You can learn from this article:
- What is Precision Investment Casting
- What Is the Process Flow of Precision Investment Casting?
- What Are the Characteristics of Precision Investment Casting?
- Factors Affecting Dimensional Accuracy in Precision Castings
- The Main Application of Precision Investment Casting
- What Are the Materials Suitable for Precision Investment Casting？
- Things to Note About Precision Casting
- When to Use Precision Investment Casting？
- Top Precision Investment Casting Company Recommendations
- China's Top Precision Investment Casting Factory
1. What is Precision Investment Casting
Precision investment casting is also called lost wax casting. It refers to the general term for the process of obtaining precision dimensional castings. Compared with the traditional metal casting process, the castings obtained by precision casting are more accurate in size and have a better surface finish.
Its products are precise, complex, and close to the final shape of the part. Can be used directly without processing or processing. It is an excellent process technology in the foundry industry, and its application is very extensive.
2. What Are the Process Flow of Precision Investment Casting?
Here are the steps of the entire precision investment casting process at besser foundry:
① Mold Making: Create a mold to make a wax model.
② Wax Model Making: Wax models are created by injection molding using a mold.
③ Wax Assembly: Assemble the wax pattern according to the casting plan. The assembled object is called a "tree".
④ Mold making: The tree is soaked in slurry (a liquid containing ceramics), drained, and sprinkled with ceramic sand before drying. By repeating this process, the ceramic is layered and molded into molds.
⑤ Let's take it off: Place the mold in a pressure cooker and only the wax inside is melted.
⑥ Mold Firing: The mold is fired to sinter and increase strength.
⑦ Casting: Molten metal is poured into a mold.
⑧ Type Disassembly: Remove the mold.
⑨ Cutting: Cutting the product from the "tree".
⑩ Finishing: Finishing the cut surface with a belt.
⑪ Inspection: Inspect and correct scratches and deformations on the product.
3. What Are the Characteristics of Precision Investment Casting?
Precision casting has advantages and disadvantages, but the benefits of its advantages far outweigh its disadvantages.
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4. Factors Affecting Dimensional Accuracy in Precision Castings
Generally speaking, the dimensional accuracy of precision castings is affected by many factors such as casting structure, casting material, mold making, shell making, roasting, pouring, etc. Unreasonable settings and operations in any of these links will cause changes in the shrinkage rate of the castings. As a result, the dimensional accuracy of the castings deviates from the requirements. The following are factors that can cause dimensional accuracy defects in precision castings:
(1) Influence of casting structure:
a. The casting wall is thick and the shrinkage rate is large; the casting wall is thin and the shrinkage rate is small.
b. The free shrinkage rate is large and the hindered shrinkage rate is small.
(2) Influence of casting material:
a. The higher the carbon content in the material, the smaller the linear shrinkage. The lower the carbon content, the greater the linear shrinkage.
b. The casting shrinkage of common materials is as follows: Casting shrinkage K=(LM-LJ)/LJ×100%, LM is the cavity size, and LJ is the casting size. K is affected by the following factors: wax pattern K1, casting structure K2, alloy type K3, and pouring temperature K4.
(3) The influence of molding on the linear shrinkage of castings:
a. The impact of wax injection temperature, wax injection pressure, and holding time on the size of the investment mold is most obvious with the wax injection temperature, followed by the wax injection pressure. The holding time will have little impact on the final size of the investment mold after the investment mold is formed. .
b. The linear shrinkage rate of wax (mold) material is about 0.9-1.1%.
c. When the investment mold is stored, further shrinkage will occur, and the shrinkage value is approximately 10% of the total shrinkage. However, after 12 hours of storage, the size of the investment mold is basically stable.
d. The radial shrinkage rate of the wax pattern is only 30-40% of the lengthwise shrinkage rate. The impact of the wax injection temperature on the free shrinkage rate is far greater than the impact on the hindered shrinkage rate (the optimal wax injection temperature is 57-59℃, The higher the temperature, the greater the shrinkage).
(4) Influence of shell material:
Zircon sand, zircon powder, Shangdian sand and Shangdian powder are used. Their expansion coefficient is small, only 4.6×10-6/℃, so it can be ignored.
