Performance of 3D-structured grinding wheels with multi-layer internal cooling channels

• Sacrificial 3D-printed inserts created multilayer channels in vitrified wheels. • Manufacturing method integrates with pressing-sintering, no post-processing. • Tangential force reduced by 49.3% with multi-layer internal channels. • Temperature variation dropped 58.6% with 3D-structured wheels. • Internal cooling doubled the removal rate without thermal overload. Grinding is a key machining process in industries that demand high precision and surface quality. However, the conventional flood cooling method is often ineffective due to the air barrier formed by the rotating wheel, which restricts fluid access to the contact zone. This causes thermal instability, high coolant use, and environmental impact. To overcome these limitations, this study investigates alumina grinding wheels with internal cooling systems, fabricated by a novel additive route. Sacrificial 3D-printed polymer inserts were embedded during pressing and eliminated during sintering, enabling multilayered channels within a monolithic abrasive matrix. This represents the first practical application of a fully embedded cooling system in vitrified grinding wheels. Two configurations, with one and three internal channel layers, were compared to a conventional wheel under external cooling. Controlled grinding tests on AISI 1045 steel were performed at varying depths of cut, and key variables such as cutting forces, force ratio, specific energy, and temperature variation (ΔT) were analyzed. The three-layer wheel showed the best performance, reducing tangential force by up to 49.3%, force ratio by 21.3%, specific energy by 50%, and ΔT by 58.6% compared to the conventional system. A detailed thermal profile enabled segmentation into cut-in, steady-state, and cut-out zones. The greatest benefit from internal cooling occurred in the steady-state region, with heating rates reduced by up to 78%. These results confirm that the proposed additive manufacturing approach offers a scalable route to produce structured wheels with embedded channels, improving coolant application, process stability, and sustainability in high-performance grinding.