Large blade inclination cutting

Since the cutting with large edge inclination can greatly reduce the chip deformation, the principle of large-edge inclination cutting is applied to the cutting process of long metal fibers, and long metal fibers with good elongation and high strength can be obtained.
Speed ​​of bevel cutting In the past, the study of bevel cutting, the blade inclination angle ls is almost limited to the range of ≤ 45 °, and the chip deformation for the blade inclination angle ls > 45 ° has not been specifically studied so far. Based on the bevel cutting with the blade inclination angle ls>45°, the deformation of the low-carbon steel plate with large-edge inclination angle is analyzed.

In bevel cutting, the cutting speed vc of the workpiece relative to a point on the cutting edge of the bevel cutting tool can be decomposed into a velocity component vn perpendicular to the cutting edge and a velocity component vT parallel to the cutting edge, ie

Vn=vccosls
vT=vcsinls

As can be seen from the above formula, the larger the absolute value of the blade inclination angle ls, the larger the velocity component vT parallel to the cutting edge, and the smaller the velocity component vn perpendicular to the cutting edge. As the blade inclination angle ls changes, the velocity components vT and vn also change.

When ls<45°, cosls>sinls, vn>vT, the metal plastic flow perpendicular to the cutting edge predominates; when ls=45°, cosls=sinls=1, vn=vT; when ls>45° ,cosls<sinls,vT>vn, the metal plastic flow parallel to the cutting edge dominates. Generally, the bevel cutting with the blade inclination angle ls>45° is called large-edge inclination cutting.
Cutting deformation test of large blade inclination cutting

The cutting deformation of the large-blade angle cutting has not been reported so far. In this paper, the rapid root knife method is used to obtain the specimen of the root of the chip. By observing the shape of the root specimen of the chip and the metallographic grinding piece, the cutting deformation of the large-edge inclination cutting is comprehensively analyzed.

1) Test conditions

·Use machine tool: B6050B planer · Tool material: high speed steel, forward angle gn=30°, normal back angle an=8°
·Workpiece material: low carbon steel (Q235) steel plate with a thickness of 1.2mm · Cutting amount: cutting speed vc=6.12m/min, cutting thickness hD=0.2mm

2) The shape of the root of the chip

Cutting with different blade inclination angles ls, two sets of chip root specimens were obtained by rapid knife drop method. The appearance of the specimen was observed by scanning electron microscopy and its deformation was analyzed.

Chip root shape at ls=0° (×60) Chip root shape at ls=60° (×60)

It can be seen that when ls=0°, the lateral deformation of the chip is very large, the middle part of the chip is obviously convex due to the extrusion of the lateral deformation, and the shear slip marks on the surface of the chip are very prominent, and the chip thickness is larger than that of FIG. many. As the blade inclination angle ls increases, the lateral deformation of the chips decreases. When ls = 60°, the chip thickness is significantly reduced, and the shear slip on the chip surface is not obvious, mainly due to the plastic flow of the metal parallel to the cutting edge during cutting.

3) Metallographic grinding of the root of the chip

The shear angle of the bevel cutting, which is deflected by the right angle cutting shear angle f, is fl, due to the presence of the bevel angle of the bevel cutting edge, the chip outflow direction is skewed by an angle fl relative to the normal of the cutting edge. Foil angle), so that f>f, which is due to the following relationship between the deformation coefficient Dh and the shear angle f:

Dh= cos(f+g0)

Sinf

Therefore, as the shear angle f increases, the deformation coefficient Dh decreases, thereby reducing the deformation of the chips.

In order to clearly observe the change in the cutting deformation caused by the change in the blade inclination angle, observation and analysis can be performed under a metallographic microscope by preparing a metallographic plate of the root of the chip.

a. The test conditions of the roots of the cuttings along the cutting edge method are collected. The test conditions of the root specimens are the same as above. The metallographic grinding discs are prepared on the cutting section of the cutting edge. The cutting angle ls is 45° when cutting. 60° and 75°. The metallographic photomicrograph of the root of the chip is shown in Figures 5, 6 and 7.

Metallographic photomicrograph of the root of the chip perpendicular to the cutting edge at ls=45° (×100)

Metallographic photomicrograph of the root of the chip perpendicular to the cutting edge at ls=60° (×100)

Metallographic photomicrograph of the root of the chip perpendicular to the cutting edge at ls=75° (×100)

When ls=45°, the cutting deformation is large, the crystal grains are pulled long, the shearing slip surface is visible, and the chips are thick; when ls is 60° and 75°, the grain deformation is relatively small. Many, the chip thickness is greatly reduced. The magnifications of the three photos are the same, and the changes in chip thickness and grain deformation can be visually observed from the photos. Therefore, when the cutting speed parallel to the cutting edge is much larger than the cutting speed perpendicular to the cutting edge, the cutting deformation can be greatly reduced.

b. Metallographic deformation of the root of the chip along the cutting edge direction The metallographic plate is prepared in the direction along the cutting edge, and the blade inclination angle ls at the time of cutting is 45° and 75°, respectively. Metallographic micrographs are shown in Figures 8 and 9.

Metallographic photomicrograph of the root of the chip along the cutting edge at ls=45° (×100)

Metallographic photomicrograph of the root of the chip along the cutting edge at ls=75° (×100)

When ls=45°, the deformation area of ​​the grains on the chips is wider, and the grains of the chips in the photograph are all deformed. When ls=75°, the grains on the chips are due to the cutting speed parallel to the cutting edge. The deformation area is significantly narrowed, and the grains in the upper part of the chip are substantially not deformed.

By analyzing the shape of the chip root and the deformation of the metallographic microstructure, the deformation of the large-edge inclination is small.

4) Relationship between blade inclination angle and deformation coefficient and shear strain

In order to visually analyze the influence of the change of the blade inclination on the chip deformation, the relationship between the chip deformation coefficient and the blade inclination angle was plotted (see Fig. 10), and the test conditions were the same as above. Through the conversion of deformation coefficient and shear strain, the relationship between shear strain and blade inclination can be obtained.

It can be seen that when ls=75°, the chip deformation coefficient approaches 1 and the deformation of the chip is small. In Fig. 11 corresponding to this figure, the shear strain e decreases greatly as ls increases.

Since the cutting with large edge inclination can greatly reduce the chip deformation, the principle of large-edge inclination cutting is applied to the cutting process of long metal fibers, and long metal fibers with good elongation and high strength can be obtained.
in conclusion
1) When cutting large-edge inclination, the velocity component parallel to the cutting edge is greater than the velocity component perpendicular to the cutting edge, which can greatly reduce the cutting deformation;

2) When the blade inclination angle ls=75°, the chip deformation coefficient is close to 1, which is mainly due to the leading role of the cutting speed along the cutting edge during cutting;

3) Applying large-edge bevel cutting to the processing of long metal fibers, high-performance metal long fibers can be obtained.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn

Marble Color Wall Board

Aluminum Board,Aluminum Marble Board,Aluminum Cement Board,Fiber Cement Cladding

Jiangmen Feifan Industrial Co.,Ltd , https://www.cementboard.net