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Green Sand Metalcasting Foundry News

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

How 3D Printing is Changing Sand Casting

Posted by Hill and Griffith Company on Jan 19, 2021 9:33:14 AM

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

Excerpt from the September 2020 The Additive Report article by Kip Hanson.

Humans began pouring the first sand castings approximately three millennia ago. And until recently, that technology has remained virtually unchanged:

• A replica, or "pattern," of the desired object is placed in an open-ended, steel molding box.

• A special type of sand is poured around the pattern, which is pounded firmly into place and then removed.

• A sprue is cut to allow molten metal to flow into the mold, along with a gate that joins the sprue to the mold cavity.

• A core is used to replicate parts having internal features.

• Molten metal is poured into the mold; when the metal cools, the completed part is removed.

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, The Additive Report

Casting Goes Digital with Sand 3D Printing, Nondestructive Testing

Posted by Hill and Griffith Company on Jan 12, 2021 5:04:14 PM

Tooling & Equipment International (TEI) used to make tooling for castings. Now, it casts prototype parts in a digital workflow using 3D printed sand molds in combination with simulation software, CT scanning and X-ray technology.

Excerpt from the January 2019 Additive Manufacturing article by Stephanie Hendrixson.

"In the early days, before numerically controlled machines, casting tools were made by highly skilled pattern makers carving mahogany into patterns and packing sand around them," says Oliver Johnson, president of Tooling & Equipment International (TEI). "You'd be talking six or nine months to make all the tooling for a part that we could do today with a 3D printed mold in two days."

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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

Novel Sprue Designs in Metal Casting Via 3D Sand-Printing

Posted by Hill and Griffith Company on Jan 5, 2021 5:07:26 PM

Excerpt from the January 2019 Additive Manufacturing article by Santosh Reddy Sama, Tony Badamo, Paul Lynch, and Guha Manogharan.

The market size of the metal casting industry was 20.23 billion USD in 2017 and is expected to grow annually at a rate of 8.87% to reach 39.94 billion USD by 2025. Engineered castings constitute about 90% of total manufactured goods and capital equipment. In United States, over 2000 metal casting facilities employ more than 200,000 people across the country. Despite having a casting market share of 80%, sand casting foundries across the globe suffer from long lead times, expensive tooling and limited flexibility. It is well known that the pattern making step in sand casting is the bottleneck and often, the most expensive component in low volume production runs. The need to remove the pattern from compacted sand mold to create casting cavity significantly restricts the geometries in traditional sand castings. The increased complexity of metal parts for industrial and mission critical applications demands new technologies. Recent advancements in 3D Sand-Printing (3DSP) which is a form of Additive Manufacturing (AM) bridges this technological gap through direct printing of sand molds in a layer-by-layer 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

Core Design is Key to Successful Castings

Posted by Hill and Griffith Company on Dec 29, 2020 8:00:00 AM

Excerpt from the November/December 2020 Casting Source by Jiten Shah.

The green sand casting process is the most widely used high-volume process because it is versatile and cost effective. In the case of an oil pan for a combine used in the agriculture industry produced by AFS Corporate Member Wabash Castings Inc. (Wabash, Indiana), the green sand process proved it versatility after eliminating some issues in the old design, which was cast in the semi-permanent mold process. Thanks to the flexibility in gating placement and design changes in the green sand process, the new casting reduced cost by using a common core for two cavities inside the part.

Critical wall thickness is maintained repeatedly with horizontally-parted green sand molding using a rugged common core for two mold cavities.

  • Critical wall section thickness (1) in the oil pan is controlled with a massive common core that is well supported at the core print. The main body core has an overhang, like a cantilever, and if not designed carefully, it could sag or deform, resulting in uneven wall thickness. This could potentially lead to shrinkage porosities and non-uniform mechanical properties due to uneven cooling rates of thinner and thicker sections within the same casting.

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

Preliminary Investigation into the Cause of Pinhole Porosity in Aluminum Metal Castings

Posted by Hill and Griffith Company on Nov 24, 2020 8:00:00 AM

Excerpt from the University of Northern Iowa dissertation by Brodie J. Biersner.

