Precision casting

What is precision casting?

Precision casting (also called investment casting, lost-wax casting,and cire perdue) is a metal shaping technique to form near net-shaped products. The basic casting principle is to pour and to fill molten metal into a disposable ceramic mold. Then, the molten metal adapts to the shape of the mold and forms the final products. The technique has been around for thousands of years, as far as the bronze age. Even though it sounds like an old trick, but the research and development is still going up to this day. Even today, the casting foundries keep working to continuously improve the quality of casting products. Therefore, precision casting is one of the longest running advanced metal-shaping technology in human history.

What is the history of Precision Casting?
Precision casting, also known as investment casting or lost wax casting, can be traced back over 5,000 years to ancient civilizations in Mesopotamia, Egypt, China, and Central America. Artisans used the process to create intricate metalwork, tools, and jewelry using natural beeswax for patterns, clay for molds, and bellows to stoke furnaces.
The process has been refined and developed into a modern high-tech process. Some notable developments include:
1907
William H. Taggart of Chicago developed a technique, wax pattern compound, investment material, and air-pressure casting machine
1980s
The invention of simulation software allowed casters to simulate mold filling and metal solidification processes, reducing the need for trial runs
Today
3D printing technology can be used to deliver metal prototypes, which can help lower costs and reduce lead times
Investment casting has been used in many commercial and industrial applications, including producing aluminum castings, steel castings, and even complete aircraft door frames.

What is Precision Casting Process?

Precision Castingis one option for creating intricate parts and components. There are several specific steps in the entire process to design and create the desired workpieces. It is named such because the workpieces are created around a shelled casting, which is later removed once the workpieces have been poured into the mold and are set.

Steps 1: Creating the Die/Pattern
The first step in the process is to create the die or pattern of the desired workpiece. The pattern is made from wax. It can be poured into a die using injection molding, carved by hand from a block of wax, or printed using a 3D printer and the appropriate wax material.
Step 2: Mounting the Wax Patterns
Investment casting tooling involves creating multiple wax patterns and attaching these onto a “gate” device. This device is where metal or other materials will be poured to eventually create the desired workpieces.
Step 3: Tree Assembly
The tree assembly finishes the mounting of the wax patterns on the “gate” device. It is called a tree at this step because each individual wax pattern is essentially a “branch” and will be one finished workpiece once the process is finalized. You may have seen tree assemblies in new board games that need to have pieces detached before use.
Step 4: Shell Molding
Once the tree is assembled, the next step is to add the shelled casting around it. First, the tree is dipped into a ceramic slurry. Then it is dipped into a stucco of fine sand. The molding must fully dry before it can be used. These two processes can be completed multiple times until the mold is thick enough to handle casting stresses.
Step 5: Wax Removal
Before the desired material can be poured into the newly shelled mold, the wax patterns have to be removed first. This is often done by heating the wax inside an oven. Steam can also be used to heat the wax. The mold is placed upside down so that the liquid wax can flow out of it and be reused to create new wax patterns.
An alternative process of wax removal is to heat the wax so that it “burns” off and is fully removed from the shelled casting.
Step 6: Mold Casting
After the wax has been removed, there will be open spaces inside the shelled casting in the shape of the formal wax patterns. Molten metal or another liquid material is poured into the casting. The material remains in the casting until it has fully cooled and solidified.
Step 7: Removing the Shelled Casting
A hammer or another tool is used to remove the shelled casting until all that is left is the original tree. In place of the wax patterns, there will now be the finished workpieces attached to the tree. After the casting has been removed, the workpieces are carefully cut off the tree.
Step 8: Finishing Operations
Each workpiece is inspected for imperfections. If any are found, they are discarded, and the material is recycled. The last step in the investment casting process is to use different finishing methods on the workpieces. They may be sanded, coated, smoothed, machined, etc. to achieve the desired results.

Precision Casting Materials
There is a large selection of alloys to choose from during the material selection process for investment casing. These include:
Stainless Steel
Stainless steels feature superior durability in comparison with many other materials. The potential of the material has led to increased use in investment casting by designers and engineers. Applications for stainless steel include gearbox parts in automotive applications,  various gears, camp components, and golf club heads.
Low Alloy Steel
Low alloy steels are among the most frequently used steels in the mechanical world due to their affordability and beneficial mechanical properties. Specialized heat-treating processes make it possible to engineer parts that have differing properties in different areas of the same workpiece. For example, varying heat treatments can be used to make one surface tough and impact-resistant, while another surface becomes wear-resistant.
Aluminum Alloy
Aluminum alloy is the most used material in investment casting. Industries that use it most frequently include aerospace, avionics,  electronics, and military.
Castings are now offered for demanding applications like airframe components thanks to the material’s improved strength and the availability of quality castings made from aluminum-silicon-magnesium alloy.
Carbon Steel
Carbon steel is a common low-cost material that comes in a variety of grades, with the classifications varying based on the amount of carbon content. The strength, ductility, and performance of carbon steel can be improved in industrial applications through heat treatment. Its ferromagnetic properties make carbon steel useful in motors and electrical appliances. It is safe, durable, and has a high structural integrity, making it one of world’s most frequently used alloys.
Super Alloy
Super alloys based in nickel and cobalt have common uses in the aerospace, energy, medical, chemical, and marine industries. Nickel-based alloys are stronger at high temperatures and cobalt-based alloys have superior corrosion, oxidation, and wear resistance over their nickel-based counterparts. Super alloys increasingly replace sheet metal because they provide high rigidity and superior service characteristics while remaining a cost-effective option.
Copper Alloy
Copper-based alloys are corrosion-resistant and feature low rates of wear. They are frequently used in applications such as ship or pump propellers, electrical components, and plumbing components. A versatile material, there are more than 400 different alloys featuring a wide variety of properties.
Many part types can be investment cast from copper-based alloys. More common types of copper-based alloys include bronze and brass. The strongest copper alloy is beryllium-copper, which has similar properties to high-strength alloy steels but with a higher corrosion resistance over longer periods.
Cast Iron
Iron castings, which often include gray iron and ductile iron, are known for their high accuracy and an affordable price tag. Ductile iron has high strength, heat-resistance, and toughness, but it has a more complex production process than other steels. This leads to a higher production cost than cast steel.

SPECIALIST IN PRECISION INVESTMENT CASTINGS

The lost wax method is very suitable for producing precision castings with complex shapes and high dimensional accuracy & quality. In addition, it offers a large freedom in both design and material choice of your desired castings. Precision castings are known as the highest quality castings available on the market.

HUAWEI  is your reliable partner in the field of precision investment castings and highly values a good client relationship. In good cooperation with you as our customer, we would like to act as a development partner, sharing our thoughts and ideas about product design, material choice, measurements or machining.
All of this is matched exactly to your wishes and demands. Achieving an optimal casting through joint dialogue is our general principle. The degree of co-development is decisive in your project’s success.

Throughout the world and in a diverse range of industry sectors we deliver value by working closely with our customers to provide custom engineered components that cater to their specific industry and applications.
Experienced with the world’s major OEMs, HUAWEI  team of experts utilize their decades of experience to create, design and produce advanced technology solutions for a broad variety of industries. We proudly serve a range of industries including mainly automobile, rail, construction equipment, material handling equipment, agricultural machinery and other industries like mining machinery, shipbuilding, petroleum machinery, construction, pump and valves, electric machine, hardware, power equipment.
 

Our company is one of the most professional Precision casting manufacturers and suppliers in China, and our investment casting foundry with powerful machining capabilities. Be free to buy bulk Precision casting from our factory. All lost wax investment casting products and machined parts are with high quality.