CN103157834B - Drill bit with low chisel edge - Google Patents

Abstract

The invention relates to a drill bit with a low chisel edge. The drill bit comprises a handle portion and a head portion, wherein the handle portion is a cylinder, the head portion is a coaxial cylinder which shares the same axis with the handle portion, two chip discharge grooves are formed in the head portion, a solid portion forming the chip discharge grooves is a knife back, intersecting lines of the two chip discharge grooves and the knife back in the axis direction respectively form two main cutting edges, intersecting lines of the two chip discharge grooves and the knife back in the radial direction form seamed edges, the seamed edges and the main cutting edges intersect to form a knife point, the chisel edge with 140-degree convexity is arranged between the two main cutting edges, and a sharp point of the chisel edge is 0.5-1mm lower than the knife point in the axis direction. Due to the chisel edge with the 140-degree convexity, knife strength is guaranteed, and meanwhile prominent centring capacity is guaranteed; the powerful centring capacity can inhibit bouncing and thereby guarantees long service life of a knife; and the drill bit is suitable for drilling machining for carbon fiber composite materials used for aviation.

Description

Low Chisel Drill

technical field

The invention relates to high-efficiency, high-speed precision cutting tools, in particular to a low chisel drill bit used for processing aviation carbon fiber composite materials, and belongs to the technical field of optical-mechanical-electrical integration processing.

Background technique

The processing of aviation carbon fiber composite materials is still a difficult point in the field of aviation manufacturing. Especially in hole processing, manufacturing defects such as arching, material delamination, and export burrs are prone to occur, which will lead to parts scrapping in severe cases. At present, due to its balanced physical properties, high toughness and wear resistance, cemented carbide is still the main tool material in the processing of aviation carbon fiber composite materials. However, how to increase the rigidity of the drilling process and reduce the cutting resistance by improving the geometric angle of the tool, and then avoid similar manufacturing defects is an urgent problem to be solved at present.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a low chisel drill bit, which aims to solve the manufacturing problems such as arching, material delamination, and exit burrs in the hole machining of aviation carbon fiber composite materials.

The purpose of the present invention is achieved through the following technical solutions:

The low chisel drill bit includes a shank and a head. The shank is a cylinder, and the head is a coaxial cylinder coaxial with the shank. There are two chip removal grooves on the head to form a chip removal groove. The solid part of the tool back is the tool back, the intersection lines of the two chip flutes and the tool back in the axial direction form two main cutting edges respectively, the intersection lines of the chip flutes and the tool back in the radial direction form edges, and the edges and the main cutting The blades intersect to form a tool tip; the feature is: a chisel edge with a convex 140° is set between the two main cutting edges, and the point of the chisel edge is 0.5~1mm lower than the tool tip in the axial direction.

Further, in the above-mentioned low chisel edge drill, the included angle formed by the main cutting edge is a concave angle of 120°.

Further, in the low chisel edge drill mentioned above, the included angle formed by the cutting edge is 60°.

Furthermore, in the above-mentioned low chisel edge drill bit, a protective flute is provided in the flute.

Still further, in the above-mentioned low chisel edge drill bit, the protective sipe is a protective sipe with a rake angle of negative 5-10°; the width of the protective sipe is 0.8-1.0 mm.

The outstanding substantive features and remarkable progress of the technical solution of the present invention are mainly reflected in:

(1) The convex 140° chisel edge not only takes into account the strength of the tool, but also ensures a relatively prominent centering ability, which is suitable for the processing site where pneumatic tools are used; the strong centering ability can restrain the beating, thereby ensuring a longer tool life;

(2) The main cutting edge of the drill bit is designed with a 120° inner concave angle, so that the axial force is directed towards the axis, avoiding the axial force towards the hole wall, and then avoiding the phenomenon of workpiece arching;

(3) The tip of the drill bit is designed to be extremely sharp at 60°, so that the workpiece can be cut briskly, thereby reducing material delamination and export burrs;

(4) The 140° chisel edge is 0.5~1mm lower than the tool tip in the axial direction. On the one hand, it can be stably centered in the cutting process. overall tool life;

(5) A protective sipe with a negative rake angle is set in the chip flute so that it does not participate in the cutting and improves its guiding ability; avoiding the "knife stabbing" caused by the influence of technological factors such as excessive jumping during the drilling process "Phenomenon.

Description of drawings

Below in conjunction with accompanying drawing, technical solution of the present invention will be further described:

Fig. 1: the structural representation of the low chisel drill bit of the present invention;

Figure 2: Schematic diagram of the included angle of the main cutting edge;

Figure 3: Schematic diagram of the included angle of the tool tip;

Figure 4: Schematic diagram of chisel blade structure;

Figure 5: Schematic diagram of the protective knife groove;

Fig. 6: B-B sectional schematic diagram of Fig. 5 .

