CN108637337A - A Forward-Reverse Helical Milling Tool - Google Patents

Abstract

The present invention discloses a forward-reverse spiral milling tool, comprising a cutting portion, a neck portion and a shank portion connected in sequence; the cutting portion comprises a front cutting area, a circumferential cutting area and a rear cutting area connected in sequence; the front cutting area is an end milling cutter structure, comprising four front cutting edges that are centrally symmetrically distributed and can be fed and cut in the forward direction along the axis of the tool; the circumferential cutting area is cylindrical and is a peripheral milling cutter structure, and a spiral cutting edge that extends to the front cutting edge and can be fed and cut in the radial direction of the tool is provided on its cylindrical surface; the rear cutting area is truncated cone-shaped, the outer diameter of its large end matches the diameter of the circumferential cutting area, the outer diameter of its small end matches the diameter of the neck portion, and the side wall of the rear cutting area is provided with an inclined cutting edge that extends to the spiral cutting edge and can be fed and cut in the reverse direction along the axis of the tool. The present invention improves processing quality, saves cost, simplifies processing, improves production efficiency and increases tool life.

Description

A Forward-Reverse Helical Milling Tool

technical field

The invention relates to the field of hole-making processing of composite materials, metals, and laminated structures of composite materials and metals, in particular to a forward-reverse spiral hole milling cutter.

Background technique

A large number of composite materials are used in the design of aerospace vehicles, and the hole making problems of composite materials, composite materials and metal laminated structures are often encountered in the assembly process of aircraft. Due to the complex structure of the aircraft, the limited working space when assembling the hole, or the special requirements of the design, for the hole making of some composite materials and metal laminated structures, the tool must cut in from the metal side and cut out from the composite material side. The commonly used hole making method is to use a drill bit to drill holes. When this processing method is used, a large axial cutting force will be generated. Another new hole-making method is to use a special end mill for helical milling. Although the axial cutting force is smaller than that of drilling, it still exists. Composite materials are usually composed of multiple layers of fibers, and the resin matrix material with weak strength is usually between different fiber layers. The axial force during processing is the main cause of damage to composite materials. During side cutting, under the action of the axial cutting force of the tool, the fiber layer near the exit side will be deformed, and the resin matrix between different fiber layers will be broken, forming processing defects such as delamination and tearing, which will affect the quality of hole making, such as Figure 7 shows the situation where machining defects are formed on the exit side of the drilled hole, and Figure 9 shows the situation where machining defects are formed on the exit side of the helical milling hole. If a backing plate is added to the back of the composite material, when the tool cuts to the side close to the exit of the composite material, the fiber layer near the exit side will be supported by the backing plate without major deformation, and the resin matrix between the fiber layers will not will be destroyed, so as to avoid the occurrence of processing defects such as delamination and tearing. As shown in Figure 8, there is a backing plate in the drilled hole, and in Figure 10, it is the case in which the helical milling hole has a backing plate. However, in actual production, in some cases, backing plates cannot be installed on the back of the composite material when making holes; in some cases, although backing plates can be added when making holes, the installation and disassembly of backing plates will greatly increase production costs and reduce production efficiency .

For the hole making of the composite material and metal laminated structure with the hole outlet on the composite material side, in order to achieve defect-free and high-quality hole making without a backing plate, a feasible method is to use a composite material and metal laminated structure The forward-reverse feed helical milling method feeds the exit end of the composite material in the direction opposite to the normal drilling or helical milling feed direction. The specific operation method is to use a special tool to machine a pre-machined hole in the direction of cutting in from the metal side and cutting out from the composite material side, and then process a pre-machined hole in the form of a helical milling hole. The cutting part of the stepped tool passes through the pre-machined hole, and the tool has a certain amount of eccentricity relative to the machined hole, and then reversely feeds from the composite material layer to the metal layer in the form of helical milling hole, and after using the cutting part The cutting edge on the stepped surface of the end and neck transition area is used to ream the pre-machined hole one or more times until the final required size is reached. With this processing method, the metal layer laminated with the composite material and the metal can be used as a backing plate to avoid processing defects such as delamination and tearing of the composite material.

