Investment casting is one of the world’s oldest manufacturing methods and despite a lot of new technology available, it remains, at its core, a manual process of pattern, mold, and cast part creation. Several process steps, such as sprue assembly and shell building have been automated, streamlining mass production. However, the requirement for tooling to deliver production-grade casting patterns takes time, keeps costs high, and continues to impose barriers to entry.
That is set to change in the coming years. Digital processes and new technologies in investment casting are poised to deliver massive time- and cost-savings and also set new possibilities for what types of parts can be cast. We are calling this the ‘Digital Foundry’ and it will change the investment casting market.
The Digital Foundry will capitalize on digital design processes, along with significantly improved technologies and materials for 3D printing, to seamlessly accelerate the product development and production cycle. This will allow foundries to create, iterate, refine and produce cast parts with improved speed and flexibility, without the cost and wait for tooling. It will also enable the production of more complex parts by delivering part designs that are ‘unmoldable’ using traditional tools.
The Digital Foundry of the future will rely far less on tooling, and as additive technology for investment casting grows into a full, production-grade process, foundries will spend less and less on production and storage of tooling and rely more on digital storage and retrieval of CAD data. As costs drop, foundries will experience better bottom-line figures, driving profitability.
Rapid response becoming normal — Foundries that adopt new digital processes will be able to respond far more quickly to customer needs, potentially charging higher prices for rapid response cast parts.
In fact, foundries already using digital technologies now can deliver cast parts in 2-5 days of receipt of the CAD data. While OEMs see a shrinking lifetime for products, and have a mission to get to market faster, waiting 6-12 weeks for tooling will eventually become intolerable and those foundries that are agile enough to get the work done quickly will win. However, foundries that evolve well into the digital space will then deliver fast turn-around times at lower costs and that is where disruption occurs and competition begins.
Beyond prototyping, into production — Until now, additive manufacturing of casting patterns has been used mainly for prototyping of cast parts. But, there are developments underway to transfer that technology into production-grade pattern production.
For example, 3D Systems has been innovating additive manufacturing technologies for this market for 20 years, and now it working to take 3D printing from prototyping into full production solutions for the Digital Foundry. The new ProJet MJP 2500 IC delivers production-grade 3D-printed wax casting patterns using new materials and new printing methodologies for fast patterns that melt-out in an autoclave, eliminating the need to burn-out the pattern. Because the patterns are built directly from a customer’s CAD data, there is no need for tooling and now those patterns can go into immediate production. With just one ProJet MJP 2500 IC, hundreds of small- to medium-sized wax patterns can be printed within the time normally reserved for tooling to be produced. In fact, at a threshold volume of about 300 parts, 3D-printed wax patterns from this solution are produced not just significantly faster but cheaper than traditionally produced patterns.
SLA (stereolithography) investment casting patterns produced with the QuickCast methodology (which was patented by 3D Systems more than two decades ago) delivered a major step forward for additive in the industry and remains the most dominant technology in use today. But, the innovation is continuing here with a step toward new build methodologies, improved surface finishes, better software, and improved materials to take SLA into production-grade casting patterns.
Sometime in the future, materials and processes may advance enough to 3D-print the shells directly, thus avoiding the need for either tooling or casting patterns. While this remains on the horizon, it suggests many possibilities for further productivity gains by eliminating the mostly manual and semi-automated sprue assembly and shelling processes.
However, another critical advantage of additive manufacturing is the ability to replace the tooling with CAD data, and to be able to produce casting patterns as soon as the CAD data is received — or to update the pattern if the design has changed, and this is significant: When traditional tooling is in place for a part, the design is by then pretty much set. If the design has to change, the OEM has to pay for tooling modifications or new tooling, as well as account for the time it takes to produce those new tools. With digital design and production processes, new casting patterns can be created as soon as the design changes are completed in CAD, overcoming weeks of time and cost to get new tooling. This supports not just fast prototyping of cast parts but also fast production of evolving end-use parts, resulting in better parts and better products.
Optimizing geometry of cast parts — A critical (but sometimes forgotten) benefit of additive manufacturing is that the layer-by-layer approach of production allows designers to arrive at part geometries that would have been regarded as ‘unmoldable", and for these to be created and put directly into the casting process.
The development of ‘generative’ design and ‘topology optimization’ design techniques has led to a flood of designs for new components that retain the strength of the component they replace, but have significantly less mass. Most of these new designs, however, cannot be molded and therefore cannot be created using conventional investment casting. They can, however, be created in the Digital Foundry using 3D printed patterns. The transition to these designs will create new opportunities for the investment casting industry.
In all, the metalcasting market gradually will see, and invest in, more digital technologies for production-grade casting. The necessary additive technologies are quickly becoming viable for metalcasting, and I anticipate that foundries gradually will become digital as the relevant technologies become affordable. The value that the digital process brings will become evident as the first foundries start to disrupt the market by delivering cast parts significantly faster than their competitors, with lower costs for production, and higher profit margins.
Tom Mueller is the founder and president of Mueller AMS, a consulting company focusing on metalcasting applications of additive manufacturing. Previously, he established two 3D-printing service companies, and worked as 3D Systems’ director of business development for metalcasting applications, and later as Voxeljet’s director of metalcasting applications. Contact him at LinkedIn.