Whenever we’re asked if we use 3D printing our answer is always the same: isn’t welding a form of 3D printing? 3D printing is, after all, the popular term for what’s more properly called additive manufacturing, and welding is most definitely an additive process. But joking aside, we believe 3D printing has a growing role to play in metal fabrication. Here’s our take, starting with an overview of the technology.
Our Definition of 3D Printing
It’s called “printing” because, in many additive processes material is sprayed or extruded in a manner similar to how a regular printer works: a print head scans over a surface, putting material where it’s needed. In 3D printing though, the distance between the base and the print head increases to allow the printing of taller structures.
Early 3D printers extruded plastic onto a table. More recently, methods have been developed to print metals. There’s a lot of jargon around the various approaches, but for metal, they come down to either depositing metal in a manner similar to welding, or powder bed / selective laser sintering approaches.
In this latter category, a thin layer of powder is deposited in a manner similar to how a silk screen printer works. A laser then rasters over the surface, selectively melting the powder to bind it together. The bed lowers and a new layer of powder is deposited for the laser to scan over and melt.
Metals for Printing
Additive technology is advancing rapidly, but at the moment the metal powders used are alloys developed specifically for the task. That said, many grades of steel are printable, and non-ferrous alloys are becoming available too. (Reflectivity and conductivity are two of the factors limiting what metals can be printed.)
Applications for 3D Printing
The “build” process (the term for 3D printing a structure), is not fast. Again, new machines are becoming more and more capable, but in general, it can take hours to print something the size of a football.
Size is also a constraint, as machines with large print envelop are extremely expensive. In addition, printed parts may display layers or strata on some surfaces and almost always need some finishing. But despite these limitations, it’s becoming clear where the niche for 3D printing lies.
There are three classes of applications for the technology:
- Where speed is required and the lead times on conventional tooling are too long
- Where a very small number of pieces are needed and conventional tooling is too expensive
- Where the optimal design is too complicated to make by conventional methods (or there are benefits in combining multiple pieces into one)
Consequently, 3D printing is used for prototype and one-off production where tooling will take long to procure or be too expensive. Low-volume production of complex parts is another area, especially where the design is highly optimized to minimize mass and maximize strength. Industries making use of these characteristics include aerospace, automotive (especially motorsport), and medical devices.
Two other areas where 3D printing contributes to cost reduction and higher efficiency are component consolidation and waste reduction.
Consolidation refers to the potential of 3D printing to combine multiple components into one single part. This simplifies BOMs and inventory management while also reducing assembly work.
A second area to consider is waste reduction, which is especially important with high-value alloys. It’s not waste-free because some parts need support to hold the powder in place as the build progresses, and these are subsequently cut away. Overall though, compared to traditional fabrication, a lot less material is discarded.
3D Printing in Metal Fabrication
The additive isn’t going to replace our conventional cutting, bending, drilling, and welding processes any time soon. Most fabrications are too big to print, and even those that would fit in a machine would be slow and expensive to make. However, we do see two broad types of application: tools and fixtures and for want of a better phrase, what we call complex, highly optimized bracketry.
Fabrication requires a lot of small tools and fixtures. These range from backstops and v-blocks for press brakes to fixtures for welding fit-up. Conventionally, they all need machining, and often assembly too. 3D printing can make these parts in less time, and that’s especially valuable when a customer needs a quick turnaround.
Fabricated structures often have a lot of brackets and internal bracing, and this adds weight, which is a problem in many transport applications. When the application warrants, it may be worth printing complex parts, and incorporating them into a larger assembly or design.
Related to this last point, 3D printing gives designers more freedom to achieve the form and function they want. Again, we can envisage small printed metal parts being included in larger assemblies, like those for truck trailers and RVs.
The Future of Additive in Fabrication
We see this as a technology that complements what we do now. As the machines get larger, faster, and cheaper and powder prices come down we’re going to see an increasing number of applications where printing makes sense. Visit our shop in a year or two and it’s not out of the question that you’ll see parts that were previously fabricated being printed instead.
Talk to some fabricators and you might get the impression little has changed in our industry in decades. We’re not one of those. We’re constantly looking for and bringing in equipment and processes that let us do more while improving quality and helping save our customers money. Our fiber lasers are an example, and 3D printers might not be far behind.
If you have parts that need producing, or you’re looking for help with a fabrication project, contact us. We’re always happy to review designs, offer our thoughts, and help you find ways of meeting your needs.