Die Casting – Setting up Manufacturing in China

Die casting in China need to be set up correctly. When done right, it can add huge value to your business. Here are some top tips on setting up die casting manufacturing in China

Jeff Crawshaw

October 28, 2020

The history: From humble origins to industrial domination

The year 1838 marked the invention of a small, hand-operated printing machine. Today, this simple machine is recognised as the foundation on which the industry rests. Die casting is considered the world’s most fundamental industry for its role in manufacturing and its support of several key industries – particularly the automotive and housing sectors.

In this blog, we trace the journey of the industry from its humble origins to its current market dominance.                 

WHAT IS DIE CASTING?

It is the process of forming metal objects by injecting molten metal under high pressure into molds or cavities called dies. When the metal cools, it takes the shape of the die and solidifies. When the die is opened, the object that comes out is called the casting.

The process is one of the fastest and most inexpensive ways to mass-produce identical objects of uniform quality and often complicated shapes. The most common castings produced today are components for automobiles (cylinder heads, gearboxes), household goods (light fixtures, door knobs), machinery (air compressors, industrial pumps), furniture (cross feet for office chairs) and premium consumer goods (skincare product packaging).

WHAT ARE THE METALS AND ALLOYS USED?

Castings are mostly made from the alloys of non-ferrous metals (no iron content, hence softer, more malleable and rust-proof) such as zinc, copper, aluminium and magnesium, and sometimes lead, pewter and tin. The dies or moulds are usually fashioned from steel.

Die cast parts have been produced and used in all sorts of applications throughout history.

HISTORY OF THE PROCESS

As mentioned earlier, the process was born in the printing industry of the mid-19th Century – a period when publishing boomed and printing was mechanised. And for the first three decades at least, it was used exclusively to produce moveable type for newspapers and books. It was only at the turn of the century that the world woke up to the many possibilities of the process and started applying it in other ways.

Here, we trace the history and evolution through a short timeline:

● 1838: The first equipment is invented – a manually-operated printing machine that uses an alloy of lead and tin to form letters

● 1846: Richard March Hoe comes out with the first successful Rotary Printing Press – a moving cylinder on which type is placed. It is capable of printing 8,000 sheets in an hour and is patented in 1847  

● 1849: The original hand-operated printing machine is patented, marking the first patent for the industry 

● 1886: The first Linotype machine is put to commercial use at the office of the New York Tribune. It works like a typewriter by using brass letter molds called matrices into which liquid lead is cast to produce lines of text

● 1890s onwards: Till now exclusive to printing, the process starts finding other uses 

● 1914: Zinc and aluminium replace lead and tin as favoured alloys, making for sturdier castings. Zinc is the easiest metal to cast while aluminium is known for its lightweight quality

● 1925: In his quest to make the perfect invisible hinge, Joseph Soss develops the Soss machine in the US. It is the first machine to enter the American market

● 1930s: Copper and magnesium (easy to machine) gain popularity as casting alloys. The addition of new material means an expanding range of products  

● 1966: Coinciding with the automotive industry’s growing reliance on the process, General Motors invents Acurad casting, which uses low-iron aluminium

● Today: After numerous improvements and advances, machines today are capable of producing large volumes of quality castings with flexible shapes, thin walls and high surface finish  

THE MARKET TODAY

The Asia-Pacific region makes up 55% of the global die casting market and is expected to remain dominant, say several market studies. The reasons for this are:

●   An expanding automotive sector, especially in China, Japan and India. The automotive industry is the largest end-user of parts

●   The growing use of cast parts in industrial machinery

●   Large-scale production facilities

●   Government initiatives, such as Made in China 2025, which focuses on 10 high-value industries in China, all of them serviced by the industry

In the Asia-Pacific region, China and India are the major producers of castings. They are unrivalled because they hold the twin advantage of cheap labour and low manufacturing costs. Being the manufacturing and exporting giant it is, China leads the field with a 65% share in the regional die casting market and a 37.6% share globally. It is not only the largest but also the fastest growing market in the world.  

CAST IN CHINA

We now know that the process originated in the printing business. And printing, history tells us, is one of the Four Great Inventions of Ancient China. So, it is perhaps fitting that China is the heart of the global industry today. But where in China can you find manufacturers?

The answer is: just about everywhere. The country has more than 26,000 metal casting facilities, thousands of which produce non-ferrous castings. It produces 49.3 million metric tons of castings in a year. There are many techniques of metal casting. Other techniques include sand casting and investment casting. (In sand casting, molten metal is poured into a sand mold, which is broken open after the metal solidifies. In investment casting, a ceramic mold built around a wax pattern of a product is used.)

A unique feature of China’s manufacturing culture is the presence of clusters of factories related to the same industry in a single province, city or region. Cangzhou city in Hebei province is known for its metal casting cluster. Quite aptly, it is home to the Iron Lion of Cangzhou, China’s oldest and largest cast iron sculpture that was made using an early metal casting technique.

But the area perhaps best associated with casting is Zhejiang province, which is not only home to some of the country’s top die casting manufacturers and suppliers, but the CHINA DIECASTING and CHINA NON-FERROUS trade fair and exhibition is held just a few hours away in Shanghai. Organised in July every year, this is the most influential trade fair and exhibition in Asia, featuring industry-leading technologies and products that attract visitors and exhibitors from across Asia and the world.

ADVANTAGES AND DISADVANTAGES

As it is with any industry, the casting process has its advantages and disadvantages:

Advantages

●   High production rate 

●   High-volume production

●   Low unit cost

●   Production of complex, intricate parts with precision, consistent measurements

●   Produced parts are stronger and lighter than those made using other casting methods such as injection molding

●   The parts are heat-resistant, corrosion-resistant

●   Simple assembly process as fastening parts can be incorporated into the castings  

●   Versatile process with a range of finishing techniques – from smooth to matt to textured

●   Dies can be re-used and have a shelf life of between 15,000 and 500,000 castings, which means they last years. For aluminum parts, for example, the die life is typically 100,000 castings   

●   Low material wastage

Disadvantages

●   High cost of dies and other tools. Large, complex tools can cost hundreds of thousands of dollars to make 

●   Warpage and shrinkage. Metals shrink when they turn from liquid to solid, resulting in defects such as cracks and tears. An experienced die caster factors in a shrinkage allowance. Warping is another defect that happens during or after the solidification process and results in a change in the casting’s dimensions        

●   Parts straight out of the die don’t have as good a surface finish as machined parts

●   Largely limited to high-volume production

●   Expensive if production quantity is small

●   Process limited to non-ferrous alloys and metals with fluidity

That said, the benefits far outweigh the drawbacks. This explains why the industry is poised for a 6.13% compound annual growth rate (CAGR) for the 2020-2025 period, according to this report.

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Sourcing Allies is a team of expert China sourcing agents that has helped western customers manufacture and source products from low-cost regions since 2006.

For more on China sourcing visit our website or write to us at info@sourcingallies.com.