JP5109485B2 - Throw-away insert for turning - Google Patents

Description

  The present invention relates to a throw-away tip used as a cutting blade of a cutting tool, and particularly to a throw-away tip suitable for turning a long shaft.

  In a turning process, when a long work material having various shapes such as a shaft is cut out from a round bar material and formed, the variation in cutting becomes large. Moreover, since it is long, it does not have sufficient work material rigidity. Therefore, when the cutting depth is temporarily high, chattering of the work material due to chip clogging occurs, resulting in deterioration of machining accuracy and machined surface roughness. In order to solve such a problem, a throw-away tip is used in which a concave breaker groove extending from the corner portion of the rake face along the transverse cutting edge in the arbitrary direction is formed (see, for example, Patent Document 1).

Alternatively, a throwing insert for turning having a chip breaker that emphasizes chip disposal in high cutting is used. As this type of turning throw-away tip, for example, a rake face is formed on the polygonal surface of a polygonal flat-plate tip body, and a pair of cutting edges extending from the corner portion are formed on the side ridges of this polygonal surface. However, there is one in which a convex spherical breaker protrusion is formed on a bisector of the corner portion (see, for example, Patent Document 2).
Japanese Utility Model Publication No. 61-064902 JP 2003-220503 A

  However, in the throw-away tip described in Patent Document 1, while cutting resistance is reduced and chip clogging is suppressed under high cutting and high feed conditions, chips are easy to extend, especially in turning with low cutting and low feeding conditions, Since the chips stretch around the shaft and the turning tool, there is a possibility that the machining may be interrupted to remove the chips, or the surface roughness of the processed surface may be deteriorated. In the throw-away tip described in Patent Document 2, the chip disposal property under high feed and high feed conditions is good, but the effect of reducing cutting resistance is small, and the same problem as in Patent Document 1 under low cutting and low feed conditions was there. In this throw-away insert, if the breaker protrusion is moved close to the corner tip in the direction of the bisector of the corner in order to enhance chip disposal at low cutting and low feed, the workpiece will be cut by clogging at high cutting and high feed conditions. Since chattering occurs in the material, the processing accuracy and the surface roughness of the processed surface may be deteriorated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a turning throw-away tip that is excellent in chip disposal and machining accuracy, and is particularly suitable for turning a long shaft. .

In order to solve the above problems, the present invention has the following configuration.
The invention according to claim 1 has a polygonal plate shape, a rake face is formed on at least one of the opposing polygon faces, and a flank face is formed on a side surface extending between the polygon faces. In the throw-away insert for turning, in which a cutting edge is formed at the intersection ridge line between the flank and the flank, the corners of the polygonal surface are respectively connected to the corners of the polygonal surface as viewed from the direction perpendicular to the polygonal surface as the rake face. A horizontal cutting edge and a front cutting edge extending are formed, and a breaker groove extending inwardly from the horizontal cutting edge is formed on the rake face so as to extend from the corner cutting edge or the front cutting edge. At least one breaker protrusion that protrudes and intersects with the bisector of the corner and protrudes from the surface of the breaker groove is formed closer to the front cutting edge than the bisector. Do It is a throw-away tip for cutting.

  According to the first aspect of the invention, since the concave breaker groove extending along the horizontal cutting edge penetrates the corner or the front cutting edge and intersects with the bisector of the corner, a particularly high cutting height is obtained. Under the feed conditions, the chips generated from the side cutting edges smoothly flow without forcibly curling in the breaker groove, so that an increase in cutting resistance is prevented. Therefore, when a long shaft with relatively low rigidity is subjected to high-cut turning, chatter is suppressed and excellent machining accuracy is realized.

  Furthermore, since the breaker protrusions that protrude from the surface of the breaker groove are formed closer to the front cutting edge than the bisector of the corner, chips generated mainly from the corners in the low cutting and low feed conditions are formed on the breaker protrusion. It is restrained and curls finely. Therefore, compared to the conventional throwaway tip having a concave breaker groove extending along the horizontal cutting edge from the corner portion of the rake face and the conventional throwaway tip having the breaker projection on the bisector of the corner, It is prevented that the chips are stretched and entangled with the work material or the turning tool, and excellent chip disposal is realized.

The invention according to claim 2 is characterized in that an inclined surface having a positive rake angle extending inward from the lateral cutting edge is formed in the breaker groove. It is an away chip.
According to the invention according to claim 2, since the cutting resistance is reduced by the inclined surface having a positive rake angle extending inward from the horizontal cutting edge and the flow of chips in the breaker groove is smooth, In high cutting processing, chatter is further suppressed, and in particular, the processing accuracy can be improved.

