Adopting the most commonly-used plastic 3D printing process and the use of alloys found in metal injection molding (MIM), Bound Metal Deposition™ (BMD) technology from Desktop Metal enables the in-house production of metal parts.
What is Bound Metal Deposition™?
BMD uses the extrusion method where bound metal rods – metal powder held together by wax and polymer binder – are heated and extruded onto the build plate, to shape a part layer-by-layer. The binder is removed via debinding following the printing process and then sintered which causes the densification of the metal particles.
Unlike common metal AM technologies, parts production does not require contact with hazardous powers nor dangerous lasers. Support removal is simplified, with parts printed together with their supports. The supports made of ceramic interface media does not bond to the metal and can be easily removed by hand after it disintegrates during sintering.
The role of infill
With the use of the extrusion method, parts can be produced with fully-enclosed, fine voids. Aside from extremely small geometries, closed-cell infill (fully-enclosed, internal lattice structure printed within the part) comes with all printed parts.
Printing and debind time are directly affected by infill. Cross-sectional thickness which is reduced through printing with infill has an effect on the time it takes to debind a part. Infill also affects the weight reduction of a part, while maintaining the design intent of the surface parts.
BMD can work with any sinterable powder that can be compounded in a thermoplastic media. Industrially-relevant metallic alloys like stainless steels, tool steels, and other metals that are difficult to process via common AM processes such as refractory metals, cemented carbides, and ceramics, can all be utilized with BMD technology.
Parts & Capabilities
Structures and geometries that were unachievable via bulk manufacturing processes previously, are now realizable with BMD. Near-net-shape parts needed for functional prototyping, jigs & fixtures, tooling applications, and in some cases, low-volume production comes with the required strength and accuracy.
Printed parts from the Studio System have the same resolution, accuracy, and surface finish as traditionally cast parts, with sintered parts achieving dimensions within ±0.8%.
To achieve critical dimensions and finish, parts can be post-processed using CNC, EDM, grinding, tumbling, media blasting, plating, welding, and heat treating.
While 3D printing has been around for decades, it has very much been focused on low volume production and mostly dealing with plastic materials.
As customers gain awareness of the solutions that they want, they are increasingly looking at specific technologies – in particularly metal which has yet to achieve broad adoption.
With metal 3D printing gaining increasing accessibility, the production of complex metal parts is no longer a long-drawn process with the availability of a wide range of materials.
Key applications include:
- Functional prototyping
- Jigs & fixtures
- Low volume production
Metal 3D printing not only enables quicker part iteration but also functional prototypes that adhere to specific thermal and chemical requirements.
Product development and time-to-market are significantly accelerated, by doing away with lead times, costly complex machining operations, and tooling needs.
With the expedition of printing that’s done in-house, engineers can focus on the iterative design process that includes functional testing.
Jigs and fixtures on the production line have complex geometries and are usually made in metal to meet stiffness and strength requirements. The ability to produce replacement parts quickly is critical for efficiency, as they tend to wear down from frequent use.
Metal parts printed with the Studio System not only meet the strength and durability requirements but can also achieve high repeatability. The BMD process also enables the ability to do print-in-place assemblies, which is not possible traditionally.
Complex geometries found in custom tooling applications are traditionally difficult to achieve with traditional manufacturing. In applications like mold cavity inserts with conformal cooling channels, the initial tooling expenses make up the majority of the overall part cost. The high costs often make it impossible to use processes like casting, injection molding, and extrusion for smaller, customized parts.
With the Studio System, tools produced are reliable, highly accurate, and durable than the plastic equivalent.
With the Studio System, designers can focus on the function of the parts for low volume production. Printed parts can be customized and produced quickly, and part costs do not increase regardless of how complex they are.