Method for processing plated-through hole in blind slot of PCB (Printed Circuit Board)

Abstract

The invention discloses a method for processing a plated-through hole in a blind slot of a PCB (Printed Circuit Board), and discloses a method for processing a plated-through hole in a blind slot of the PCB, which comprises the following steps of: hole positioning: positioning the plated-through hole in the PCB; drilling: drilling a circle of a plurality of tool holes around the existing plated-through hole of the PCB; and depth-controlled milling: milling steps on the PCB according to design requirements. Before the blind groove is subjected to depth-controlled milling, the plated-through hole is firstly positioned, then the tool hole is subjected to depth-controlled milling around the plated-through hole, and the hole wall of the plated-through hole is subjected to multiple times of small-amount cutting through the tool hole, so that the hole wall of the plated-through hole cannot be processed during depth-controlled milling; therefore, the problems of hole wall copper tension fracture and burrs of the plated-through hole due to the mechanical damage process during machining in a depth-controlled milling mode are avoided.

Description

Technical Field

[0001] The present invention relates to the field of PCB processing technology, and in particular to a method for processing a metallized hole in a PCB blind slot. Background Art

[0002] The design of plated holes in PCB blind slots has gradually increased in high-end PCBs. This type of design is usually done after the outer layer of the PCB has been completed. The blind slot cannot be processed by the lamination and decapping process. The controlled depth milling process must be used for secondary processing. The through hole in the blind slot is already a finished product. When the controlled depth milling method is used, the plated holes will have problems such as cracking and burrs in the hole wall due to mechanical damage during the process. At this stage, they are all repaired manually one by one, which is inefficient and the yield rate cannot be guaranteed. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for machining a plated hole in a blind slot of a PCB, which can avoid the problem of copper cracking and burring in the hole wall caused by mechanical damage during the controlled depth milling process.

[0004] A method for processing a metallized hole in a PCB blind slot according to an embodiment of the present invention includes the following steps: Hole positioning: positioning the existing metallized holes on the PCB; Drilling: Drill a circle of several tool holes around the existing metallized holes in the PCB; Controlled depth milling: Mill steps on the PCB according to design requirements.

[0005] The invention has at least the following beneficial effects: before the blind groove is processed by controlled depth milling, the metallized hole is first located, and then the tool hole is processed by controlled depth milling around the metallized hole, and the hole wall of the metallized hole is processed by the tool hole multiple times with small amounts of cutting, so that the hole wall of the metallized hole will not be processed during controlled depth milling, thereby avoiding the problem of copper cracking and burrs on the hole wall of the metallized hole due to mechanical damage during processing by the controlled depth milling method.

[0006] According to some embodiments of the present invention, in the drilling step, the drilling depth of the tool hole is 0.1 mm greater than the depth required for milling in the depth-controlled milling step.

[0007] According to some embodiments of the present invention, in the drilling step, the centers of several tool holes are on the concentric circle edge lines of the metallized holes, the diameters of the concentric circles where the centers of the several tool holes are located are set to D2, the diameter of the metallized holes is set to D1, and the diameters of the several tool holes are set to D3. Then, when drilling the tool holes, D2 < D1 + D3 needs to be satisfied.

[0008] According to some embodiments of the present invention, in the drilling step, (D3+D1)-D2≥0.2 mm.

[0009] According to some embodiments of the present invention, in the drilling step, diameters of several tool holes are greater than 0.6 mm.

[0010] According to some embodiments of the present invention, in the drilling step, a minimum distance between outer circles of two tool holes on both sides of any tool hole is greater than 0.4 mm.

[0011] According to some embodiments of the present invention, in the drilling step, two adjacent tool holes partially overlap.

[0012] According to some embodiments of the present invention, in the drilling step, the drilling sequence of the tool holes adopts symmetrical cross drilling to maximize the distance between two consecutive drillings.

[0013] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 is a cross-sectional view of a PCB according to an embodiment of the present invention; Figure 2 A schematic diagram of a drilling step according to an embodiment of the present invention (top view); Figure 3 for Figure 2 A partial enlarged view of point A in the middle.

[0015] Reference numerals: PCB 10, blind slot 20, plated hole 30, depth-controlled milling cutter 40, tool hole 50, concentric circle 60 where the center of the tool hole is located. DETAILED DESCRIPTION

[0016] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0017] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0018] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0019] Reference Figures 1 to 3 The present invention discloses a method for processing a metallized hole in a PCB blind slot, comprising the following steps: Hole positioning: positioning the existing metallized holes on the PCB; Drilling: Drill a circle of several tool holes around the existing metallized holes in the PCB; Controlled depth milling: Mill steps on the PCB according to design requirements.

