3 technical challenges of large format 3D printers.

Large-Format 3D Printing

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The 3D printing industry is a global niche market worth 10 trillion USD that focuses primarily on the development of machines (AMFG, 2020). Within this sector, there are currently hundreds of companies dedicated to manufacturing 3D printers using FDM (fused deposition modeling) technology, most of which have rectangular build volumes ranging from 200 mm to 400 mm.

Few companies currently offer printers with print areas larger than these—not because there is no market demand, since many segments of the industrial sector require much larger sizes, but because there are certain technical problems that need to be solved, and some of these companies have not been able to do so successfully:

• High molten material flow rates

Filament 3D printing has a natural limit determined by the amount of molten material that can be extruded through a nozzle. It is not feasible to use desktop-class extrusion systems because print times would increase dramatically. Therefore, one of the most important technical aspects of a "large-format" machine is the material flow rate that the machine’s extruder is capable of handling. The Big-T model, for example, features an extrusion system capable of using up a standard 1-kilogram spool in approximately 1 hour, whereas a desktop model with E3D-type hotends would take 22 hours—which, in terms of volumetric flow rate, represents more than 20 times the rate per unit of time. This feature, combined with the ability to achieve higher travel speeds, makes it possible to produce giant parts in incredibly short amounts of time.

• Speeds comparable to those of desktop 3D printers

In 3D printing, speed is a key factor in production. With the development of advanced materials that rival the quality achieved by processes such as plastic injection molding, increasing the number of parts printed per unit of time is an essential goal if one wants to take the next step and enter the business of manufacturing end-use parts. To achieve this, motion and electronic control systems must work in tandem to achieve micrometric precision, typically in configurations widely used in the “desktop” machine industry that are replicated from one machine to another.

But when designing a giant machine—and achieving print strokes of up to 1 meter, as in machines like the Big-T—it is necessary to refine the engineering. In these cases, it is necessary to rethink technical specifications typically inherited from the desktop industry—such as the use of Nema 17 stepper motors, pulleys, and GT2 belts with simplified machine structures— and instead adopt robust structures engineered to withstand the challenges posed by the machine’s own weight and the vibrations caused by the inertia of a heavier print head’s movement, as well as motion configurations derived from industrial-grade machines such as CNC machining centers or SMT machines. Additionally, the power demands resulting from the use of more robust components—with specifications superior to those in the desktop sector—require more sophisticated electronics and controllers, as well as custom firmware to maximize their performance.

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• Calibration and "leveling" of the first layers.

Just as with the foundation of a building, the first layer of a 3D-printed object determines the success of the entire project, and achieving this is particularly difficult when the print surfaces are very large. Trideo’s 1 m³ Big-T model employs a comprehensive calibration formula that uses automatic digital compensation for minor curvatures in the print surface, combined with automated balancing of the Z-axis motion system, to ensure that the first layer is equidistant from the surface at every point. Furthermore, uniform surface heating and the use of surface adhesives complement the formula for perfect adhesion.

The industry demands machines capable of 3D printing large parts. The time has come when the cost-benefit ratio is now comparable to that of alternative technologies such as machining or lamination, but with all the added value offered by additive manufacturing and at a fraction of the development time.

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