However, the above-mentioned processing method requires a special processing tool. The front end of the tool is an end mill structure, the diameter of the cutting part is larger than the neck, and the rear end of the cutting part needs to have a specially designed cutting edge. At present, there is a lack of such special tools.

Contents of the invention

In view of the above problems, the present invention researches and designs a forward-reverse helical milling tool. First, a through and smaller pre-processing hole is helically milled from the inlet side forwardly, and then reversely helically milled from the outlet side. Milling out the final aperture is used for the hole making of laminated structures of composite materials and metals, which solves the shortcomings of easy delamination, tearing and other defects at the exit of composite materials and the time-consuming and laborious installation of backing plates. The present invention adopts technical means as follows:

A forward-reverse helical hole milling tool comprising a cutting portion, a neck and a shank connected in sequence;

The cutting part includes a front cutting area, a circumferential cutting area and a rear cutting area connected in sequence;

The front-end cutting zone is an end mill structure, including four front-end cutting edges that are symmetrically distributed along the axis of the tool and can be forwardly fed and cut;

The circumferential cutting area is cylindrical and has a circumferential milling cutter structure, and a helical cutting edge extending to the front cutting edge and capable of feeding and cutting along the radial direction of the cutter is provided on the cylindrical surface;

The rear cutting area is in the shape of a truncated cone, the outer diameter of its large end matches the diameter of the circumferential cutting area, and the outer diameter of its small end matches the diameter of the neck. An inclined cutting edge extending to the helical cutting edge and capable of cutting in reverse along the axis of the tool is provided on the side wall, and the other end of the inclined cutting edge extends to the neck.

The length of the neck is greater than the depth of the through hole to be processed, the diameter of the shank is a value convenient for clamping, and the length meets the clamping requirements of common processing equipment.

Helical grooves are provided between the adjacent front cutting edges, between the adjacent spiral cutting edges and between the adjacent inclined cutting edges to facilitate chip discharge.

The cutting part is provided with a cooling hole for realizing the cooling zone and lubrication of the cutting area during processing, and the cooling hole is connected with the rear end of the shank.

Under the premise of not affecting the overall rigidity of the tool, the difference between the diameter of the cutting part (that is, the diameter of the circumferential cutting zone) and the diameter of the neck is as large as possible, so as to realize the Material is removed quickly.

The helix angle of the helical cutting edge is less than 30°, so as to ensure that chips can be discharged smoothly when the tool is milling holes in reverse helical direction.

The axial length of the circumferential cutting zone is as small as possible and larger than the lead of the feed path during reverse helical milling.

The front end cutting area, the circumferential cutting area, the rear end cutting area and the neck have rounded transitions among each other, and the radius of curvature of the rounded corners is 0.2 mm to 1 mm, so as to improve the Abrasion resistance.

Among the four front-end cutting edges, one group of opposite front-end cutting edges extends to the axis of the tool and intersects, so that the tool removes the front material when the tool is fed along its axis, and the other group The opposite front cutting edge does not extend to the axis of the cutter and then terminates, so as to facilitate manufacturing.

In addition to being used for hole-making of composite materials and metal laminates, the present invention can also be used for hole-making processing of single-layer or multi-layer composite materials, metals and laminates. Make a through and small pre-machined hole, and then helically mill a hole from the entrance side that is less than the depth of the hole to be processed to reach the final diameter of the first half of the hole, and then reverse helically mill the second half from the exit side Process the hole to obtain the through hole to be processed.

Compared with the prior art, the present invention has the following beneficial effects:

1. It can avoid defects such as delamination and tearing that exceed the processing requirements of the composite material, and improve the processing quality. During the first forward feed helical milling hole using the present invention, since there is no backing plate on the back of the composite material, large processing defects may occur, but the defective material will be in the subsequent reverse feed helical milling hole It is cut off during the process, and the reverse feed helical milling process will not produce new processing defects. This is because the direction of the axial force on the composite material changes during the reverse-feed helical milling process, which will not cause deformation of the fiber layer on the exit side that may cause delamination and tearing. When the tool reverse feeds the helical milling hole close to the interface between the composite material and the metal layer, the metal layer can act as a backing plate, so that the fiber layer of the composite material here does not have defects such as delamination and tearing.

