Design of a low-cost, high-temperature inverted build environment to enable desktop-scale additive manufacturing of performance polymers

Abstract

A heated build environment in Fused Filament Fabrication (FFF) additive manufacturing (AM) is used to promote layer bonding in printed parts and reduce the difference in temperature between the extrusion and environment decreasing the shrinkage, residual stresses, and part deformation. A build environment capable of maintaining a high-temperature (>200 °C) is often required to enable high-quality FFF printing of high-glass-transition, high-performance polymers such as nylon, PPSF, and ULTEM. Industrial-scale AM systems are capable of printing such polymers, as they offer a controlled, high-temperature printing environment; however, the machine cost often exceeds >$100,000. High-temperature printers are now available and at lower costs; however, the cost is still expensive (∼$30,000). Many of these printers use bed heating rather than controlled environment heating, which can lead to inhomogeneous heat transfer and inconsistent properties. The key barrier to offering high-temperature environments for desktop-scale FFF systems in a cost-effective manner is that the electrical components must be compatible with, protected from, or removed from environments exceeding 100 °C.To enable desktop-scale FFF printing of high-performance polymers at a low cost and high quality, the authors present a novel inverted FFF system design that provides a build environment of up to 400 °C. The inverted configuration effectively isolates the system electronics from the heated build environment, which allows for the use of inexpensive components. In this paper, the authors verify the inverted design concept analytically via a computational fluid dynamics model. The concept is then experimentally validated via a comparison of the strength of PPSF components printed on the inverted desktop-scale FFF system.