Difference Between Die Casting vs Sand Casting
Sand casting is the most traditional method, which uses sand to make a cavity and pour it to obtain a casting. However, the pressure of the molten metal in sand casting is often insufficient, resulting in defects such as insufficient filling and cold shutting; thus, a new casting method has emerged: pressure casting, that is, die casting.
Die casting artificially provides pressure to enhance molten metal’s fluidity and filling capacity and obtain better quality castings. Die casting is a method in which molten alloy liquid is poured into a pressure chamber, the cavity of a steel mould is filled at high speed, and the alloy liquid is solidified under pressure to form a casting. The main features distinguishing die casting from other casting methods are high pressure and speed.
The Main Difference Between Sand Casting and Die Casting
What are The Advantages of Die Casting Compared with Sand Casting
High precision and surface quality
The die-casting process excels in precision and surface quality due to its unique process and operation method.
The high pressure brought by die casting allows the molten metal to fill every part of the mould, including some complex geometric shapes and tiny structures, which ensures the high precision of die castings.
The metal mould used in die casting effectively transfers heat, and the rapidly cooled metal helps to reduce thermal stress and grain growth and improves the material properties and surface quality of castings. Metal moulds have a high surface finish and precision that can be transferred directly to the casting, in contrast to the wood or sand moulds used in sand casting, which struggle to provide the same surface quality.
High production efficiency
The die-casting process can be applied to large-scale production, inseparable from a high degree of automation.
This high degree of automation includes using automated equipment and process flow. Once the moulds and equipment are set up, human intervention is almost unnecessary, reducing labour costs and potential operating errors and making the production process more stable and controllable.
Die casting also has a fast production cycle, only a few seconds to a few minutes, and each mould can produce multiple castings quickly, improving output and production efficiency.
High material utilization
The metal moulds used in die casting have long-term reusability and can be used tens of thousands of times or more without damage or wear.
In the die-casting process, because the design of the mould and the high pressure allow the metal to be fully utilized, there is almost no metal waste. The only possible scrap is the small amount of cooled metal that remains in the mould, which can often be recycled and remelted without waste.
In contrast, sand casting usually requires the manufacture of single-use sand moulds, resulting in lower material utilization and more waste.
Longer mold life
Dies used in die casting have a longer lifespan.
This is due to their high wear resistance, precision manufacturing, surface treatment, proper maintenance and economic efficiency. These moulds are usually made of high-strength tool steel or alloy materials, which can withstand high-pressure injection metal’s impact and high-temperature environment, so they are highly wear-resistant.
High-precision machining reduces the possibility of wear. The unique surface treatment further improves wear and corrosion resistance. Proper maintenance practices, such as regular cleaning and lubrication, as well as timely repairs and component replacements, can also help extend the life of your moulds.
Compared with sand casting, die casting is generally more environmentally friendly.
Die casting has a high material utilization rate, and almost all raw materials are used to make final castings, which helps to reduce raw material costs and reduce waste of resources.
Die casting can also save energy, reducing energy consumption in heating and cooling processes due to the fast cooling process and shorter production cycles.
It also reduces the need for chemical treatments, as metal moulds and rapid cooling help achieve high-quality surfaces and dimensions, reducing chemical contamination of the environment.
Since die casting typically does not generate large amounts of waste or hazardous waste, it reduces the cost of waste handling and disposal. In contrast, sand casting can involve handling and disposing of large volumes of sand moulds and waste.
Sand casting is less expensive compared to die casting, which is an efficient, precise and sustainable metal casting process for applications requiring high quality castings and mass production.