CN109894653B

CN109894653B - Precise micro drill bit for processing high-end communication board

Info

Publication number: CN109894653B
Application number: CN201910218105.7A
Authority: CN
Inventors: 周培峰
Original assignee: Jiangmen Jiantao Hi Tech Co ltd
Current assignee: Jiangmen Jiantao Hi Tech Co ltd
Priority date: 2019-03-21
Filing date: 2019-03-21
Publication date: 2020-11-24
Anticipated expiration: 2039-03-21
Also published as: CN109894653A

Abstract

The invention belongs to the field of design of a precise micro drill bit, and discloses a precise micro drill bit for processing a high-end communication board, which comprises a drill handle, a drill tip and a drill diameter arranged between the drill handle and the drill tip, wherein the drill diameter is provided with two adjacent spiral chip removal grooves, two sides of a connecting surface formed by the two adjacent spiral chip removal grooves are ground to form a blade zone, a grinding surface formed by the two blade zones on the same connecting surface is a shovel back, the drill tip comprises two main cutting tool surfaces, two auxiliary cutting tool surfaces connected with the long side line of the main cutting tool surfaces, and a cross edge is arranged at the connecting part of the two main cutting tool surfaces, the drill tip formed between the two main cutting tool surfaces is 123-133 degrees, and the spiral angle of the spiral chip removal groove is 38-42 degrees; the invention aims to solve the problems that the circuit board is scrapped due to serious cutter breakage of a drill bit, the chip removal is poor, the hole deviation is caused, the hole wall is rough, the hole site precision is high and the like in the process of processing a high-end circuit board by using a precision drill bit.

Description

Precise micro drill bit for processing high-end communication board

Technical Field

The invention relates to the field of design of precision micro-drill bits, in particular to a precision micro-drill bit for processing a high-end communication board.

Background

With the development of economy and the progress of society, energy conservation becomes inevitable and socially recognized. Modern electronic components are lighter, thinner, shorter and smaller, and the requirement on reliability is higher and higher, so that the quality of a printed circuit board is continuously improved, the structure of the board is continuously changed, the requirement on the quality of board drilling is higher and higher, and along with the continuous improvement and change of the application market requirement, the drilling processing technology of a high-end communication board enters a stage which is both opportunistic and challenging. Chinese patent No. CN201820796205.9, published 2019-02-15) discloses a micro drill for drilling holes in PCB, comprising a drill handle and a working part arranged at one end of the drill handle, the working part comprises a drill point and a drill body, the drill body is arranged between the drill point and the drill handle, the drill point is provided with a first drill core, the drill body is provided with a second drill core, the first drill core and the second drill core are of forward cone structures, the working part is provided with two chip grooves, a cutting edge is arranged on a cutting edge between two adjacent chip grooves, each cutting edge is provided with a grinding back part which is formed on one side of the cutting edge through grinding, each grinding back part extends backwards to the root part of the corresponding chip groove, and the back grinding depth of the back grinding part at the rear end is smaller than that of the front end, so that the integral rigidity of the micro drill bit is enhanced, and the chip removal performance of the micro drill bit can be improved. Patent "special drill for processing PCB slotted hole" (patent No. CN201520254233.4, published japanese 2015-11-18) discloses a special drill for processing PCB slotted hole for processing slot type hole, comprising a drill tip and a drill body, wherein the drill tip is provided with two main cutting edges, a cross edge, two auxiliary cutting edges, two main cutter faces and two auxiliary cutter faces; the drill body is provided with two spiral chip grooves; the main cutting edge is the arc, bore the body and respectively have one section piece of cloth portion towards the inside mill of the direction of drill point axis on two brill backs that two chip grooves correspond, form a piece of cloth limit between the groove limit of the chip groove of being connected with main cutting edge on every piece of cloth portion and the place brill back of the body, the helix angle of piece of cloth portion is the same with the helix angle of chip groove, it can reduce drill bit and pore wall friction, it generates heat to restrain the drill point, it produces to reduce gluey sediment, and then can avoid the advantage of the crooked condition of the spot hole appearance that bores. However, the above two patents do not disclose a technical scheme for solving the problems of high cutter breakage rate, poor chip removal, deviated holes, rough hole walls, hole position precision and the like in the process of processing the circuit board, so that the processing quality of the micro drill for drilling the holes cannot meet the process requirements of the circuit board holes.

