SPECIAL END CUTTING EDGE ATTACHED CUTTER FOR CARBON FIBER REINFORCED POLYMER/PLASTIC WITH DESIGNABLE MICRO-TOOTH CONFIGURATION

Abstract

A special end cutting edge attached cutter for carbon fiber reinforced polymer/plastic with designable micro-tooth configuration, having an end cutting edge, a peripheral cutting edge with variation inverse helical groove, a peripheral cutting edge with constant inverse helical groove and a shank. Two parallel V-shaped chip pockets are designed on the end cutting edge of the cutter in two cutting edge directions which are symmetrical around a cutter axis as a center. The structure may enhance chip removal performance during high-speed milling of impenetrable slots and impenetrable windows, reduce wear of the end cutting edge, conduct configuration design for micro-teeth of the peripheral cutting edge, reduce the cutting thickness of the micro-tooth cutting edges, and effectively solve the problem of damage of the micro-tooth edges. A section of peripheral cutting edge with variation left-hand inverse helical flute angle is designed near the end cutting edge.

Claims

1. A special end cutting edge attached cutter for carbon fiber reinforced polymer/plastic with designable micro-tooth configuration, wherein the special end cutting edge attached cutter with designable micro-tooth configuration for CFRP comprises an end cutting edge, a peripheral cutting edge with variation inverse helical groove, a peripheral cutting edge with constant inverse helical groove and a shank; wherein the end cutting edge is designed with a rake face of end cutting edge, a flank face of end cutting edge, and a secondary flank face of end cutting edge, and also has a chip pocket of end cutting edge; parallel V-shaped chip pockets are designed on the end cutting edge in two cutting edge directions which are symmetrical around a cutter axis as a center, and the V-shaped chip pocket presents such a structural shape that a bottom is narrow and a top is wide; to ensure that the V-shaped chip pocket has good chip removal performance and is closely connected with the chip pocket of end cutting edge, the sizes of a design structure of the V-shaped chip pocket are determined: the bottom width is L1, the top width of V-shaped chip pocket is L2, the depth of the V-shaped chip pocket is L3 and tilt angles of two side surfaces of the V-shaped chip pocket satisfy .sub.1=.sub.2; the peripheral cutting edge with variation inverse helical groove is of an asymmetric- and spiral-stagger structure, and m right-hand flutes and n left-hand flutes are staggered to form a plurality of equidimensional micro-teeth; to reduce the vibration of the end cutting edge and a transition part of peripheral cutting edge during slot milling, a section of peripheral cutting edge with variation left-hand inverse helical flute angle is designed near the end cutting edge; the peripheral cutting edge with variation left-hand inverse helical flute angle points to the end cutting edge direction and the change relationship of the helical angle of the left-hand flutes is .sub.1<.sub.2<.sub.3; a three-dimensional stereographic cutter is sectioned along an axial direction and then is unfolded; the peripheral cutting edge with constant inverse helical groove that represents the configuration mode is selected to form a two-dimensional schematic diagram of micro-tooth configuration of the cutter by using a tangential direction and an axial direction to form a coordinate system; the right-hand flutes and the left-hand flutes are staggered to form micro-teeth; the micro-teeth comprise a lower cutting edge and an upper cutting edge; in the design process of the cutter, tool geometric parameters are known, i.e., length A of the micro-tooth, width B of the right-hand flute, helical angle of the right-hand flute, number of milling blade Z.sub.1 and milling cutter diameter D; the configuration mode of the micro-teeth is mainly determined by the following variables: tangential length d of the left-hand flute, tangential length c between adjacent micro-teeth, helical angle of the left-hand flute, tangential length f of micro-tooth, and number Z.sub.2 of the left-hand flute; specific steps of the design method are as follows: step 1: calculating the tangential length c between adjacent micro-teeth through the milling cutter diameter D and the number Z.sub.1 of milling blade; $\begin{array}{cc}c=\frac{nD}{Z_1}& \left(1\right)\end{array}$ step 2: selecting the tangential length d of the left-hand flute as an independent variable parameter; establishing a triangle using the width B of the right-hand flute and the tangential length d of the left-hand flute as sides; and calculating the helical angle of the left-hand flute through the geometrical relationship of the triangle: $\begin{array}{cc}\frac{\sin .Math..Math.\left(+\right)}{d}=\frac{\cos .Math..Math.}{B}& \left(2\right)\end{array}$ similarly, establishing a triangle by using the length A of the micro-tooth and the tangential length f of the micro-tooth as side lengths; and calculating the tangential length f of the micro-tooth and the number Z.sub.2 of left-hand flute through the geometrical relationship of the triangle; $\begin{array}{cc}\frac{\sin .Math..Math.\left(+\right)}{f}=\frac{\cos .Math..Math.}{A}& \left(3\right)\\ f=\left(D{Z}_2\right)-d& \left(4\right)\end{array}$ step 3: judging whether the relationship d<c<f is satisfied; if so, covering the lower cutting edge and the upper cutting edge of each micro-tooth by the cutting edge of a previous micro-tooth so that two edges of each micro-tooth are overlapped; if not, returning to step 2 to reselect the tangential length d of inverse flute.

