The process of sand casting is quite flexible. It is beneficial in terms of economies of scale for large production. Besides, the process is flexible in terms of producing complex parts to replace welded or assembled components. Molds made of silica sand have good temperature resistance capacity. They have good mechanical strength that helps them cast almost all metals like aluminium, brass, bronze, steel, or cast iron used in the engineering industry.

However, each application is to be done by careful selection of the right techniques while producing sand molds and pouring liquid metals. The key factors to drive the selection process of sand casting are as follows:

• Production quantity
• The complexity of the parts
• Tolerance level
• Level of acceptable quality

Steps to Know in Respect of Sand Casting

Let’s have a look at the major steps.

• Pouring – This is the step where hot liquid metal is poured into the sand molds. The step can be accomplished by any of the following methods:
• Tilting the ladle manually
• Bottom pouring ladle – the plug can be managed to ensure opening of the metal flow
• Automatic pouring machine to run the pouring operation – the operation is controlled by a computer

Now which technology for pouring will be chosen depends on the production quantity. If it is a shorter run, manual pouring would be the right choice. But for a larger run of the same part, automated pouring would be better.

• Designs – The part molds are produced in various ways based on the complexity and the main ways are,
• Green sand molding – it can be either automatic or manual
• Chemically-bonded sand molding – it is done manually

Large production, small parts, and simple geometries help to facilitate automated green sand molding. On the other hand, larger and complex parts along with short production runs are usually made with costly chemically-bonded molds.

However, you can combine the sand molds with cores or loose sand parts during the production of castings for more intricate geometries that can’t be otherwise achieved by other commonly used methods. In the case of the complex parts, the geometry may be needed to change for accommodating requirements needed for the molding process. This includes the addition of drafted surfaces to pull the patterns for shaping the molds.

• Level of tolerance – Sand casting method is not one of the most precise metal casting procedures. But you can achieve a tolerance level of +-0.030” on the parts that are smaller than 6 inches with an extra +-0.003” for every extra inch over 6 inches. Achieving more tolerance level is possible with non-typical process control. However, to make things cost-effective, it would be good to add machining operations on surfaces that require high accuracy.

These are a few important things that you must know in order to choose the right method of sand casting to facilitate your operations depending on your individual requirement.