Additive Impact Part 2
By Marc Saunders, Director - Global Solutions Centres at RenishawAdditive Manufacturing 3D printing Renishaw
Exploring the various ways that AM could disrupt your market.
If you haven’t already read Additive Impact Part 1, I suggest that you do so before reading this post.
Metal 3D printing has the potential to shake up the way that we design and make products, creating opportunities for valuable innovations and whole new business models. In this second post of two, I am exploring the nature of the changes that additive manufacturing (AM) could bring to product markets, and the steps that companies can take to lead this disruption.
In the first post Additive Impact Part 1, I introduced a staircase model of AM adoption, and explained how the production and lifetime benefits of AM increase as you move up through the levels. These benefits build up as you employ more and more of the unique characteristics of AM.
Having explored the first two steps of the staircase in Part 1, I’m going to move on to the two upper steps in this post.
Level 2 – Part consolidation
This is the first step where we start to change the design of our product to take advantage of additive manufacturing’s ability to make complex shapes. In this instance, we are looking to simplify our product by combining collections of parts into a single, integral build. There are three AM capabilities in play at this level:
AM enables detailed features to be designed and built into components in a single operation, rather than requiring additional process steps. We take complexity out of the process and put it into the part.
Consolidating these multiple steps into a single additive operation reaps many production cost benefits including; reduced tooling costs, shorter overall processing time, shorter lead time, and replacement of complex assembly processes with a single, automated build.
Removal of joints
Joints find their way into product designs to enable complex shapes to be produced that cannot be formed in a single conventional manufacturing operation. Joints mean mating features, fixings, connectors, gaskets and seals. They add to the part count, the weight, the processing time and the assembly time of a product. They also create points of potential weakness and mismatch between parts that have been separately manufactured, resulting in potential failure modes and performance shortfalls. Joints are best avoided!
AM enables complex shapes – e.g. the twisting waveguide shown below – to be made in a single operation. This can lead both to cost savings in assembly and to a range of lifetime benefits in use.
It is possible to produce interlinked mechanisms in a single AM build, that then require no further assembly. The results can be neat, functional and highly attractive.
Level 3 – DfAM optimized
So now we’ve reached the top step, where the most advanced capabilities are deployed. We are employing Design for AM (DfAM) principles to take full advantage of the freedom available to us. Here, everything is open to optimization, resulting in some radical and customized solutions. There are quite a few capabilities to think about here:
Hollow / porous structures
Many parts are produced conventionally with solid structures, even though a hollow structure is often as strong, simply because it is too difficult or expensive to get at the material in the middle. AM enables hollow structures to be readily produced in a single operation, with the added bonus of reduced material use and shorter build times. Lattices can also be used to lighten components, often by as much as 50%, whilst retaining stiffness.
Another technique for light-weighting is topological optimization. The principle here is to define the interfaces that the component has with the rest of the mechanism and the loads that it has to carry. Then we look at the stresses in the material that these loads induce and remove material that is under the least strain. This leaves the most efficient way for the material to transmit the specified loads.
The example below is a bracket in a space application, where weight really is at a premium. The conventional bracket evolves into a hollow freeform shape – we call it the ‘fingers of fate’ – reducing mass by a third. The lead time to design and produce a radical new design can also be surprisingly short.
AM gives us the freedom to design unusual, organic forms, which can be used in creative ways to design attractive products, such as jewellery.
Increased surface area
Load-bearing interfaces often require a large surface area to ensure good adhesion. This is particularly true in orthopaedic implants, where clinicians want to promote integration between the metal implant and the neighbouring bone, to build a strong bond and to prevent ‘stress shielding’ and subsequent surgical revision. This is an area of intense research just now, with investigations into Osseo integration with regular and irregular lattices designs.
Another application that benefits from large and carefully designed interface surfaces is bonding of metal and composite parts.
Increased heat transfer
Heat exchangers are a great application for AM. To maximize heat transfer between one fluid and another, a heat exchanger ideally comprises a network of complex micro-channels with thin primary walls, and complex secondary surfaces. The unique capability of AM to produce detailed internal and external features cost-effectively means that more efficient heat exchangers are possible, enabling either lighter weight, or higher performance, or both. This is of obvious interest for motorsport, road vehicle design and green energy applications.
Conformal cooling, mentioned in part #1 in the context of mould tool design, can also be applied to components that require cooling during their use. Intricate channels that follow the component surface enable heat to be efficiently carried away from the component core.
High strength alloys
The difficulty of machining some alloys can prevent their practical use, even though they may exhibit highly desirable thermal and mechanical properties. AM is essentially a welding process, and so, provided the alloy can be ‘atomized’ into a powder, it may be possible to process such challenging materials using laser techniques. Exotic alloys are generally expensive, so minimizing waste through near-net-shape processing is also helpful.
AM’s ability produce fine lattices opens up the possibility to make metal ‘foams’ with carefully tailored properties. Such micro-structured materials could be designed to include anisotropic properties – e.g. different stiffness and thermal conductivity in different planes. This is a bit like topological optimization, but on a microscopic scale. Standard and bespoke architectured materials open up new possibilities for light weight, high performance products. The examples below are provided by Betatype.
Build the bill of materials
Because AM requires no tooling, you can combine different elements of a product together in a single build. This means that you can make all the major components of a product in one go, so that they can then be post-processed and assembled together. This makes for easier scheduling, reduced stocking, and offers the option to combine this with localized production and mass customization for superior service.
A good example of this is the build we did for the world’s first 3D printed mountain bike.
Provided that you have a CAD model for the part you’re trying to make, it makes very little difference in cost and build time terms if that part is exactly the same as others that have gone before, or if it is slightly different. The lack of tooling required for additive manufacturing means that customized part production can be very cost-effective. A great example of this is Renishaw’s dental implants business – we make hundreds of unique restorations every day, based on designs sent to us by different dental labs. These are consolidated into a single build to keep costs low.
Mass customization relies on an effective upstream process chain: accurate measurement of the situation in which the part will be deployed, user-friendly CAD design of the custom product, and software to convert the CAD model into a producible AM build.
The benefit to the user of customized parts is better adaptation to its context, which can lead to easier fitting, better outcomes, and a higher value service. When combined with other AM capabilities, customized production opens up opportunities to disrupt mass produced business models.
Summary – Part 2
So we’ve completed our journey to the top of the staircase, employing more and more additive manufacturing capabilities along the way. Of course, it’s not essential to use all of these in your AM product – just pick those that will create the greatest value for your customers, and save you the most in bringing your innovative new product to market.
I hope that this framework is useful to help you to analyse how additive manufacturing could impact on your market, and to think about the approach that you could take to lead the change in your sector.
This blog originally appeared on www.renishaw.com. It has been republished on Design Engineering’s website with permission from Renishaw.