Beyond the print: XJet’s approach to production-ready metal parts

In the AM industry, we often talk of accelerated printing rates and the shortening time it takes for a part to go from a CAD model to a physical structure in the printer, but the focus on this specific (though vital) step in the production chain can sometimes obfuscate how long it takes to go from design to a truly finished, industry-ready component. In short, it is rare for a metal part to be considered finished as soon as it comes off the build platform.

XJet, a specialist in material jetting solutions for metal and ceramic materials, calls this phenomenon the gap between “print complete” and “production ready”. “The metal AM industry has become adept at showcasing the moment a build completes—the satisfying image of a pristine part emerging from a powder bed or the smooth surface fresh off a print platform,” the company elaborates. “Technology specifications typically highlight build volume, layer thickness, laser power and material options, but what happens in the hours, days or weeks after printing receives far less attention in presentations and capability brochures.”

As any manufacturer will know, all the steps after printing can significantly influence turnaround times, labor needs and costs. Steps like support removal, which typically require the work of skilled technicians and specialized tools; heat treatment cycles that require distortion compensation strategies; surface finishing steps that can end up accounting for up to 80% of the total manufacturing time for complex geometries; and part handling protocols for delicate parts that can’t undergo automated post-processing. That’s not to mention any time related to iteration cycles or failures.

In order to shorten and eventually close the gap between “print complete” and “production ready”, it is therefore necessary to drive efficiency across the entire production chain. This is the holistic approach taken by XJet in its aim to provide customers with a first-time-right solution that integrates an automated architecture covering the entire digital manufacturing cycle.

Integrated hardware, from print to post-process

At the foundation of XJet’s end-to-end metal AM solution is its NanoParticle Jetting (NPJ) technology. This technology, commercialized through the company’s Carmel 3D printer series, is a powderless process that uses thousands of printing nozzles to selectively deposit an ink (made up of a patented liquid and metal nanoparticles) onto a build tray. Nozzles also simultaneously deposit a support material precisely where it is required to prevent the collapse of overhanging or challenging geometries. With each layer complete, the build tray lowers and a new layer is deposited. This process is carried out at temperatures reaching up to 160 degrees Celsius, which causes the “liquid jacket” around each of the metal particles to evaporate and the metal particles to bond as they are deposited, resulting in metal structures that have comparable density and metallurgy to conventionally manufactured metal parts.

The very nature of the NPJ process effectively streamlines post-production steps. For instance, the support material used in XJet’s process is water-soluble and can thus be easily removed using a simple automatic washing process, eliminating the need for any manual support removal and the work of skilled technicians. The support removal is carried out using the company’s SMART (Support Material Automated Removal Technology) solution, a hands-free system that can be easily programmed for different job types and has full monitoring of the washing process.

Notably, the sintering stage in XJet’s workflow provides an advantage because the resulting shrinkage is isotropic (uniform in all three axes) and highly predictable. This is because NPJ uses metal nanoparticles in its build material, which results in a ‘green part’ with very little air or bonding agent to be removed. Specifically, the shrinkage factor is predictable (≈15%0, while other binder-based processes often experience higher and non-uniform shrinkage, reaching up to 25%.

Moreover, as a powderless process (the inks are securely packaged in cartridges), XJet’s solution only uses the necessary material and does away with any need for depowdering or powder management—steps that not only add time to end-to-end production chains, but also introduce safety concerns. Overall, XJet’s workflow—which comprises NPJ printing, washing and sintering—can print metal parts with complex geometries and a high quality surface finish (1440 DPI resolution and layers under 10 microns). This eliminates the need for post-processing steps like machining and grinding, sometimes employed after printing to smooth rough surfaces and achieve tight tolerances.

First-time-right with XJet software suite

Underpinning the aforementioned hardware solutions is XJet’s software suite, which offers users an intuitive and highly automated process for preparing, printing and post-processing parts. The software suite comprises three programs, starting with automatic parts planning software X-Plan. With X-Plan, users can easily upload CAD models and benefit from automated part orientation and fast parts layout, as well as choose from various preset AM modes. Moreover, users do not have to modify their part design to account for sintering shrinkage, this is done automatically by the software.

The second software in the suite is X-Hub, a job management program that integrates a proprietary slicer, job management tools and automatically generates highly efficient support structures for the entire build tray. Because XJet uses dedicated, soluble support material, the software is optimized to place support material only where structurally necessary. This eliminates the time, effort and guesswork traditionally required for manual support design, ensuring the most material-efficient placement and achieving the best possible print quality without requiring highly skilled technicians.

XJet also has its X-Print program, a production software that comprises system controls and management tools. Accessed through a user-friendly touchscreen GUI, X-Print also offers users various wizards to facilitate the digital production process. This three-point software suite is ultimately designed to streamline production preparation and controls, minimizing user input while ensuring that the process is optimized.

How design freedom drives value

As we’ve seen, XJet’s NPJ-based digital production chain emphasizes a streamlined approach that not only accelerates printing time but also facilitates and eliminates post-printing steps. In summary, XJet’s solution can shorten a production process that could have taken weeks to mere days by:

• Easing support removal using an automated washing station
• Printing high-resolution parts that require little to no finishing
• Combining debinding and sintering in a single step

The ability to print small, complex, high-resolution metal parts that require minimal (if any) finishing after sintering is highly appealing to end users in precision-driven segments like the aerospace, healthcare and consumer markets. As XJet puts it, its target customers are from high-value sectors where accuracy and complexity justify premium manufacturing.

Notably, XJet is not among the AM companies seeking to position its technology as a replacement for traditional manufacturing. Its solution brings something wholly new to the table that was previously impossible due to design limitations associated with conventional metal production approaches.

In the consumer segment, for instance, XJet’s end-to-end metal AM solution has several applications, including watch wristbands and accessories that can be printed with no tooling and minimal assembly, customizable jewelry made from precious metals, and complex eyewear temple endpieces. In healthcare, the precision of XJet’s technology has proven ideal for a range of applications, such as high-precision surgical tips for robotic arms and hypodermic tubing, which can be scalably customized. In the aerospace and industrial sectors, the metal AM process has value in the creation of complex machinery components, hydraulic systems and more.

These industries and others can benefit significantly from the company’s efforts to close the gap between as-printed and production-ready parts, achieving shorter and highly automated production cycles that require minimal post-processing steps. In the case of certain geometries, XJet has completed job cycles within just 48 hours, from CAD models to production-ready parts.

Expanding access with the Carmel Pro

This streamlined production ability has just been expanded to a wider user base through the launch of the Carmel Pro, a compact and cost-efficient NPJ platform. The new solution offers the same level of precision and quality as the larger Carmel systems, while opening the door to small-to-medium businesses, research centers and jewelry manufacturers, for whom the larger-scale solutions may have been prohibitive in terms of cost.

Carmel Pro has a build volume of 350 x 140 × 80 mm (the Carmel 1400 by contrast has a build volume of 500 x 140 mm) and is compatible with all XJet materials—including current and future ceramic and metal inks. The hardware also includes four material channels, facilitating multi-material prints. Most notably,the system is priced 60–70% lower than previous high-tier Carmel systems, costing in the range of $300,000. This new platform brings XJet’s unique value proposition—an integrated, streamlined production process—to a wider customer base, further empowering users to develop innovative and intricate products.

This article was originally published in VoxelMatters’ VM Focus Metal AM eBook. Read or download the full eBook for free at this link.