We like to innovate at Fishy Filaments and we like to work with innovators in their own fields.
In this post we look at the recent work we’ve been doing with a company, based in Denmark, called AddiFab.
AddiFab have developed a hybrid manufacturing process called Freeform Injection Moulding or FIM. As we understand it they 3D print a mould from a dissolvable resin using a technique called Stereolithography or SLA. That mould or multiple moulds are then loaded into an modified injection press and plastic injected into them.
Why (I hear you cry) would you 3D print a mould rather than the form itself ? Surely you are just adding complexity ?
Well, yes and no and it mostly comes down to one thing in terms of engineering and a second in terms of economics.
All layer-by-layer 3D printing technologies suffer from a common engineering issue. Its known as anisotropy. Its one of the long term arguments against additive technologies and can result in weaknesses being present along the joins between each layer.
By contrast injection moulding suffers far, far less from these material discontinuities and so can claim a higher degree of isotropic strength (identical strength along each axis of strain). Unfortunately injection moulds cannot be used to provide the same radical geometries that 3D printing can, so we have battle lines drawn between the two camps.
AddiFab’s hybrid process would seem to bring these two camps much closer together.
Its not perfect. It can’t be used in the same ways as true mass manufacturing processes but for short runs and functional prototypes where the time cost of cutting a steel mould would impact overall project success, its a really fantastic compromise, especially for small parts.
Time cost and production speed are slighty different here.
Production speed is the simple time to make one part from a raw material.
Since FIM can be semi-automated, i.e. multiple identical dissolvable moulds can be made, loaded into a press and shot at the same time, then all the full moulds set to dissolve at the same time, it is a geniuine half-way house between single part production and mass manufacturing. So the time to make 10 parts is roughly the same to make one, and depending on the size of the parts and of the production run it is quite easy to see runs of 1,000 parts or so being economic. If, as in the gallery below, the part can be linked by a conventional system of sprues, then that could be in the multiple thousands.
The quality is great and the fact that you can check the functional fit of injection moulded parts without cutting a mould is a big step for rapid prototyping and limited run production. The step change though is the ability to injection mould 3D print-style geometries, and I’m not sure how that will impact product design. It will take designers to be aware of the opportunity before any big changes start to happen and that is really the goal of this post.