A method, system, apparatus and device for laser drilling through holes

Abstract

The present application relates to the field of laser processing, and particularly relates to a method, system, device and equipment for laser drilling a through hole, the method comprising determining an axial position of a target through hole on a plate containing adhesive, using a drilling laser to perform guided through hole rotary cutting drilling on the plate with the axial position of the target through hole as the center to obtain a guided through hole with a radius Rd, and using the drilling laser to perform target through hole rotary cutting and reaming drilling around the guided through hole on the plate with the axial position of the guided through hole as the center to obtain a target through hole with a diameter D. When drilling the plate containing the adhesive layer, the guided through hole is first drilled at the target through hole to provide plasma and chip discharge space for the target through hole rotary cutting and reaming drilling. The heat accumulation in the guided through hole and the target through hole during rotary cutting and reaming is greatly reduced, and the adhesive shrinkage and inner wall crack depth of the inner wall of the target through hole can be greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and specifically to a method, system, apparatus, and equipment for laser drilling through holes. Background Technology

[0002] Currently, laser drilling for through-holes in circuit boards is becoming increasingly mature. However, when using lasers to drill through-holes in circuit boards with adhesive layers, significant adhesive shrinkage occurs, directly leading to unreliability in subsequent electroplating. Therefore, laser drilling of adhesive-containing circuit boards is currently difficult to widely apply. If mechanical drilling is used, the frictional heat generated by the rotating drill bit also directly causes adhesive shrinkage in the through-holes, making mechanical drilling of adhesive-containing circuit boards extremely difficult. Whether using laser drilling or mechanical drilling, the circuit board industry has yet to find a good solution for drilling through adhesive-containing circuit boards, unable to resolve the adhesive shrinkage problem that arises during drilling. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method, system, apparatus and equipment for laser drilling through holes, which can solve the problem of glue shrinkage when drilling through holes in glue-containing materials.

[0004] In a first aspect, the present invention provides a method for laser drilling through holes, the method comprising the following steps:

[0005] Determine the axial position of the target through hole on the plate to be drilled. Using the axial position of the target through hole as the center, use a drilling laser to perform guided through hole rotary drilling on the plate to obtain a guided through hole with a radius of Rd.

[0006] Centered on the axis of the guide hole, the drilling laser is used to perform rotary cutting and enlarging drilling around the guide hole on the plate to obtain a target through hole with a diameter of D.

[0007] The board material is an adhesive board or a single or multi-layer composite material board with a softening temperature of less than 300 degrees Celsius.

[0008] During the process of rotary cutting and reaming drilling of the target through hole, a negative pressure space channel for the discharge of debris from rotary cutting and reaming drilling of the target through hole is provided below the guide through hole.

[0009] The method for setting up the negative pressure space channel is as follows: a fixture plate is placed below the plate, and a negative pressure through hole is pre-machined on the fixture plate. The negative pressure through hole is connected to the guide through hole. The fixture plate is placed on the drilling platform honeycomb plate, and the drilling platform honeycomb plate is connected to the negative pressure equipment system. Then, a negative pressure is formed in the drilling platform honeycomb plate to adsorb and fix the fixture plate and the plate. Thus, a negative pressure is formed in the negative pressure through hole, so that airflow passes through the guide through hole. The airflow flows from above the plate towards the direction of the corresponding hole on the fixture plate.

[0010] Secondly, the present invention provides a system for laser drilling through holes, the system comprising the following modules.

[0011] The guide through-hole rotary cutting and drilling module is used to determine the axial center position of the target through hole on the plate to be drilled, and to perform guide through-hole rotary cutting and drilling on the plate using a drilling laser with the axial center position of the target through hole as the center to obtain a guide through hole with a radius of Rd.

[0012] The target through hole rotary cutting and enlarging drilling module is used to perform target through hole rotary cutting and enlarging drilling on the plate around the guide through hole with the axis position of the guide through hole as the center, and to obtain a target through hole with a diameter of D.

[0013] The board material is an adhesive board or a single or multi-layer composite material board with a softening temperature of less than 300 degrees Celsius.

[0014] During the process of rotary cutting and reaming drilling of the target through hole, a negative pressure space channel for the discharge of debris from rotary cutting and reaming drilling of the target through hole is provided below the guide through hole.

[0015] The method for setting up the negative pressure space channel is as follows: a fixture plate is placed below the plate, and a negative pressure through hole is pre-machined on the fixture plate. The negative pressure through hole is connected to the guide through hole. The fixture plate is placed on the drilling platform honeycomb plate, and the drilling platform honeycomb plate is connected to the negative pressure equipment system. Then, a negative pressure is formed in the drilling platform honeycomb plate to adsorb and fix the fixture plate and the plate. Thus, a negative pressure is formed in the negative pressure through hole, so that airflow passes through the guide through hole. The airflow flows from above the plate towards the direction of the corresponding hole on the fixture plate.

[0016] Thirdly, the present invention provides a circuit board laser drilling through-hole device, the device including a processor, a memory and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the method described above when it is executed.

[0017] Fourthly, the present invention provides a device for laser drilling through holes in circuit boards, the device comprising a machine base, a laser, and the aforementioned laser drilling device, wherein the laser drilling device is electrically connected to the laser.

[0018] The machine platform is used to place the processing materials;

[0019] The laser is used to generate the processing beam;

[0020] The laser drilling device is used to control the laser to operate according to the steps described above, so as to complete the laser processing of the plate.

