I had a look at Grid Logic’s highly unusual powder-based metal 3D printing system.
The company has been around for around six years, so I was surprised I hadn’t run into them earlier. Nevertheless, they have one of the most unusual metal 3D printing processes I’ve seen. It can not only produce metal parts, but also parts made with more than one metal.
Here’s an example of a part made with two very different metals, something that is not easily possible with most of the other 3D printing processes, which were designed to print only in a single material. Even more interesting is that their process does not require any binder material.
Here’s how the process works.
The machine has a set of hoppers on top that contain the base metal powders involved in the job. These are pure metal powders, and Grid Logic currently supports Inconel 625/316L, 316L, Inconel 625/CuCrZr, Inconel 625/Silicon Steel, 316L/Copper, and Ti6Al4V.
The printing process begins with selective deposition of these powders. Here you can see how the print head can lay down powders in regions, with several different metals possible on each layer. They use a 3mm nozzle, and layers can be 0.5-25.0mm in height.
However, these layers are just loose powder at this point. Then things get interesting: the powder is deposited layer by layer in a canister, which is then sealed.
The canister then undergoes a post-printing process where heat and pressure are applied to the powder in the canister. This allows the metal powders to sinter and fully consolidate. This is done with hot isostatic pressing equipment, and that is the ultimate constraint on the build volume possible with this approach: you can print as large as your post-processing equipment allows. Grid Logic said they’ve made parts as large as 1m cubed using their process.
Like binder jet sintering, the powder deposition shrinks slightly, just not as much. It is a predictable amount, and therefore it is possible to produce parts of desired sizes.
The interesting part of the process is that it produces absolutely pure metal parts, as there is no use of binders that might leave residue. It’s also possible to make thicker parts that are sometimes challenging with binder jet approaches.
How long does it take to print using this process? It’s not fast, as we were told it could take 72 hours to complete an automobile wheel. Pressing also takes time, and an example cited was a 200mm part taking four hours.
The selective deposition of materials means you can do some interesting things, like the metal interleaving shown here. This allows dissimilar materials to easily connect.
We were told there were a number of industrial applications used with Grid Logic’s process, particularly in the nuclear and shipbuilding industries. They also see many heat exchangers being made with copper.
Their process is quite similar to powder metallurgy, which is a well-known process in industry. If a manufacturer already uses that process, it’s a fairly easy step to add in Grid Logic’s capabilities.
Via Grid Logic
