At Meteor Foundry, core making is a big part of what we do. Over 2,000 square feet of factory floor space in our plant is dedicated to the art of core making. Just as a little refresher, cores are often used to form the internal cavities or undercuts in castings. Once they are used, cores are destroyed in order to get to the final cast part. Despite being disposable, cores are an integral part of the casting and molding process. There are two main types of sand cores that Meteor offers: Shell cores and CO2 cores.
First, sand coated with a resin binder is blown into a pre-heated metal core box. This heat transfer causes the binder to react, fuse the sand granules together, creating a shell out from the core box cavity surface profile. Time and temperature cycle determine the thickness of the sand shell; excessive sand is removed by rotating the core box, leaving a hollow. Shell cores are lightweight, have a fine surface and detailed finish, as well as a good shelf life. As one might expect, each application demands a different size and configuration. Shell cores are perfect for higher volume manufacturing, as well as projects that demand more precise internal finishes.
A mixture of sand and a liquid silicate binder is introduced into a core box. This molding sand mixture is then combined with CO2 gas, acting as a catalyst to bind the sand and harden. The CO2 core process offers a number of different advantages, including a relatively lower tooling cost versus shell, is capable of producing larger sand cores when needed, is good for low volume production, and molding sand is more readily recyclable after re-processing. The CO2 core is heavier by volume and has less shelf life than the shell process.
At Meteor Foundry, we have spent over half a century improving and innovative in the field of core making. The next big step for Meteor will be our introduction of more efficient, automatic core making machines. It is just another example of how the team at Meteor Foundry Co. is planning to compete in the global market.