tailieunhanh - Modular Tooling and Tool Management Part 6

Tham khảo tài liệu 'modular tooling and tool management part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Modular Tooling and Tool Management 261 in a similar fashion to that of a fly-cutter creating a periodically scored surface - after each cutter revolution - degenerating the milled surface texture Chipping due to vibration - as all of the inserts are not set the same then the most prominent one will take the largest cuts on both the minor and peripheral cutting edges causing shock loading as the cut is engaged thereby increasing cutter vibration and potential thermal effects44 creating the likelihood of chipping here on the most exposed cutting inserts Rapid growth of wear - because of a prominently set and poorly positioned cutting insert in relation to the others in the cutter body it will absorb the greatest cutting loads which will lead to shortened tool life this being exacerbated by pronounced vibrational tendencies resulting from unbalanced cutting forces and torque. NB All of these factors will contribute to a shortened cutter life. Conversely if the face milling cutter s insert run-out is small then a good surface finish and stable and predictable tool life will result. Mounting and Adjusting Single-Blade Reamers The cutting head of a single-blade reamer was previously illustrated in Fig. 74a. The replaceable blade is positioned longitudinally by a blade end stop and 44 Thermal fatigue can be present when cutting is interrupted - as is the case for milling with a prominently exposed cemented carbide cutting insert. Numerous cracks are often observed at 90 to the cutting edge and are often termed Combcracks - due to their visual appearance to that of a typical hair-comb. These cracks are the result of alternating expansion and contraction of the surface layers as the cutting edge is heated during cutting then cooled by conduction into its body during intervals between cuts. This very fast alternating heating and cooling cycle develops the cracks normally from the hottest region of the rake face - this being some distance from the cutting edge which tends to