What is a Lost Foam Casting?

A lost foam casting is created by a type of evaporative-pattern casting process where a polystyrene foam pattern is used to form a mold. The foam pattern is coated and is embedded in a flask with a ceramic bead medium compacted around it to support the foams external form.  The foam is evaporated as molten iron is poured into the flask, with the iron precisely duplicating all of the features of the foam pattern.

Lost foam is advantageous for complex castings that would normally require cores.  It is dimensionally accurate, maintains an excellent surface finish, requires no draft, and has no parting lines.  The foam is easy to manipulate, carve, and glue which allows for consolidating many foam pieces into one complex component.

The polystyrene foam pattern can be cut with a CNC machine which makes this process an excellent option for rapid prototype castings.  There is no expensive tooling to be purchased upfront and it is a relatively quick process from designing 3D model to cut foam to iron casting in hand.


 Here is an example of a foam pattern and the finished iron casting.

Lost Foam Castings with Seneca Foundry

In 2010, a long standing customer approached Seneca Foundry to help solve a casting problem. Seneca Foundry responded to the customer need by developing our lost foam process. Our engineers took on the project by researching, experimenting, and developing the manufacturing system to efficiently produce high quality castings. From the beginning, the working relationship with the customer was the driving success in this start up.

With a reliable and consistent process in place, Seneca continued to grow this line by developing a close relationship with Austin Group, LLC. Specializing in lost foam rapid prototyping, Austin Group, LLC has earned its high reputation in the lost foam world by developing some of the most complex designs in the industry. For lower prototype quantities (one to twenty pieces), a Fabricated Foam method is capable of producing complex part designs without constructing any tooling.  This method is highly cost effective and typically a very low lead time to turn the prototype idea into a casting in hand. This method allows for designs to be tested and modified with less capital and time invested than traditional methods.

To meet the increasing customer demands of lost foam castings, Seneca Foundry responded by investing in additional capital equipment in 2017 that would allow us to more than double our lost foam thru put as well as improve operator ergonomics, increase the quality of the ceramic bead medium, and improve efficiencies within the process.

Check out our short video on the Lost Foam Process:


Simply click HERE to contact Seneca Foundry today for additional information on Lost Foam, we are looking forward to working with you on your next project.