(5) Influence of shell roasting:
Since the expansion coefficient of the mold shell is small, when the mold shell temperature is 1150°C, it is only 0.053%, so it can be ignored.
(6) Effect of casting temperature:
The higher the pouring temperature, the greater the shrinkage; the lower the pouring temperature, the smaller the shrinkage, so the pouring temperature should be appropriate.
5. The Main Application of Precision Investment Casting
Precision investment casting has innumerable applications in a range of industries. We summarize some of them below.
- Aerospace industry: such as engine parts, air and fuel system parts, engine turbine blades, combustion chambers, internal mechanical parts, etc.
- Automotive Industry: The automotive industry requires precision and complex parts such as braking systems and engine parts.
- Medical device industry: In the medical device industry, many products require high biocompatibility and precision, such as implants and joint replacement materials used directly on the human body.
- Dairy and food industry: commercial dishwashers, meat slicers, ice machines, candy production equipment, coffee machines, etc.
- Firearms: The firearms industry relies on investment casting to produce precision parts such as: receivers, triggers, hammers, etc.
- Power generation industry: including oil, gas, wind and nuclear energy, all use precision investment casting
6. What Are the Materials Suitable for Precision Investment Casting
In general, all ferrous and non-ferrous metals can be used to produce parts in the precision casting process.
| ● Steel | ● Stainless Steel | ● Carbon Steel | ● Tool Steel |
| ● Aluminum | ● Nickel | ● Cobalt | ● Ductile Iron |
| ● Alloy | ● Copper | ● Beryllium Copper | ● Brass |
7. Things to Note About Precision Casting
Although investment casting has many advantages, there are also some disadvantages and precautions when applying it. By understanding these points and addressing them appropriately, you can maximize the potential of investment casting.
The strength of molds in investment casting is often lower than in other casting methods. This low strength can be a problem, especially when producing large castings. This is because larger castings require greater strength and durability.
The investment casting process sometimes results in low yields. Low production volumes mean products are produced less efficiently, which can lead to increased manufacturing costs.
8. When to Use Precision Investment Casting
Precision investment casting is ideal for casting metal castings with complex shapes. He can cast metal parts weighing 75 pounds or more.
Precision investment casting is suitable for high volume orders, and the time and labor saved by eliminating or reducing secondary machining can easily make up for the cost of new tooling. Small batch production is unlikely to make up for the investment. Typically, for runs of 25 or more parts, investment casting is the logical choice.
9. Top Precision Investment Casting Company Recommendations
The leading market players have positioned themselves strongly by offering a wide range of investment cast products with various designs, materials, and specifications. Companies always tend to offer products using innovative and advanced methods to cope with customer demands.
Rising foreign investments and increasing government initiatives for the development of the automotive sector, mostly in India, Taiwan, and China, are expected to boost market growth over the forecast period. Some prominent players in the global investment casting market include:
- Besser, Inc.
- Doncasters Group Ltd.
- Hitachi Metals, Ltd.
- MetalTek International
- Signicast
- Precision Castparts Corp (Berkshire Hathaway)
- Zollern GmbH and Co. KG
If you need an investment casting company, you can check out the following:
- Top 10 Investment Casting Manufacturers in China
- Top 10 Investment Casting Manufacturers in the USA
- Best 10 Investment Casting Manufacturers in the UK
- Top 5 Investment Casting Companies in Canada
- Top 5 Investment Casting Companies in the German
- Top 5 Investment Casting Companies in Australia
10. China's Top Precision Investment Casting Factory
Besser is a leading investment casting manufacturer and supplier in China. Since 2002, Besser has specialized in precision investment casting with various surface finishes.
Widely supply all kinds of precision casting parts, such as architectural hardware, auto parts, mechanical products, pump valves, etc.
We develop various precision castings through stainless steel castings, carbon steel castings, alloy steel castings. Just send us your CAD or 3D drawings for a one-stop custom service.
We handle large and small orders, so if your requirements are on the low side, you don't need to be restricted. We ensure that orders of all sizes follow the same quality standards.