Core making is the first step in the casting production process. The core must be strong enough to support itself during the pouring process and yet it must break down at the proper time to prevent unwanted casting cracks from forming. We utilize both phenolic ester and urethane systems depending on the application. Additionally, a variety of core washes are also incorporated into the process depending upon the metal grade that will be used.
The core makes up the internal cavities of the casting. These cores, made manually, can be made from silica, olivine, or chromite sand. But similar to molding (see below), process sheets are created for every core box, so the operator knows exactly how to make them. The core needs to be strong enough to hold up to handling, coating, and pouring, but break down to allow the casting so contract during solidification.
Sivyer Steel makes heavily cored, complex geometry castings. This is accomplished through “lots” of cores and by placing them in the molds correctly. Since we are a job shop, we can take the time to make these complex castings. Some high quantity production type foundries aren’t able to accommodate this and still meet specified cycle times.
Sand Cast Molding
Sivyer Steel utilizes 100% phenolic ester binder systems in our air set molding process. We have 2 molding lines which utilize steel flasks ranging up to 150” x 210”. We utilize state of the art, programmable sand mixers capable of delivering up to 2000 pounds per minute while selecting from 4 different sand options. Our equipment can produce molds capable of consuming up to 24,000 net tons of steel per year.
Molding is the second process in metal casting production. Molds are made by mixing sand with a resin, and then compacting the sand around a pattern, made to the shape of the casting. They are made from predominantly wood patterns, that can be mounted or loose, depending on customer EAU. Making high quality molds makes high quality castings!
Molds, all horizontally parted, can range from a few hundred pounds of sand to over 100,000 lbs. Our molding and core processes can range from very simple, to very complex. All of these processes are controlled throughout the engineering department and distributed out on the floor through our ERP system.
Each casting, no matter what the quantity, size, shape, complexity, etc. has a set of detailed processes instructions created to instruct the foundry workers on how to create the highest quality molds and cores for our customers. In turn, an order today, or an order 1, 2, or 10 years from now, is made the same way.