Description

DESCRIPTION OF DRAWINGS

[0016] FIG. 1 is a structural schematic diagram of an end cutting edge attached cutter with designable micro-tooth configuration.

[0017] FIG. 2 is a left view of an end cutting edge attached cutter.

[0018] FIG. 3 is an enlarged view of an end cutting edge in FIG. 1.

[0019] FIG. 4 is a peripheral cutting edge with variation inverse helical groove.

[0020] FIG. 5 is a flow chart of calculation of overlapped configuration mode of two micro-tooth edges.

[0021] FIG. 6 is an expanded view of overlapped configuration mode of two micro-tooth edges.

[0022] FIG. 7(a) is a three-dimensional cutter of an embodiment 1.

[0023] FIG. 7(b) is a three-dimensional cutter of an embodiment 2.

[0024] FIG. 8(a) is wear of a cutter micro-tooth of overlapped configuration mode of two micro-tooth edges.

[0025] FIG. 8(b) is wear of a cutter micro-tooth without considering micro-tooth configuration mode.

[0026] In the figures: I end cutting edge; II peripheral cutting edge with variation inverse helical groove; III peripheral cutting edge with constant inverse helical groove; IV shank; 1 V-shaped chip pocket; 2 rake face of end cutting edge; 3 flank face of end cutting edge; 4 secondary flank face of end cutting edge; 5 chip pocket of end cutting edge; 6 micro-tooth; 7 right-hand flute; 8 left-hand flute; 9 lower cutting edge; 10 upper cutting edge; L1 bottom width of V-shaped chip pocket; L2 top width of V-shaped chip pocket; L3 depth of V-type chip pocket; L4 depth of chip pocket of end cutting edge; L5 length of peripheral cutting edge when inverse helical flute angle is .sub.1; L6 length of peripheral cutting edge when inverse helical flute angle is .sub.2; L7 length of peripheral cutting edge when inverse helical flute angle is .sub.3; .sub.1, .sub.2 and .sub.3 variation helical angles of variation left-hand inverse flute; .sub.f1 primary relief angle of end cutting edge; .sub.f2 secondary relief angle of end cutting edge; .sub.1 left-side tilt angle of V-type chip pocket; .sub.2 right-side tilt angle of V-type chip pocket; A length of micro-tooth; B width of left-hand flute; helical angle of right-hand flute; Z.sub.1 number of milling blade; D milling cutter diameter; d tangential length of inverse flute; c tangential length between adjacent micro-teeth; helical angle of left-hand flute; f tangential length of micro-tooth; and Z.sub.2 number of flute.

DETAILED DESCRIPTION

[0027] Specific embodiments of the present invention are further described below in combination with accompanying drawings and the technical solution.

Optimal Embodiments

[0028] FIG. 2 is a structural schematic diagram of a V-shaped chip pocket protected in claim 1 of the present invention. FIG. 5 and FIG. 6 are design methods for micro-tooth configuration of the peripheral cutting edge of the milling cutter protected in claim 1 of the present invention. It can be seen from the drawings that the structure of the V-shaped chip pocket can smoothly remove the chips and the cutting heat from the bottom, so as to prevent the chips from being accumulated between the cutting edge and a processing surface and prevent serious wear of the end cutting edge. The design method for micro-tooth configuration ensures that the two micro-tooth edges are configured to be overlapped. This mode can effectively avoid the problem of corner chipping at the micro-tooth edges caused by large cutting thickness. The micro-teeth after corner chipping cannot effectively cut fibers and thus causes that the quality of the processing surface will not meet the requirements. Detailed description of the present invention is described below in detail in combination with accompanying drawings and the technical solution.

[0029] The end cutting edge attached cutter for high-speed CFRP milling in the present embodiment is shown in FIG. 1. The end cutting edge attached cutter comprises an end cutting edge I, a peripheral cutting edge II with variation inverse helical groove, a peripheral cutting edge III with constant inverse helical groove and a shank IV.

