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According to the Antarctic Bear, not long ago, three domestic companies jointly released a new application of "3D printing+precision casting" to provide customers with small batch and complex structure metal parts manufacturing services. This is a revolutionary change brought about by two 3D printing industry observers, marking a new leap in 3D printing technology: from making samples to manufacturing final parts, from single sample production to small-scale multi batch production, and even large-scale production. Here is the Antarctic bear, a precision casting technique using FDM 3D printing.

Step 1. 3D printing

Polycast is a new type of 3D printing material that utilizes FDM 3D printers and Polycast materials to print samples, specifically designed for casting processes. Has good 3D printing performance. Even if the bottom plate of the printer is not heated, this material will not warp. The bottom plate and bracket of the sample can be very suitable. Easy to peel off, optimized the interlayer adhesion performance of polycrystalline silicon material. In this way, the brackets and floors can be easily and effectively removed, greatly accelerating the production process.

Step 2. surface polishing

When printing materials, you can polish the sample. Polycrystalline silicon is a polishing equipment that matches the material. Polycast is the second line in the spectrum of Polymaker materials that can be polished. This method of atomizing polishing and grinding the surface layer greatly simplifies the post-processing process and provides surface quality for the next step of precision casting technology.

Step 3. shelling

After the printing and polishing processes of the samples are completed, we move to the precision casting workshop to start wax tree production and prepare for shell making in the next manufacturing process. We can start investment casting now.

Firstly, immerse the sample in the mud. The casting workshop adopts a fully automatic shell making device system, and the samples obtain uniformly distributed surface coatings during uniform rotation. After completing a series of mud penetrations with different degrees of viscosity on the workpiece, a shell will form on the surface of the workpiece, which is very important. It is the contact surface of high-temperature metal solution during the casting process.

Next, the sample will undergo a sand staining process, which is a mixture of fine silica sand. Sand stains can enhance the durability of molds and shorten the drying time of castings. After the sample is completely dried, it enters the next conveyor belt through the reciprocating cycle of the production line and undergoes mud and sand stain treatment again.

The above process will continue to repeat until the shell thickness reaches the expected effect. For example, the shell thickness of stainless steel castings needs to reach 30 mm. The entire shell making process will last for 2 days, and the samples will be shuttled through the transfer matrix in the workshop, waiting for drying and repeating again.

Now the mold is starting the heating process. When the kiln temperature reaches 900 degrees Celsius, the sample model can completely evaporate. The shell left after evaporation is used to cast metal molds, which means that samples previously made through 3D printing will burn out during this process. This is the main engineering characteristic of Polycast materials. The vaporization degree of polycrystalline silicon in high temperature environment can be comparable to traditional wax free casting. At normal flow rate, there will be no material residue in the shell. After the interior of the mold shell is completely purified, it can be removed from the kiln and cooled naturally. The mold will be cleaned to eliminate the possibility of residual impurities. We have obtained a smooth contact surface for the mold shell.

Step 4. foundry

Then heat the shell again and cast the metal as stainless steel. By using an electromagnetic induction heating device, the eddy currents generated by magnetic field induction are continuously transformed into thermal effects generated by the melting of stainless steel into liquid eddy currents, starting the melting process from the inside of the metal. This method does not use a direct heating source, greatly reducing the possibility of impurity mixing, and any surface floating slag and impurities will be scraped off. Or burn them.

When stainless steel is heated to 1612 degrees Celsius and the mold is heated to 1300 degrees Celsius, the casting process can begin. The mold will be taken out of the kiln and lifted to the bottom of the furnace. At this point, the operator melts the stainless steel solution and pours it into the shell mold. The parts will be placed on the conveyor belt. The process of natural cooling.

After cooling, stainless steel castings can be peeled off from the mold. This stripping process will be applied to pneumatic jacks. The jack will break the shell and separate the casting from the mold. The castings and risers of stainless steel castings will be removed to form the final castings. Nanjing 1001 Factory currently has domestic production. The intelligent industrial fff3D printing cluster can simultaneously print hundreds of polycrystalline silicon material modules for 3D printing.

After the 3D printing polishing is completed, it is directly sent to the precision casting workshop for seamless connection with precision casting. This means that we have achieved large-scale production of 3D printing and precision casting processes. The manufacturing dimensions of this process are 450x450x450mm. The Nanjing 1001 factory is currently in operation. Develop ultra large 3D printing equipment to expand the scale of wax mold manufacturing to over 1 meter.

Let's experience some application cases of Foundry. For example, we used 3D printing to create a model of a vortex fan. Compared with traditional lost wax casting, it greatly shortens the delivery time. By using 3D printing and precision casting, you have seen the possibility of eliminating the wax mold stage in traditional casting techniques, but with its complexity. Our manufacturing methods for geometric parts and personalized manufacturing have deeper significance. Designers and engineers can use this technology to explore and promote the boundaries of free casting.