Introduction

Sand Mold Design
There are many molding methods available to produce a metal casting. The majority of metal castings however are produced with sand molds. This method for the production of metal casting has advanced over the years—from the materials utilized to the types of molding equipment and processes. Historically there was a lot of manual labor required for the production of a sand mold. Today, high speed molding machines are used with minimum amounts of human labor required. For sand casting to be successful for foundry applications, certain criteria must be met. The principal feature is good compatibility between the binder system and the sand aggregate chosen. This combination must also be compatible with the metal alloy used to produce the casting.

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

Green Sand Casting Process

Posted by Hill and Griffith Company on Nov 3, 2020 5:01:03 PM

Excerpt from the Metal Casting Institute website.

Green sand casting is generally considered the easiest casting system because it is possible to use an existing part as a pattern for a one-off project. However, it is also used for some high volume projects also. The major benefit of this process is that the sand is easily recycled with low smell and a low ecological impact. When used to form parts out of aluminum alloys, the sand mixture has an impact on the final quality due to the potential for hydrogen gas pick up in the metal from the moisture in the sand. Therefore, with aluminum, green sand is generally used to form simple shapes and parts that aren't susceptible to leakage.

The process has four primary factors considered important:

  1. Sand Quality
  2. Pattern precision and alignment between cope and drag
  3. Gating and riser design
  4. Metal Control

 

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

Following the Trends to Better Designs, Better Castings

Posted by Hill and Griffith Company on Oct 27, 2020 5:08:18 PM

Excerpt from the September 2020 Foundry Management & Technology Article by Robert Brooks.

CAD meets casting simulation, and then 3D printing, as a specialty manufacturer effectively converts another complex assembly to a more efficient, lightweight casting.

One or two technology cycles ago, metal casters were enthusiastically adopting simulation programs to identify the causes of quality defects during casting production. That wave of development, still in progress, was prompted by the emergence of CAD programs that optimized casting design. One trend line in the current metal casting technology cycle is adaptation of CAD files to guide additive manufacturing programs, as in 3D-printing of bonded sand into optimally designed molds and cores.

Now, all these trend lines are converging with still another initiative in metal casting — redesigning castings (or fabrications, or other assemblies) as lighter, more functionally effective cast structural elements of vehicles, machines, etc. In the example of one manufacturer, coordinating these trends also made it possible to expedite the design of a customized machine to maximize the potential of its market niche.

 

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

Changes to New Sand Additions at Cadillac Casting

Posted by Hill and Griffith Company on Oct 20, 2020 7:29:57 PM

Excerpt from the October 2020 Modern Casting Article by Travis Hepfner.

An AFS Green Sand Division revealed foundries are handling new sand additions differently from what has historically been standard. Here, one foundry shows why and how it eliminated new sand additions altogether.

A recent survey by the AFS Green Sand Division asking foundries about their new sand addition practices revealed what was once considered a common practice was not so definitive for every plant. While 300 lbs. of new sand per 1 ton of iron poured has been an industry baseline, discussions with many sand foundries showed that for some, the practice of adding new sand had been eschewed for using their core sand as “new” molding sand.

In the survey of 47 sand foundries, 10 were not adding new sand, other than the core sand input. One of those foundries was AFS Corporate Member Cadillac Casting. While presenting at the virtual 2020 Sand Casting and Additive Manufacturing Conference last month, Travis Hepfner, quality engineer at Cadillac Casting, shared the foundry’s path to eliminating new sand additions.
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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Coatings, Green Sand Release Agents, Green Sand Metalcasting, Core Binders, Green Sand Additive Products, Modern Casting Magazine

Solidification Structure in Sand Casting

Posted by Hill and Griffith Company on Oct 13, 2020 3:44:58 PM

Excerpt from the Complete Casting Handbook (Second Edition) 2015 by John Campbell.

External chills

Placing a block of metal on the pattern in a sand mold and subsequently packing the sand around it to make the rest of the mold is a widely used method of applying localized cooling to that part of the casting. A similar procedure can be adopted in gravity and low-pressure die-casting by removing the die coat locally to enhance the local rate of cooling. In addition, in dies of all types, this effect can be enhanced by the insertion of metallic inserts into the die to provide local cooling, especially if the die insert is highly conductive (such as made from copper alloy) and/or artificially cooled, for instance by air, oil or water.

Such chills placed as part of the mold, and that act against the outside surface of the casting, are strictly known as external chills to distinguish them from internal chills cast in and become integral with the casting.

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

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