What is Squeeze Die Casting?
Squeeze die casting is more like an adjustment to the regular die casting process where casting and forging metal occur in a single step. Squeeze die cast has two types.
- Indirect squeeze casting
- Direct squeeze casting
The process of squeeze die cast works for not only non-ferrous metals but also ferrous metals. But it is mostly used to cast aluminum, copper, and magnesium alloys. Squeeze cast aluminum alloy parts has better mechanical strength than normal aluminum die casting parts.
The Step-by-Step Guide for Squeeze Die Casting
- At first, melt the metal.
- Then pour it into the lower half part of the cavity.
- When the liquidus metal starts to solidify, press the top half die (punch) on the metal.
- Hold the die (punch) until the metal solidifies completely.
- Finally, eject the part using the ejector.
The squeeze pin technology die casting is a part of squeeze casting. This technology reduces the parts’ shrinkage. The squeeze pin’s efficiency depends on both the pressurization duration and pin position.
Benefits of Squeeze Die Casting
- When casting and forging combine, it results in better mechanical properties for the components made by squeeze casting than normal casting parts.
- As the process is done with tightly sealed dies and high pressure, so the parts have low shrinkage.
- It is great for mass production because the process saves energy by operating through software programming.
- It is suitable for both non-ferrous metal (such as non-ferrous aluminum alloy)and ferrous metal, unlike most other die casting processes.
- The squeeze casting metal components have lower porosity than parts made by other casting processes.
- Manufacturers can use automatic machines for this process and thus reduce the cost of production.
Which Parameters Should Be Kept in Mind for Squeeze Die Casting?
For squeeze die cast, you have to keep some points in mind. These are:
Tooling and Casting Temperatures
The tooling temperature should be between 190 to 315oC. But the casting temperature will depend on which metal you are using. Usually, it has to be 6 to 55oC more than the liquidus temperature.
Pressure Level and Duration
The pressure level should be between 50 to 140 MPa in general. Applying pressure for 30 to 120 seconds can achieve satisfactory results for castings weighing about 9 kg.
There has to be a time delay between pouring the liquid metal and the punch before you can apply pressure on the melted metal.
Lubricating the dies with a colloidal graphite spray is better than using the dies directly for squeeze die cast of aluminum, copper, and magnesium alloys.
What Are the Differences between Die Casting and Squeeze Casting?
The below table shows a comparison of squeeze casting vs die casting:
|Squeeze Casting||Die Casting|
|It combines the benefit of forging and casting.||It does not offer the benefits of forging.|
|The velocity of pouring molten metal is slower than regular die casting.||Melted metal is poured faster than squeeze casting.|
|It takes longer than usual die casting to eject the final part.||The final part can be ejected faster than squeeze casting.|
|Squeeze cast parts have less porosity than normal die cast parts.||Normal die-cast parts have more porosity than squeeze cast parts.|
|Both high and low pressure can be applied simultaneously for squeeze casting.||Either high or low pressure can be applied for regular die casting.|
|Squeeze casting parts have lower shrinkage than regular die casting parts.||Die casting parts have higher shrinkage than squeeze casting parts.|
Which Defects Can Be Avoided by Squeeze Die Cast?
Practically no die casting method can completely get rid of defects. But the development of new techniques in die casting helps to reduce the defects as much as possible.
The most common defect in die casting parts occurs due to air void entrapment inside the cavity. Though squeeze casting parts are not 100% free of porosity, the parts have much less porosity than regular die-cast parts.
Another problem of regular die casting is the shrinkage of parts after solidification. This happens when the liquidus state metal is not dense enough before ejection or due to applying low pressure. Squeeze die cast reduces this issue by applying high pressure through the punch in the top die.
What Are the Applications of Squeeze Die Cast?
Squeeze die cast parts have better strength, better density, less weight, and more precise parts than normal casting parts.
- Brackets, chassis frames, nodes, steering knuckles
- Pistons and Engine blocks
- Alloys discs, SS blades, brass pipes
- Military bombshells, aluminum dome roofs, bevel gears, etc.