GB696417A - Improvements in or relating to methods of machining by milling, grinding or the likeand apparatus therefor - Google Patents

Abstract

696,417. Copy milling. ROLLS-ROYCE, Ltd. Jan. 1, 1951 [Jan. 11, 1950], No. 780/50. Class 83 (iii). [Also in Group XXIII] In a copy-milling or copy-grinding machine, for turbine or compressor blades 29 with inclined surfaces 29c on either or both the root or tip platforms 29a, the blade and the tool 32 are traversed relative to each other by causing angular movement of the blade or tool about an axis 20 which is contained in the plane of the tool and does not pass through the blade. If the platforms have inclined surfaces at one end only, the axis 20 lies in the plane of the inclined surface, but if both platforms have inclined surfaces, it lies on the intersection of the planes of these surfaces, so that the whole of the blade profile, including the parts near the inclined surfaces, can be machined at one setting. A slide 12 is vertically movable in the machine frame 10 and carries another slide 13 which is horizontally reciprocable by an electric motor 18 and crank drive 19. The work-carrier or carriers 11 and the carrier 22 for the pattern 30 are oscillated on vertical pivots 20, 23 on the slide 13 by a motor 26, crank 25 and link 21. A follower 31 is mounted for limited vertical movement in the frame so that it controls vertical movement of the slide 12 in the opposite direction by an electric motor 15 and skew drive 16 or by hydraulic or mechanical means. The angular traverse, indicated by arrows 35 in Fig. 3, may be rapid and the linear traverse (arrows 36), slow so that the cuts are substantially circular arcs, or the angular traverse may be slow and the linear traverse rapid, so that the cuts are substantially along radial lines from the axis 20. The linear traverse and the copying movement may be applied to the tools instead of to the blades and an equivalent to the linear traverse may be obtained by rotating the blades and the pattern about corresponding axes remote from and parallel to their spanwise axes.