As a supplier to General Motors, TEI uses the world's largest 3D sand printer to produce casting cores for the series production of large-format, weight-saving structural components for the Cadillac CELESTIQ. By using 3D printing in the development and design of components, OEM manufacturers can realize completely new, functionally optimized designs. Suppliers benefit from the fast and flexible integration of 3D-printed cores into existing production lines.

TEI, an expert in highly complex castings for the mechanical engineering and manufacturing industry, has been working with voxeljet since 2018. What began with a three-year contract for 500,000 liters of 3D-printed sand has developed into a success story for both companies. TEI is the only company in the USA that owns three VX4000 3D printers from voxeljet, which are among the largest 3D sand printers in the world with a build volume of 4 x 2 x 1 meters. With the third VX4000, TEI has now expanded its additive manufacturing capacity to up to 2.5 million liters per year. This enables the US company to realize further technically demanding projects such as the series production of lightweight components for the underbody structure of the all-electric Cadillac CELESTIQ.

Each casting replaces up to 40 components

The innovative underbody structure consists of six large precision sand-cast aluminum parts. In order to realize the complex structures as economically and lightly as possible, TEI relies on additive manufacturing for the production of all inner cores. This allows stiffening features to be incorporated into the hollow profiles, which is not economically feasible with conventional manufacturing. A total of 51 additively manufactured sand cores are used in the production of each vehicle underbody. TEI prints these using the VX4000 printers, each of which prints hundreds of inner cores for multiple vehicle sets in just one night. After printing, the cores are smoothed, coated with a refractory coating, placed in sand molds and finally cast in a low-pressure filling process. Each of the six castings reduces the number of parts by 30 to 40 components compared to a typical stamped design. Because each structural part has fully machined interfaces, the six castings can be precisely assembled and very tight tolerances can be maintained for the production of the assemblies.

Short delivery times for weight and design-optimized lightweight components

The large-format mold and core printing on the VX4000 3D printers makes production leaner and therefore faster and more economical compared to conventional manufacturing. Significantly fewer components need to be produced, which simplifies and speeds up assembly. "By eliminating tools and thanks to the large build volume of the VX4000 printers, we can significantly reduce delivery times and produce lightweight components with optimized topologies. This would not be possible using conventional methods," explains Oliver Johnson, President of TEI. In addition, 3D sand printing enables completely new designs and lightweight structures. The result is geometrically optimized parts that are very important for the automotive and aviation industries. This is important for implementation by suppliers: New function-optimized designs can be implemented quickly and flexibly with the VX4000 3D printers and printed cores can be easily integrated into existing production.

"We are excited to have TEI as a strong partner and user of 3D sand printing in the US. The purchase of the third VX4000 printer builds on previous system installations at TEI's corporate site in Livonia, Michigan, and will allow the company to grow rapidly and realize unique projects like this one," said Michael Dougherty, Managing Director at voxeljet America Inc. "Together, we will further establish additive manufacturing technology in industrial manufacturing and intensify our collaboration. We are proud to support the company with our unique 3D printing technology and once again demonstrate that our printed casting technology is making its way into production and enabling unprecedented designs."