Metal 3d printing is a type of additive printing that prints 3D parts layer by layer by using metal. For the method to work, a digital data file is transmitted to a machine that then builds the components.
Metal has always been one of the most reliable resources given to mankind, from the middle ages till now, it has been in the forefront of most heavy duty materials, and for a good reason. Thus the idea of being able to shape and print this durable and strong material with high precision into any desired shape is as enticing as it can get.
The Process of metal 3d printing
This task of metal 3D printing can be broadly divided into 3 distinct steps.
- Shaping and printing – process of visualizing the final design and a preliminary print.
- Washing – removal of compounds which are required to hold the design in place via chemical reaction.
- Sintering – burning off the trace amounts of binding compounds whilst also forming one cohesive unit.
Shaping And Printing –
Software to design metal parts
The desired shape is first visualized using software such as AutoCAD or TinkerCAD (CAD = computer aided design), which work similarly to how Photoshop works for graphical production and editing.
The final design gets one step closer to the finished product by processing these designs through specialized software which accounts for the structural integrity of the finished product by adding mesh in between the layers and providing a base (called raft) for easy release of the product after production. This software can also account for any kind of shrinkage which will happen throughout the subsequent processes whilst accounting for the build material of the end result.
This final design gets fed into the 3D printing machine.
3D printing machines
The 3D printing machine first prepares what’s called the “bed” or the base layer in simple terms. The preparation process includes leveling the bed whilst also making it easy enough to remove the product after the print.
Now it’s time to decide which metal you want to get in the final print. Now-a-days, it’s common to see the metal you’re trying to print in the form of metal powder combined in a 2-part plastic binder, which makes the metal much safer and reliable to use in the printing process.
The possible metal which can be printed this way right now includes –
- Stainless steel
- Tool steel
(several other metals are in development for this method of metal printing)
This binded material is combined with a release material (generally ceramic), which, as the name suggests, is for easy release of the printed metal structure.
The printing of the product happens according to the final design provided by the software in a layer-by-layer process when the metal mixed with binding material and the release material gets mixed and heated and finally gets extruded onto the bed.
The product now obtained after the printing is called “green part”
The now-freshly printed “green part” is submerged in a special solvent such as polyethylene glycol or methyl methacrylate in order to remove the binding material, which we have taken to be ceramic and plastic in our case.
The wash time might vary from hours to even days on end, depending on how thick the thickest region is on the printed product. But the fact that this time is fixed means that this time is mostly unmonitored time.
After the washing process, the product is now called a “brown part”.
The brown part is a collection of metal powder in a printed solid structure. This structure is now passed through a specialized furnace which first runs at a lower temperature in order to burn off any binding material remaining whatsoever to complete the debinding process, and then it goes to a much higher temperature, at the point which the metal powder present melts and integrates to get the final metal product we wanted.
Like the washing process, the temperature and time is set on the material and thickness of the final product, and due to the automation of the forges involved, even this process can be one which can go unmonitored.
During the forging process, the layer between support (raft) remains powderized, which means that the final product can easily be removed from the base, which has provided the added benefit to avoid too much shrinkage during the processing phase.
After removing the product from the base (raft), which is usually one hammer-tap away, the final product is ready to be used as it is, or can be polished or post-processed depending on the use case.
Benefits And Drawbacks Of Metal 3D Printing
Fast and flexible designing
As the softwares involved does not require much proficiency to get desired results, this leads to fast designing and prototyping of the products.
High level of precision
Due to the very nature of the process being carried by machines and pre-calculations done, the end result has a high level of precision.
The materials are already calculated and the processing happening with the materials involved in mind, the waste generation is almost negligible in the long run.
Cost-effective in small to medium production batches
As the products involved can be mass printed, with a high level of precision, this means that the overall costs are lower than if we had to consider manual labor to do the same task.
Easy to access
Metal 3D printing is evolving rapidly, thus making it cheaper and more accessible to a wider range of enthusiasts as well as engineers.
The size of the printing machine determines the maximum size of the products it can yield, which is not much when one’s trying to build for an industry which requires much larger parts.
Less cost effective in bulk production as compared to molding
The technology is constantly evolving, and hence this might not be the case in the future, but for now, if you want to produce parts in very large quantities, you’re better off cast-molding the product as opposed to 3D printing it.
Future Of Metal 3D Printing
In our opinion, metal 3D printing is here to stay. With the possibilities to create parts at your own will, with little monitoring time due to the heavily automated nature of the job, this creates much more room for creativity and faster prototyping, whilst also carving a place for itself in small to medium scale production and automobile and aerospace manufacturing.
And as the technology keeps improving, this once niche area can become more and more accessible to give wings to creative endeavors of individuals and aspiring enthusiasts
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