[0020] It is understandable that before controlling the depth of the blind groove, the metallized hole is located first, and then the tool hole is processed by controlling the depth of the metallized hole. The hole wall of the metallized hole is processed by the tool hole multiple times with small amounts of cutting, and the hole wall of the metallized hole will not be processed during the controlled depth milling, thereby avoiding the problem of copper cracking and burrs on the hole wall of the metallized hole due to mechanical damage during the controlled depth milling process.

[0021] Furthermore, in an embodiment of the present invention, in the drilling step, the drilling depth of the tool hole is 0.1 mm greater than the depth required for milling in the depth-controlled milling step.

[0022] It is understandable that by completely machining away the copper wall of the plated hole in the blind groove area through a deeper tool hole, the copper cracking and burr problems of the hole wall caused by controlled depth milling of the blind groove can be avoided.

[0023] Furthermore, in an embodiment of the present invention, in the drilling step, the centers of several tool holes are on the concentric circle edge lines of the metallized holes, the diameters of the concentric circles where the centers of the several tool holes are located are set to D2, the diameter of the metallized holes is set to D1, and the diameters of the several tool holes are set to D3, then when drilling the tool holes, D2 < D1 + D3 needs to be satisfied.

[0024] It is worth noting that by setting the diameter D3 of the tool hole and the diameter D2 of the concentric circle where the centers of the tool holes are located, it is possible to ensure that the tool hole cuts the hole wall of the metallized hole.

[0025] Further, in an embodiment of the present invention, in the drilling step, (D3+D1)-D2≥0.2 mm.

[0026] Furthermore, in an embodiment of the present invention, in the drilling step, diameters of the plurality of tool holes are greater than 0.6 mm.

[0027] It is understandable that in the embodiments of the present invention, using a larger gong cutter to process the tool hole can improve the processing efficiency.

[0028] Furthermore, in an embodiment of the present invention, in the drilling step, the minimum distance between the outer circles of two tool holes on both sides of any tool hole is greater than 0.4 mm.

[0029] It is worth noting that by limiting the minimum distance between the outer circles of two tool holes on both sides of any tool hole, it is possible to avoid excessive overlap of multiple tool holes, reduce the number of tool holes, and improve processing efficiency.

[0030] Further, in an embodiment of the present invention, in the drilling step, two adjacent tool holes partially overlap.

[0031] It can be understood that the partial overlap of adjacent tool holes can ensure that the copper layer of the hole wall of the metallized hole is completely cut without any residue.

[0032] Furthermore, in an embodiment of the present invention, in the drilling step, the drilling sequence of the tool holes adopts symmetrical cross drilling to maximize the distance between two consecutive drillings.

[0033] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0034] Of course, the present invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for processing a metallized hole in a PCB blind slot, characterized in that: The following steps are involved: Hole positioning: positioning the existing metallized holes on the PCB; Drilling: Drill a circle of several tool holes around the existing metallized holes on the PCB, and cut the hole walls of the metallized holes several times with small amounts of cutting through the tool holes; Controlled depth milling: Mill steps on the PCB according to design requirements.

2. A method for processing a metallized hole in a PCB blind slot according to claim 1, characterized in that: In the drilling step, the gong hole depth of the tool hole is 0.1mm greater than the depth required for milling in the controlled depth milling step.

3. A method for processing a metallized hole in a PCB blind slot according to claim 1 or 2, characterized in that: In the drilling step, the centers of several tool holes are on the concentric circle edge lines of the metallized holes. The diameters of the concentric circles where the centers of the several tool holes are located are set to D2, the diameter of the metallized holes is set to D1, and the diameters of the several tool holes are set to D3. Then, when drilling the tool holes, D2 < D1 + D3 must be satisfied.

4. The method for processing a metallized hole in a PCB blind slot according to claim 3, characterized in that: In the drilling step, (D3+D1)-D2≥0.2mm.

5. The method for processing a metallized hole in a PCB blind slot according to claim 3, characterized in that: In the drilling step, several tool holes have diameters greater than 0.6 mm.

6. A method for processing a metallized hole in a PCB blind slot according to claim 5, characterized in that: In the drilling step, the minimum distance between the outer circles of two tool holes on both sides of any tool hole is greater than 0.4 mm.

7. A method for processing a metallized hole in a PCB blind slot according to claim 6, characterized in that: During the drilling step, two adjacent tool holes partially overlap.

8. The method for processing a metallized hole in a PCB blind slot according to claim 5, characterized in that: In the drilling step, the drilling sequence of the tool holes adopts symmetrical cross drilling to maximize the distance between two consecutive drill holes.

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