The core features of 3D printed investment casting technology are digital drive, complex structure empowerment, and agile response to demand, making it a disruptive process in aerospace, medical, high-end automobiles and other fields. With the maturity of material innovation and hybrid manufacturing mode (3D printing + traditional casting), the technology is penetrating from prototype manufacturing to mass production, driving the manufacturing industry to a smarter and more sustainable direction.
Investment casting (lost wax casting) is a precision casting process with thousands of years of history. It is widely used in aerospace, medical, automotive and art manufacturing because it can produce metal parts with complex geometries and high surface accuracy. However, traditional investment casting relies on the process of handmade wax molds, which has pain points such as long cycle, high cost and many design restrictions. In recent years, the introduction of 3D printing technology has completely changed this situation and promoted investment casting into the era of digital manufacturing.
Here are the steps of 3D printed investment casting.
8 steps of 3D printing investment casting:
1. CAD modeling, 3D printing lost foam
Use CAD software to design the digital file of the molten casting model, then export it in .STL format and print it using a 3D printer (SLA technology 3D printer is recommended). The printing process usually takes only a few hours.
2. Check whether the molten casting model has holes
Perform post-processing such as surface grinding on the 3D printed model to remove the surface layer lines. Then carefully check whether the model has holes or cracks.
3. Surface slurry coating
Send the model to the foundry, first smear the surface of the model with ceramic slurry. This layer of slurry should fit closely with the investment casting model, and the quality of the first layer of slurry will directly affect the surface quality of the final casting.
4. Shell making
After applying the ceramic slurry, stick sand on its outer layer. After it dries, repeat the steps of applying slurry and sticking sand until the shell reaches the ideal thickness.
5. Firing and cleaning
When the shell is dry, it is placed in a furnace and burned until the molten casting model inside is completely burned out. At this time, the shell will also become ceramic due to the heat. After being taken out of the furnace, the inner surface must be thoroughly cleaned by water washing and other methods, and then dried and preheated.
6. Casting
The molten liquid metal is filled into the empty shell by pouring, pressure, vacuum suction, centrifugal force, etc., and then it is cooled.
7. Demolding
After the liquid metal is completely cooled and formed, the ceramic shell outside the metal is completely cleaned by mechanical vibration, chemical cleaning or water flushing.
8. Post-processing
The metal model is surface treated or further machined, and its dimensional accuracy, density and other mechanical properties can also be tested at this time.
3D printing technology is reshaping the value chain of investment casting, making "mass customization" production possible. With the advancement of materials science and digital twin technology, it is expected that more than 40% of investment casting prototypes and 30% of small batch production will turn to 3D printing solutions in the next 3-5 years. This change not only improves manufacturing efficiency, but more importantly, it unleashes the design imagination of engineers and promotes high-end manufacturing in a smarter and more sustainable direction.