CN111121586A

CN111121586A - Method for testing residual thickness of PCB (printed circuit board) back drill

Info

Publication number: CN111121586A
Application number: CN201911425161.4A
Authority: CN
Inventors: 李桂群; 曾海涛; 陈永华; 夏海华
Original assignee: GCI Science and Technology Co Ltd; Zhuhai GCI Science and Technology Co Ltd
Current assignee: GCI Science and Technology Co Ltd; Zhuhai GCI Science and Technology Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-05-08

Abstract

The method for testing the residual thickness of the PCB back drill comprises the steps of S1, drilling module holes, drilling the module holes on the technological frame of the PCB, wherein the diameter of each module hole is 1.0-1.5 mm, and the distance between each module hole and the frame edge of the technological frame closest to the module hole is 3-5 mm; s2, drilling a module hole to a preset depth; and S3, judging whether the bottom of the module hole has copper sheet, if so, ending the test. Through directly boring the module hole at PCB, the hole bottom in module hole is looked to the eye, when the copper sheet appeared at the hole bottom, then the PCB back-drilled is incomplete thick qualified, need not to make quartzy section, improves production efficiency and reduction in production cycle input cost.

Description

Method for testing residual thickness of PCB (printed circuit board) back drill

Technical Field

The invention belongs to the technical field of PCBs, and particularly relates to a method for testing residual thickness of a PCB back drill.

Background

Printed circuit board (pcb), also called printed circuit board (pcb) or printed circuit board (pcb), is called printed circuit board for short, and is cut into a certain size by using an insulating board as a substrate, and at least one conductive pattern is attached to the insulating board and holes (such as component holes, fastening holes, metalized holes, etc.) are distributed on the insulating board to replace a chassis of an electronic component in the prior art and to realize the interconnection between the electronic components.

In the existing PCB manufacturing process, the residual thickness of the back drill of the PCB needs to be checked, the traditional checking method is to manufacture crystal slices to measure the residual thickness of the back drill, however, the traditional method brings the following defects:

1. the time for slicing each crystal is 30min, so that the production efficiency is reduced;

2. when the crystal slice is manufactured and sampled, the back drilling hole in the PCB unit is required to be taken to be used as the residual thickness of the crystal slice measurement back drilling hole, and the production cycle investment cost is increased.

Therefore, it is desirable to provide a method for inspecting residual thickness of PCB backdrill, which can improve the production efficiency and reduce the input cost of the production cycle.

Disclosure of Invention

The invention mainly aims to provide a method for testing residual thickness of back drilling of a PCB, which can improve the production efficiency and reduce the input cost of the production period.

In order to achieve the main purpose, the method for testing the residual thickness of the back drill of the PCB comprises the steps of S1, drilling a module hole, drilling the module hole on a process frame of the PCB, wherein the diameter of the module hole is 1.0-1.5 mm, and the distance between the module hole and the frame edge of the process frame closest to the module hole is 3-5 mm; s2, drilling a module hole to a preset depth; and S3, judging whether the bottom of the module hole has copper sheet, if so, ending the test.

By the scheme, the module hole is directly drilled in the PCB, the hole bottom of the module hole is visually observed, when the copper sheet is arranged at the hole bottom, the PCB back drilling residual thickness is qualified, crystal slices do not need to be manufactured, the production efficiency is improved, and the production cycle input cost is reduced.

Drawings

The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived on the basis of the following drawings without inventive effort.

FIG. 1 is a flowchart of an embodiment of a method for inspecting PCB backdrilling residual thickness according to the present invention.

Fig. 2 is a structural diagram of a PCB after module holes are drilled according to an embodiment of the method for testing the residual thickness of the PCB back drill of the present invention.

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. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 and 2, the method for inspecting the residual thickness of the PCB back drill of the present embodiment includes S1, drilling a module hole on a process frame 2 of the PCB, where the diameter of the module hole 1 is 1.0mm to 1.5mm, the hole distance L1 between the module hole 1 and a frame edge of the process frame closest to the module hole is 3mm to 5mm, and the hole distance is the distance from the center of the module hole 1 to the frame edge; s2, drilling a module hole 1 to a preset depth H2; and S3, judging whether the bottom of the module hole 1 has copper sheet, if so, ending the test.

In step S1, four module hole groups, each including four module holes 1, are drilled.

The PCB is an eight-layer board structure.

In step S1, a hole is drilled into the PCB from the CS surface of the PCB.

The second layer of the PCB is provided with a circuit surface, the distance H between the bottom of the module hole 1 and the circuit surface is 150um, the distance from the circuit surface to the CS surface is H1, the preset depth is H2, and the preset depth H2 is H1-H, that is, H2 is H1-150 um.

In step S3, it is determined whether there is copper sheet at the bottom of the module hole 1, if not, step S4 is executed to confirm that the PCB back drilling residual thickness is not qualified, and then the inspection is terminated.

In step S3, it is visually determined whether or not there is a copper skin at the bottom of the module hole 1.

Through directly boring module hole 1 at PCB, the hole bottom in module hole 1 is looked to the eye, when the copper sheet appeared at the hole bottom, then the PCB back drilling is incomplete thick qualified, need not to make quartzy section, improves production efficiency and reduction in production cycle input cost.

Finally, it should be emphasized that the present invention is not limited to the above-described embodiments, but only the preferred embodiments of the invention have been described above, and the present invention is not limited to the above-described embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for testing residual thickness of PCB back drilling is characterized by comprising the following steps:

s1, drilling a module hole, and drilling the module hole on the technological frame of the PCB, wherein the diameter of the module hole is 1.0-1.5 mm, and the distance between the module hole and the nearest frame edge of the technological frame is 3-5 mm;

s2, drilling the module hole to a preset depth;

and S3, judging whether the bottom of the module hole has copper sheet, if so, ending the test.

2. The inspection method according to claim 1, characterized in that:

in the step S1, four module hole groups are drilled, each of which includes four module holes.

3. The inspection method according to claim 2, characterized in that:

the PCB is of an eight-layer plate structure.

4. A method of testing as claimed in claim 3, wherein:

in step S1, a hole is drilled into the PCB from the CS surface of the PCB.

5. The inspection method according to claim 4, characterized in that:

the second layer of PCB is provided with the circuit face, the hole bottom in module hole with the distance of circuit face is 150 um.