Die Casting Design

Die-casting can be done using a cold chamber or hot chamber process.

1. In a cold chamber process, the molten metal is ladled into the cold chamber for each shot. There is less time exposure of the melt to the plunger walls or the plunger. This is particularly useful for metals such as Aluminum, and Copper (and its alloys) that alloy easily with Iron at the higher temperatures.

2. In a hot chamber process, the pressure chamber is connected to the die cavity is immersed permanently in the molten metal. The inlet port of the pressurizing cylinder is uncovered as the plunger moves to the open (unpressurized) position. This allows a new charge of molten metal to fill the cavity and thus can fill the cavity faster than the cold chamber process. The hot chamber process is used for metals of low melting point and high fluidity such as tin, zinc, and lead that tend not to alloy easily with steel at their melt temperatures. die casting, aluminum die casting, aluminum casting, ADC-12 die casting, automotive die casting part, motorcycles spare part, aluminum pressure die casting

Automotive die casting
Automotive die casting

3. Die casting molds (called dies in the industry) tend to be expensive as they are made from hardened steel-also the cycle time for building these tend to belong. Also, the stronger and harder metals such as iron and steel cannot be die-cast

Aluminum die casting process introduction

Though the term die casting can refer to any kind of casting using a die such as gravity die casting or low pressure die casting, yet here die casting only refer to high pressure die casting. Aluminum die casting is a process of casting Aluminum alloy under pressure, can produce precision parts in high volume at low costs. There are two processes of aluminum die-casting namely hot chamber die casting and cold chamber die casting. Parison die casting introduced cold chamber die casting process from1980’s. Now the die casting machines which Parison die casting is applying are cold chamber die casting machines.

Illustration of cold chamber die casting process

In a cold chamber die casting process, the molten aluminum alloy is ladled into the cold chamber for each shot. There is less time exposure of the melted alloy to the plunger walls or the plunger. This is particularly useful for aluminum alloy that alloys easily with Iron at the higher temperatures.

After the molten aluminum alloy is ladled into the cold chamber, the piston will inject it into the cavity of the die casting mold through three different pressure phrases. The pressured molten aluminum alloy gets in sequence through spure system, running system, and gate system into the cavity of the die casting mold.

The filled cavity with affection of cooling system shapes the desired aluminum die casting products. Then the moving die moves away from the fix die, while the ejectors push out the casting.

Advantage of aluminum die casting process

A.high volume but low cost Compared with aluminum sand casting and gravity casting, aluminum die casting can produce precision parts in high volume at low costs.

Aluminium die casting
Aluminium die casting

B.good surface finish and good dimensional accuracy Aluminum die casting generally has good surface finish and good dimensional accuracy. For many parts, post-machining can be totally eliminated, or very light machining may be required to bring dimensions to size.

The disadvantage of aluminum die casting process

A.high cost of die casting mold The cost of tooling of die casting is much more expensive than those of sand casting, gravity casting, and investment casting.

B.high porosity Though the porosity of die casting can be adjusted by using much higher pressure with a much larger and heavier mold, the porosity can not be avoided and is much more than that is of low-pressure casting and gravity casting. Furthermore, porosity leads die casting parts to be not suitable for heat treatment. Thus the consistency can not be compared with gravity castings.

FAQ’s of aluminum die casting process

what is aluminum die casting process?

what is the cold chamber die casting process?

what is the difference between cold chamber and hot chamber die casting process?

What is the application of die casting process?

what kinds of metal can be applied in die casting process?

why is the cold chamber die casting process preferable for aluminum casting rather than hot chamber die casting process?

what is the application of die casting products?

what kinds of post-treatments can be available for aluminum die casting products?

what is the difference between aluminum high-pressure die casting and low pressure die casting?

what is gravity die casting? Is it the same as high pressure die casting process?

