Abstract
• Air temperature above a heated horizontal plate exponentially decreases with a characteristic decaying constant l c . • Near environment strongly affects the part cooling when printing at high resolutions (low layer thickness). • Closed chamber raises the far environment temperature, hence delaying the part cooling and are specifically beneficial for large scale printing. Heated build plates are common yet essential components in many additive manufacturing (AM) machines. However, their influence on the air temperature above and the subsequent impact on the AM process are barely discussed. This article proposes a simple model for the air temperature above the plate T a ( z ) , which exponentially decays from the plate temperature to the far environment temperature by a characteristic dimension l c in the range of 2–9 mm. The model has been empirically validated for three fused filament fabrication (FFF) machines, including open and closed systems, small and large build chambers. Temperature simulations in printed parts suggest that T a ( z ) plays a critical role when printing at low layer thicknesses, such as 300 µm. Besides, adding an enclosure to FFF machines can significantly raise the far environment temperature inside the chamber, delaying the part cooling. However, its effect is noticeable for the portion above 10 mm only.
Highlights
The heated build plate, known as building platform or print bed, is a common but essential component in a few additive manufacturing (AM) techniques, such as fused filament fabrication (FFF), continuous fibre reinforced printing, and aerosol jet® printing
One such good example is the heated chamber apparatus patented by Stratasys® [7,8], which controls the whole building environment during printing and delays the cooling by reduced convection
The heated build plate plays an essential role in fused filament fabrication (FFF)
Summary
The heated build plate, known as building platform or print bed, is a common but essential component in a few additive manufacturing (AM) techniques, such as fused filament fabrication (FFF), continuous fibre reinforced printing, and aerosol jet® printing. An elevated air temperature has long been identified to be beneficial to printing in FFF since it delays the part cooling [2,3], promotes bond qualities [4,5], part quality and integrity [6] One such good example is the heated chamber apparatus patented by Stratasys® [7,8], which controls the whole building environment during printing and delays the cooling by reduced convection. A hot air film could form around the upmost layers by attaching a heat collector [9] or a wide flat heating coil [10] to the hot-end, reduces the local convection intensity As another example, Prajapati et al [11] integrated extra nozzles to actively dispense hot-air towards the printed parts for pre-and-post heating. All these efforts can effectively slow down the part cooling
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