Vacuum Casting Process Explained
19 July, 2022
May 9, 2020 at 2:43 am
If you’ve only recently come across 3D printing (also known as additive manufacturing) you might be surprised to learn of the scale of possibilities of this technology. For example, did you know that it’s possible to 3D print a house in less than 48 hours?
3D printing is making it possible to produce complex parts in a way that is technically very difficult or impossible using normal manufacturing processes. This is particularly true in the case of parts, products and prototypes 3d printed from metal.
When 3D printing in plastic a CAD design / .STL file is used by a 3d printer to create layer upon layer of melted resin, to build the 3d printed part from the ground up. The final product may then require some surface finishing, depending on the fineness of the print and the intended end use.
There are two common ways of 3d printing in metal, some of which have similar aspects to the process of printing in plastic:
One technique for 3d printing in metal utilizes a bed of powdered metal and a lazer to superheat the powder and meld it together (it is as cool as it sounds!). The 3d printer uses a CAD / STL file to direct the lazer to fuze together layers of the powdered metal in the shape of the 3d printed product, building it layer upon layer.
This video gives a brief overview of how this process works:
Sintering uses a combination of metal powder and binding material to build the 3D print from the ground up much like in 3d printing with plastic. However once the piece is printed initially, it then has to go through a process of removing the binding material. The last stage in the process is to super heat the 3d printed part to fuse the metal together.
In fact, in both scenarios the printed piece is often heated in an oven after printing as a way to remove residual stresses and to improve the “fatigue life” of the product, the amount of times it can be used before it begins to deteriorate.
Because the process of 3d printing in metal is more involved and has more steps, and because of the materials used, it is currently more expensive to print in metal than plastic. That said, the applications for parts printed in metal are greater as they are more durable than parts printed in plastic.
Because 3D printing in metal is a reasonably new technology, there are limited types of metal we can print in. Currently we are able to print your project in steel, stainless steel or aluminium.
As research continues in the area of additive manufacturing in metal we expect to be able to print in an increasingly wide range of metal products in the future.
One of the biggest uses of 3d printing metal is prototyping metal parts for the automotive, aerospace and related industries. Typically a prototype will first be made in plastic to ensure it is up to specification and there are no issues with it. This is cheaper than printing in metal and realizing you’ve made a mistake after the part is printed, as the process of 3d printing in metal is more involved. Once the part is accurate from the initial plastic print, it is then printed in metal and used in various test applications to ensure the prototype will perform as expected. Once this is confirmed the part can go into mass production, safe in the knowledge that the mass produced parts will function as intended.
One industry that is particularly interested in 3d printing in metal is the aerospace industry. 3D printing in metal allows companies to create one off or small run parts that don’t require the costly process of creating a mold, which is only economical when producing parts at scale.
In these applications the part itself may be a little pricey up front because it’s 3D printed, but because of the special characteristics of printing in metal the parts can be strong but also very light, saving a lot of money in fuel costs due to less overall weight in part (and therefore the aircraft), leading to a high net gain for the airline.
There are many other industries that can benefit from 3d printing in metal, particularly those who rely heavily on machinery whose parts can break or wear down, or who need to customize machinery for specific purposes. Rather than replacing entire machines or trying to source hard to find replacement parts, 3d printing in metal is an easy answer. While 3d printed parts are not currently as durable long term as traditionally fabricated metal parts, the possibilities of 3d printing in metal are almost endless, compared to traditional fabrication techniques (eg. machining, welding, cutting, etc.) which have various limitations, for example, not being able to easily manipulate closed internal spaces of metal parts.
3D printing in metal is also perfectly suited to hobby and restoration work. Take for example restoring a classic car. You may need parts which are just not available anymore, and which make more sense to print in metal than plastic. This could include parts inside the car, eg. window levers, or even parts for the motor itself that have corroded and can no longer be found commercially.
The possibilities for 3D printing are almost endless. Check out this amazing bridge 3D printed in steel for example.
If you have a prototyping or other product or part development project in mind we’d love to hear from you!
We’d be happy to discuss whether 3D printing in metal is the best approach for you project, or whether another approach may be more cost effective or appropriate for the application you’re considering.
If you’re new to the idea of 3D printing in metal and would like to learn more about the science behind the process, or how much 3D printing costs per hour you may be interested in the linked article and following video: