Smoothing out the rough
Additive manufacturing can produce almost any part you want, in almost any geometry and with minimal set up costs. However…
While it is true that every production process has its advantages and disadvantages, 3D printing is continuously evolving – certainly more rapidly than other manufacturing technologies – so you should always check to see what recent developments there have been.
And now Protolabs’ new post-process named ‘vapour smoothing’ – a first for European digital manufacturing – has developed additive manufacturing further. It enables parts 3D printed from the commonly used material PA-12 and the elastic TPU-01 to be 3D printed with a smooth surface finish similar to that produced by injection moulding.
Bridging the gap
Before this technology was available you had to compromise. Sure, you could have any shape or geometry you wanted in these commonly specified two materials if you used selective laser sintering (SLS) or Multi Jet Fusion (MJF), but the surface quality would not be to the same high level as injection moulding.
Vapour smoothing bridges that gap between the two processes. It’s no longer a case of sacrificing design freedom, or cost of set up for low production runs if you want an aesthetic or sealed surface. Now you can have it all.
Before this automated process became available, like most 3D printing manufacturers we could produce a smoother surface manually, but for hard-to-reach areas this would not be possible. Now thanks to this process all surfaces for PA-12 and TPU-01 parts can be ‘smoothed out’ whether for aesthetic or functional purposes.
The secret of this process is that instead of intervening with a manual or mechanical process such as CNC machining, chemical vapour smoothes out the surfaces. And because, as the name suggests, it involves vapour, it can reach the places that a mechanical process cannot.
How it works
We are one of the first European digital manufacturers to use AMT’s PostPro3D – a process that passes strict health and safety regulations. Unlike other processes, vapour smoothing does not remove material from the part.
Instead, we place several parts in a rack in a sealed processing chamber, heat them and then introduce a finishing agent. This evaporates and the vapour spreads across all of the parts’ surfaces where it creates a controlled chemical melt. This reduces the peaks and troughs on the surface by liquifying and redistributing materials evenly in a carefully regulated atmosphere.
Once finished the equipment evacuates the finishing agent to a collection vat so there is no residue left on the parts. All that remains is for us to ship them to you.
Not only are you left with smoother parts, which feel and look better from an aesthetics point of view, but the process makes the parts water and air tight by sealing up even the smallest cavities. This smoother surface is also far easier to clean, which for some applications, such as for the medical sector is a vital factor.
Mechanical properties are not affected by the process and indeed both elongation at break and impact strength are actually significantly improved.
Opening up more applications for 3D printing
This new ability to smooth and seal all of the surfaces allows 3D printed PA-12 and TPU-01 parts to be used in more applications than ever before.
Leak proofing 3D printed parts makes them suitable for tanks, fluid bearing pipes and ducts, valve covers and oil sumps in the automotive industry. And because parts are rendered sweat proof thanks to the vapour smoothing process, it opens up numerous applications within the medical and industrial sectors where the ease of cleaning plastic parts is a major issue.
Vapour smoothing has removed a disadvantage when it comes to 3D printing PA-12 or TPU-01 parts. It allows you all of the design possibilities of additive manufacturing while retaining the surface finish that in the past you might only expect from injection moulding.
A whole world of new opportunities is now possible for design engineers. It also proves that engineers need to constantly keep abreast of the rapidly changing world of 3D printing. The processes are constantly evolving and improving which in turn opens up many more opportunities for designers.