CN110976942A

CN110976942A - Back drilling cutter for PCB micropore back drilling

Info

Publication number: CN110976942A
Application number: CN201911090294.0A
Authority: CN
Inventors: 王小平; 刘梦茹; 何思良; 纪成光; 袁继旺; 陈正清
Original assignee: Shengyi Electronics Co Ltd
Current assignee: Shengyi Electronics Co Ltd
Priority date: 2019-11-08
Filing date: 2019-11-08
Publication date: 2020-04-10

Abstract

A back drilling tool for PCB micropore back drilling comprises a tool handle and a tool body integrally connected to the tool handle, wherein the tool body is provided with chip guide grooves spirally distributed along an axis, the edge parts of notches of the chip guide grooves form an auxiliary cutting edge and a tail root rake, one end of the tool body, which is far away from the tool handle, is provided with tool tips, the chip guide grooves extend to two sides of the tool tips, so that a main cutting edge and a rear rake are formed on the tool tips, the side surfaces of two opposite sides of the tool tips form an included angle, the joint of the two included angles forms an ineffective cutting line, and the thickness L of the tool core on the axis of the tool body is the core thickness; the core thickness of the drill bit is 0.05-0.06 mm, the point angle of the back drill bit is 90-120 degrees, and the helix angle of the back drill bit is 40 degrees. According to the invention, through reasonably setting the parameters of the spiral angle, the sharp angle and the core thickness, the problem of hole blocking caused by back drilling of the micropore is effectively solved, the drilling quality of the micropore is effectively ensured, and the drilling capability of the drill is improved.

Description

Back drilling cutter for PCB micropore back drilling

Technical Field

The invention relates to the field of manufacturing of PCBs, in particular to a back drilling tool for PCB micropore back drilling.

Background

With the development requirement of high frequency and high speed of communication equipment, the PCB is developed towards high integration, thinning and miniaturization, so that the aperture of a processing hole on the circuit board is smaller and smaller, the wiring density is larger and larger, and space-saving designs such as multi-line wiring in one hole, wiring among back drilling holes and the like are more and more. In high speed, during high density's PCB design, the via hole design is littleer and smaller, can leave more wiring spaces on this model, in addition, for satisfying high-speed signal integrality, need carry out the back drilling to tiny via hole, get rid of unnecessary incomplete copper, it is a very big challenge to the stifled hole problem of micropore back drilling like this. The problem of back drilling hole plugging cannot be solved by the traditional back drilling drill, and a novel drill needs to be developed urgently to solve the problem of back drilling hole plugging.

Disclosure of Invention

In view of the above, there is a need to provide a back-drilling tool that effectively prevents back-drilling from blocking a hole, in view of the shortcomings in the prior art.

A back drilling cutter for PCB micropore back drilling comprises a cutter handle and a cutter body connected to the cutter handle in an integrated forming manner, wherein the cutter body is provided with chip guide grooves which are spirally distributed along an axis, the rotation angle of the chip guide grooves along the axis is a spiral angle, the edge parts of notches at two sides of the chip guide grooves form an auxiliary cutting edge and a tail root rake on the outer side surface of the cutter body, one end of the cutter body, which is far away from the cutter handle, is provided with a cutter point, the chip guide grooves extend to two sides of the cutter point, so that a main cutting edge and a rear root rake are formed on the cutter point, an included angle is formed at the side surface of the opposite two sides of the cutter point, the included angle is a cutter sharp angle, an ineffective cutting line is formed at the joint; the core thickness of the drill bit is 0.05-0.06 mm, the point angle of the back drill bit is 90-120 degrees, and the helix angle of the back drill bit is 40 degrees.

Furthermore, the outer side surface of the cutter body between the two chip guide grooves of the back drilling cutter is provided with a blade back and a blade area.

Furthermore, the cutter body is grooved along the direction of the main shaft on the invalid cutting line, and then a small sub-groove is formed.

Further, the depth of the small subslot is 1/4 the core is thick.

Further, the small subslot is arc-shaped or triangular.

In conclusion, the back drilling tool for PCB micropore back drilling has the advantages that: through carrying out reasonable setting to spiral angle, sword closed angle, the thick parameter of core, the effectual micropore back drilling hole blocking problem of solving to effectively guarantee microporous drilling quality, improve the drilling ability of brill sword, have stronger popularization meaning.

Drawings

FIG. 1 is a side view of a backdrill blade for PCB micro-via backdrilling of the present invention.

Fig. 2 is a bottom view of the backdrill blade for PCB micro-hole backdrilling shown in fig. 1.

Fig. 3 is a schematic structural view of another angle of the back drill used for PCB micro-hole back drilling shown in fig. 1.

