Whenever we talk about die casting, one of the first things that come to our mind is HPDC, or High-Pressure Die Casting to be exact. The HPDC is a complex process that forces molten metal inside a sealed mold cavity to ensure the perfect shape and size. The process also uses extreme pressure to ensure that the mold solidifies without any issues. Most of the time, this process is done in a hydraulic machine to harness its extreme compressive power.
Once it is ensured that the liquid metal inside the mold is fully solidified, the die is released. After that, the die cast mold cavity is removed on the next process cycle.
You will be surprised to know that the molten metal injection taking place in this HPDC process takes only a fraction of a second. The average metal injection in High pressure die casting is usually under 90ms. And the average pressure that is applied in this casting process is around 1000 bar.
High-pressure vs low-pressure die casting: What is the difference
Regardless of which type of die casting you want to use, the core objective always stays the same: melting the metal at a high temperature and solidifying it into your desired shape. However, depending on our casting method, we can classify them into various sub-categories. Each of these subcategories has something unique to offer.
Now the most popular method for casting is, without a doubt, the application of positive pressure. This pressure forces the metal into the mold cavity and fills every part of the volume to ensure the desired shape. However, how we apply this pressure can differ on various casting methods.
Depending on how we are accomplishing the positive pressure, there are two different categories of die casting. They are,
- High-pressure casting.
- Low-pressure casting.
In a low-pressure die casting method, the aluminum die casting manufacturer uses a very low pressure of around 10 PSI. This force makes sure that the molten metal travels from the hot furnaces and goes slowly inside the mold. This not only takes a lot of time but can also cause small bubbles inside the mold that can decrease the structural integrity of the parts made.
Sometimes manufacturers also use only the gravity for filling the mold and letting the metal set in place/
On the other hand, a high-pressure die casting uses extremely high pressure and a horizontal setup. The extreme pressure can go up to 20,000 PSI or more. Due to this extreme pressure, the process becomes very quick and efficient.
Advantages Of Using High-Pressure Die Casting
The main reason behind high-pressure die casting being so popular is because of its overwhelming amount of advantages. Below are some of the most significant advantages to assist you in making your decision about which casting methods to choose.
- In the usual low-pressure casting method, you can not build highly complex parts. It’s because gravity does not make the liquid go into a very tiny and difficult mold. As a result you can not create precise tools. However, when it comes to high-pressure die casting, you can create pretty much any complex tools and make it as accurate as you want.
- In gravity die casting, the time it takes to solidify and for the metal to get pored in the mold is pretty significant. And as gravity casting is mainly a manual process, it also takes up a lot of the production to get the thing started. However, with high-pressure die casting, the production is highly efficient. As all the process is completely automated, you will get the highest yield in the shortest possible time.
- Due to port finishing, you will have a very good surface on the die cast aluminum parts.
- Regardless of how small the wall thickness is, the molten metal can easily be injected into everyone inside the cavity when using high-pressure die casting. That means you will not have to worry about the liquid metal not filling any part of the cavity.
- Due to the higher pressure castingprocess, you are sure to get superior mechanical properties from the aluminum pressure die casting parts made. It also will feature tighter dimension tolerance than parts made by gravity die casting.
- And finally, as everything is automated and nothing is wasted, you can get economic advantages on both the large and small volume production.
Even after all of these advantages, there are quite a few that we missed. Like how High pressure die casting does not require much machining after the cast is finished. It is because the process makes sure the dimensional accuracy of the final part is top notch. Moreover, it offers smooth finishing, saving you tons of money on that would otherwise be spent on machining.
High-pressure die casting — hot and cold chamber systems
When it comes to high pressure die casting, there can be two individual system. Let us take a look at what they are and how they differ from one another.
Hot chambers
If you are working with metals like zinc and lead or magnesium that hot chambers is the way to go. As these metals have significantly lower melting point, they need the hot chamber to get fully utilized. Of the two method we are going to talk today, Hot chamber method is the quickest.
It also requires much less pressure to get the metal out of the furnace. 1,000 to a 5,000 PSI is usually the pressure range.
Cold chambers
Cold chamber is usually made for die cast aluminum parts and copper. These metals have a higher melting temperature than the previously mentioned ones.
This chamber requires much less pressure to get fully utilized and also takes more time to finalize the process.
Final thoughts
With all of this in mind, High-pressure die casting is rising in popularity every single day. If you want nothing but the best high-pressure die-casting manufacturing, then CEX casting has got your back. We offer top-of-the-line aluminum die cast process to make sure you end up with nothing but the most reliable and economical solution for your specific needs.