2. There is no need to use an additional backing plate on the exit side of the composite material, which saves costs, simplifies the processing process, and improves production efficiency.

3. Improve tool life. When the front end cutting area of the tool used in the present invention is used for forward helical milling, it is allowed to produce processing defects within a certain scale, so after the cutting edge of the front end cutting area of the tool wears to a certain extent, it can continue to be used even if the processing quality declines, until it occurs The processing defects exceed the allowable value. When the present invention uses the reverse feed helical milling hole in the rear end cutting area, since the metal layer can serve as a backing plate, even if a certain degree of wear occurs, processing defects will not occur on the side of the composite material close to the metal.

Based on the above reasons, the present invention can be widely applied in fields such as hole making and processing.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is an axonometric view of a forward-reverse helical hole milling tool in Embodiment 1 of the present invention.

Fig. 2 is a front view of a forward-reverse helical hole milling tool in Embodiment 1 of the present invention.

Fig. 3 is a schematic diagram of the front end cutting area in Embodiment 1 of the present invention.

Fig. 4 is an isometric view of a forward-reverse helical hole milling tool in Embodiment 2 of the present invention.

Fig. 5 is a front view of a forward-reverse helical hole milling tool in Embodiment 2 of the present invention.

Fig. 6 is a schematic diagram of the front end cutting area in Embodiment 2 of the present invention.

Fig. 7 is a schematic diagram of the formation principle of processing damage on the outlet side of the composite material under the existing drilling processing method in the background technology of the present invention.

Fig. 8 is a schematic diagram of the processing damage suppression principle when there is a backing plate on the outlet side of the composite material in the existing drilling processing method in the background technology of the present invention.

Fig. 9 is a schematic diagram of the formation principle of processing damage at the outlet side of the composite material under the existing helical milling hole processing method in the background technology of the present invention.

Fig. 10 is a schematic diagram of the principle of processing damage suppression when there is a backing plate on the outlet side of the composite material under the existing helical milling hole processing method in the background technology of the present invention.

Fig. 11 is a schematic diagram of the process of machining the pre-machined hole in the forward feed and machining the final aperture in the reverse feed helical milling hole.

Fig. 12 is a physical diagram of the tool in Embodiment 1 of the present invention.

Fig. 13 is an enlarged view of the actual cutting part of the tool in Embodiment 1 of the present invention.

Fig. 14 is an enlarged view of the real object of the cutting area at the rear end of the cutting part of the tool in Embodiment 1 of the present invention.

Fig. 15 is the exit quality of the hole obtained by the forward-reverse feed helical milling hole processing of the composite material and the metal laminated structure by the cutting tool of the present invention and the preprocessing obtained by the first forward feed helical milling hole from the inlet side Comparison chart of hole export quality processing effect.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A forward-reverse helical milling tool is used for composite materials and metal laminated holes. First, a through and smaller pre-machined hole is helically milled from the entrance side forwardly, and then reversed from the exit side. The final aperture is helically milled, as shown in Figure 11, the forward feed is used to process the pre-machined hole, and the reverse feed is used to process the final aperture of the helical milling hole, which is used for the hole making of composite materials and metal laminated structures. The exit side of the composite material is prone to defects such as delamination and tearing, and the installation of the backing plate is time-consuming and labor-intensive. In addition to being used for hole-making of composite materials and metal laminates, the invention can also be used for hole-making processing of single-layer or multi-layer composite materials, metals and laminates. Firstly, a through-hole and small pre-machined hole is machined on the composite material by helical milling, and then a hole in the first half of the final hole is helically milled from the inlet side with a depth smaller than that of the through-hole to be machined. After that, Reverse helical milling of the second half of the machining hole from the exit side to obtain the through hole to be processed. The invention can also be used in the hole making of metal materials, and the flash and burrs on the outlet side of the metal materials can be eliminated by reverse helical milling.