[0030] Two parallel V-shaped chip pockets 1 are designed on the end cutting edge I of the end cutting edge attached cutter in two cutting edge directions which are symmetrical around a cutter axis as a center. The bottom width of the V-shaped chip pocket 1 is L1=2.1 mm; the top width of the V-shaped chip pocket is L2=3.8 mm; the depth of the V-shaped chip pocket is L3=1.5 mm and tilt angles of two side surfaces of the V-shaped chip pocket 1 satisfy .sub.1=.sub.2=50; a primary relief angle .sub.f1 of the end cutting edge is 7; and a secondary relief angle .sub.f2 of the end cutting edge is 14. The peripheral cutting edge II with variation inverse helical groove is of an asymmetric- and spiral-stagger structure. A section of peripheral cutting edge with variation helical angle is designed near the end cutting edge. The peripheral cutting edge points to the end cutting edge direction. When the helical angle of the left-hand flute 8 is .sub.1=66.7, a corresponding length of the peripheral cutting edge is L5=0.5 mm; when the helical angle of the flute 8 is .sub.2=67.5, a corresponding length of the peripheral cutting edge is L6=0.4 mm and when the helical angle of the flute 8 is .sub.3=75.7, a corresponding length of the peripheral cutting edge is L7=0.5 mm.

[0031] In the design of the cutter, considering reduction of burrs and axial force, basic tool geometric parameters are determined as follows: helical angle of the right-hand flute is 15, length A of the micro-tooth 6 is 1.3 mm, width B of the flute is 0.8 mm, number Z.sub.1 of milling blade is 12 and milling cutter diameter D is 10 mm; tangential lengths of inverse flute are respectively selected as follows: d.sub.1=2 mm and d.sub.2=2.3 mm; tangential length c between adjacent micro-teeth, helical angle of the left-hand flute, tangential length f of micro-tooth and number Z.sub.1 of the flute are determined; and several different configuration modes are analyzed. Specific steps of the design method are as follows:

[0032] step 1: calculating the tangential length c between adjacent micro-teeth as 2.618 mm through the milling cutter diameter D and the number Z.sub.1 of milling blade in accordance with formula (1);

[0033] step 2: respectively selecting tangential lengths of inverse flute as follows: d.sub.1=2 mm and d.sub.2=2.3 mm; and in accordance with formulas (2), (3) and (4), respectively calculating .sub.1=66.7, .sub.2=69.7, f.sub.1=3.25 mm, f.sub.2=3.7375 mm, Z.sub.21=6 and Z.sub.22=5; and step 3: analyzing the micro-tooth configuration mode under different values of the tangential length d of inverse flute through the geometric parameters calculated in step 1 and step 2:

[0034] At this moment, d.sub.1<c<f.sub.1 and d.sub.2<c<f.sub.2 are satisfied. Such configuration mode that the upper cutting edge and the lower cutting edge of the micro-tooth are overlapped. Based on three-dimensional mapping software SolidWorks, two cutters can be designed, as shown in FIGS. 7(a) and (b), and each micro-tooth has a lower edge overlap 4 and an upper edge overlap 5.

[0035] To verify the application effect of the special end cutting edge attached cutter for CFRP which considers micro-tooth configuration design, when spindle speed is 6000 rpm and feed rate is 800 mm/min, the CFRP with a thickness of 8 mm is subjected to an impenetrable slot milling experiment. The experiment finds: in the milling process, there is no phenomenon of corner chipping at the micro-tooth edges of the peripheral cutting edge of the cutter which considers micro-tooth configuration design, as shown in FIG. 8(a); there is a phenomenon of corner chipping at the micro-tooth edges of the peripheral cutting edge of the cutter which does not consider micro-tooth configuration design, as shown in FIG. 8(b).

INDUSTRIAL APPLICABILITY

[0036] The special end cutting edge attached cutter for CFRP with designable micro-tooth configuration in the present invention is especially suitable for milling processing of impenetrable slots, impenetrable windows and special-shaped impenetrable hole structures in CFRP members. The parallel V-shaped chip pockets are designed on the end cutting edge of the cutter in two cutting edge directions which are symmetrical around a cutter axis as a center, so as to effectively enhance the chip removal and heat radiation performance of the cutter, reduce the wear of the chips to the end cutting edge and ensure the processing quality of bottom surfaces of the impenetrable windows and the impenetrable slots. The peripheral cutting edge with variation inverse helical groove in the cutter can reduce cutting tool vibration during milling processing. Considering reasonable micro-tooth configuration of the peripheral cutting edge of the cutter may avoid the problem of corner chipping on two micro-tooth edges caused by large cutting thickness, thereby effectively protecting the edges with poor micro-tooth strength and ensuring that the micro-teeth of the peripheral cutting edge of the cutter have long-term excellent cutting performance. Therefore, the cutter of the present invention is intended to enhance the service life of the cutter with respect to the milling processing of the CFRP, and its industrial application not only can reduce tool change time and increase processing efficiency, but also can reduce the use cost and finally enhance economic benefits of enterprises.