Binder jet 3D printing is widely regarded as the fastest additive manufacturing method for production-volume output. In addition to its speed, binder jetting is a flexible technology allowing for a variety of materials to be processed and scaled for mass output as well as large-format applications.
Sand binder jetting has been used in foundries for more than two decades to create tooling for metalcastings. The upper end of the foundry market has been benefiting from additive manufacturing, using traditional ExOne sand 3D printers to create molds and cores for sandcasting that slash lead times and enable complex, consolidated geometries without traditional hard tooling that has to be machined, stored, and repaired.
ExOne’s latest offering, the S-Max Flex robotic 3D printer is a new, designed-from-the-ground-up system resulting from ExOne’s late 2021 acquisition by Desktop Metal. The introduction of the S-Max Flex reflects Desktop Metal’s core strategy to aggressively drive widespread adoption of Additive Manufacturing 2.0 through accessible, area-wide 3D printing technologies, such as binder jetting, integrated with select, high-performance materials and targeted applications. Behind Desktop Metal’s mission is a desire to help more manufacturers benefit from AM 2.0’s improved time to market, increased design flexibility, reduced waste, and greater financial savings while de-risking supply chains.
Much like ExOne’s premium, market-leading S-Max models, this new system also binder jets sand molds and cores for metalcasting. A key difference with this model is its affordability, driven by a streamlined printing strategy featuring a conventional robot arm for motion control and leveraging Desktop Metal’s advanced Single-Pass Jetting (SPJ) technology to print into an automated telescoping job box that grows with the build.
And the S-Max Flex enters a market primed for adoption. While 3D printing technology has remained largely out of reach for most of the market, many foundries are as busy as ever with re-shoring initiatives and increased demand for quick-turn production to ease strains on the supply chain. The need for foundries to remain flexible and ready for a more digital future has never been stronger.
3D printing sand molds and cores straight from CAD files enables foundries to eliminate the months-long lead times and high costs of traditional patterns and coreboxes. The design freedom of AM also allows designers to innovate parts made with the reliable casting process – creating complex, consolidated geometries that enable lightweighting and optimized part performance not possible with traditional processes.
Digital production also helps ease the labor shortages many foundries are facing. In the foundry today, manual assembly is required to glue multiple traditionally formed cores into a final shape for casting. This intricate process requires skilled labor, a resource that is increasingly hard to find. Moreover, assembly typically leads to increased scrap resulting from human error in core misalignment while core-glue off-gassing during molten metal pouring also introduces porosity, compromising final part quality.
Complex core shapes create the interior geometry of a casting. This vapor recovery fuel nozzle is produced by Alpha Foundry Company in Wright City, Missouri and features value-added features because it utilizes additive manufacturing. What used to be six individual core pieces that required manual assembly is now printed as one monolithic part on the S-Max Flex. The final aluminum casting benefits from precision interior passages and small cross sections that could not be produced with conventional metalcasting methods.
3D printing a core design as a single complex, consolidated geometry eliminates the need for assembly and all the labor, scrap, and complications that come with it. This design freedom is leading to iterative and optimized cast metal parts more akin to their directly 3D printed metal counterparts and by delivering an accessible sand 3D printing solution suitable for just about every foundry, Desktop Metal and ExOne aim to bring extensive efficiency gains to the casting market with the S-Max Flex.
Ambitions Outside the Foundry
And the S-Max Flex is poised to bring the benefits of additive manufacturing beyond the foundry, and beyond sand. Indeed, this scalable binder jetting solution also holds the potential to support printing with a variety of materials for a range of large-scale applications.
Already, S-Max systems print sand for resin infiltration to produce durable, rapid tooling for plastic thermoforming, composite layup, and sacrificial tooling applications. Similar techniques, where forms are printed in powder and then infiltrated to a strength certified for exterior use are being used for architectural restoration or design elements today. Forust, another brand in the Desktop Metal portfolio, plans to use the S-Max Flex’s large form factor to upcycle byproducts from traditional wood waste streams into upscale designs like automotive interiors or guitars. Meanwhile, Carnegie Mellon University has used binder jetting technology to print reclaimed powdered concrete into urban furniture in research of more sustainable architectural design.
As large-format binder jetting continues to evolve, the new S-Max Flex robotic system is lowering the barriers of entry for foundries around the world to get into digital casting while opening possibilities for new materials and innovations to create more sustainable products.