CPM Industries' Blog

3 Types of Cores used in Sand Castings (Part 2)

Posted by Tim Carlstedt

      Back for more?! In the second of an installment about Core Knowledge, we will be discussing a few more common names and terms associated with Loose Pieces.  Loose pieces are used by Pattern Makers to create attributes that cannot be created normally without modification.  The types of loose pieces that we will discuss today are the Attached Pieces, Drawbacks, and Pick-Out Pieces. (P.S If you haven't read part 1 yet, then go check it out first)

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Tags: Casting Design, Green Sand Casting Method, Casting Knowledge, Pattern/Foundry Tooling

3 Types of Cores Used to Make Sand Castings

Posted by Tim Carlstedt

How are hollow passage ways or special features put into a casting?


Through the Use of Cores that are Placed into the Mold Box!! 

In this part 1 of 2, we will discuss the common names and terms for Cores and Coreboxes that are used in the horizontal green sand casting method.  At CPM Industries, we often use Cylinder Cores, Balanced Cores and Dovetail Cores with Patterns to create the necessary passageways to meet the component's characteristics.  The article below discusses three types of cores that are placed on the parting line of the casting.

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Tags: Ductile Iron Castings, Casting Design, Aluminum Castings, Cast (Gray) Iron Castings, Magnesium Castings, Sand Casting Design Improvements, CPM Industries, Green Sand Casting Method, Casting Knowledge, Pattern/Foundry Tooling

Sand Casting vs. Investment Casting

Posted by Tim Carlstedt

What are the advantages and disadvantages between the Green Sand Casting Method and the Investment Casting Method?

This is a common question for the metal casting industry and CPM wanted to shed some light on the subject.  In this entry, we will first look at a comparision of the two different methods, followed by a explanation of the table, then lastly another table highlighting the advantages and disadvantages of each method in comparison.

 

Comparison of Green Sand Casting vs. Investment Casting

 

Green Sand Casting Method

Investment Casting Method

Relative Cost in Quantity

Low

Highest

Relative Cost for Small Number

Lowest

Medium

Permissible Weight of Casting

Unlimited up to approx. 1 ton

Ozs to 100 lbs.

Thinnest Section Castable (Inches)

1/10

1/16

Typical Dimensional Tolerance (Inches)

.012

.01

Relative Surface Finish

Fair to Good

Very Good

Relative Mechanical Properties

Good

Fair

Relative Ease of Casting Complex Design

Fair to Good

Best

Relative Ease of Changing Design in Production

Best

Fair

Typical Base Tolerances

+/- .040 – 1.00 in

+/- .003 - .008 in

Typical Surface Finish

150 – 350 RMS

63 – 125 RMS

Minimum Wall Thickness

.140 - .250 in

.094 - .187 in

Typical Tooling Cost

$800 to $5,000

$3,000 to $10,000

Well, WHAT DOES THAT MEAN TO ME?!

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Tags: Ductile Iron Castings, Ductile Iron Sand Casting, Casting Design, Aluminum Castings, Cast (Gray) Iron Castings, Magnesium Castings, Aluminum Sand Casting, CPM Industries, Green Sand Casting Method, Casting Knowledge, Secondary Machining, Finished Surfaces, Prototype Sand Castings, Pattern/Foundry Tooling, Patterns for Sand Castings, Cast Iron (Gray) Sand Casting, Investment Casting Method

Balance Core use in Sand Casting Pattern

Posted by Tim Carlstedt

This post is in response to several searches performed by our readers that wanted to know what a "Balance Core" is and how it is used in a sand casting.  Since we do have an House Pattern Shopat CPM Industries, I thought it would be appropraite to explain this particular type of core and it's importance in Pattern/Foundry Tooling for Sand Castings. 

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Tags: Casting Design, CPM Industries, Green Sand Casting Method, Pattern/Foundry Tooling

What Materials are Sand Cast Patterns made out of?

Posted by Tim Carlstedt

Sand Cast Patterns can be made out of several different types of materials


For Lower Volume runs (1, 10, 50, 100, etc.) that are typically involved in prototyping, then a Poly-Urethane Board will be used to create the pattern.  At CPM, we normally work with Brownboard and Redboard, which are types of Poly-Urethane Boards, to create our Prototype / Short Run Castings

 

The benefits of using this material is the ease of machinability, changing, and lower cost.  These are not meant for high volume and will wear down more quickly over time.  For Example, Brownboard is best served for quantities of less than 100, while Redboard can withstand much larger quantities due to it's strength.  Redboard is often used for Air Set Sand Castings which can will increase the life of the Redboard tool.

The Poly-Urethane Pattern will then be placed in/on a mold box or matchplate.  This will be variant on the size of the part, quantites, and other project goals.  For example, some large casting's patterns cannot fit into automated machines that use matchplates, so a mold box will be utilized.  For most short runs, a mold box is used due to the time it takes to create a matchplate and cost of the matchplate.  As you can tell there are more factors that feed into the decision of the correct material and what type of pattern to create. 

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Tags: CPM Industries, Green Sand Casting Method, Casting Knowledge, Prototype Sand Castings, Pattern/Foundry Tooling, Patterns for Sand Castings, Air Set Casting Method, EAU of Casting Projects

A CPM Example: From CAD Model to Finished Aluminum Sand Casting

Posted by Tim Carlstedt

A Look into CPM's Turn-Key Capabilities for an Finished Aluminum Sand Casting!

    We were recently asked to show an example of a Turn-Key Cast Component that we have made here at CPM Industries.  So, why not share it with the world!  What does Turn-Key mean to us?  This means that the project will go from Engineering Assistance, Pattern Tooling, Casting, and Secondary Machining.  We also perform any other additional testings that may be required.

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Tags: Casting Design, Aluminum Castings, Aluminum Sand Casting, Casting Wall Thickness, CPM Industries, Secondary Machining, Finished Surfaces, Pattern/Foundry Tooling

Aluminum Plaster Casting? What is that?

Posted by Tim Carlstedt

  Recently, I was asked to describe what Plaster Casting was and the benefits of using this method.  What a perfect topic!  At CPM, we provide Aluminum Plaster Castings primarily to Simulated Die Casting in Short Runs of 15-30 for Prototyping and Testing Operations. For runs of 1 or 2 parts, then it is often best to go with a Rapid Prototyping such as a SLA.

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Tags: Casting Design, Aluminum Castings, Aluminum Sand Casting, Simulated Die Casting, Plaster Casting Method, CPM Industries, Casting Knowledge, Prototype Sand Castings, Pattern/Foundry Tooling

Cope & Drag of a Sand Casting Pattern

Posted by Tim Carlstedt

Today's Question: What Does Cope and Drag Mean in the Sand Casting Process? 


   Cope and Drag refer to the two halves (top and bottom, respectively) of a Pattern or Mold that is used in the Green Sand Casting Method.  So let's get down to the basic of how a casting is made and figure out how all the steps work together.  The first step is that a pattern must first be planned and created.

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Tags: Casting Design, CPM Industries, Green Sand Casting Method, Pattern/Foundry Tooling

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