investment casting wax injection

Which machineries are needed in an investment casting foundry?

Investment casting is a precision casting process that produces high-quality metal parts with complex shapes and fine details. Investment casting equipment are used to produce these parts, we suggest you to read the processes of investment casting first in order to understand why these machineries are needed. In this article, we’ll explore the various types of investment casting machineries and their functions.

Wax Injection Equipment: The wax injection equipment is used to inject molten wax into the steel or AL mold to form the wax pattern. This machinery includes a wax tank, wax injection nozzle, wax injector, and wax pattern assembly. The equipment should be able to accurately control the temperature and pressure of the wax injection process to ensure consistent and high-quality wax patterns.

Ceramic Shell Production Equipment: The ceramic shell production equipment is used to create the ceramic shell that encases the wax pattern. This machinery includes a shell building station. The equipment should be able to create a strong and durable ceramic mold that can withstand the high temperatures and pressure of the casting process.

Melting and Pouring Equipment: The melting and pouring equipment is used to melt the metal and pour it into the ceramic mold. This machinery includes a furnace, a crucible, a ladle, and a pouring system. The equipment should be able to accurately control the melting temperature and pouring rate to ensure that the metal flows smoothly into the mold and fills all the intricate details of the wax pattern.

Cleaning and Finishing Equipment: The cleaning and finishing equipment is used to remove the ceramic shell and any residual wax from the cast metal part. This machinery includes a shell breaking machine, a shot blasting machine or a sandblasting machine and a grinding machine. The equipment should be able to provide the desired surface finish and dimensional accuracy of the final part.

Quality Control Equipment: The quality control equipment is used to verify that the final part meets the required specifications. This machinery includes various measuring tools such as a coordinate measuring machine (CMM) or a 3D scanner, a surface roughness tester and a metal composition analyzer. The equipment should be able to accurately measure the dimensions, chemical composition of the metal and surface finish of the final part to ensure its quality.

Other than the machineries mentioned above, an investment casting foundry still needs some other equipment such as dewaxing furnace, cutting machine, grinding machine, dust remover machine and more. Investment casting machineries are crucial components of the investment casting process. They play a significant role in determining the quality and consistency of the final product. By using high-quality machineries and maintaining them properly, investment casting foundries can produce high-quality metal parts that meet the demanding requirements of various industries.


Comparison between investment casting and sand casting

Investment casting and sand casting are two different methods of metal casting, both of which involve pouring liquid metal into a mold to create a metal part. Investment casting and sand casting have their own advantages, so you can’t simply say which one is better, but which one is more suitable for producing your products. As a professional investment casting foundry, the difference between investment casting and sand casting are often asked by our customers, so we wrote this article to compare two casting methods.

Investment casting (Lost wax casting)

Investment casting is a precision casting process that uses a lost wax process to shape the metal into a component. Firstly, we have to make a set of molds, lost wax casting molds are usually made of aluminum, if quantity of the component is large, we will also use steel molds. The process of investment casting, also known as lost wax casting, we inject wax into the mold to produce a wax pattern, and the wax patterns are assembled onto a sprue (what we called a “tree”), and then wrapped in refractory slurry on the outside of the tree to make a ceramic shell. Pour the molten metal into the shell. After cooling, we get the metal castings. Investment casting has the following advantages:

  • Investment casting can produce parts with complex shapes with very thin walls.
  • High accurate, investment castings can achieve high dimensional tolerance request.
  • Smooth surface finish can save further machining or surface finish process.
  • Material of investment casting can be Ferrous, nonferrous or duplex alloys. Investment casting can be quite economical by repeat runs.
Sand casting

Sand casting uses sand to form the mold surface. The mold made of sand has some flexibility, so when the liquid metal cools and hardens, there are fewer cracks, tears or other types of defects. Sand casting has the following advantages:

  • The cost of sand casting is lower especially in shorter runs.
  • Sand casting can produce larger castings.
  • Ferrous and non-ferrous metals can be also used.
  • Post-cast tooling cost is lower.

Differences Between Investment Casting & Sand Casting

Production design: In investment casting, ceramic shell is formed from liquid slurry, so investment castings can be designed into almost any shape, and engineers have great freedom to add the complex structures and shapes required in the design. In sand casting, the product is often designed to be tapered, so sand casting parts can be taken out from the sand mold easily with less friction. Sand castings with internal cavities or voids are more difficult to make. Sand castings requires insertion of a suitable core into the mold to form the internal structure, sometimes multiple cores may be needed.

Weight: Investment casting can make castings in weight less than 450 grams, while sand casting cannot cast small pieces with complex structures.

Surface finish: The surface of investment casting and sand casting has a big difference. Because of the material of the mold, the surface of the investment casting parts is smooth and can achieve high tolerance requirements. After removing the gate and blasting, the castings can be used directly. In sand casting, the mold has to be split apart to release the castings, so the parting line is more obvious. And because the sand is rough, the surface is also relatively rough and requires additional time and cost to process.

Cost: The complexity and preparation process of the investment casting process makes it cost more than sand casting. Comprehensively speaking, investment casting method is usually superior to other casting methods, especially in product details and surface finish. Shanghai Heda Castings Co., Ltd, a professional precision foundry with nearly 20 years of experience, is ISO-9001 certified. We can provide one-stop solution for your investment casting parts, from mold design to finished castings, machined castings, as well as heat treatment and surface treatment if requested. Please feel free to contact us if you need any assistance with your investment castings.