The invention according to claim 3 is the throw-away tip for turning according to claim 1, wherein the breaker projection is formed in a convex spherical shape.
According to the invention according to claim 3, since the contact area between the surface of the breaker protrusion and the chip is narrowed by the breaker protrusion formed in the convex spherical shape, the work material due to the collision of the chip with the breaker protrusion is reduced. Therefore, chattering is further suppressed and machining accuracy is further improved.

The invention according to claim 4 is characterized in that the corner and the side cutting edge are formed so as to be inclined so that the tip of the corner is at the highest position and gradually becomes lower as it is further away from the corner. It is a throw-away tip for turning of any one of 1-3.
According to the invention which concerns on Claim 4, since it becomes a downward slope in the direction along a corner and a horizontal cutting edge, reduction of the cutting resistance especially in high cutting can be achieved.

  According to the present invention, in shaft turning, an increase in cutting resistance and chip clogging can be prevented at high cutting depth, and excellent chip disposal can be achieved at low cutting depth. Therefore, especially in the turning of a long shaft, the chip disposal and the processing accuracy can be improved.

  Embodiments to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a drawing for explaining a throw-away tip for turning to which the present invention is applied, wherein (a) is an enlarged front view of a corner portion, (b) is an enlarged plan view of a corner portion, and (c) is a drawing. It is the S1-S1 sectional view taken on the line in (a). FIGS. 2A and 2B are enlarged plan views of a corner portion showing another aspect of the breaker protrusion. FIG. 3 is a perspective view of a corner portion according to another embodiment to which the present invention is applied. FIG. 4 is a perspective view of a corner portion of a conventional throw-away tip. FIG. 5 is a perspective view of a corner portion of another conventional throw-away tip.

  The throw-away tip for turning according to the present embodiment is not shown in its entire shape, but at least one of a pair of opposing rhombus surfaces of the tip body 1 having a substantially rhomboid plate shape with an apex angle of 55 ° is scooped. The other side is a seating surface, and the side surface extending between the pair of rhombus surfaces is a flank surface, and the ridge line between the rake surface and the flank surface is a cutting edge (see FIG. 1). .

  As can be seen from FIGS. 1A and 1B, the diamond-shaped corner portion 2 serving as the rake face 3 has a straight horizontal cutting edge 5b and a front cutting edge respectively extending from a corner 5a having an arc shape in plan view. 5c is formed. Further, the rake face 3 is formed with a breaker groove 6 that is concave inward from the horizontal cutting edge 5b and extends along the horizontal cutting edge 5b. As shown in FIG. 1C, the breaker groove 6 has a cross section orthogonal to the horizontal cutting edge 5b, and descends inclined surface 6a, flat surface 6b, and upward inclined surface 6c in this order from the horizontal cutting edge to the inside. Is formed, intersects with the bisector B of the corner and penetrates the corner 5a or the front cutting edge 5c in a plan view.

  Furthermore, at least one breaker protrusion 7 is formed on the rake face 3 so as to protrude from the surface of the breaker groove 6. In plan view, the breaker protrusion 7 is formed so that its center is located closer to the front cutting edge 5c than the bisector B of the corner (see FIGS. 1A and 1B).

  The turning throw-away tip having the above configuration is fixed to a predetermined position of, for example, a bite holder (not shown) by using a fixing means and used for turning a work material. In the present throw-away tip, chips generated from the side cutting edge 5b that is arranged on the front side in the feed direction and mainly performs cutting flow in the breaker groove 6 and spontaneously curl or contact the up-slope surface 6c. And curl. Here, since the breaker groove 6 penetrates the corner 5a or the front cutting edge 5c and intersects with the bisector B of the corner, the breaker width W as viewed in the cross-section perpendicular to the cutting edge of the breaker groove 6 and A sufficient volume of the breaker groove 6 is secured. For this reason, for example, even under temporary high cutting and high feed conditions in turning of the shaft, chips are smoothly discharged without clogging in the breaker groove 6, so that an increase in cutting resistance is prevented, and a relatively low rigidity Even when the shaft is turned, chattering is suppressed and excellent machining accuracy is realized.

