... engraving materials:PCB board,Fiberboard,carbon plate,MDF,Acrylic Radius Bottom Engraving Bits Material: Tungsten solidOverall Length: 40-80mmModel Number: tw ... /45/60/90. Application processing materials: Acrylic, color plates, PVC, plastic, resin, nylon, aluminum panels, MDF and other specifications: The tip ... easy word title keyword: Flat knife, chisel, knife engraving. Radius Bottom Engraving Bits