[0021] The beneficial effects of the laser drilling method, system, apparatus, and equipment provided by this invention are as follows: When drilling a plate containing an adhesive layer or a plate that is not heat-resistant, a guide hole is first drilled at the target through hole to provide plasma and chip discharge space for the rotary drilling of the target through hole. A light-free period is set during the rotary drilling of the guide hole and the rotary drilling of the target through hole, which is also the cooling period inside the hole. This greatly reduces the heat accumulation inside the hole during the rotary drilling of the guide hole and the rotary drilling of the target through hole, and can significantly reduce the shrinkage of the inner wall of the target through hole and the depth of the inner wall crack. Attached Figure Description

[0022] Figure 1 This is a flowchart of a laser drilling method for through holes according to the present invention;

[0023] Figure 2 This is a schematic diagram of the entire drilling process in the method of the present invention;

[0024] Figure 3 This is another schematic diagram of the entire drilling process in the method of the present invention;

[0025] Figure 4 This is a cross-sectional view of the guide hole width annular groove rotary drilling in the method of the present invention;

[0026] Figure 5 This is a schematic diagram of the cross-sectional formation of the guide hole in the method of the present invention;

[0027] Figure 6 This is a cross-sectional view of the guide hole in the method of the present invention;

[0028] Figure 7 This is a cross-sectional view of the narrow annular groove rotary drilling of the guide hole in the method of the present invention;

[0029] Figure 8 This is a schematic diagram of the target through-hole rotary cutting, reaming, and drilling process in the method of the present invention;

[0030] Figure 9This is another schematic diagram of the target through-hole rotary cutting, reaming, and drilling process in the method of the present invention;

[0031] Figure 10 This is a diagram showing the fit between the sheet metal and the fixture plate during the rotary cutting, enlarging, and drilling of the target through hole in the method of this invention.

[0032] Figure 11 This is a structural block diagram of a laser drilling system according to the present invention.

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 1. Target through hole; 2. Third motion trajectory; 3. First motion trajectory; 4. Second motion trajectory; 5. Guide hole; 6. First laser focal spot; 7. Second laser focal spot; 8. Thin-walled area; 9. Third laser focal spot; 10. Plate; 11. Second annular groove; 12. First annular groove; 13. Guide hole column; 14. Single laser focal spot; 21. Third annular groove; 22. Guide hole position; 33. Negative pressure through hole; 34. Fixture plate. Detailed Implementation

[0035] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0036] like Figure 1 As shown, a method for laser drilling through holes includes the following steps:

[0037] Determine the axial position of the target through hole on the plate to be drilled. Using the axial position of the target through hole as the center, use a drilling laser to perform guide hole rotary drilling on the plate to obtain a guide hole with a radius of Rd.

[0038] Centered on the axis of the guide hole, the drilling laser is used to perform rotary cutting and enlarging drilling around the guide hole on the plate to obtain a target through hole with a diameter of D.

[0039] The board material is an adhesive board or a single or multi-layer composite material board with a softening temperature below 300 degrees Celsius.

[0040] In addition, the guide hole is a guide through hole or a guide blind hole.

[0041] The substrate can be a circuit board, but is not limited to circuit boards. It can also be any material with a softening temperature below 300 degrees Celsius, or a composite multilayer material containing a softening temperature below 300 degrees Celsius. For example, cutting and drilling PET material, rotary cutting and drilling prepreg, rotary cutting and drilling LCP (liquid crystal polymer, the most promising material for 5G circuit boards), cutting and drilling ferrite with organic protective films on both the upper and lower surfaces, etc.

[0042] The guide hole can be a through hole or a blind hole. When the guide hole is a through hole, the drilling laser drills through the material to obtain the through hole; when the guide hole is a blind hole, the drilling laser leaves the bottom layer of the material un-drilled. In this case, the blind hole can still provide plasma chip removal and heat dissipation space for the drilling laser to enlarge the target through hole. The purpose of not drilling through the material is to reduce the drilling time of the target through hole.

[0043] Preferably, during the rotary drilling process of the guide hole, the drilling laser performs a rotary cutting motion with two concentric circular trajectories to cut out the guide hole.

[0044] Preferably, the drilling laser performs a rotary cutting motion along two concentric circular trajectories, and the specific process of rotary cutting out the guide hole is as follows:

[0045] The axial center position of the target through hole is determined on the plate. The laser focus spot center of the drilling laser is centered on the axial center position of the target through hole, and a rotary cutting motion with concentric circular trajectories of radii R1 and R2 is performed on the plate to obtain the guide hole.

[0046] Wherein, R1≤R2, Rd=R2+r2, and R2-R1≤r1+r2, r1 is the effective spot radius when the drilling laser drills the circular trajectory of the guide hole cutting radius R1, and r2 is the effective spot radius when the drilling laser drills the circular trajectory of the guide hole cutting radius R2.

[0047] The drilling laser performs a rotary cutting of concentric circular trajectories with radii R1 and R2 on the plate material in an alternating rotary cutting manner, and the order and number of alternating rotary cuttings can be set arbitrarily.

[0048] In this specific embodiment, the board material is a circuit board comprising at least two copper layers and one adhesive layer; Figure 2 This is a schematic diagram illustrating the entire drilling process in the method of the present invention. Figure 2 In the figure, 10 refers to the board material, which is specifically a multilayer circuit board with a structure from top to bottom of "copper-PI-adhesive-PI-copper-adhesive-PI-copper", where PI is polyimide material and the adhesive is a semi-cured adhesive used in the circuit board industry; in this embodiment, the thickness of the board material 10 is 330 micrometers.

[0049] In this specific embodiment, the method steps of the present invention are as follows:

[0050] The first step is to obtain the laser processing drawings;

[0051] Determine the target through-hole diameter D set in the laser processing drawing file, i.e. Figure 2In the figure, 1 is the target through hole, and the diameter of the target through hole 1 is D. In this specific embodiment, D is 150 micrometers.

[0052] Determine the radii R1 and R2 of the rotary drilling parameters for the guide hole, such as... Figure 2 As shown, 5 is the guide hole, 4 is the first motion trajectory of the center of the laser focus spot when the guide hole 5 is rotated to cut a circular trajectory with radius R1 by the drilling laser, the first motion trajectory 4 is a circle with radius R1, and 3 is the second motion trajectory of the center of the laser focus spot when the guide hole 5 is rotated to cut a circular trajectory with radius R2 by the drilling laser, the second motion trajectory 3 is a circle with radius R2.

[0053] Determine the radius parameter R of the target through hole 1 by rotary cutting and enlarging, such as Figure 2 As shown, 2 is the third motion trajectory of the center of the laser focal spot when the laser drills the target through hole 1 to rotate and enlarge the circular trajectory with radius R. The third motion trajectory 2 is a circle with radius R.

[0054] The radius parameters R1, R2, and R are the distances from the laser focus spin-cutting motion center to the center of the laser focus spot on the corresponding spin-cutting path, respectively. In this embodiment, the laser focus spin-cutting motion center is the axis of the target through hole 1. Theoretically, the guide hole 5 is coaxial with the axis of the target through hole 1.

