What if Vacuum Casting was called 3D Printing?

In all the publicity associated with 3D printing, we hear so little about vacuum casting.

Is this because it’s not as ‘sexy’, or perhaps its because you can’t do it sat in front of a computer, or maybe its just been there for so many decades that no one is interested?

Aesthetics with functional materials, all sizes, any colour, any finish.

Time to redefine the deliverables perhaps, so how about:

“ New 3D printing process combining aesthetics with functional materials, that range from soft elastomeric to hard high temperature capable polyurethanes (as in CLIP!). Parts available in as little as 24 hours and almost unrestricted in size. Any colour, any finish. As used by large and small companies the world over ”

Would that not get peoples attention?

Alright, I accept we are not 3D printing directly, but the input today is a 3D printed master pattern. It usually requires skill to ‘finish’ it to a cosmetic standard, and then vacuum casting clones it, often into a more functional material.

The unsung hero of the last 25 years

The potential of this process is huge, yet it remains an almost unsung hero of the last 25 years. Of course originally, the master pattern would have been created by model making, but with the advent of 3D printing, this really began to take over. So from the mid 90’s the process gained a link to CAD. 3D printing supplied the CAD to physical master link that really opened up the applications in product development.

The key to the process is skill

The key to the process is skill; hand skill frequently born out of model making that allow for the dressing of that 3D printed part into something that really looks good; and then the duplication to provide a batch of parts.

So, great process, when do I use it?

As stated earlier, the master we use is usually Stereolithography or CNC machined, but can be from a number of processes. The ones that do not suit the process are SLS and FDM. These are then dressed to give the required finish, including texture.

The dressing is expensive, both in time, skill and labour and if we wanted a batch, would be prohibitive. This is the primary driver for using vacuum casting, as once we have done the work on the master, we cast a silicone tool. The tooling picks up the detail on the master exactly and we then get it for free on every subsequent casting.

A huge range of casting materials

There is a huge range of casting materials, usually polyurethane (PU) that can be pigmented or painted to give the required finish. So be it clear, flexible, textured, frosted all can be produced without build lines! (On a practical note it is usually only the outside or A surfaces that are dressed, as build lines internally are seldom regarded as an issue)

So the applications are in meeting aesthetic requirements, material properties or the manufacture of small batches of parts.

Great process, often forgotten in the hype.  As William Shakespeare said “What's in a name?”