Interview first published in the July/August 2021 issue of 3D ADEPT Mag, then online in January 2022. Roles, materials and outlook reflect 2021.
Reducing development lead times is a major challenge for manufacturers. Additive manufacturing can help, but its value for a mould must be assessed across the complete manufacturing route: printing, machining, heat treatment, finishing and inspection.
Mantle’s TrueShape technology combines metal-paste deposition and machining to produce tooling components.
Based in San Francisco, Mantle publicly introduced TrueShape on 24 February 2021, announcing previously undisclosed funding of $13 million. The company initially targeted tooling.
Its co-founders are Ted Sorom, a mechanical design engineer and CEO at the time of the interview, and chemist Steve Connor. They described having worked on the company for more than five years by that point.
Their respective professional experiences led to the development of TrueShape to the extent that from the very beginning of his career, Connor built up expertise and decided to specialize in nanoparticles and metal pastes. He has even developed a successful “lower-cost replacement for the expensive silver metal pastes used in the solar industry.” “He then shifted gears to see if similar technology could be used for additive manufacturing”, Sorom told 3D ADEPT Media.
Sorom’s experience in mouldmaking helps explain this choice. Indeed, right after he obtained his degree, he “joined a vertically integrated company that made high-end equipment using CNC machined metal and injection molded plastic parts.”
“I designed the parts and molds upstairs and then went downstairs and made the molds before putting them into full production. I saw first-hand how time-consuming and expensive the toolmaking process was for even a simple plastic part. Our new product launch schedules were gated by tooling. Unfortunately, my experience is not unique; almost every manufacturing company struggles with these same challenges. At Mantle, we’ve focused our efforts on addressing these challenges”, he recalls.
Understanding the backbone of the manufacturing industry
Tooling encompasses the tools needed to manufacture and inspect parts: moulds, forging or stamping dies, jigs, fixtures, gauges and cutting tools. Their geometry and surface condition directly influence the resulting parts.
As the design and fabrication of these tools directly affects the production quality of the end-user industry, the choice of the manufacturing process leveraged here is of paramount importance. “Tooling applications require outstanding surface finish and a high degree of accuracy”, Sorom points out. To deliver such rendering, Mantle decided to combine the best of both worlds: traditional machining and additive manufacturing.
Most importantly, as far as AM is concerned, the founders see an opportunity here for this technology to make a big impact on high-volume production of products.
TrueShape
Conventional mouldmaking can involve programming, machining and finishing. Lead times depend on complexity, tolerances and available capacity; claimed gains from an additive solution need to be compared on an equivalent basis.
TrueShape deposits a proprietary metal paste and then machines the geometry before sintering. This feedstock, intended for printing and sintering, should not be confused with resin-and-hardener repair compounds.
In Mantle’s case, the paste consists of metal particles and liquid carriers, which one extrudes to build up the parts layer-by-layer.
“Then we heat and dry the paste inside the printer, which removes the liquid carrier and leaves a “green body” that is relatively soft and can be machined quickly and easily. The machining creates the accuracy, surface finish, and fine features needed for precision parts like moulds. The final step is a sintering step, which is important because it fuses the metal particles and establishes the final material properties. We sinter in a high-temperature furnace that brings the parts’ temperature to just below the material’s melting point, and then cools it off. When the parts come out of the furnace, they are high-hardness tool steels with extraordinarily smooth surfaces that can go directly into injection mould tooling applications with no post-processing of the mould surfaces”, the CEO told 3D ADEPT.
Mantle thus seeks to limit certain mould-surface finishing operations. Drying, machining before sintering and the furnace cycle remain part of the process; inspection, any additional finishing and further treatments depend on the intended tool.
The approach should be evaluated against accuracy after sintering, surface finish, steel properties and tool life. Repeatability depends on controlling the complete process, including sintering shrinkage.
At the time of the interview, Mantle presented two materials comparable to P20 and H13 tool steels. Paste distribution alone does not establish a stronger microstructure: properties need to be characterised for the material and process cycle used.
Sorom cites a global medical-device manufacturer that used TrueShape for steel mould inserts. According to Mantle’s reported results for this case, tooling lead time fell from seven weeks to eight days, with a cost reduction exceeding 50%. These figures concern that tooling, not complete device production or medical-device authorisation.
The next step in the pipeline
In 2021, Mantle presented tooling as the first application for its precision components, while considering other markets.
“Other application areas include precision jigs and fixtures and low volume / spare parts for industrial applications”, the CEO notes. “We also anticipate that, several years from now, our technology will be qualified for end-use medical, aerospace, and automotive applications”, he completes.
These qualification and product-expansion prospects reflect 2021. At that time, shipment of the first systems was still a milestone anticipated by the editorial team; this passage does not describe the current state of commercial deployment.
This exclusive feature has first been published in the July/August edition of 3D ADEPT Mag.
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