Example 1

As shown in Figures 1-3, a forward-reverse helical milling tool includes a cutting part 1, a neck 2 and a shank 3 connected in sequence;

The cutting part includes a front cutting area 4, a circumferential cutting area 5 and a rear cutting area 6 connected in sequence;

The front-end cutting zone 4 is an end mill structure, including four front-end cutting edges that are symmetrically distributed in the center and can be forwardly fed and cut along the axis of the tool, and the front-end cutting edges are perpendicular to the axis of the tool;

The peripheral cutting zone 5 is cylindrical and has a peripheral milling cutter structure, and its cylindrical surface is provided with a helical cutting edge that extends to the front cutting edge and can be fed and cut along the radial direction of the cutter;

The rear end cutting zone 6 is in the shape of a truncated cone, the outer diameter of its large end matches the diameter of the circumferential cutting zone 5, the outer diameter of its small end matches the diameter of the neck 2, and the rear end The side wall of the cutting zone 6 is provided with an inclined cutting edge that extends to the helical cutting edge and can be cut in reverse along the axis of the cutter, and the other end of the inclined cutting edge extends to the neck 2 ;

The length of the neck 2 is greater than the depth of the through hole to be processed, the diameter of the shank 3 is a value convenient for clamping, and the length meets the clamping requirements of common processing equipment.

Helical grooves are provided between the adjacent front cutting edges, between the adjacent spiral cutting edges and between the adjacent inclined cutting edges to facilitate chip discharge.

The cutting part 1 is provided with a cooling hole 7 that realizes the cooling zone and lubrication of the cutting area during processing. The cooling hole 7 is connected to the rear end of the shank 3. Inside.

On the premise of not affecting the overall rigidity of the tool, the difference between the diameter of the cutting part 1 and the diameter of the neck 2 is as large as possible.

The helix angle of the helical cutting edge is less than 30°.

The axial length of the circumferential cutting zone 5 is as small as possible and larger than the lead of the feed path during reverse helical milling.

The front cutting area 4 , the circumferential cutting area 5 , the rear cutting area 6 and the neck 2 have round transitions among each other, and the curvature of the round corners is 0.2mm˜1mm.

Among the four front-end cutting edges, one group of opposite front-end cutting edges 8 extends to the axis of the tool to intersect, and the other group of opposite front-end cutting edges 9 does not extend to the axis of the tool. end at the axis.

As shown in Fig. 12-Fig. 15, it is the physical picture of the cutter and the forward-reverse feed spiral milling hole processing of the composite material and metal laminated structure using the cutter of the present invention to obtain the outlet quality of the final hole and the first time from the inlet The comparison chart of the export quality processing effect of the pre-machined hole obtained by the side forward feed helical milling hole.

Example 2

As shown in Figures 4-6, a forward-reverse helical milling tool includes a cutting part 10, a neck 11 and a shank 12 connected in sequence;

The cutting part includes a front cutting area 13, a circumferential cutting area 14 and a rear cutting area 15 connected in sequence;

The front end cutting area 13 is an end mill structure, including four front end cutting edges that are symmetrically distributed around the center and can be forwardly fed and cut along the axis of the tool, and the front end cutting edges are perpendicular to the axis of the tool;

The circumferential cutting zone 14 is cylindrical and has a peripheral milling cutter structure, and is divided into a front section of the cutting zone and a rear section of the cutting zone. The front section of the cutting zone has a front helical cutting edge that can be fed and cut along the radial direction of the tool , the rear section of the cutting zone has a rear helical cutting edge that can be fed and cut along the radial direction of the tool, and the helical cutting edge and the rear helical cutting edge have opposite and symmetrical directions of rotation, the The helix angles of the front helical cutting edge and the rear helical cutting edge are equal, the front helical cutting edge extends to the front end cutting edge, and the rear section of the cutting zone adopts the opposite direction of rotation to make the tool reversely advance When helically milling holes, the chips are discharged toward the cutting part, which makes chip removal easier and improves the quality of the processed hole wall;

The rear end cutting zone 15 is in the shape of a truncated cone, the outer diameter of its large end matches the diameter of the circumferential cutting zone 14, the outer diameter of its small end matches the diameter of the neck 11, and the rear end The sidewall of the cutting zone 15 is provided with an inclined cutting edge that extends to the helical cutting edge and can be cut in reverse along the axis of the cutter, and the other end of the inclined cutting edge extends to the neck 11 ;

The length of the neck 11 is greater than the depth of the through hole to be processed, the diameter of the shank 12 is a value convenient for clamping, and the length meets the clamping requirements of common processing equipment.