[0055] During the rotary drilling of the guide hole 5 and the rotary reaming of the target through hole 1, the laser parameters for different rotary cutting paths can be different. Therefore, the effective spot radius of the drilling laser varies depending on the path. When the drilling laser drills the circular trajectory of the guide hole 5 with a rotary cutting radius R1, the effective spot radius of the drilling laser is r1. Figure 2 As shown, 6 is the first laser focal spot when the drilling laser drills the circular trajectory of the guide hole 5 with a radius of R1. The first laser focal spot 6 is a solid circle with a radius of r1. When the drilling laser drills the circular trajectory of the guide hole 5 with a radius of R2, the effective spot radius of the drilling laser is r2. Figure 2 As shown, 7 is the second laser focal spot when the drilling laser drills the circular trajectory of the guide hole 5 with a cutting radius R2. The second laser focal spot 7 is a solid circle with a radius of r2. When the drilling laser performs a circular trajectory of the target through hole 1 with a cutting radius R, the effective spot radius of the drilling laser is r, as shown. Figure 2 As shown, 9 is the third laser focal spot when the target through hole 1 is rotated and enlarged in a circular trajectory with a radius R during drilling. The third laser focal spot 9 is a solid circle with a radius r.

[0056] Therefore, we can know that the radius of the guide hole 5 is Rd = R2 + r2.

[0057] The parameters satisfy the following relationship:

[0058] D=2*(R+r); R2-R1≤r1+r2; R-R2≤r+r2+⊿;

[0059] like Figure 2 As shown, the thickness of the thin-walled region 8 between the target through hole 1 and the guide hole 5, which is separated by the drilling laser cutting, is ⊿.

[0060] The second step involves the laser focal spot of the drilling laser rotating and cutting within the guide hole 5 in a circular trajectory with radii R1 and R2, centered on the axis of the target through hole 1 on the plate 10, until the guide hole 5 is drilled through or a guide blind hole is generated. In this embodiment, the guide hole 5 is a guide through hole, but it can also be a guide blind hole. At this point, the plate is not drilled through. The un-drilled portion of the material is generally a relatively heat-resistant material, and in the final stage of enlarging the target through hole, a traditional drilling method can be used to directly rotate and cut through it.

[0061] For example, in Figure 2 In the process, the first motion trajectory 4, the second motion trajectory 3, and the third motion trajectory 2 are all concentric circles centered on the axis of the target through hole 1. The first laser focus spot 6 of the drilling laser rotates along the first motion trajectory 4 to drill the hole. After rotating one revolution, the laser focus switches to the second motion trajectory 3, and the second laser focus spot 7 of the drilling laser rotates along the second motion trajectory 3 to drill the hole. At this time, the laser pulse energy of the drilling laser can be the same or different. If the laser pulse energy of the drilling laser is different, then r1 ≠ r2; if the laser pulse energy of the drilling laser is the same, then r1 = r2. The radius difference between the first motion trajectory 3 and the second motion trajectory 4 is as follows: R2 - R1 ≤ r1 + r2. This ensures that the inner and outer circles of the drilling laser rotation maintain a certain degree of overlap, such as... Figure 4 11 is a second annular groove formed on the plate 10 by the second laser focal spot 7 along the second motion trajectory 3; 12 is a first annular groove formed on the plate 10 by the first laser focal spot 6 along the first motion trajectory 4; the second annular groove 11 and the first annular groove 12 may partially overlap.

[0062] The alternating rotary cutting motion of the guide hole 5 refers to the following process: after the first laser focus spot 6 rotates one or more times on the first motion trajectory 4, the laser focus switches to the second motion trajectory 3 and rotates one or more times with the second laser focus spot 7. Then, the laser focus returns to the first motion trajectory 4, completing one cycle of alternating rotary cutting. Then, the laser focus continues to rotate a predetermined number of times on the first motion trajectory 4 with the first laser focus spot 6, entering the next round of rotary cutting. A typical approach is to first rotate one time with the first laser focus spot 6 on the first motion trajectory 4, then switch the laser focus to the second laser focus spot 7 and rotate one time on the second motion trajectory 3, before returning to the first motion trajectory 4 for the next alternating rotary cutting. Alternatively, it is also possible to first rotate on the second motion trajectory 3, then on the first motion trajectory 4, and so on, alternating between the two. In fact, the rotary cutting parameters on the second motion trajectory 3 and the first motion trajectory 4, including rotary cutting speed, number of rotary cutting turns, laser pulse energy, laser pulse repetition frequency, etc., can be set independently and combined to form a round of rotary cutting of the guide hole 5. Subsequently, the guide hole 5 is cyclically cut multiple times according to this cycle until the guide hole 5 is drilled through or a guide blind hole is obtained.

[0063] The cyclic cutting refers to completing one round of cutting within a single guide hole, and then switching the drilling laser to other guide holes to perform corresponding cutting within those guide holes, until multiple guide holes have completed their corresponding cutting, thus completing one cyclic cutting. After one or more cyclic cuttings, the drilling of a series of guide holes is completed.

[0064] The third step involves the laser's focal spot center rotating around the guide hole 5 in a circular trajectory with a radius of R, centered on the guide hole 5, to enlarge the target through hole 1. During the enlargement and enlargement process, after every N rotations, a cooling time (no light within the hole) is set, generally recommended to be at least 100 microseconds, before proceeding to the next round of enlargement and enlargement of the target through hole 1, until the plate 10 is drilled through, where N≥1. During the enlargement and enlargement process of the target through hole 1, the plasma sparks generated by the laser enlargement and enlargement can be ejected towards the hole opening on the plate surface, and the plasma explosion wave generated by the laser focal enlargement and enlargement can break through the thin-walled region 8 with a thickness of Δ between the guide hole and the target through hole, allowing the plasma sparks generated by the laser enlargement and enlargement to also be ejected into the guide hole 5, generally Δ≤10 micrometers.

