Since its invention in the early 1950s, lost-foam casting has been a go-to technique for producing detail-oriented and highly dimensionally accurate metal products in several industries. In addition, this casting technique significantly minimizes fabrication costs in foundries due to the minimized need for extra machining.

Lost-foam casting is ideal for creating metal products in several industries, including automotive, arts, defense, agriculture, and computer technology. The process is suitable for a wide material range, such as cast iron, alloy steel, ferrous alloy, carbon steel, and alloy aluminum, enabling the production of different metal parts. Manufacturers leverage lost-foam casting to fabricate products, such as cylinder blocks, valves, automotive engines, gearbox details, fire hydrants, cylinder heads, and 3D models, since the technique creates castings with high dimensional accuracy. This technique is also well-suited for creating highly detailed and complex products, such as lamp posts, pump housing, pan support, gas burners, and fences. If the designs of your metal products are complicated and you prioritize excellent finishing and dimensionally accurate products, lost-foam casting is the most viable option.

1.Use Foam Molds for Foam Pattern and Gating System Production
In lost-foam casting, foam patterns mimic the precise geometry of the finished metal object. The gating system has passages that direct molten metal into the mold and may be integrated into the foam pattern or attached (glued on) later. These passages enable precise designs and streamlined metal flow, resulting in castings that are accurate and effective.

2. Bond Patterns and Runners to Create a Mold Bundle Module
Tightly bind the foam patterns and gating mechanisms to form the mold bundle module prior to casting. This assembly makes the casting process easier by ensuring precise component alignment, reducing mistakes, and facilitating reliable, consistent manufacture of complex metal parts.

3. Apply Dip Paint and Allow the Paint to Dry
An application of refractory dip paint follows the assembly of the mold bundle module. When this paint dries, it creates a protective ceramic coating that improves the mold's surface toughness, heat resistance, and capacity to handle the temperature and pressure of the molten metal.

4. Place the Module in a Sandbox and Fill It with Dry Sand
Coat the mold bundle module, set it within a molding flask, and cover it in dry sand. This phase ensures accurate replication of the desired metal part by supporting the module's shape, keeping it in place during casting, and facilitating uniform sand compaction.

5. Vibrate Molding to Fill the Cavity and Compact the Sand
Sand may now flow into every nook and cranny of the mold bundle module thanks to vibrations imparted to the molding flask. Through careful sand compaction and the elimination of air spaces, this procedure enables the creation of a high-quality casting with exact measurements and fine details.

6. Pour Molten Metal to Vaporize the Foam and Create Desired Castings
Carefully pour the molten metal into the mold, replacing the vaporized foam patterns. The metal solidifies to create the desired casting as it fills the spaces the foam left behind. As a result, the finished product closely resembles the planned form while minimizing flaws and blemishes. This technique supports complicated and complex shapes.

7. Clean the Castings After They Have Cooled
After the castings have cooled and set, clean the casting to get rid of any remaining sand, ceramic shells, and other impurities. To produce high-quality and aesthetically pleasing metal parts, this phase means that the final castings fulfill quality requirements, have smooth surfaces, and are ready for subsequent finishing procedures or assembly.

Lost foam casting is a process used to make complex and intricate metal parts. This method has the ability to create full, net-shape patterns with unparalleled dimensional accuracy and precision. It also cuts several steps out of the manufacturing and assembly processes that ultimately lead to saving time and extra labor costs.

Lost foam casting is best suited for intricate designs found in automotive, marine, agricultural, military, and heavy truck applications. It is also a perfect solution for mass-produced pieces that all need to be uniform in dimension and shape.

Let's dive deeper into six benefits of using lost foam patterns.

1. Dimensional Accuracy

The net shape capabilities of lost foam outpace all other technologies. With other casting methods, the material is simply meant to fill the mold but with lost foam casting, the polystyrene foam actually expands within the space, filling out every detail of tight internal passageways.

Other methods may require creating several patterns to piece together later if a part is intricately detailed or complex, leading to potentially inaccurate final castings. But with lost foam casting, the entire part can be cast as a whole, dynamic, 3-dimensional unit that is far more accurate and detailed with little risk of being thrown out for misconstruction.

While some methods have a challenge keeping dimensional accuracies in internal passageways, the best companies have a process that lends itself to intricate design, fully captured internal passages and perfect net shape dimensional accuracy that isn’t seen in other technologies.

2. Reduced Steps in Machining

Lost foam casting helps reduce the number of steps in the manufacturing process which translates to less time and labor costs.

While most other casting methods require additional machining and assembly steps to piece parts together and smooth out the rough edges, with lost foam casting, the process can help reduce the forming, conditioning or finishing steps required. By condensing intricate designs into a single unit, it minimizes the time and energy spent creating the final product.

Lost foam casting also reduces the amount of metal in the finished part. Since other technologies cannot provide the same net-shape accuracy — and oftentimes cannot obtain a whole cast — additional metal is used then extracted when joining pieces together. But with lost foam casting, there is less of a need for extra materials or effort.

In fact, it can help reduce the amount of overall waste, so it is an environmentally friendly option as well. Plus, lost foam castings can limit the amount of flash that requires secondary steps. because there is limited flash with lost foam casting.And since lost foam casting can provide a consistent surface finish, it can save manufacturers additional time and steps to get the right finish. Speed and accuracy are benefits every step of the way with lost foam.
3. Integration of Assemblies

Castings allow for fewer parts, which minimizes machining and assembly and ultimately reduces the cost of the end product. Detailed casts that would have been split into several parts using other technologies can be cast as a single and whole unit, cutting out several assembly steps and possible errors.


There is much less concern that pieces won't line up or fit together properly when using a full mold casting. And no need for additional welding or assembly steps to create the part.
Lost foam casting is best used for anything with internal passages, thin walls, or intricate design, such as cooling system housings, engine blocks and cylinder heads. It is perfect for any part with complex details and dimensions that cannot be fully captured otherwise.

And lost foam casting has a design flexibility that isn't seen in other casting systems. Design improvements are common over the life of a part and sand casting requires new tools and new parts to be able to accommodate these design changes. With lost foam, changes are easily accommodated in the patterns without the need for new tools.

4. Works With Five Molten Metals

Lost foam casting lends itself to intricate design and a variety of metals.

The expanded polystyrene (EPS) foam is designed to support ductal and grey iron, aluminum, brass and stainless steel, which are all commonly used in manufacturing. The metals just need to be hot enough to evaporate the polystyrene during casting.

5. Lower GWP Than Green Sand Casting

Creating foam patterns for foundries requires lower water and energy consumption than other alternatives. Lost foam allows for energy savings during the process when benchmarked against sand casting and leaves less of a carbon footprint.

There is also less metal used and less waste generated which makes for a cleaner manufacturing site. And since the sand in the lost foam casting process is not mixed with any binders, sand recovery is faster, easier and cleaner. Reusing and recycling sand cuts material costs as well.

The accuracy of lost foam casting means faulty products are not being tossed out due to the increased likelihood of errors found in the green sand casting process.

6. Widest Variety of Densities on the Market

Lost Foam Patterns by Atlas Molded Products are one of the most versatile products available. They feature parts from 1.4 pcf to 5.0 pcf (pounds per cubic foot). Patterns are also available with 3-4 mm wall thickness in order to minimize the weight of the castings.

They also do not contain any conflict materials and are resistant to most commonly found chemicals and chemical vapors.