Temperature control to increase inter-layer bonding strength in fused deposition modelling

Abstract

Fused Deposition Modelling (FDM) provides opportunities for new development in numerous areas. Z-directional anisotropic strength caused by weak inter-layer bonding has been recognized as the reason for limited industry adoption of FDM. This paper aims to investigate increasing the Z-directional strength of Acrylonitrile Butadiene Styrene (ABS) using a temperature controlled print environment. The ambient temperature during printing was increased to reduce heat transfer from the print, thereby encouraging more polymer chain inter-diffusion between layers. Dogbone specimens were printed at ambient print temperatures between 24.8°C and 71.2°C and tensile tests were performed. A thermal camera was used to identify heat loss in the FDM process. Ultimate tensile strength was found to increase by a maximum of 104% compared to open enclosure printing. A stylus profiler and scanning electron microscopy were used to compare the quality of the inter-layer bonds, suggesting that additional polymer inter-diffusion occurred at hotter ambient temperatures. A weak positive relationship was found between ambient air temperature and inter-layer part strength. Further experimentation could provide scope to determine an ideal ambient print temperature that is likely to be dependent on print settings and the printer used.