Alloy Die Casting

Alloy Die Casting Description:

Aluminum Alloy Die Casting A380 is the most common of the aluminum die casting alloys. It offers the best combination of casting and product properties. It is used for a wide variety of products such as garden equipment, chassis for electronic equipment, engine brackets, housings for automotive alternators, starters and water pumps, home appliances, furniture, office equipment hand tools, and power tools. Alloys 383 and 384 are alternatives to 380 that are specified when very intricate components require improved die filling characteristics and improved resistance to hot cracking. Alloy 360 offers high corrosion resistance and superior strength at elevated temperatures than 380. Other properties are essentially equivalent. Alloy 413 offers the best die fill characteristics making it excellent for pressure tightness applications. it is the choice for products such as hydraulic cylinders and pressure vessels. Its casting characteristics make it useful for very intricate components.

aluminum die casting
aluminum die casting

Alloy 390 was developed for automotive engine blocks. Resistance to wear is excellent, but ductility is the lowest of the die casting alloys, with elongation less than 1%. Special surface treatment systems allow engine pistons to run directly on the alloy surface, eliminating the need for ferrous alloy liners. It can also be used for valve bodies and bearing surfaces subject to abrasion and wear.

Alloy 518 is used in escalator components, conveyor components, and marine and aircraft applications It offers good ductility and very good corrosion resistance. It can be polished and anodized for a decorative finish. Zinc Alloy Die Casting Zinc alloys are versatile, cost-effective materials which can be used in a diverse range of die casting applications. As precisely formulated metal alloys, they offer the mechanical properties of medium strength metals. Advantages of Zinc Alloy Die Casting Overall, zinc alloys have significant advantages as casting materials for small components, with excellent physical and mechanical properties, castability and finishing characteristics. Hot chamber die-cast zinc alloys can be cast to tight tolerances, complex detail, net shape, and the alloy¡¯s dimensional stability ensure part-to-part consistency over long production runs. Net shape manufacturing is one of the main advantages of hot chamber die-cast zinc alloys.

The most commonly used zinc alloys are ZAMAK™ 2, ZAMAK™ 3, ZAMAK™ 5, Acuzinc. These alloy families offer higher tensile strengths than most aluminum and magnesium alloys, higher yield strengths, greater impact resistance, higher Brinell hardness, and better ductility. ¡¡è Zinc alloys facilitate higher die casting cycle speeds versus aluminum and other metal alloys, more complex shapes, thinner sections, smoother surface finishes, surface finishes, and higher standards of dimensional accuracy. Compared to plastic, zinc alloys are several times stronger and many times more rigid. Their mechanical properties compare favorably with powdered iron, brass, and screw-machined steel. Zinc has inherent EMI/RFI shielding properties.

CNMCast uses only high-grade zinc alloys certified for purity. Although these materials are completely recyclable, scrap is never re-melted or re-used within our process. Zamak 3 die casting is the standard for the Zamak series of zinc alloys; all other zinc alloys are compared to this. Zamak 3 has the base composition for the Zamak alloys (96% zinc, 4% aluminum). It has excellent castability and long term dimensional stability. More than 70% of all North American zinc die castings are made from Zamak 3. ZAMAK #5 offers high tensile strength, hardness, and creep resistance than zamak# 3, and somewhat lower ductility.

It is preferred whenever these properties are required. Some die casters use only zamak# 5, which is usually an acceptable alternative to zamak# 3. ZAMAK #7 is essentially a high purity form of zamak# 3 with slightly higher ductility and lower hardness. The other mechanical properties are identical to zamak# 3.

The alloy also exhibits higher fluidity than zamak# 3 or3 5, which theoretically allows slightly thinner walls. Zamak# 7 may be specified when high ductility is required. ZA-8 is rapidly growing in popularity for pressure die casting.

ZA-8 can be cast in hot chamber die casting machines for fast cycle rates, It has improved strength, hardness and creeps properties over the ZAMAK alloys with the exception of a No. 2 alloy which is very similar in performance. ZA-8 is readily plated and finished using standard procedures for ZAMAK. When the performance of Zamak No. 3 or No. 5 is in question, ZA-8 is often the die casting choice because of high strength and creep properties and efficient hot chamber castability.

