Effect of atmosphere on thermal debinding of DLP-printed ceramics

Abstract

This study investigates the effect of the gas atmosphere on the size limit for defect-free thermal binder removal in 3D-printed alumina bodies fabricated using digital light processing (DLP). Binder removal from cylindrical specimens with diameters ranging from 5mm to 15mm was carried out in either nitrogen or air atmospheres under different heating schedules. In nitrogen, defect-free debinding was achieved for specimens up to 15mm in diameter. In contrast, defect-free binder removal in air was limited to specimens as small as 5mm. Thermogravimetric analysis and microstructural characterization were employed to elucidate the role of the atmosphere in binder removal and defect formation. Microstructural differences between debinding in air and nitrogen were identified. Based on these results, mechanisms of binder removal in ceramic DLP printed bodies with acrylate-based crosslinked binder systems are proposed, and critical steps for achieving defect-free processing are discussed.