  Further, in a plan view of the throw-away tip, a breaker projection 7 protruding from the surface of the breaker groove 6 is located in the breaker groove 6 at a position closer to the front cutting edge 5c than the bisector B of the corner. Is formed. That is, the breaker protrusion 7 is formed asymmetrically with respect to the bisector B of the corner, and the distance from the side cutting edge 5b to the center of the breaker protrusion 7 is larger than the distance from the front cutting edge 5c to the center. It is arranged to be. For this reason, chips generated mainly from the corner 5a and flowing in the substantially normal direction of the corner 5a under the low cutting and low feed conditions are surely restrained by the breaker protrusion 7 and deformed into a regular curl shape to be constant. Spilled in the direction or broken up. As a result of the breaker protrusion 7 contributing greatly to the improvement of chip disposal in this way, the chips do not stretch and get entangled with the work material or tool holder, etc., surface roughness deteriorates due to chip rubbing on the machined surface, and chip removal is achieved. Problems such as a reduction in machining efficiency due to work are solved.

  On the other hand, in the high cutting and high feed conditions, the chip flow direction approaches a direction perpendicular to the horizontal cutting edge 5b, so that the action of the breaker projection 7 restraining the chips becomes small, and the upward inclined surface of the breaker groove Since 6c is arranged at a distance from the horizontal cutting edge 5b than the breaker projection 7, the force acting on the work material and the throw-away tip when the chip is deformed in a curl shape is greatly reduced, Since chattering of the work material is prevented, excellent machining accuracy and good surface roughness can be obtained. In consideration of further enhancing the above effect, it is desirable that the highest point of the breaker protrusion 7 is lower than the highest point of the upward inclined surface 6c of the breaker groove.

  The breaker protrusion 7 mainly contributes to chip disposal in low cutting and low feed conditions, and it is sufficient that at least one is provided. For example, as shown in FIG. The two breaker protrusions 7a and 7b having an elliptical shape may be provided so that the center thereof is located closer to the front cutting edge 5c than the bisector B of the corner. Also in this case, as in the previous embodiment, the breaker protrusions 7a and 7b are formed asymmetrically with respect to the bisector B of the corner, and the center of each breaker protrusion 7a and 7b from the side cutting edge 5b. Is arranged so as to be larger than the distance from the front cutting edge 5c to the center. Further, as shown in FIG. 2B, the auxiliary breaker protrusion 8 may be provided at a position that is separated from the tip C of the corner and closer to the horizontal cutting edge 5b than the bisector B of the corner. The addition of the auxiliary breaker protrusion 8 is extremely effective for improving the chip disposability under high cutting and high feed conditions. In this way, in the conventional throw-away tip with a general three-dimensional breaker, the breaker protrusion is provided on the bisector of the corner or at a symmetrical position with respect to the bisector, whereas this throw Since the away chip has a feature that the breaker protrusions 7, 7a, 7b and the auxiliary breaker protrusion 8 are provided at asymmetric positions with respect to the bisector B of the corner, both the low cutting condition and the high cutting condition are used. The chip disposability can be improved.

  In this throw-away tip, in the breaker groove 6, a downward inclined surface 6a having a positive rake angle extending inward from the side cutting edge 5b may be formed. In this case, as shown in FIG. 1C, the downward inclined surface 6a is inclined inward and downward through a flat land surface (not shown) extending directly or horizontally from the horizontal cutting edge 5b. It is formed as a flat shape or a curved shape. In this way, when the downward inclined surface 6a is formed continuously with the horizontal cutting edge 5b, the back rake of the turning tool to which the throwaway tip is attached increases, so that the cutting resistance is reduced. Furthermore, since the flow of the chip | tip produced | generated from the horizontal cutting edge 5b is accelerated | stimulated, chip disposal property improves.

  In the throw-away tip illustrated in FIG. 1, the breaker protrusion 7 is formed to protrude in a convex spherical shape from the surface of the breaker groove 6. This is because the contact area between the surface of the breaker projection formed into a convex spherical shape and the shearing surface of the chip is narrowed to reduce the load on the work material due to the contact and chip clogging. Is. As a result, chattering of the work material is suppressed and further improvement in machining accuracy is realized. The breaker protrusion is not limited to a convex spherical shape, but has a convex curved surface shape having an elliptical shape in plan view as illustrated in FIG. 2A, or a convex polyhedral shape having a polygonal shape in plan view although not shown. It can be changed.

  In this throw-away tip, as shown in FIG. 1B, the corner 5a and the side cutting edge 5b are formed so as to be inclined so that the tip C of the corner becomes the highest position and gradually becomes lower as the distance from the corner 5a increases. It is desirable that In a turning tool equipped with a throw-away tip having such a configuration, the cutting edge inclination angle increases and the main component force and back component force of the cutting resistance decrease, so the effect of preventing chattering of the work material is remarkable. It becomes. In FIG. 1B when the throwaway tip is viewed from the side, the corner 5a and the side cutting edge 5b are inclined in a convex curve shape downward, but the present invention is not limited to this. As long as it is downwardly inclined in the direction of moving away, a mode (not shown) that forms a convex curve upward or a mode (not shown) that forms a straight line may be used.

