Wear characteristics of multi-tooth milling cutter in milling CFRP and its impact on machining performance

Abstract

Multi-tooth milling cutters with segmented right-hand helical cutting edge (SRHCE) and segmented left-hand helical cutting edge (SLHCE) could effectively reduce milling damages for carbon fiber reinforced polymer (CFRP) composites. However, rapid tool wear is still challenging for long-distance milling, and especially wear characteristics of multi-tooth milling cutter and their impacts have not been fully understood. This paper investigated the wear characteristics of the uncoated multi-tooth milling cutter with SLHCE and SRHCE under various feeds per tooth (0.01–0.15 mm/tooth) and a constant spindle speed of 3000 rpm and the effects of tool wear on machining performance by theoretical and experimental analyses. SLHCE and SRHCE experienced abrasive wear, while the wear of SLHCE is slighter than SRHCE because a clearance was formed between SLHCE and nominal tool periphery. Consequently, the profiles of worn SRHCE and SLHCE were different, and they were in ellipse arc and circular arc shape, respectively. The half axis length of ellipse arc worn profile of SRHCE decreased significantly with increasing feed per tooth, while the cutting edge radius of SLHCE changed irregularly. As tool wear aggravated with longer cutting distance, the machining qualities generally worsened, including increased burr damages and surface roughness, and cutting force also increased. Fewer burr damages were found on the top ply, as SLHCE dominated the cutting of the top ply with slighter tool wear because of the clearance, compared to the bottom ply, where SRHCE dominated cutting. In addition, the lowest feed per tooth (0.01 mm/tooth) induced severe tool wear and produced worse machining qualities, especially under longer cutting distances, while the milling force was relatively low. Therefore, more attention should be paid to the SRHCE for multi-tooth milling cutters, and a higher feed rate is preferred under similar conditions.