Stainless steel impeller casting uses 3D printing technology

3D printing is defined by the F42 Committee of the American Society of Testing and Materials to create objects by sedimenting materials using print heads, nozzles or other printer technology. This paper discusses a special three-dimensional printing technology called binder injection, which is the process of deposition of liquid binder through the nozzle to connect the powder material. The bonded material is sand, which can be cast directly made by three-dimensional printing.

How it works?

3D printing works like a 2D printer at home or office. However, this process uses a thin paper layer of special casting grade sand and specially designed binders to make casting mold parts instead of paper. There are only a few steps to repeat the process until the desired shape is produced. Under the guidance of computer-aided design (CAD) data, sand is diffused and binders are selectively distributed.

Then, reduce the platform with a certain increment and lay a new layer of sand. Then, use CAD data to apply the binder to this new configuration again. This process is repeated until the parts are completed. At that time, the parts could be extracted from the surrounding sand and used for casting applications.

The three-dimensional printed sand core impeller with a diameter of 26 inches has five veins, and the resistance diagram is shown in the figure.

Sand, hardening and special engineering binder can be used to process and drag half of the mold and core. These are the foundation of casting parts. Printed sand can also be used to represent the form, simulation or engineering model of parts. It provides a tactile part, which can be used to fit and even install fixtures in the machining workshop. After spraying, it looks like sand and gravel casting, weighing about 0.06 pounds per cubic inch.

The core of any conventional molding technology that can be used for casting is safe for any alloy. This core may be complex and does not require any assembly, because the 3D printing process eliminates traditional tools, such as the core box. One advantage of not having core components is that the internal core channel of the casting is cleaner, there are no fins on the core assembly joints, no casting defects, no bad core components, or no mud at these connections.

This 3D printing process reduces the post-casting cleaning of internal channels, resulting in better internal pump channels. This internal core can also be manufactured without stretching, which can provide better pump performance or efficiency.

A three-dimensional printed impeller sand core with a diameter of 26 inches has five blades, as shown in the figure.

By producing cores that do not require core boxes, the design and efficiency rules are not limited by the manufactureability of casting molds. This is not an all-encompassing technology. It must be used with existing processes or as a standalone process. Pump manufacturers and end users should merge them at a reasonable time and place

For cores that may be too subtle to be transported, a solution can be provided. The core can be printed in a sealed box to ensure complete delivery. Think of it as a Russian nesting doll. A 3D printer can make all dolls at the same time and place at the same time. The end user opens the build box and removes the core. 

It can be used like any other core in the casting application.

Flexibility

Another advantage of this printing core is that it can be changed at any time. There is no need to evaluate the mold cost to make changes. If the pump shell pattern has enough design, and all the end user needs is to upgrade the internal channel, then it can be printed without tools and fuss. This may be a huge advantage, disposable or sample.

The 28-inch diameter three-dimensional printed sand core impeller has six blades. The resistance diagram is shown below.

Many people like to try something before investing heavily in permanent tools or proving an engineering idea. The three-dimensional printing process allows sampling without being affected by the high cost of casting tooling and the long production cycle related to the mold.

Printing sand can also be made into casting molds. These molds can print and simulate any molding process, so that the foundry can collect valuable information about filling, solidification and yield. This helps foundries improve, verify and optimize the process before ordering tooling, thus eliminating tooling changes at the start of production. In order to quickly enter the market, 3D printing can help require immediate castings and molds to be completed in a few weeks or months. One of the slogans of additive manufacturing is to make what users want when they want it.

A three-dimensional printed sand core impeller with a diameter of 28 inches has six veins, as shown in the figure.

Additional benefits

For traditional products, 3D printing has great development prospects. Damaged casting tools will not need to be replaced or repaired for work that only runs occasionally. The lost tools do not need to be replaced. The company can print the solution and use any available tools.

Again, this is not an all-encompable technology. Mix and match to maintain a low cost, which is only needed when needed. In the future, the mode may be stored on the server or flash drive, not in the repository.

The more complex the casting is, the more difficult the core of manufacturing is, and the more manufacturers and end users should try 3D printing as a solution.

This change in the way pump parts are manufactured can save money and time, and enable parts and products to enter the market faster. Engineers can also test multiple solutions at the same time, and then invest in expensive permanent tools. They don't need to sacrifice design efficiency for the ability to make products quickly.

Three-dimensional printed sand model of 7 propellers with a diameter of 30 inches

Start-up process

End users should study and try this technology. To start this process, they should communicate with 3D printing technology providers. It is important to communicate and coordinate well with 3D suppliers. Users should honestly discuss the risks involved and what is most important to them - such as cost, quality and time. They should use their time with the provider to explain the technology, and should ask the provider what it can provide and what it cannot provide.

Users must understand that not everything can be made by 3D printing, and it should not be like this. The bad experience of any new technology is expensive for everyone. Solution providers, manufacturers and end users shoulAvoid using good solutions for wrong issues.

By finding the right vendor functions and process matching for the application, end users should be able to use components faster and less. This technology can save costs in prototyping and production. Manufacturers and end users should conduct research to determine whether 3D printing is their choice.