[0065] The radius difference between the radius R of the third motion trajectory 2 and the radius Rd of the guide hole 5 is less than the sum of the radius r of the third laser focal spot 9 and the thickness Δ of the thin-walled region 8. This can be expressed by the formula: R-Rd=R-(R2+r2)≤r+Δ. It can also be expressed by the radius difference between the third motion trajectory 2 and the second motion trajectory 3: R-R2≤r+r2+Δ. This ensures that during hole enlargement, the outer side of the third laser focal spot 9 is inside the guide hole 5, or the third laser focal spot 9 can break through or blast the thin-walled region 8 with a thickness of Δ towards the guide hole 5. This facilitates the discharge of high-temperature plasma and debris from rotary cutting and hole enlargement, and greatly reduces the shrinkage and number of cracks on the inner wall of the target through hole after completion.

[0066] During the rotary cutting and enlarging process of the drilling guide hole 5 and the target through hole 1, the laser parameters of different rotary cutting paths can be the same, and the effective laser spot radius of the same laser parameters is the same.

[0067] In this embodiment, the thickness of the plate 10 is 330 micrometers, the diameter D of the target through hole 1 is 150 micrometers, R = 67.5 micrometers, the rotary cutting radius R2 is 50 micrometers, the rotary cutting radius R1 is 30 micrometers, r1 = r2 = 10 micrometers, r = 7.5 micrometers, and Δ = 0. The diameter Rd of the guide through hole 5 is 60 micrometers.

[0068] To further understand the method of the present invention, the rotary drilling of the guide hole is further described.

[0069] When the focal spot of the drilling laser alternately spins and cuts concentric circular trajectories with radii R2 and R1, the order can be reversed. During each round of cutting, the processing parameters such as the number of laser spins and / or the spin speed corresponding to the R1 and R2 paths can be determined as needed.

[0070] like Figure 3 As shown, the drilling laser can first spin along the first motion trajectory 4 and then jump to the second motion trajectory 3 for further spin cutting; or it can first spin along the second motion trajectory 3 and then jump to the first motion trajectory 4 for further spin cutting. The number of spin cuts, the spin cutting speed, and the drilling laser parameters on the first and second motion trajectories 4 and 3 can all be set independently. For convenience, the number of spin cuts and the spin cutting speed can generally be set to the same parameters. It is generally best to spin continuously one or two times on one path before jumping to the other path.

[0071] like Figure 4As shown, 11 is the second annular groove processed on the plate 10 by the second laser focal spot 7 along the second motion trajectory 3; 12 is the first annular groove processed on the plate 10 by the first laser focal spot 6 along the first motion trajectory 4; the second annular groove 11 and the first annular groove 12 together form a relatively wide annular groove, which facilitates the ejection of the bottom material of the second annular groove 11 and the first annular groove 12 under the action of the first laser focal spot 6 and the second laser focal spot 7, and reduces the explosive impact and heating of the first laser focal spot 6 and the second laser focal spot 7 on both sides of the bottom of the groove, reducing the cracks and shrinkage of the adhesive layer on the inner side of the guide hole 5, or the shrinkage of other soft and low-temperature materials. 13 is the guide hole column formed in the middle of the guide hole 5 without laser processing. Under the action of the first laser focal spot 6 and the second laser focal spot 7, the second annular groove 11 and the first annular groove 12 will be drilled through by rotary cutting, and the guide hole column 13 will lose its support and leave its original position within the guide hole 5, such as Figure 5 As shown, the guide hole post 13 disappears, forming a cavity, ultimately forming... Figure 6 The guide hole position is 22, corresponding to Figure 2 5. Middle guide hole.

[0072] For some special high-temperature adhesive circuit boards, the second motion trajectory 3 and the first motion trajectory 4 can coincide, and the first laser focal spot 6 and the second laser focal spot 7 can coincide, resulting in a narrow circular groove cross-section as shown in the image. Figure 7 As shown, in this case, the temperature inside the annular groove is relatively high when the drilling laser is rotary cutting the annular groove, so it is only suitable for laser drilling of some circuit boards that use high-temperature adhesive.

[0073] Figure 7 The single-path rotary cutting method using a single laser focus spot 14 along a single cutting radius path has a significant drawback: when the single laser focus spot 14 interacts with the bottom material of the substrate 10, it generates a plasma explosion shock wave, similar to a depth charge, impacting the bottom and sides of the groove. This can easily accumulate heat, causing shrinkage or impact cracks on the sidewalls of the guide holes. If the cracks are too deep, they can lead to cracks in the sidewalls of the target through-holes, resulting in plating solution remaining in the cracks after plating, causing reliability issues for the circuit board. Therefore, this single-path rotary cutting method is only suitable for some substrates using high-temperature resistant adhesives, and it is best to set a cooling time for the rotary cutting and drilling within the guide hole 5. Of course, during the cooling time of this guide hole, the drilling laser can process other guide holes under the switching of the scanning galvanometer, and after completing a certain amount of processing or processing time, it returns to this guide hole for the next round of rotary cutting and drilling; this cycle is repeated until the guide hole is drilled through.

[0074] On the other hand, it is recommended that most circuit boards use pilot hole drilling. Figure 4 The combined path rotary cutting grooving method shown reduces the impact effect of the drilling laser focus at the bottom of the deep groove on the guide hole sidewall, thereby reducing the number and depth of cracks in the guide hole sidewall. The crack depth direction is perpendicular to the laser transmission direction.

[0075] Also, the description Figure 7 The drawback of this method is that for plates containing materials with low softening temperatures, a drilling method involving first drilling the guide hole 5 and then rotary cutting to enlarge the hole must be used. The drilling method of this invention avoids the plasma impact and high-temperature accumulation that occur inside the plate when drilling with the laser focus on relatively thick plates, which can lead to shrinkage and microcracks in the inner wall of the target through-hole due to the formation of an inner wall adhesive layer or a layer of heat-sensitive material.

[0076] Preferably, ⊿=0, R-R2≤r+r2.

[0077] like Figure 3 As shown; this ensures that when the target through hole 1 is enlarged and drilled, the outer side of the third laser focal spot 9 is inside the guide hole 5, which is absolutely convenient for the discharge of high-temperature plasma and debris during rotary cutting and enlargement, greatly reducing the impact and heating of the third laser focal spot 9 on the outer sidewall of the target through hole 1, thus greatly reducing the degree of shrinkage and the number of cracks on the inner wall of the target through hole.

[0078] Preferably, let the shrinkage size of the inner wall of the guide hole be X micrometers, and the radius of the guide hole be Rd, where Rd = R2 + r2, then Rd + XD / 2 ≤ 12 micrometers.

