WHAT IS GRAVITY DIE CASTING?
Gravity die casting is one of the oldest methods for metal or metal alloy casting. Here, the metal is poured inside the cavity in liquidus form using a ladle or a vessel. The cavity hole has to be on the top surface. There is no external force but gravity that fills the cavity after pouring the molten metal.
Gravity die casting machines have the following types:
Sometimes it is necessary to tilt the die to control the pouring. Manufacturers use sand cores to keep holes or pores in the casting part if necessary.
Aluminum gravity die casting is better and faster than the sand casting of aluminum. But conventional aluminum die casting, where an external force is used to push the molten metal, is better than gravity casting.
Step-by-Step Process of Gravity Die Casting
Most gravity die casters do this manually. However, the process is quite similar for both manual and automatic machines.
- At first, heat the die and spray coating inside the cavity.
- Then melt the metal and convey it through a ladle. Note that if the casting machine is manual, then you have to pour the molten metal by hand.
- After that, slowly pour the liquid metal into the cavity.
- Then wait for it to solidify.
- Next, take out the part after opening the die.
- Finally, machine the part as necessary.
What Are the Benefits and Drawbacks of Gravity Die Casting?
The benefits of gravity die casting are:
- No external force is necessary for pushing the molten metal.
- Gravity die cast components have better density than sand casting parts.
- This process costs less than most other processes like vacuum casting, squeeze casting, etc.
- Gravity casting parts have less porosity and better grain structure than sand casting parts.
- For medium or small volume production, it is cheaper than other methods.
- Gravity casting components have good mechanical properties, which are great for heat treatment.
- The component’s surface has a better finishing than most other casting parts.
Some of the drawbacks of gravity die casting are:
- Manual gravity die casting takes more time than other casting processes.
- Automatic gravity die casting parts are less precise than manual gravity casting parts.
- It is complicated to manufacture complex parts using this method.
Is Gravity Die Cast Good for Mass Production?
When gravity casting was first invented, manufacturers used this technique to produce simple parts rather than complex ones. But in time, the technology updated, and sand cores were introduced in gravity casting. Now manufacturers can make complex parts with the gravity casting method.
However, now there are more updated die casting methods that are faster for producing certain casting parts. Many die casting manufacturers prefer these methods more than gravity die cast for mass production.
However, it is significantly cheaper than most other methods. Though this method takes more time, it saves a lot of money because gravity die-cast machines cost less. Also, this method is simpler than most other casting methods.
So choosing a gravity die cast for the mass production of simpler parts is better. But it will be a loss if manufacturers use this method for a large volume of complex parts’ production.
Of course, if the production volume is small or medium, the gravity casting method is a better choice than most other die casting methods.
What Are the Applications of Gravity Die Cast?
It is not impossible to make complex parts using the gravity casting method because of today’s updated technology. Many industries like automotive, kitchen components, lightings, etc. use this process to manufacture different parts and appliances.
Some common gravity die cast applications include:
- Automobile parts like engine pistons, blocks, cylinder heads, brake calipers, etc.
- Lighting parts like LED light housings, base materials, etc.
- Kitchen components like spoons, pots, etc.
Which Castings Can Be Alternatives to Gravity Die Cast?
For large volume production of intricate parts, aluminum die casting is a good alternative to gravity die cast. Another good alternative is Sand casting. But sand casting parts require more post-production machining, and so it is costlier in some cases.
For making more precise parts, HPDC (high-pressure die casting) is a good alternative. But HPDC is more expensive, and so it is better to use it for complex mass production.