3D Printing with Multiple Materials in One Process

A Wall Street Journal article in 2018 explored the then-shortcomings of 3D printing regarding the constraint that feedstock materials pose for fabrication and manufacturing.

They wrote:

Some plastics cannot be made in a form suitable for 3D printing or require specialized equipment. Metals are most commonly printed using metal powder. Since cross-contamination must be avoided, cleaning the equipment between runs of different materials is very time-consuming, so that most metal 3D printers run only one type of material.

This could be changing as researchers are now finding ways to alleviate this problem.

Ordinarily we think of 3D printing as utilizing a feedstock that's homogenous to produce one particular part or component. Recently, however, researchers at Washington State University have succeeded in using 3D printing as a one-step process that prints structures using two different materials.

This advancement is somewhat disruptive. It could potentially help manufacturers expedite manufacturing steps and processes. They have come up with a way to use one additive manufacturing machine or 3D printer, and from that equipment make very complex products in one evolution or operation.

Their research has uncovered an alternate method for something that, until now, has been restrictive. Parts are normally printed using separate feedstocks, one at a time. The researchers are making it possible to use multiple materials in the printer seamlessly. This will allow any fabricator or manufacturer to create custom parts and design with one evolution, and ultimately print it out.

Improved Property Control

What's unique is that the custom part may now have properties that are better controlled, such as heat conduction, corrosion protection, and environmental adaptation within the materials. They and others are expecting this method to be the next step in a higher level of manufacturing that could possibly unleash a new generation of design that optimizes additive manufacturing as a useful and scalable means of fabrication.

With multi-materials in the feedstock of 3D printers, manufacturers won’t necessarily need the adhesives or joint connections now required. Typically this connection was only as strong as the adhesives used. This new method will join two very strong materials and eliminate any weak spots that resulted from those adhesive materials.

A unique application that the researchers used involved a laser-based 3D printer that joined materials to print a nickel chromium and copper structure in one step. Inconel 718 is a nickel chromium alloy used to fabricate sheet metal parts as part of an aircraft engine for liquid fuel rockets. Because materials are expected to withstand very high temperatures, they cool very slowly. Researchers added copper to the amalgamation of materials in the 3D printing process to speed up the cooling process.

As a result, they found that the part cooled 250 percent faster. This meant a much longer life and a higher fuel efficiency for the newly fabricated engines. This process demonstrated that one simple improvement in additive manufacturing can potentially have a great effect on the finished product.

A New Tool in the Designer’s Toolkit

The researchers at Washington State University posit this process as a new tool in the designer's toolkit, as it allows them to be bold and creative in approaching part fabrication using additive manufacturing. They basically have more options. More specifically, designers can vary the composition and put specific functionality into a product that has been very difficult to achieve during the 3D printing process. They're now able to singularly do this with one process, in one machine.

In that sense, this newly developed process is unique and will continue to be introduced via proof-of-concept before it becomes better known and widely accepted. There will also be more trial and error and a learning curve from its use before it's fully refined. It could be a game-changer for additive manufacturing in the future of manufacturing parts with very specific material in composite needs.