[0079] The purpose of this invention is to minimize shrinkage during through-hole drilling in multilayer boards. With the advent of the 5G era, the low dielectric constant materials used are not heat-resistant, with softening temperatures generally around 200-300 degrees Celsius, especially some adhesive materials and LCP (liquid crystal polymer) materials. Therefore, the shrinkage of the guide hole or the shrinkage of the heat-sensitive material layer must not exceed 12 micrometers of the inner wall of the final through-hole formed by hole enlargement; otherwise, the final target through-hole shrinkage exceeding 12 micrometers will be judged as a defective product. A more stringent standard is that the shrinkage after copper plating of the through-hole must be less than 12 micrometers, which is higher than the requirement of this invention. This is because new shrinkage is introduced during a series of processes before copper plating.

[0080] Preferably, during the rotary drilling process of the guide hole, a light-free period is set between each two adjacent cycles of rotary drilling.

[0081] The set time period of no light is actually used for cooling inside the hole, and the cooling time inside the hole can be set arbitrarily as needed.

[0082] Please see Figure 7 .if Figure 2In this context, R2 = R1, and the first laser focal spot 6 and the second laser focal spot 7 are combined into one, which is the same laser focal spot. Figure 7 The single laser focal spot 14 is used in the guide hole 5. During the rotary drilling process, the single laser focal spot 14 can perform the next round of rotary drilling at the guide hole 5 after one or more rotary cuts, and after the drilling laser in the hole can stop emitting light for a period of time (the cooling time in the hole). This process continues until the guide hole is completed.

[0083] For example, the drilling laser makes one revolution each along the first motion trajectory 4 and the second motion trajectory 3. The hole will cool down for a period of time, such as 200 microseconds or 1 millisecond. Then the drilling laser makes one revolution each along the first motion trajectory 4 and the second motion trajectory 3 again; and so on.

[0084] For example, the drilling laser makes N1 and N2 turns respectively according to the first motion trajectory 4 and the second motion trajectory 3. The hole will cool down for a period of time, such as 200 microseconds or 1 millisecond. Then the drilling laser will make N1 and N2 turns again according to the first motion trajectory 4 and the second motion trajectory 3 respectively; and so on. N1 and N2 are both greater than or equal to 1, and are not necessarily integers.

[0085] Preferably, during the rotary drilling process of the guide hole, and during the period of no light in the guide hole, the drilling laser is switched to another guide hole or another object to be processed for laser processing.

[0086] The laser processing here can be rotary drilling of the corresponding guide hole or other types of laser processing on the corresponding guide hole, such as laser cleaning.

[0087] Laser processing of other objects to be processed here includes, but is not limited to: cutting and drilling slotted holes, cutting and drilling non-functional holes in circuit boards (no processing requirements for the inner wall of the hole, only drilling through is required), cutting irregular curves, drilling positioning holes (no processing requirements for the inner wall of the hole, only drilling through is required), etc.

[0088] During the period of no light in the hole, the drilling laser can be switched by the scanning galvanometer to the corresponding guide hole drilling position of other target through holes to perform corresponding guide hole rotary cutting drilling or other types of laser processing. After the guide hole of other through holes has been rotary cut for a certain number of turns or for a certain period of time, or after other types of laser processing has been completed, the scanning galvanometer will switch back to the current guide hole to continue the next round of alternating rotary cutting drilling.

[0089] Please see Figure 7 .if Figure 2In this context, R2 = R1, and the first laser focal spot 6 and the second laser focal spot 7 are combined into one, which is the same laser focal spot. Figure 7 A single laser focal spot 14 is used. During the rotary drilling process of the guide hole 5, the single laser focal spot 14 can stop emitting light for a period of time (hole cooling time) after one or more rotary cuts. During this time, the drilling laser can be switched by the scanning galvanometer to other guide holes for a certain number of rotary cuts (or for a certain time), and then switched back by the scanning galvanometer to the original guide hole 5 for the next round of rotary drilling. The other guide holes can be one or more.

[0090] For example, the drilling laser makes N1 and N2 rotations respectively according to the first motion trajectory 4 and the second motion trajectory 3. The drilling laser is then switched by the scanning galvanometer to other guide holes for drilling. After a certain number of rotations or time, the drilling laser is switched back to the original guide hole by the scanning galvanometer, and again makes N1 and N2 rotations respectively according to the first motion trajectory 4 and the second motion trajectory 3. Then the drilling laser is switched to another location for processing, and the cycle continues, until all guide holes are processed. N1 and N2 are both greater than or equal to 1 rotation, but are not necessarily integers.

[0091] Preferably, during the rotary drilling process of the guide hole, a period of no light is set in the hole, that is, a cooling time stage is set in the hole during the rotary drilling of the guide hole. Under this premise, the rotary drilling of the guide hole only requires one circular path rotary drilling, R1 = R2.

[0092] In laser-guided hole drilling, due to the inclusion of an in-hole cooling time stage, and assuming controllable heat generation during laser-guided hole drilling, the laser only needs to perform a single circular path for cutting the through hole, where R1 = R2. Each round of laser cutting in the guided hole drilling process can consist of one or more rotations. This reduces laser processing time in the processing of some heat-resistant sheet materials.

[0093] Preferably, the specific process of rotary cutting, reaming, and drilling the target through hole is as follows:

[0094] The laser focus spot of the drilling laser is centered on the axis of the guide hole. It performs multiple intermittent rotary cutting and reaming motions with a radius of R around the guide hole on the plate until the plate is drilled through to obtain the target through hole.

[0095] Where D=2*(R+r), R-R2≤r+r2+⊿, 0≤⊿≤10 micrometers, r is the effective spot radius of the drilling laser when performing the target through hole rotary cutting and enlarging drilling motion, and ⊿ is the thickness of the thin-walled region between the target through hole and the guide hole.

[0096] The multi-round intermittent rotary cutting and reaming motion refers to the drilling laser making N rotations in the guide hole each time, followed by a period of no light in the hole, before the next round of rotary cutting and reaming motion is performed, where N≥1.

[0097] Preferably, during the process of rotary cutting and reaming drilling of the target through hole, and during the period of no light in the hole, the drilling laser is switched to another guide hole and rotated around the other guide hole to perform rotary cutting and reaming drilling of the corresponding target through hole.

