the United States to global dominance in manufacturing throughout much of the 19th and 20th centuries.

Today, tucked behind the Weir Minerals building off of North Cedar Street, you’ll find the Hazleton Casting Company(HCC)—a specialty high alloy foundry that utilizes centuries-old techniques for its casting operations, which serve makers of pumps and valves among many other manufacturers. But you’ll find something else there, too: a quiet glimpse into the future of industrial foundry operations.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Additive Manufacturing

Defect Detective: Common Green Sand Flaws

Posted by Hill and Griffith Company on Oct 22, 2019 3:47:48 PM

Green sand quality control, including good critical visual inspection, helps avoid scrapped castings.

Excerpt from the July 2018 issue of Modern Casting by the AFS Institute

Quality control begins with prevention. Metalcasters can control five areas of green sand mold making in order to prevent mold defects:

  • The selection of type of sand and clay and the amount of moisture needed to make the mold. 
  • Consistent mulling, using the right sequence of raw materials, and selecting the right temperature of the sand.
  • The cleanliness and condition of horizontal and vertical patterns, as well as core placement.
  • Selection of scrap metal and determining what can be reused and what must be discarded.
  • Testing for quality ensures the part meets the requirement of the buyer. While casting can be tested many ways, one of the major casting quality tests used after the casting is made is visual inspection.


Nine common types of green sand casting defects can be visually identified:

  • cracks
  • holes
  • rough surfaces
  • tear-up/drop
  • friable edges
  • excess parting spray
  • missing components
  • loose sand
  • sand contamination
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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Modern Casting Magazine

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