The sand casting process requires a wooden or metal pattern, a sand core box, a furnace to melt the raw metal, grinders for fettling and removing flash, finishing equipment to improve the surface of the casting, various machines to finish the parts, as needed.

Molten metal is poured into the sand cast mold and, after it has cooled, the sand is removed manually or automatic shakers. The metal part is then fettled (by grinding) to clean up the excess metal flash (parting line), risers, gates, and spruces and then cut off and then a surface-treated via shot blasting or a similar process is used to get parts ready for finish machining.

Metal Alloys are obtained in the form of specked out ingots or scrap. These are then melted and alloyed to the metal specifications required.

1.The first step in the process is placing the wood or metal pattern, which replicates your metal part design, into a metal or wooden sand mold box.
2.Next, the box is filled with sand, which is compressed firmly around the mold/pattern to form the part cavity. Generally, a resin is added to the sand ahead of molding, so it cures solidly around the pattern.
3.The mold is then carefully removed from the sand leaving behind a cavity.
4.Molds are typically made in two halves: an upper portion (the cope) and a lower portion (the drag). These two halves are placed together to form the complete cavity, ready for metal to be added.
5.Molten metal is then poured into a spruce or runner, which is the hole in the sand to fill up the cavity.
6.The boundary between cope and drag is known as the parting line and this is ground off.
7.A riser (vent hole) that allows gas to escape as molten metal fills the cavity is also needed and excessive metal fills this as well. The riser can be part of the pattern or it can be added manually after the two sand mold halves are placed together.
8.Metal is melted in an electric induction or gas-fired furnace to the required temperature and is ladled or poured into the spruce that fills the mold cavity that was formed by the pattern. Gasses and air escape through the riser and once this hole is filled with molten metal, it indicates that the mold cavity has been filled completely.
9.Once the metal has had time to solidify and cool, the sand is removed.
10.The metal runners, risers, gates are still part of the casting and these are cut off with a cutting wheel or removed by a saw. The flash is also removed by grinding. This process is called fettling.
11.The castings are then cleaned by various methods (shot blast, etc.) to remove any residual sand and to blend any imperfections or parting lines.
12. The casting is now ready for machining.

 

Sand casting molds also know as patterns are made of wood or aluminum and can be changed to accommodate any small changes in designs so small changes are very inexpensive.  Sand casting can produce a wide range of different parts in weights ranging from less than 10 grams to thousands of kgs. XHX Precision Industry excels at casting parts with simple to complex geometries for industries across the industrial and architectural spectrums. Some examples of the parts we produce are listed below.

 

Our foundries can produce custom patterns in wood or aluminum to use in the sand casting process to produce any new or legacy metal parts you require. No matter what industry you are in, XHX Precision Industry can supply the metal parts you need!