[0098] When the drilling laser performs rotary cutting and reaming drilling on the target through hole 1, after each round of rotary cutting N (N≥1) turns, a time period of no light (cooling time in the hole) is set in the hole. The drilling laser can be switched by the scanning galvanometer to other target through holes to be reamed for target through hole reaming and rotary cutting motion. After a certain number of turns or time of reaming and rotary cutting, the scanning galvanometer will switch back to the target through hole to continue the next round of reaming and drilling motion.

[0099] Specifically, during the rotary reaming drilling process of target through-hole 1, after the drilling laser emits light and performs a certain number of rotary cuts or for a certain time, the laser emission is paused; or, after the drilling laser emits light and performs a certain number of rotary cuts or for a certain time at the target through-hole, the scanning galvanometer switches the laser to another target through-hole for rotary reaming. For this target through-hole, each time there is no light inside the hole, it means that the current round of reaming is complete, and the hole enters the cooling time phase. One round of reaming of target through-hole 1 can be one or more rotary cuts. Target through-hole 1 requires multiple rounds of rotary reaming drilling to be fully completed.

[0100] The setting of the cooling time period inside the target through hole greatly reduces the heat accumulation inside the target through hole during rotary cutting and reaming, so that the temperature inside the hole is always lower than the softening temperature of the material inside the target hole, or only a very small amount of material overheats, which greatly reduces the shrinkage of the target through hole or the shrinkage of heat-sensitive materials inside the hole.

[0101] exist Figure 8In the diagram, 21 is the third annular groove cut by the third laser focal spot 9 along the third motion trajectory 2. The outer side of the third annular groove 21 is the inner wall of the target through hole 1. The inner side of the third annular groove 21 is separated from the guide hole 5 by a thin-walled region 8 with a thickness of ⊿. When the third laser focal spot 9 is cutting and expanding the hole, the high-temperature plasma and chip explosion impact generated can push open the adjacent thin-walled region 8 with a thickness of ⊿ on the inner side of the plate 10, opening up the connection space between the third annular groove 21 and the guide hole position 22. This allows the high-temperature plasma and chips generated by the laser processing at the bottom of the third annular groove 21 to be discharged into the guide hole 5 in addition to being discharged into the hole opening. This greatly reduces the heating of the inner wall of the target through hole 1 by the high temperature generated during hole expansion, and can reduce the shrinkage of the inner wall of the target through hole.

[0102] Figure 9 and Figure 8 The difference lies in the fact that the thin-walled region 8 with a thickness of Δ, which was cut out between the guide hole 5 and the target through hole 1, does not exist, i.e., Δ = 0. Figure 2 The target through hole 1 is connected to the guide hole 5. When the third laser focal spot 9 is rotating and expanding the hole, the high-temperature plasma and chips generated are discharged into the guide hole 5 in addition to being discharged into the hole opening. This greatly reduces the heating of the side wall of the through hole 1 by the high temperature generated during hole expansion, as well as the impact of the explosion shock wave on the inner wall of the target through hole 1. It can maintain the integrity of the inner wall of the target through hole and reduce the shrinkage and crack depth of the inner wall of the target through hole.

[0103] Preferably, when the guide hole is a guide through hole, during the rotary cutting and reaming drilling process of the target through hole, a negative pressure space channel for discharging the debris from the rotary cutting and reaming drilling of the target through hole is provided under the guide through hole.

[0104] The negative pressure space channel is used for the discharge of debris from rotary drilling for through-hole enlargement.

[0105] When drilling through holes in a typical sheet metal, a jig plate is placed underneath the sheet metal. The jig plate has pre-machined holes of the same distribution, but with larger diameters. Below the jig plate is the machine's honeycomb plate platform, which is connected to the ventilation system. Therefore, after the guide hole 5 is machined, airflow will pass through the guide hole 5. The airflow flows from the top of the sheet metal towards the corresponding hole on the jig plate. In this way, the chips generated during the rotary cutting and reaming of the target through hole can be discharged downwards. At the same time, the discharge of chips also carries away the heat from the reaming process, which helps to reduce the temperature inside the hole and reduce the shrinkage of the hole wall after rotary cutting and reaming of the target through hole.

[0106] like Figure 10As shown, 34 is a fixture plate with a negative pressure through hole 33. The negative pressure through hole 33 communicates with the guide hole 5 drilled on the circuit board 10. The fixture plate 34 is placed on the honeycomb plate (not shown in the figure) of the drilling platform. The honeycomb plate is connected to the negative pressure equipment system. A negative pressure is formed in the honeycomb plate to adsorb and fix the fixture plate 34 and the board 10. Therefore, there is a negative pressure in the negative pressure through hole 33, which is conducive to the discharge of processing debris in the guide hole.

[0107] Preferably, the board material is a circuit board comprising at least two copper layers and one adhesive layer; during the process of rotary cutting and reaming drilling of the target through hole, after the rotary cutting and reaming movement depth passes the last adhesive layer in the drilling depth direction, different rotary cutting speeds and / or laser power are used to drill through the subsequent material layers on the board material.

[0108] The subsequent material layer is a relatively heat-resistant insulating layer and / or a metal layer.

[0109] The main purpose of this invention is to reduce the shrinkage of adhesive in drilling multilayer boards, especially the shrinkage problem after copper plating. Once the laser drilling has passed through the adhesive layer, the insulating and conductive materials of the subsequent circuit board are relatively heat-resistant materials. Therefore, relatively high laser power, relatively fast rotary cutting speed, and relatively many consecutive rotary cutting times can be used for rotary drilling, which can relatively improve the overall efficiency of through-hole drilling.

[0110] Preferably, during the process of rotary drilling of the guide hole and / or rotary drilling of the target through hole, the laser focus of the drilling laser is located on the surface and / or inside of the plate.

[0111] Preferably, during the rotary drilling of the guide hole and / or the rotary drilling of the target through hole, multiple laser focal points are set along the drilling depth direction, and the laser focal points decrease as the drilling depth increases; during the rotary drilling of the guide hole, each laser focal point corresponds to one or more alternating rotary cutting movements between different paths in the hole; or / and, during the rotary drilling of the target through hole, each laser focal point corresponds to one or more alternating rotary drilling movements between holes.