Fig. 4 is a schematic structural view of another angle of the back drill used for PCB micro-hole back drilling shown in fig. 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

As shown in fig. 1 to 4, the present invention provides a back-drilling tool for PCB micro-hole back-drilling, the back-drilling tool for PCB micro-hole back-drilling comprises a tool holder (not shown) and a tool body 10 integrally connected to the tool holder, the tool body 10 is provided with chip guide grooves 11 spirally distributed along an axis, an angle of rotation of the chip guide grooves 11 along the axis is a helical angle (shown as an included angle B in the figure), edge portions of notches at two sides of the chip guide grooves 11 form a secondary cutting edge 13 and a tail root rake 14 at an outer side of the tool body, one end of the tool body 10 away from the tool holder is provided with a tool nose 12, the chip guide grooves extend to two sides of the tool nose 12, so as to form a primary cutting edge 17 and a rear rake 18 on the tool nose, the side surfaces at two opposite sides of the tool nose 12 form an included angle (shown as a tool tip angle a in the figure), and a joint of the two included angles forms an ineffective, the thickness L of the cutter core on the axis of the cutter body 10 is the core thickness.

The invention changes the core thickness of the conventional back-drilling cutter from 0.08mm to 0.05-0.06 mm. When the diameters of the drill cutters are the same, the chip removal amount is the same, the thinner the core is, the larger the dust removal space of the chip guide groove 11 is, the smaller the extrusion force among the drill cuttings is, the lower the probability of adhesion on the drill cutters is, and the smoother the dust removal is. The thinner the core is, the poorer the rigidity of the drill is naturally, and the more easily the cutter is broken; the thicker the core, the longer the ineffective cutting edge in the middle. The core thickness is reduced to promote the reduction of ineffective length of the back drill and increase the chip removal performance of the back drill.

The point angle of the conventional back drilling tool is changed from 130 degrees to 90 degrees to 120 degrees. The larger the drill point angle is, the larger the length of the drill point line is, namely the larger the ineffective cutting length is, and the ineffective cutting edge acts on the hole copper, so that the hole copper is continuously cut, and the hole is blocked. Therefore, the drilling angle is reduced to increase the effective cutting length and reduce the probability of causing hole blockage. Changing the drill point angle of the conventional back drilling drill from 130 degrees to 120 degrees; the smaller the point angle, the higher the hole site precision and the stronger the dust discharge capacity.

The invention changes the helix angle of the conventional back drilling cutter to 40 degrees from the original 35 degrees to 40 degrees. The bigger the spiral angle is, the stronger the cutting ability is, and the stronger the dust discharge ability is, in order to strengthen the chip removal performance, avoid the back drilling copper scraps not in time discharging and lead to the back drilling stifled hole, but the spiral angle increases the drill rigidity worse, considers synthetically that the spiral angle is adjusted by 5 from original angle, when guaranteeing the drill rigidity, improves cutting, dust discharge ability stronger.

The outer side surface of the tool body between the two chip guide grooves 11 of the back drilling tool is provided with a blade back 15 and a blade band 16, the tool body 10 is grooved on an invalid cutting line 19 along the direction of a main shaft, so that a small sub-groove 110 is formed, the cutting capacity of the back drilling tool is effectively improved by the small sub-groove 110, and the small sub-groove 110 can be arc-shaped or triangular and has the depth of 1/4 with the core thickness.

The above-mentioned embodiments only express one embodiment of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The utility model provides a back of body bores sword for PCB micropore back drilling which characterized in that: the integrated chip cutting machine comprises a cutter handle and a cutter body connected to the cutter handle in an integrated forming mode, wherein chip guide grooves which are distributed spirally along an axis are arranged on the cutter body, the angle of rotation of the chip guide grooves along the axis is a helical angle, the edge parts of notches on two sides of the chip guide grooves form an auxiliary cutting edge and a tail root rake on the outer side surface of the cutter body, one end, far away from the cutter handle, of the cutter body is provided with a cutter point, the chip guide grooves extend to two sides of the cutter point, so that a main cutting edge and a rear rake are formed on the cutter point, an included angle is formed on the side surface of the opposite two sides of the cutter point, the included angle is a cutter sharp angle, an ineffective cutting; the core thickness of the drill bit is 0.05-0.06 mm, the point angle of the back drill bit is 90-120 degrees, and the helix angle of the back drill bit is 40 degrees.

2. The backdrill bit for PCB micro-via backdrilling of claim 1, wherein: the outer side surface of the cutter body between the two chip guide grooves of the back drilling cutter is provided with a blade back and a blade area.

3. The backdrill bit for PCB micro-via backdrilling of claim 1, wherein: the cutter body is grooved along the direction of the main shaft on the invalid cutting line, and then a small sub-groove is formed.

4. The backdrill bit for PCB micro-via backdrilling of claim 3, wherein: the depth of the small subslot is 1/4 the core is thick.

5. The backdrill bit for PCB micro-via backdrilling of claim 3, wherein: the small sub-groove is arc-shaped or triangular.