While new additive manufacturing machines are brought to market regularly, it isn’t often that you hear about a new AM process. So you can imagine how interested we were to speak to Israeli metal AM company Tritone about its recently developed MoldJet Technology, which was first unveiled at Formnext 2019. The technology is being brought to market in the Tritone DOMINANT system and offers a new solution for medium-volume production (tens of thousands of parts per year) of metal components. To learn more about the promising AM method and its unique capability, we caught up with Omer Sagi, Vice President of Products and Business Development at Tritone.
A bit about Tritone
Tritone was founded in 2017 by Ofer Ben-Zur (CEO), former founder of Kornit Digital (KRNT), an industrial company specializing in inkjet printers and inks for textiles, and Hagai Peled, a chemist with vast experience in inkjet materials development. They leveraged their deep knowledge of digital printing to inform their new venture and develop a metal AM process that combines polymer inkjet printing with metal binder-powder (paste) deposition.
Today, the Tritone team is working hard to bring the DOMINANT system to market. The company’s ambitious new metal AM process is supported by a single investor, Fortissimo Capital. Sagi elaborates: “They decided to back us because they love the idea of an attractive systems-consumable model and know our team very well. Fortissimo Capital has raised $1.7 billion to date and has 37 companies in its portfolio. Crucially, their support and commitment have given us the freedom to focus on developing our technology and not spend all our time chasing investors.”
With its MoldJet process and DOMINANT AM system, Tritone is hoping to fill a gap in the market for metal parts production: medium-volume manufacturing. “I believe that metal injection molding (MIM) will always have the advantage when you’re talking about hundreds of thousands or millions of parts,” Sagi explains. “But there are so many businesses that are looking to fulfill low to medium level production volumes—thousands or tens of thousands of parts per year—and this is where metal AM can really shine.”
A six-step solution
Keen to differentiate itself in the growing AM market, Tritone has developed a unique (and now patented) metal 3D printing technology that uses cost-effective, off-the-shelf MIM powders. The MoldJet process is fascinating and involves multiple steps, including polymer mold printing, metal paste deposition, layer-by-layer quality inspection and more. Read on for a detailed look at how the technology works.
The DOMINANT metal AM system comprises six trays and six stations: each tray moves from station to station resulting in the production of near-net-shaped metal parts. The first station the tray goes through is for mold printing. This station uses a polymer material and four inkjet printheads to rapidly deposit the first layer of a mold, covering the negative space. Each layer has a variable height between 40 and 200 microns.
At the second station, for material placement, a number of things happen. First, a roller passes over the mold layer to ensure that it is level and smooth. Next, a paste consisting of a water-based binder and MIM powder, is deposited into the mold cavity. A blade then passes over the metal paste to remove excess material and compress it inside the cavity. In the next station, the build tray undergoes a drying and hardening process. This patented step uses warm air and a vacuum setting to evaporate the water from the metal paste. This results in dense and strong green parts.
The next station, detect and control (DAC), is also unique to Tritone. Here, the tray undergoes a quality check for every printed layer. This process involves a high-resolution camera that captures each layer and then an analysis by an AI-driven algorithm to detect any inconsistencies or errors. If there is a defective layer, it can simply be removed using an integral cutting tool and re-printed. From there, the tray is moved to a low-temperature oven station to remove the polymer mold.
“This step also makes the green part stronger,” Sagi says. “And from there, the tray goes into the sintering furnace. Our green parts have less than 2% binder, which means that even before they go into the sintering furnace they have a good density. After sintering, we have demonstrated the ability to achieve densities upwards of 99%. In the case of stainless steel, for example, we reach over 99.5% density, almost like the raw material.”
The Tritone DOMINANT system is also built for continuous use, leveraging its multi-station approach to build up multiple trays of parts at once.
“Each tray is completely independent and they each go to a separation station,” Sagi elaborates. “So if one tray is going into the mold station, another can be moving ahead to material placement, and another can be undergoing quality control. And when one of the trays is finished, you don’t need to wait until they all are: if you are working with the same material, you can simply put a new tray into the lineup and start a new job. This means the machine can keep working all the time. It is also automated for workflow thanks to a carousel that moves the trays from station to station. If you do want to replace a material, all you have to do is remove the paste tube and replace the cartridge with a new one.”
Presently, the DOMINANT system has a throughput of about 1.6 liters per hour and it is able to print parts with varying resolutions. For example, a part can be built with a layer at 200-micron resolution and a subsequent layer at 40 micron resolution, allowing for users to tune the precision of parts where necessary.
If even higher tolerances are needed, parts can undergo CNC machining after sintering.
Another notable aspect of the process comes into play in the sintering stage. Parts can either be sintered in-house by end users with the necessary equipment or parts can be sent to partners with larger-scale sintering capabilities. “When a company purchases a machine, they don’t need to purchase the furnace, they can just send the parts to a partner company, or they can use their own sintering equipment,” Sagi says. This feature is enabled thanks to the strength of MoldJet Technology’s green parts, which are robust enough to not only be handled but also shipped.
The power of MIM powder
At the crux of MoldJet Technology—and any other additive manufacturing process—are materials. In Tritone’s case, the company has based its process on MIM powders, which are readily accessible and cost competitive when compared to specialized AM powders for laser powder bed fusion. According to Sagi, this materials approach has several benefits.
For one, manufacturers can use their own MIM metals that have already been certified and combined with Tritone’s supplements. “In the case of unique materials, we can open the system so customers can use their own metals,” he says. “Because we’re using off-the-shelf powders which are mixed with our binders, it can really shorten our customers’ time-to-market.”
Another key advantage centers on usability and safety. “Unlike many metal 3D printing processes, the end-user is never exposed to metal powder with our technology,” he explains. “Our materials are delivered as a paste in cartridge form, meaning that users do not require any special equipment and, because we print at room temperature, you don’t need special filters or humidity control.” Using controlled paste also allows uniform and repeatable printing across trays.
Today, Tritone is focusing on about eight materials, including stainless steel, tool steels and high-temperature alloys. Its MoldJet process is also compatible with titanium, copper-based alloys and technical ceramics. Sagi adds: “Every time we have been asked to develop new material, it didn’t take long to do, because of how our pastes are made. We can basically print with any material that is available for MIM.”
After a few initial installations of the DOMINANT system, and closing distribution deals across Europe, Tritone Technologies introduced the new Tritone DIM, a mid-range metal AM platform at Formnext 2021. Powered by Tritone’s patented Moldjet technology, DIM addresses the needs of consumer goods and consumer electronics manufacturers, service bureaus, R&D and educational departments to create end-use metal parts.
“After the initial success of our DOMINANT system, we are proud to expand our market reach with the DIM system. The market is ready to shift gear from prototyping to production of high-quality metal parts, and we are proud to be at the forefront of this emerging revolution,” said Omer Sagi, VP Products and Business Development at Tritone.
This article is a modified version of the article that first appeared on 3dpbm’s AM Focus 2020 Metal eBook