Disclosure of Invention

The invention aims to provide a precise micro drill for processing a high-end communication board, which solves the technical problems in the prior art. The technical scheme is that the angle of a drilling point angle and the coaxiality and concentricity tolerance of a drilling diameter are strictly controlled, the angle of a spiral angle is designed to keep the sharpness of a cutting edge and have extremely strong bending strength, and the cutter breaking rate of the precision micro-drill is controlled within 3 per thousand to 8 per thousand, so that the problems of high cutter breaking rate, poor chip removal, deviated holes, rough hole bodies, hole position precision and the like of micro-drills for processing circuit boards are solved, and the processing quality of the precision micro-drill can completely meet the technical processing requirements.

The technical scheme provided by the invention is as follows: the utility model provides a precision micro drill for processing high-end communication board, includes drill handle, drill point, locates the bore diameter between drill handle and the drill point, the bore diameter on be equipped with two adjacent spiral chip grooves, the both sides on the face of being connected that two adjacent spiral chip groove formed grind the land that forms through grinding, the abrasive surface that two lands on same face of being connected formed is for boring the back of the body, the drill point include two main cutting knife faces, two vice cutting knife faces that link to each other with main cutting knife face long side sideline, be equipped with a chisel edge at the junction of two main cutting knife faces, a serial communication port, the concave radian of main cutting knife face is 1rad ~ 5rad, two main cutting knife faces between the drill point angle that forms be 123 ° -133 °, spiral flute's helix angle be 38 ° -42 °.

In the above-mentioned precision micro drill for processing high-end communication boards, the spiral flutes extend from the drill tip to the bottom of the drill diameter and are located at positions radially opposite to each other on the drill diameter surface.

In the precision micro drill for processing the high-end communication board, the drill back extends to the drill diameter of 0.8-1.2 MM from the front end of the drill diameter.

In the above-mentioned precision micro drill for processing high-end communication boards, the point angle is 128 °.

Compared with the prior art, the invention has the beneficial effects that: the precision micro drill bit for processing the high-end communication board has the advantages that the drill point angle formed between two main cutting tool faces is 128 +/-5 degrees, the spiral angle of the spiral chip removal groove is 38-42 degrees, the drill bit has good rigidity, bending strength, wear resistance and toughness, the cutter breaking rate of the precision micro drill bit for the multilayer copper high-end communication board in the processing process can be controlled within 3-8 per thousand, the problems of high cutter breaking rate, poor chip removal, deviated holes, rough hole walls, hole position precision and the like of the precision micro drill bit are solved, and the drilling quality of the precision micro drill bit completely meets the processing technological requirements of drilling circuit board holes.

Drawings

FIG. 1 is a schematic view of a semi-finished drill bit of the present invention.

FIG. 2 is a schematic view of the drill bit of the present invention for forming helical flutes.

Fig. 3 is a schematic view of the major and minor faces of the inventive drill bit after tip sharpening.

Description of the drawings: 1-drilling diameter, 2-drilling diameter inclined plane, 3-drilling handle, 4-main cutting edge, 5-edge zone, 6-spiral chip groove, 7-main cutting tool face, 8-auxiliary cutting tool face, 9-chisel edge and 10-auxiliary cutting edge.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example (b): referring to fig. 1-3, a precision micro drill for processing a high-end communication board comprises a drill handle 3, a drill tip and a drill diameter 1 arranged between the drill handle 3 and the drill tip, wherein the rear end of the drill handle 3 is rounded, so that the problem that the drill cannot be completely sent into a chuck of a working head when the drill diameter 1 and a spiral groove are processed, the total length of a product is shortened or processing equipment is damaged is avoided; a drill diameter inclined plane 2 is arranged between the drill handle 3 and the drill diameter 1, so that the slotted grinding wheel is prevented from being worn on the drill handle when a spiral groove is formed, the slotted grinding wheel is prevented from being damaged, and dust can be guided to be discharged when a hole is drilled; two adjacent spiral chip grooves 6 are arranged on the drill diameter 1, and two sides of a connecting surface formed by the two adjacent spiral chip grooves 6 are provided with cutting edges 5 formed by grinding, so that the cutting edges 5 can reduce excessive contact between the drill diameter and a hole wall during drilling and improve the finish degree of the hole wall during drilling; the grinding surface formed by the two blade bands 5 on the same connecting surface is a drill back, and the drill back is obtained by cutting the rest part of the drill diameter 1 through a back grinding wheel; the depth of the drill back accounts for 80-84% of the drill diameter, the drill tip comprises two main cutting tool faces 7, the tool face angle of the drill tip is 12-15 degrees, two auxiliary cutting tool faces 8 connected with long side lines of the main cutting tool faces 8 and the angle of the auxiliary cutting tool faces is 28-31 degrees, and a chisel edge 9 is arranged at the connection position of the two main cutting tool faces 7; the main cutting knife face 7 is used for cutting a workpiece, and the auxiliary cutting knife face 8 is located on the rear side of the main cutting knife face 7, so that chip removal is guided, and excessive contact between the main cutting knife face and the workpiece is reduced. The point angle formed between the two main cutting tool surfaces 7 is 123-133 degrees, and the helical angle of the helical flute 6 is 38-42 degrees; the spiral angle is an included angle between a spiral line of the outermost circle on the spiral groove of the drill bit and the central axis of the drill bit after the spiral line is unfolded into a straight line, and the drill diameter has the maximum rigidity and bending strength on the plane.

