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What is Sand Casting?
Sand casting (sometimes called sand mold casting) is a technology that has existed for thousands of years and is a preferred metal casting process to produce shaped parts that weigh from less than a pound to thousands of pounds. Sand casting is versatile and cost-effective even for low volumes because of low tooling costs. Nearly any part configuration made using another metal casting process can be reduced to a pattern and created as a sand casting.
In sand casting, a pattern of the desired finished part, including the metal delivery system (gates and risers), is constructed out of hardwood, urethane, metal, or foam. Sand containing bonding material to maintain shape is packed around the pattern. The pattern is then removed from the bonded sand, leaving a cavity in the sand mold in the shape of the part. Molten liquid metal is poured into the cavity, and the metal solidifies. The sand is then removed through a shakeout process. Other cast attachments including the metal delivery system are removed, leaving the desired part.
MetalTek uses the air set or no-bake molding process. Sand is chemically bonded together to create a tighter bond and doesn’t require a heat source to solidify the no-bake mold.
Internal passageways including intricate structures can be included in sand casting by adding cores. This makes sand casting a popular choice for pump and valve applications. Sand castings are typically at least partially machined before use.
Sand castings can be readily produced in nearly any ferrous or non-ferrous alloy. We primarily pour ferrous alloys like stainless steel.
If your project requires stainless steel sand castings, please contact us today. If you require sand castings in a non-ferrous alloy, we will evaluate the project to determine if MetalTek is a good fit.
MetalTek produces sand castings up to 15 ft. (4.6 m) linear with ship weight up to 18,000 lbs. (8,165 kg).
See the video to the right to learn more about sand casting.
As an alternative to packing sand around the pattern, many customers take advantage of MetalTek’s patternless molding technology. A reverse of the casting is machined from sand to create the mold, rather than forming sand around a pattern. Production then proceeds normally. Timing is quicker than traditional sand casting, design changes are easy to implement, and hard patterns need not be stored or maintained.
Sand Casting Video
when to use sand casting
External shaping exists
Internal structures and passageways are used
Desired size ranges from a few pounds to 18,000 lbs. (8,165 kg)
As-cast surface finish of 250 – 500 RMS is acceptable
Post-cast machining is acceptable to achieve desired surface finish
Extremely tight tolerances are not required
Frequent design changes are expected
Tooling and pattern costs for investment casting are too high
Periodic cost of maintaining the tooling and pattern is acceptable
Converting multi-piece component to a single casting
Wicket Gate Assembly Components
MetalTek provides multiple wicket gate assembly components in a variety of alloys and sizes.
Francis Turbines feature an inward flow reaction to spin the turbine and count on consistent material and fin profiles.