Zamak 5 die casting
Zamak 5 die casting

ZA-12 is also a good pressure die casting alloy, using the cold chamber process, which provides a sounder structure than ZA-27, as well as higher die-cast elongation and impact properties. For these reasons, die-cast ZA-12 often competes with ZA-27 for strength application. An excellent bearing alloy, ZA-12 is also platable, although plating adhesion is reduced compared to the ZAMAK alloys. ZA-27 is the high strength performer of the zinc alloys and is die-cast using the cold chamber process.

It is also the lightest alloy and offers excellent bearing and wear resistance properties. ZA-27, however, requires care during melting and casting to assure sound internal structure, particularly for heavy wall sections. It may also need stabilization heat treatment when tight dimensional tolerances are required. ZA-27 is not recommended for plating. However, when brute strength or wear-resistant properties are needed, ZA-27 has demonstrated extraordinary performance.

China Die Casting Process

China Die Casting Process

Aluminum Die Casting is a 6000 year old manufacturing process. Aluminum die Casting is a manufacturing process by which a liquid material is usually poured into a die mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Die Casting China was grow up since 1960, and rapidly grown up in recently 20 years.

Die Castings are used in areas like transportation, aerospace, defense, mining, construction, maritime, fluid power, & domestic household. Some cast components include: engine blocks, suspension parts for  auto mobiles, cooling fan components & fluid flow components like valves, pumps, pipes, and fittings. To cut the emissions there is a need to improve the fuel efficiency and make the vehicle lighter in weight. Non ferrous metal like aluminium is lighter than steel and has density one third of that of steel. Aluminium has a lower density of 2.7 gm/cc compared to 7.8 gm/cc of steel. Aluminum and aluminum alloys are lightweight with good corrosion resistance, ductility and strength. Aluminium is a light silver coloured metal placed 13 on the periodic table and is important group 3 element. It has good resistance to corrosion and due to its aesthetics it makes a suitable alloy for varied applications.
 Dr. Dinesh & Ramesh is in the process of manufacturing Aluminium die casting of various alloys including LM6, LM9, LM25, A356, 413, AlSi8Mg3, AlSi10Mg amongst others. There are various casting processes including Gravity Die Casting (Permanent Mold Casting), Low Pressure Die Casting, High Pressure Die Casting, Investment Casting, Sand Casting processes. Dr. Dinesh & Ramesh have expertise in the Gravity Die Casting and Low Pressure Die Casting processes since 1979.
In Gravity Die Casting process the metal is filled under the influence of gravity hence the name Gravity Die Casting.  The metal is carefully directed through an ingate under the influence of gravity to fill the die. There are various gates and sprues through which Aluminium enters the dies (usually made of iron alloys).There is provision of various risers to allow proper feeding and give defect free homogenous casting. It is the experience and knowledge of the foundry engineer to provide optimum risering and gating to give defect free parts. Dr. Dinesh & Ramesh has that experience and knowledge of more than 30 years to give customers value and quality. At DRE, we have always been up to speed with technology and have developed various equipments at our facility to increase productivity and sustained quality of our products to our customers.
Die Casting China Companies has also developed its own proprietary equipment for Low Pressure Die Casting. This is a relatively newer process in which metal enters into a die in a very controlled and turbulence free manner. An air tight furnace is kept underneath the metallic mold, and under air pressure (upto 25 psi – depending on the size of the casting) the liquid metal rises up from the furnace into the metallic die on top of the furnace. A very good control of the molten metal is achieved in this process resulting in reliable, pressure tight and homogenous parts. Various critical components in the industry are made through this process for eg: Engine blocks of automobiles, cyclinder heads, alloy wheels, crticial electrical components, special purpose pressure tight parts to name a few.
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Mechanical Properties of Malleable Iron