Detailed ways

The design concept of the low-chisel drill bit of the present invention is to improve the sharpness of the drill bit, change the traditional processing method in which the chisel edge of the drill bit touches the workpiece first, and change the traditionally designed convex angle into a 120° inner concave angle to avoid radial force when drilling. A protective sipe with a negative rake angle is used at the rear end of the drill to improve the stability of the guide and reduce the secondary cutting of the workpiece by the edge of the drill, thereby inhibiting the tendency of the workpiece to produce arches and burrs.

As shown in Figure 1, the low chisel drill bit includes a shank 1 and a head 2, the shank 1 is a cylinder, the head 2 is a coaxial cylinder coaxial with the shank, and the head has a Two chip flutes 3, the solid part forming the chip flute is the back 4, the intersection line of the two chip flutes 3 and the back 4 in the axial direction forms two main cutting edges 5, the chip flute 3 and the back 4 The intersection line in the radial direction forms an edge 6, and the edge 6 intersects with the main cutting edge 5 to form a tool tip 7; a chisel edge 8 with a convex 140° is set between the two main cutting edges, as shown in Figure 4, on the axis The directional chisel edge point is 0.5~1mm lower than the tool tip. On the one hand, it can be stably centered in the cutting process. On the other hand, due to the increase of the actual edge length, the heat dissipation capacity of the drill is improved, and the overall life of the tool is significantly improved. . The main cutting edge undertakes the main drilling task. The inner cutting edges intersect to form a convex 140° chisel edge 8, which plays a centering role and reduces the radial runout during processing. The edge 6 is used for guiding, and the outer edge formed by the edge The circle diameter is the drill diameter. In the drilling process, the tool tip 7 first touches the workpiece, and it is the working position with the longest working time and the highest linear speed.

As shown in Figure 2, the included angle formed by the main cutting edge is a concave angle of 120°, so that the axial force is directed toward the axis, avoiding the axial force toward the hole wall, and thus reducing the phenomenon of workpiece arching.

As shown in Figure 3, the angle formed by the tool tip is 60°, and the tool tip is extremely sharp, which can cut the workpiece lightly and reduce material delamination and exit burrs.

As shown in Fig. 5, a protective sipe 9 is provided in the flute, and as shown in Fig. 6, the protective sipe is a protective sipe with a rake angle of negative 10°; the width of the protective sipe is 0.8~1.0mm. To avoid the phenomenon of "knife sticking" caused by the influence of technological factors such as excessive runout during the drilling process, a protective sipe with a negative rake angle is set in the chip removal flute so that it does not participate in cutting and improves its guiding ability.

The low chisel drill bit is made of solid carbide material, which is suitable for the processing characteristics of aviation carbon fiber composite materials due to its high hardness and wear resistance. Usually choose ISO K05~K10 grades, when the hole is deep or the rigidity of the processing system is poor, you can choose ISO K30~K40 grades with good toughness.

Since the low chisel drill bit is a high-efficiency and high-precision metal cutting tool, the tip and cutting edge are extremely sharp, and it is easy to produce microscopic chipping on ordinary equipment and affect the life of the tool. It must be manufactured on high-rigidity equipment such as a five-axis CNC tool grinder. Observe the state of the cutting edge under a magnifying glass of 200 times. The key control dimensions ensure the manufacturing accuracy through tolerances: the main cutting edge is concave at 120°±1.5°; the included angle of the tool tip is 60±1.5°; the chisel edge is convex at 140°-137°;

In summary, the low-chisel drill bit of the present invention is suitable for drilling of carbon fiber composite materials for aviation. Through the optimization of the geometric structure, manufacturing defects such as arched edges, material delamination, and exit burrs can be avoided, and PVD coating can be used. And other auxiliary process means to achieve high tool durability, the application prospect is promising.

It should be understood that: the above is only a preferred embodiment of the present invention, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the protection scope of the present invention.

Claims (3)

1. low chisel edge drill bit, comprise shank and head, shank is a cylinder, head is the coaxial clyinder of one and shank coaxial line, head has two chip areas, the entity part forming chip area is the knife back, and two chip areas and the intersection of the knife back on the radial line direction of drill bit form two main cutting edges respectively, chip area and the intersection of the knife back on the axial direction of drill bit form seamed edge, and seamed edge is crossing with main cutting edge forms point of a knife; It is characterized in that: the chisel edge arranging convexity 140 ° between two main cutting edges, at axis direction chisel edge cusp lower than point of a knife 0.5 ~ 1mm, the angle that main cutting edge is formed is re-entrant angle in 120 °, and the angle that point of a knife is formed is 60 °.

2. low chisel edge drill bit according to claim 1, is characterized in that: be provided with protection cutter groove in described chip area.

3. low chisel edge drill bit according to claim 2, is characterized in that: the width of described protection cutter groove is 0.8 ~ 1.0mm.