[0112] Generally, printed circuit boards containing adhesive are multilayer boards with considerable thickness, exceeding the focal depth of the drilling laser. Therefore, multiple laser focus positions need to be set during the drilling process. For example, if the board thickness is 200 micrometers, we can directly place the laser focus 100 micrometers below the board surface. If the board thickness is 400 micrometers, we can do the following: First, drill the pilot hole with the laser focus initially on the board surface; second, when the pilot hole cutting depth exceeds 100 micrometers, lower the laser focus by 100 micrometers; third, when the pilot hole cutting depth exceeds 200 micrometers, lower the laser focus by another 100 micrometers; fourth, when the pilot hole cutting depth exceeds 300 micrometers, lower the laser focus by another 100 micrometers, until the pilot hole is drilled through. At this point, the laser focus returns to the surface of the circuit board material to perform rotary drilling for the target through-hole. Rotary drilling for the target through-hole can be divided into the following steps: First, rotary drilling with the laser focus positioned 100 micrometers below the board surface; second, when the rotary drilling depth exceeds 200 micrometers, the laser focus drops to 200 micrometers, and the laser continues rotary drilling until the desired through-hole is drilled through. The laser focal depth is generally around 100 to 200 micrometers. Therefore, in actual board drilling, whether several laser focus positions need to be set can be predetermined in the software according to the actual drilling requirements.

[0113] Preferably, during the rotary drilling process of the guide hole, the drilling laser cuts out the guide hole in a spiral motion, or in alternating rotary cutting motions using two or more concentric circular trajectories.

[0114] The guide hole can be drilled by spiral motion to cut the guide hole 5, or by using two or more concentric circular trajectories to cut the guide hole.

[0115] Figure 2 The laser focusing spot center of the first motion trajectory 4 and the second motion trajectory 3 is used to spin-cut the trajectory, and a wide circular groove is made for drilling the guide hole. If the plate is relatively thin, such as below 200 micrometers or 300 micrometers, the first motion trajectory 4 and the second motion trajectory 3 can overlap, and the guide hole with an acceptable degree of shrinkage of the inner wall can also be processed.

[0116] When machining the guide hole, a wide circular groove can also be machined using a spiral, for example, a spiral with an inner radius of r1 and an outer radius of r2. This process can be repeated multiple times until the guide hole is machined.

[0117] When two or more concentric circular trajectories are used to cut the guide hole, the cutting process of any two adjacent concentric circular trajectories is the same as the process of cutting the guide hole using two concentric circular trajectories described above.

[0118] Preferably, during the rotary drilling of the guide hole and / or the rotary enlargement drilling of the target through hole, the laser parameters of the drilling laser on different rotary cutting paths are the same or different.

[0119] In another embodiment, such as Figure 11 As shown, the present invention provides a system for laser drilling through holes, the system comprising the following modules:

[0120] The guide hole rotary cutting and drilling module is used to determine the axial center position of the target through hole on the plate to be drilled, and to perform guide hole rotary cutting and drilling on the plate using a drilling laser with the axial center position of the target through hole as the center to obtain a guide hole with a radius of Rd.

[0121] The target through hole rotary cutting and enlarging drilling module is used to perform target through hole rotary cutting and enlarging drilling on the plate around the guide hole with the axis of the guide hole as the center, and to obtain a target through hole with a diameter of D.

[0122] The board material is an adhesive board or a single or multi-layer composite material board with a softening temperature below 300 degrees Celsius, and the guide hole is a guide through hole or a guide blind hole.

[0123] In another embodiment, the present invention provides a circuit board laser drilling through-hole device, the device including a processor, a memory and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed, implements the steps of the method described above.

[0124] In another embodiment, the present invention provides a device for laser drilling through holes in a circuit board, the device including a machine base, a laser, and the aforementioned laser drilling device, wherein the laser drilling device is electrically connected to the laser.

[0125] The machine platform is used to place the processing materials;

[0126] The laser is used to generate the processing beam;

[0127] The laser drilling device is used to control the laser to operate according to the steps described above, so as to complete the laser processing of the plate.

[0128] Specifically, the device may also include necessary imaging and displacement devices for alignment, optical path devices, etc.

[0129] The method, system, apparatus, and equipment for laser drilling through holes provided by this invention have the following advantages:

[0130] 1. When drilling through holes in plates with adhesive layers, a guide hole is first drilled at the target through hole to provide plasma and chip discharge space for the rotary drilling of the target through hole, which greatly reduces the heat accumulation in the hole during rotary drilling of the target through hole and significantly reduces the adhesive shrinkage and inner wall crack depth of the target through hole.

[0131] 2. The drilling of the pilot hole adopts different rotary cutting radius paths and the different paths meet a certain overlap rate, which can obtain a relatively wide rotary cutting annular groove, which facilitates the removal of the lower layer material before the pilot hole drill penetrates, avoids the deep-sea bomb effect of the laser focus inside the material during pilot hole drilling, and reduces heat accumulation and shrinkage and crack depth of the pilot hole sidewall during pilot hole drilling.

[0132] 3. When the target through hole is rotary cut and enlarged, multiple rounds of rotary cutting and drilling are used. Between adjacent rounds of rotary cutting and enlargement at the same target through hole, a time period of no light in the hole (in-hole cooling time) is set to cool the heat brought by each round of rotary cutting and enlargement drilling, further reducing the heat accumulation of laser drilling caused by the rotary cutting and enlargement of the target through hole, and further reducing the shrinkage of the target through hole wall after enlargement.

[0133] 4. Each guide hole corresponds to a negative pressure space channel for the discharge of chips from the rotary drilling of the target through hole. These chips are generated at extremely high temperatures. The negative pressure chip discharge channel further reduces the heat accumulation on the hole wall during the target through hole enlargement, thereby further reducing the shrinkage of the hole wall after the target through hole is enlarged.