The different grades of malleable iron are essentially the result of different heat treatments. Just as a medium carbon steel can be heat treated to a wide range in properties so can malleable iron, but malleable is even more versatile. The combined carbon content, on which heat treatment depends, can be adjusted from none, as when the microstructure is entirely ferritic, to that of a fully pearlitic structure. Read more

Mechanical Properties of Cast Carbon and Low Alloy Steels

For the purpose of this article, carbon steels are considered to be those steels in which carbon is the principal alloying element. Other elements that are present and that, in general, are required to be reported are manganese, silicon, phosphorous and sulfur. In a sense, all of these elements are residuals from the raw materials used in the manufacture of the steel, although the addition of manganese is often made during the steel making process to counter the deleterious effect of sulfur and silicon is added to aid in deoxidation. Read more

White and High Alloy Irons

An important group of alloyed irons that fall outside of the ordinary types of Alloy Die castings have been designated the white and high alloy irons, or the special irons. The high alloy irons are considered separately because their alloy content exceeds 3% and they cannot be produced by ladle additions to irons of otherwise standard compositions.

The high alloy irons are usually produced in foundries that are specially equipped to produce the highly alloyed compositions. These irons are often melted in electric arc or induction furnaces, which provide for precise control of composition and temperature. The high alloy irons are sold at premium prices and are expected to outperform ordinary compositions in applications that involve severe service conditions. The foundries that produce these irons may be equipped with heat treating furnaces and quenching equipment or cooling facilities to provide for the most economical use of alloys. Read more

Mechanical Properties of Compacted Graphite Iron

    Compacted graphite iron is a fairly recent addition to the family of commercially produced aluminum casting irons. Its characteristics are intermediate to those of the gray and ductile irons. As in gray iron, the graphite in CG iron is in the form of interconnected flakes. This facilitates the production of sound castings, especially those of complex shape or with intricately cored passages. However, the relatively short span and blunted edges of CG graphite provides improved strength, some ductility, and a better machined finish than gray iron. Read more

Mechanical Properties of Cast Iron

Ductile iron is characterized by having all of its graphite occur in microscopic spheroids. Although this graphite constitutes about 10% by volume of ductile iron, its compact spherical shape minimizes the effect on mechanical properties. The graphite in commercially produced ductile iron is not always in perfect spheres. It can occur in a somewhat irregular form, but if it is still chunky as Type II in ASTM Standard A247, the properties of the iron will be similar to cast iron with spheroidal graphite. Of course, further degradation can influence mechanical properties. The shape of the graphite is established when the metal solidifies, and it cannot be changed in any way except by remelting the metal.  Read more

Tech Properties Gray Iron

  Microscopically, all gray irons contain flake graphite dispersed in a silicon-iron matrix. How much graphite is present, the length of the flakes and how they are distributed in the matrix directly influence the properties of the iron.

The basic strength and hardness of the iron is provided by the metallic matrix in which the graphite occurs. The properties of the metallic matrix can range from those of a soft, low carbon steel to those of hardened, high carbon steel. The matrix can be entirely ferrite for maximum machinability but the iron will have reduced wear resistance and strength. An entirely pearlitic matrix is characteristic of high strength gray irons, and many castings are produced with a matrix microstructure of both ferrite and pearlite to obtain intermediate hardness and strength. Alloy additions and/or heat treatment can be used to produce gray iron with very fine pearlite or with an acicular matrix structure. Read more

Aluminum Casting

The term “cast iron” designates an entire family of metals with a wide variety of properties. It is a generic term like steel which also designates a family of metals. Steels and cast irons are both primarily iron with carbon as the main alloying element. Steels contain less than 2% and usually less than 1% carbon, while all cast irons contain more than 2% carbon. About 2% is the maximum carbon content at which iron can solidify as a single phase alloy with all of the carbon in solution in austenite. Thus, the cast irons by definition solidify as heterogeneous alloys and always have more than one constituent in their microstructure. Read more