tailieunhanh - Milling Cutters and Associated Technologies Part 2

Tham khảo tài liệu 'milling cutters and associated technologies part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Milling Cutters and Associated Technologies 159 a A tangentially-mounted cutting inserts on a high-shear face-mill with a large approach inclination angle. Courtesy of Ingersoll b An identical face-milling cutter insert geometry but with the inserts being designed and positioned with various pitches - to modify the cutter density. Courtesy of Sandvik Coromant Figure 82. Face-milling cutters having inclined approach angles with either high-shear . tangentially-mounted inserts or cutter insert density variations. Courtesy of Ingersoll Courtesy of Sendrik Coromant 160 Chapter 4 Chip flow may be hampered - the vectored angle for exhausting chips may be compromised High radial force component16 - . in relation to the axial force produces unfavourable loads on the spindle creating vibration tendencies hence the feeds must be restricted Positive geometry triangular inserts should not be used - these weaken insert corners whereas rhomboid-shaped insert geometries or similar offer much stronger insert cutting edges. For general-purpose milling operations intermediate approach angles such as inserts having an 75 approach are common see Fig. 82a as they provide good edge strength in combination with a favourable relationship between insert size and cutting depth. Moreover if these 75 approach-angled inserts are tangentially-mounted . as depicted in Fig. 82a the edges are even stronger because of the body of the insert is more fully-supported than is generally the case for most of the radially-mounted variants. Equally an insert with an 45 approach angle will spread the load over a longer cutting edge Fig. 83b . This 45 insert approach geometry provides good chip-flow for long-chipping materials with a low radial force component in comparison to that of the axial force what is more a strong insert edge allows higher feedrates to be utilised Fig 83a . When roughing-cuts are necessary or difficult-to-machine workpiece materials must be milled requiring strong insert