  Next, the chip disposal when the shaft is turned using a throw-away tip for turning to which the present invention is applied and a conventional throw-away tip which is a comparative product will be described.

  FIG. 6 is a view showing a chip shape when turning using the throw-away tip for turning (invention) to which the present invention shown in FIG. 3 is applied. FIGS. 7 and 8 are diagrams showing chip shapes when turned using the comparative product 1 shown in FIG. 4 and the comparative product 2 shown in FIG. 5, respectively. In these figures, the horizontal axis is the feed f (mm / rev), and the vertical axis is the cut ap (mm). Moreover, the area | region enclosed with the thick line shows the area | region where the chip processing property which can be used practically was acquired. As can be seen from these figures, the invention has a breaker protrusion 7 protruding from the surface of the breaker groove 6 at a position closer to the front cutting edge 5c than the bisector B of the corner. Under the low cutting conditions, the entanglement of chips seen in the comparative product 1 and the comparative product 2 was improved, and the practical area was expanded to the low feed condition side. On the other hand, under the high cutting conditions, the comparative product 2 generated chip clogging, whereas the inventive product was less likely to cause chip clogging, so that the practical area was expanded to the high feed condition side.

  The result of measuring the cutting force using the same throw-away tip is shown in FIG. Using a shaft made of carbon steel for machine structure S45C (JIS G 4051) as a work material, turning is performed under the conditions of cutting speed Vc = 200 m / min, cutting ap = 2.0 mm, feed f = 0.3 mm / rev. It was. FIG. 9 shows the average value, minimum value, and maximum value of the cutting resistance of each throw-away tip in this turning process. As can be seen from this figure, the invention has a significantly reduced cutting resistance compared to the comparative product 2 shown in FIG. 5, due to the unique configuration of the breaker groove 6, the breaker protrusion 7, and the auxiliary protrusion breaker 8. Compared with the comparative product 1 shown in FIG. 4, a significant improvement in chip disposal was achieved while suppressing an increase in cutting resistance slightly.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining the throw away tip for turning to which this invention is applied, (a) is an enlarged front view of a corner part, (b) is an enlarged plan view of a corner part, (c) is in (a). It is S1-S1 sectional view taken on the line. (A) And (b) is an enlarged plan view of the corner part which shows the other aspect of breaker protrusion. It is a corner part perspective view of other embodiment to which this invention is applied. It is a corner part perspective view of the conventional throw away tip. It is a corner part perspective view of other conventional throw away tips. It is a figure which shows the chip shape of invention. It is a figure which shows the chip shape of the comparative product. It is a figure which shows the chip shape of the comparative product. It is a figure which shows the cutting resistance of invention product, comparative product 1, and comparative product 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tip body 2 Corner part 3 Rake face 4 Relief face 5a Corner 5b Side cutting edge 5c Front cutting edge 6 Breaker groove 6a Downward inclined surface 6b Flat surface 6c Upward inclined surface 7, 7a, 7b Breaker protrusion 8 Auxiliary breaker protrusion B Bisecting line C Corner tip

Claims (4)

Forming a polygonal plate, a rake face is formed on at least one of the opposing polygon faces, a flank face is formed on the side surface extending between the polygon faces, and the ridge line between the rake face and the flank face In the throw-away insert for turning formed with a cutting edge,
When viewed from the direction perpendicular to the polygonal surface to be the rake face, a corner cutting edge and a front cutting edge respectively extending from the corner are formed in the corner portion of the polygonal surface,
In the rake face, a breaker groove that is concave inward from the side cutting edge and extends along the side cutting edge penetrates the corner or the front cutting edge and intersects the bisector of the corner. Formed,
At least one breaker protrusion protruding from the surface of the breaker groove is formed closer to the front cutting edge than the bisector ,
A throw-away tip for turning, wherein a height of the breaker protrusion is formed lower than a height of the breaker groove .   The throw-away tip for turning according to claim 1, wherein an inclined surface having a positive rake angle extending inward from the side cutting edge is formed in the breaker groove.   The throw-away tip for turning according to claim 1, wherein the breaker protrusion is formed in a convex spherical shape. The corner and the side cutting edge are formed so as to be inclined so that the tip of the corner is at the highest position and gradually becomes lower as it is further away from the corner. A throw-away tip for turning as described in 1.

Images