Helical grooves are provided between the adjacent front cutting edges, between the adjacent spiral cutting edges and between the adjacent inclined cutting edges to facilitate chip discharge.

The cutting part 13 is provided with a cooling hole 16 to realize the cooling zone and lubrication of the cutting area during processing. The cooling hole 16 is connected with the rear end of the shank 12. Inside.

On the premise of not affecting the overall rigidity of the tool, the difference between the diameter of the cutting part 10 and the diameter of the neck 11 is as large as possible.

The helix angle of the helical cutting edge is less than 30°.

The axial length of the circumferential cutting zone 14 is as small as possible and larger than the lead of the feed path during reverse helical milling.

The front cutting zone 13 , the circumferential cutting zone 14 , the rear cutting zone 15 and the neck 11 have round transitions among them, and the curvature of the round corners is 0.2mm˜1mm.

Among the four front-end cutting edges, one group of oppositely arranged front-end cutting edges 17 extends to intersect with the axis of the tool, and the other group of oppositely arranged front-end cutting edges 18 does not extend to the axis of the tool. end at the axis.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

The invention is applicable to the hole making of composite materials and metal laminated structures, and is also applicable to the hole making of composite material single layer, composite material laminate, metal single layer and metal laminate, through the way of reverse feeding helical milling hole Avoid processing defects such as burrs and flashes on the exit side.

Claims (9)

1. a kind of forward direction-reverse acting spiral milling cutter, which is characterized in that including sequentially connected cutting portion, neck and shank；

The cutting portion includes sequentially connected front end cutting region, circumference cutting region and rear end cutting region；

The front end cutting region be end mill structure, including central symmetry distribution and can along the axis forward direction of the cutter feed cut Four nose-cut-ting edges cut；

The circumference cutting region is cylinder and is all milling cutter constructions, cylindrical surface be equipped with extend to the nose-cut-ting edge and The helical cutting edge that can be cut along the radial feed of the cutter；

The rear end cutting region is in truncated cone-shaped, and the outer diameter diametrically with the circumference cutting region of big end matches, small The outer diameter diametrically with the neck at end matches, and the side wall of the rear end cutting region, which is equipped with, extends to the spiral shape Cutting edge and the oblique cutting edge that can be cut along the axis feed reversing of the cutter, the other end of the oblique cutting edge extend To the neck.

2. cutter according to claim 1, it is characterised in that：The length of the neck is more than the hole of through-hole to be processed It is deep, a diameter of numerical value convenient for clamping of the shank, and length meets the clamping requirement for commonly using process equipment.

3. cutter according to claim 1, it is characterised in that：Between the adjacent nose-cut-ting edge, the adjacent spiral The helicla flute convenient for chip discharge is equipped between the adjacent oblique cutting edge between shape cutting edge.

4. cutter according to claim 1, it is characterised in that：The cutting portion, which is equipped with, realizes cutting zone in processing The cooling hole of cold-zone and lubrication, the cooling hole are penetrated through with the shank rear end.

5. cutter according to claim 1, it is characterised in that：Under the premise of not influencing the cutter overall stiffness, institute The difference for stating the diameter and the diameter of the neck of cutting portion is big as possible.

6. cutter according to claim 1, it is characterised in that：The helical angle of the helical cutting edge is less than 30 °.

7. cutter according to claim 1, it is characterised in that：The axial length of the circumference cutting region is small as possible and is more than The helical pitch of track is fed when reverse acting spiral hole milling.

8. cutter according to claim 1, it is characterised in that：The front end cutting region, the circumference cutting region, it is described after Hold cutting region and the neck that there is round-corner transition each other, the radius of curvature of the fillet is 0.2mm~1mm.

9. cutter according to claim 1, it is characterised in that：In four nose-cut-ting edges, one of which is opposite to be set The nose-cut-ting edge set, which extends at the axis of the cutter, to intersect, the nose-cut-ting edge that another set is oppositely arranged It is not extend at the axis of the cutter and terminates.