Tensile strength improvement of FDMed ABS parts by a WIP heat treatment


  • Seong Je Park
  • Yong son
  • Il HyukAhn


Background/Objectives: Fused deposition modeling (FDM) has been widely adoptedowing to low-cost machines from the machine manufacture vendors, based on open-source. In the FDM process, a filament (a primary material used in FDM) is melted for passing a heating block. The melted filaments are fused in a layer-by-layer manner until a final part is obtained. The mechanical properties of the part fabricated by FDM process are dependent on the bonding strength of two successive layers or two neighboring lines in the fusion of the melted filaments. In the fusion of the two successive layers or two neighboring lines, voids and cracks are inevitable. However, they should be removed to improve the mechanical properties. In this study, the authors propose a method to reduce defects such as voids and cracks. Methods/Statistical analysis: Warm isostaticpress(WIP)is used to alleviate the defects for the part formed through FDM. In the WIP process, the pressure, temperatureand holding time for two process parametersare the main process parameters to be controlled. The shapes of process profileswere designed by referring to high isostatic pressure process profiles. The tensile tests were conducted with specimens fabricated with the process profiles. Measured results of tensile tests were compared to evaluate the effects of the process parameters on thevoids. Findings: During WIP, warpage does not occur below 0.8 glass transition temperature (Tg) forthe acrylonitrile butadiene styrene(ABS) used. To prevent warpage, the maximum temperature wasset to 0.8 Tg. Pressure and processing time were controlled for the fabrication of specimens. By comparingthe results from the tensile tests, wediscovered that WIPcould be an effective method to reduce mechanical defectsin a part formed through FDM without unfavorable shape deformations. Improvements/Applications: The tensile strength for the ABS part formed through FDM increased to 11% compared withthe standard specimen without WIP.