In the embodiment, the spiral chip grooves 6 extend from the drill tip to the bottom of the drill diameter 1 and are positioned at the positions which are opposite to each other in the radial direction on the surface of the drill diameter 1; the spiral groove is formed by cutting the surface of the drill diameter 1 by the diamond grinding wheel during slotting, dust is discharged during drilling, and the drill bit is prevented from being broken due to blockage of the drill hole; the drill back extends to 0.8-1.2 MM of the drill diameter 1 from the front end of the drill diameter 1, and aims to reduce the contact between the surface of the drill and the hole wall and ensure that the smoothness of the inner hole wall is higher.

In the present embodiment, the point angle is 128 °, and the angle of the point angle has a great influence on the accuracy of the drilling; when the drilling point angle is small, the positioning is easy, but the precision is poor; otherwise, the precision is good but the positioning is difficult, and when the point angle is 128 degrees, the precision is good and the positioning is also difficult.

The drill bit of the invention with phi 0.3X 5.5MM and the drill point angle of 128 degrees and the conventional drill bit with phi 0.3X 5.5MM and the drill point angle of 130 degrees are adopted, and the processing parameters are as follows: grinding three times under the conditions of S98KRPM, F50iPM, U1000iPM and H1000, and comparing the CPK value, the nail head value and the hole wall roughness of the drill bit.

The CPK value is a parameter representing the process capability, and the reference standard is as follows:

TABLE 1 CPK rating criteria

The head of the drill is formed by that the copper foil on the inner layer can not be cut smoothly during drilling, but is stretched and deformed into the shape like the head of a nail by tensile force.

The nail head value is the ratio of the length of the nail head to the thickness of the copper foil, and the size of the nail head is generally required to be not more than 50% of the thickness of the copper foil.

The roughness of the hole wall is the roughness of the inner wall of the circuit board after drilling, and the roughness of the hole wall is generally less than or equal to 1.0mil, and 1mil is 25.4 um.

The comparative results are shown in table 2 below:

TABLE 2 comparison of the grinding effect of the inventive drill bit with that of the conventional drill bit

The results show that the CPK value, the nail head value and the hole wall roughness of the drill bit are superior to those of the conventional drill bit, the drilling quality of the drill bit is still high after the drill bit is repeatedly ground, and the drilling quality of the conventional drill bit is obviously reduced after the conventional drill bit is repeatedly ground.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The utility model provides a precision micro drill bit for processing high-end communication board, includes drillstock, drill point, locates the brill footpath between drillstock and the drill point, the brill footpath on be equipped with two adjacent spiral chip grooves, the both sides of being connected on the face that two adjacent spiral chip groove formed are through the margin that the grinding formed, the abrasive surface that two margins on same connection face formed is for boring the back of the body, the drill point include two main cutting knife faces, two vice cutting knife faces that link to each other with main cutting knife face long side sideline, be equipped with a chisel edge at the junction of two main cutting knife faces, a serial communication port, the concave radian of main cutting knife face is 1rad, two main cutting knife faces between the drill point angle that forms be 123 °, 128 ° or 133 °, spiral angle of spiral chip groove be 38 ° or 42 °, the back of the body extend to drill diameter 0.8 ~ 1.2MM by the brill footpath front end.

2. The precision microbit of claim 1, wherein the helical flutes extend from the drill tip to the bottom of the drill diameter and are located diametrically opposite each other on the drill diameter face.