Shell Mold Casting

Advantages of Shell Molding

Shell mold casting – often referred to as shell molding – is a precision casting process where resin coated sand bonds together thermally making a thin shell around a pattern to form a mold. The process involves heating a metal pattern and then introducing resin coated sand on top of the heated pattern plates to create a hardened shell. This shell acts as the mold for pouring molten metal, allowing for the creation of complex and high-precision parts.

The shell molding process is known for producing castings with excellent surface finishes and tighter tolerances, making it a preferred method for industries that require high-quality castings. Compared to other casting methods – such as green sand – shell mold casting delivers more consistent results with fewer imperfections.

Hiler Industries boasts two modern foundries that produce millions of castings every year — all using the shell mold process. Since 1946, we have been providing our customers the highest quality castings, in a variety of metals, all with an excellent surface finish and near-net shape.

Applications of Shell Mold Casting

Shell mold casting is widely used in industries where precision and high-quality surface finishes are essential. Some of the most common shell mold casting applications include:

Automotive components: Engine blocks, transmission housings and brake components benefit from the precision and durability of shell mold castings.
Wear Resistant parts: Due to the metallurgy of abrasive resistant castings providing an elevated hardness level, secondary processing such as machining is not favorable. Given the near net shape capabilities, the shell mold process is ideal for these applications.
Industrial machinery: Gears, valves and pump housings for heavy machinery are commonly cast to produce complex shapes with tight tolerances.
Electrical equipment: Housings for electrical systems are another common application for shell mold casting.

Shell molding is versatile and can be used with various materals – including aluminum, cast iron and steel – making it suitable for a wide range of industries.

Advantagesof Shell Molding

There are several advantages of shell molding over other casting methods including:

Superior Machining Qualities

A major benefit of shell molding is the excellent machining characteristics achieved through this process. Many photomicrograph inspections have shown that shell castings have what might be termed “cooling rate inversion.” Unlike green sand castings, permanent mold and die castings — which all have hard skins and “soft” interiors — shell mold castings have “soft” skins and hard or dense interiors. As a result, shell mold castings have superior machining qualities vs. green sand and other types of castings.

Less Weight

Another major benefit is the potential for less machining stock required. Over the years, we have found that .060 stock is more than ample. This is helpful in two ways:

The casting will weigh less, and thereby cost less
Less machining stock is removed, which improves machining time and lowers machining cost

There have been times when we worked with customers and eliminated machining entirely.

Additional Advantages

Superior surface finish: Shell mold castings typically have smoother surfaces, reducing the need for additional finishing work.
Tighter tolerances: The process allows for more precise control over dimensions, potentially minimizing the need for post-casting machining.
Improved machinability: Shell castings have a “soft” outer shell and a hard interior, which improves machining qualities compared to other casting methods.
Consistency: The process delivers consistent dimensional results and reduced side shift, allowing predictability when machine fixturing is applicable.

General Tolerance Information(Unit of Measure: Inches)

Same side of parting line:	± .020 for 1st 3″	Add ± .003 / inch over 3″
Across parting line:	± .030 for 1st 3″	± .003 / inch over 3″
Draft:	Typically 1°	Certain applications at 0° draft.
Typical Finish Stock:	.060″ maximum
Hole size cast into part:	DIAMETER	DEPTH
	Less than 0.5″	Equal to diameter
	0.5″ – 1.0″	Equal to 1.5 times diameter
	Greater than 1.0″	Equal to 2 times diameter

Note: The above information is modified by the individual casting complexity and to agreement between the customer and Hiler Industries. For example, we have held some dimensions to ± .010, obtained less than 1° draft, and used some finish allowances less than .030.

Shell mold casting is a versatile and cost-efficient solution for producing highly detailed metal parts. Its precision and ability to create intricate designs make it an excellent choice for various industries. When combined with Hiler Industries’ decades of experience, the process becomes even more valuable due to our commitment to quality and customer satisfaction. Whether you’re dealing with complex geometries or require a superior surface finish, choosing shell mold casting services with Hiler gives you the highest level of craftsmanship.

To learn more about how we can meet your casting needs, please reach out to us today. We look forward to working with you.

Superior Machining Qualities

Less Weight

Additional Advantages

Discover Quality Shell Casting and Molding Solutions