Selective laser melted uniform and functionally graded lattice structures diamond tools: Microstructure, compressive behavior and grinding performance of CuSn20-bonded diamond composites

Selective laser melted (SLMed) porous metal-bonded diamond grinding tools have been proved to own abundant chip storage space and good self-sharpening property. SLMed porous CuSn20-bonded diamond tools were systematically investigated to elucidate the influence of Uniform Lattice Structures (ULS, UL-30 %–50 % porosity) and Functionally Graded Lattice Structures (FGLS, GL-P and GL-V) on compressive behaviour and grinding performance in this work. Gyroid type cellular architectures were designed in MATLAB, fabricated via SLM with CuSn20 alloy and diamond (15 vol%), and characterised by SEM, EBSD and Raman spectroscopy. Quasi-static compression and finite element method revealed that ULS specimens exhibited porosity-dependent elastic modulus (1469.32–648.5 MPa) and compressive strength (47.83–19.78 MPa), with failure mode transitioning from 45° shear-dominated (UL-30 %) to layer-by-layer bending-dominated (UL-50 %). The Gibson–Ashby model accurately predicted ULS properties (R2 > 0.99), whereas Kelvin–Voigt and iso-stress models estimated FGLS modulus within 11 % but over-predicted strength due to brittle interfacial fracture. Grinding BK7 glass with ULS tools (UT-30 % to 50 %) demonstrated decreased material removal rate (MRR) (314.04–285.76 mm3 min−1) and wear ratio (WR) (28.81–25.47) with increasing porosity. In contrast, FGLS tools (GT-P1, P2) achieved superior MRR (327.15 mm3 min−1), WR (96.12 and Ra (1002 nm) by synergistically combining dense G-region for grinding and porous R-region for chip removal, thereby mitigating stress concentration and extending tool life. These findings provide a quantitative basis for tailoring gradient porosity in SLMed diamond tools and applicable to high-precision machining of optical glass, brittle alloys and ceramic bearings.