A Q&A with Renishaw Canada’s Mark Kirby about the current state of additive manufacturing
How is additive manufacturing being used in key market sectors such as aerospace, automotive and medical industries?
Additive manufacturing is enabling OEMs to create new types of products. Aerospace manufacturers such as GE are embracing what we would call a Level 3 application, with parts consolidation, complex internal passageways and most critically, improved performance at a system level. Airbus is doing similar things with cleverly designed manifolds that involve additive manufacturing combined with machining, because machining still has a central role to play with this technology.
The automotive industry is using additive manufacturing extensively but mainly for prototypes, special tools and low volume production work. There are some issues in terms of material properties. If the material properties from additive manufacturing are not identical to the proposed production process (eg forging with its unique grain flow), then how can a manufacturer reliably predict performance? These are some of the barriers.
In the medical sector there is some interesting work particularly with lattice structures that are difficult or impossible to produce any other way. The market for orthopedic implants is in the billions of dollars but we have to look at how additive can provide higher value compared to other processes such as forging and casting.
How does additive manufacturing fit in with traditional machining processes?
Hybrid machines are a new breed of machines that combine traditional machining with additive manufacturing technology. Machine tool manufacturers are taking different approaches on how to combine additive and subtractive capability. The market will be the judge of these machines, which are just emerging now. The ability to locally add base material via additive, and then machine it, is where the hybrid machines will score big, that is, if the resulting part is accepted by industry. I think these machines will find a niche and become complementary to machining from solid. They will be probably best suited for parts with low feature intensity and also for larger parts.
What parameters does a manufacturer use to determine whether additive manufacturing would be a good fit?
Additive manufacturing and high volumes don’t go together; additive is fundamentally a slow process. You do have some shops, such as Burloak, who are providing both machining and additive bureau capability, but the emerging need lies with the OEMs, who own their designs. For job shops, they don’t have design authority, they build to print. In this case, additive won’t do it better for them because the technology is not a straight substitution for a traditional machining process.
How does a manufacturer ensure the quality of the metallic powders used for additive manufacturing and what impact can a poor quality metallic powder have on the additive manufacturing process?
With additive manufacturing you move away from the purchase of a block of metal with a certificate of conformity to essentially dealing with a foundry inside a machine. So poor quality metallic powders will have an impact on the process. There are about 10 to perhaps 20 materials available for additive manufacturing and our approach is to help people understand how different metallic powders and different formulations will work in the future. There are some exciting developments and we’re working with research institutions.
What does Renishaw expect to see within the next five to ten years in additive manufacturing?
Additive hasn’t really flexed its muscle yet as a transformative manufacturing technology. As more people become engaged in real projects with this technology it will generate more accessible, transferable knowledge. Renishaw is recognized for its work in process capability in subtractive manufacturing and we’re developing that same partnership approach for additive. We’re also looking at how to improve current processes. For instance, our EVO Project is targeted at developing a machine designed specifically for industrial use. Powder handling is a labour-intensive process, so this will be fully automated in the EVO machine.
What downfalls are there with additive manufacturing technology?
Don’t purchase a new technology based just on (today’s) spec. This is a significant investment decision so the best advice is to look at how the combination of technology, architecture and support can be made to work in your manufacturing operation. There is a rush by some to take part in this technology because it’s new, but you have to think about this from the aspect of redesigning a part. This technology is not a substitute to make a product less expensive, but it can be a disruptive technology that allows you to reconceive how a system is configured and outperform a competitive product.