An in process laser localized pre deposition heating approach to inter layer bond strengthening in extrusion based polymer additive manufacturing
Abstract Material extrusion based 3D printing processes have shown importance in the overall development of the field of additive manufacturing and displayed tremendous potential to becoming a cross cutting tool for research, engineering, developmental work in a wide array of disciplines. In the context of the Fused Deposition Modeling (FDM, one form of Materials extrusion based 3D printing) one of the main process issues lies in the property anisotropy of parts built using this method, even with process optimization. To address this issue, we report a near IR laser based pre deposition heating method to locally heat up the region of an existing layer near the nozzle before an extrudate comes in contact with the heated region. This in process approach raises the inter layer interface temperature to above the critical temperature to increase the interpenetrating diffusion, and therefore the inter layer bond strength. A 50% increase in the inter layer bond strength in parts built with this approach is demonstrated. The in process pre deposition local heating approach reported here represents an effective means to increase the inter layer bond strength, and property isotropy of FDM parts. Further, this approach is capable of real time monitoring and controlling of temperatures at the inter layer and inter filament interfaces across the entire volume of a built part, allowing control of the physics of the FDM process to achieve desired mechanical properties.