Design and machining performance of a novel bidirectional involute structured fixed abrasive lapping pad inspired by biological streamlined morphological features

Conventional lapping tools with simple uniform textures and defective morphological designs exhibit inadequate abrasive and fluid distribution greatly restricting machining quality. This article designs a novel fixed abrasive lapping pad with a bidirectional involute groove structure based on flow field simulation and investigates its lapping performance, optimizing its geometric structure dimensions by Taguchi design. Lapping experiments were conducted to compare a hexagonal boss-structured pad and a circular boss-structured pad under different speed ratios, workpiece radius, and eccentric distances. Optimization results showed that the new-structured fixed abrasive lapping pad achieved optimal flow performance when configured with a base radius of 25 mm, a groove depth of 1.5 mm, a groove width of 2.5 mm, and 10 unidirectional grooves. Comparative tests indicated the new fixed abrasive lapping pad reduced surface roughness of K9 glass by 20%, 21%, and 25% versus circular boss structured, and by 48%, 52%, and 50% versus hexagonal boss structured, under different speed ratios, workpiece radii, and eccentric distances. Additionally, new structured features provide highly stable machining efficiency, with material removal rate fluctuations of 22% (speed ratio), 7% (workpiece radius), and 36% (eccentric distance). Relative to boss-structured pads, the proposed new-structured pad yields a lower surface roughness under the same processing parameters for difficult-to-machine materials.