Critical mass

The holy grail of 3D printing is for it to become a viable mass-production technology. Could a new technological leap make that possible?

For all the claims made for 3D printing, it has long been agreed that it is not suitable for mass production and is unlikely to threaten subtractive manufacturing methods in this respect. However, 3D printing offers unique opportunities to produce three-dimensional, often complex shaped parts in one single step and, while predominantly prototypes and sample parts have been produced in small numbers so far, many industries are increasingly interested in industrial mass production.

With this in mind, Silicon Valley based company Carbon has developed Digital Light Synthesis (DLS) technology, which can accelerate the production of parts up to a hundredfold compared to previous processes. After years of R&D, Carbon developed a novel polyurethane liquid resin suitable for production parts.

Covestro is a key partner in the scale-up and high-volume production of this material. Covestro is among the world’s largest polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, construction, wood processing and furniture, and electrical and electronics industries.

The company invested a significant sum to enable production in commercial quantity. This resulted in it proving the mass production viability of the 3D-printing process and the material, which is a real success story for the partnership.

“Our biggest challenge in the upscaling of additive manufacturing until series production lies in the supply of suitable materials in the required quality and quantity,” explains Patrick Rosso, global head of additive manufacturing at Covestro. “By partnering with companies like Carbon, we are pushing existing scale boundaries and supporting various industries along the value chain on their way to digital mass production.”

Covestro is currently researching materials to enable an extended range of industrial applications. To this end, the company is upgrading laboratories for 3D printing at its Leverkusen, Pittsburgh and Shanghai sites, where it develops and tests material solutions for serial additive manufacturing in collaboration with different customers.

The DLS technology developed by Carbon is now being used for the first time on a large scale. Similar to stereolithography, the workpiece is created in a vat of liquid plastic resin that is cured by means of UV radiation.

At Carbon’s DLS technology, oxygen is supplied from below to counteract the curing and thus creating a liquid dead zone. For this purpose, the bottom of the vessel is made of a light- and air-permeable membrane, similar to a contact lens. Due to this dead zone, the printed part can be pulled continuously upward without the formation of individual layers.

Production using DLS technology is up to 100 times faster than with stereolithography – another important prerequisite for industrial mass production. In that context, a proprietary process combines software, hardware and materials. It imparts the desired technical and mechanical properties to the finished parts.