[0134] Readers should understand that in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0135] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0136] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of laser drilling a via hole, characterized by: Includes the following steps, Determine the axial position of the target through hole on the plate to be drilled. Using the axial position of the target through hole as the center, use a drilling laser to perform guided through hole rotary drilling on the plate to obtain a guided through hole with a radius of Rd. Centered on the axis of the guide hole, the drilling laser is used to perform rotary cutting and enlarging drilling around the guide hole on the plate to obtain a target through hole with a diameter of D. The plate material is an adhesive plate or a single or multi-layer composite material plate with a softening temperature below 300 degrees Celsius; a guide through hole is first drilled at the target through hole to provide plasma and chip discharge space for the target through hole enlargement rotary drilling; During the process of rotary cutting and reaming drilling of the target through hole, a negative pressure space channel for the discharge of debris from rotary cutting and reaming drilling of the target through hole is provided below the guide through hole. The method for setting up the negative pressure space channel is as follows: a fixture plate is placed below the plate, and a negative pressure through hole is pre-machined on the fixture plate. The negative pressure through hole is connected to the guide through hole. The fixture plate is placed on the drilling platform honeycomb plate, and the drilling platform honeycomb plate is connected to the negative pressure equipment system. Then, a negative pressure is formed in the drilling platform honeycomb plate to adsorb and fix the fixture plate and the plate, thereby forming a negative pressure in the negative pressure through hole, allowing airflow to pass through the guide through hole. The airflow flows from above the plate towards the negative pressure through hole on the fixture plate.

2. The method of laser via drilling according to claim 1, characterized in that: During the rotary drilling process of the guide hole, the drilling laser performs a rotary cutting motion with two concentric circular trajectories to cut out the guide hole.

3. The method for laser drilling through holes according to claim 2, characterized in that: The drilling laser performs a rotary cutting motion along two concentric circular trajectories to cut out the guide hole. The specific process is as follows: The axial center position of the target through hole is determined on the plate. The laser focus spot center of the drilling laser is centered on the axial center position of the target through hole, and a rotary cutting motion with concentric circular trajectories of radii R1 and R2 is performed on the plate to obtain the guide through hole. Wherein, R1≤R2, Rd=R2+r2, and R2-R1≤r1+r2, r1 is the effective spot radius when the drilling laser drills the circular trajectory of the guide through hole with a cutting radius R1, and r2 is the effective spot radius when the drilling laser drills the circular trajectory of the guide through hole with a cutting radius R2. The drilling laser performs a rotary cutting of concentric circular trajectories with radii R1 and R2 on the plate material in an alternating rotary cutting manner, and the order and number of alternating rotary cuttings can be set arbitrarily.

4. The method for laser drilling through holes according to claim 3, characterized in that: If the shrinkage size of the inner wall of the guide hole is X micrometers, then Rd+XD / 2≤12 micrometers.

5. The method for laser drilling through holes according to claim 3, characterized in that: During the process of rotary drilling of the guide hole, a dark period is set in the hole between each two adjacent cycles of rotary drilling.

6. The method for laser drilling through holes according to claim 5, characterized in that: During the rotary drilling process of the guide through hole, and during the period of no light in the guide through hole, the drilling laser is switched to other guide through holes or other objects to be processed for laser processing.

7. The method for laser drilling through holes according to any one of claims 3 to 6, characterized in that: The specific process of rotary cutting, reaming, and drilling the target through hole is as follows: The laser focus spot of the drilling laser is centered on the axis of the guide hole. It performs multiple intermittent rotary cutting and reaming motions with a radius of R around the guide hole on the plate until the plate is drilled through to obtain the target through hole. Where, D=2*(R+r), R-R2≤r+r2+⊿, 0≤⊿≤10 micrometers, r is the effective spot radius of the drilling laser when performing the target through hole rotary cutting and enlarging drilling motion, and ⊿ is the thickness of the thin-walled region between the target through hole and the guide through hole; The multi-round intermittent rotary cutting and reaming motion refers to the drilling laser performing N rotary cuts inside the hole each time during the drilling process of the target through hole, followed by a period of no light inside the hole, before proceeding to the next round of rotary cutting and reaming motion, where N≥1.

8. The method for laser drilling through holes according to claim 7, characterized in that: During the process of rotary cutting and reaming drilling of the target through hole, and during the period of no light in the hole, the drilling laser is switched to other guide through holes and rotates around the other guide through holes to perform rotary cutting and reaming drilling of the corresponding target through hole.

9. The method for laser drilling through holes according to claim 7, characterized in that: The board material is a circuit board containing at least two copper layers and one adhesive layer; during the process of rotary cutting and reaming drilling of the target through hole, after the rotary cutting and reaming movement depth passes the last adhesive layer in the drilling depth direction, different rotary cutting speeds and / or laser power are used to drill through the subsequent material layers on the board material.

10. The method for laser drilling through holes according to claim 7, characterized in that: During the process of rotary drilling of the guide through hole and / or rotary drilling of the target through hole, the laser focus of the drilling laser is located on the surface and / or inside of the plate.

11. The method for laser drilling through holes according to claim 10, characterized in that: During the process of rotary drilling of the guide through hole and / or rotary drilling of the target through hole, multiple laser focus positions are set along the drilling depth direction, and the laser focus positions decrease as the drilling depth increases. During the guided through-hole rotary cutting drilling process, each laser focal point position corresponds to one or more alternating rotary cutting movements between different paths within the hole; or / and, During the target through-hole rotary cutting and reaming drilling process, each laser focal point position corresponds to one or more alternating reaming and rotary cutting movements between holes.

12. The method for laser drilling through holes according to claim 1, characterized in that: During the process of rotary drilling of the guide hole, the drilling laser cuts out the guide hole in a spiral motion, or in two or more concentric circular trajectories in turn.

13. The method for laser drilling through holes according to any one of claims 1 to 6, characterized in that: During the process of rotary drilling of the guide through hole and / or rotary drilling of the target through hole, the laser parameters of the drilling laser on different rotary cutting paths may be the same or different.

14. A system for laser drilling through holes, characterized in that: Includes the following modules, The guide through-hole rotary cutting and drilling module is used to determine the axial center position of the target through hole on the plate to be drilled, and to perform guide through-hole rotary cutting and drilling on the plate using a drilling laser with the axial center position of the target through hole as the center to obtain a guide through hole with a radius of Rd. The target through hole rotary cutting and enlarging drilling module is used to perform target through hole rotary cutting and enlarging drilling on the plate around the guide through hole with the axis position of the guide through hole as the center, and to obtain a target through hole with a diameter of D. The plate material is an adhesive plate or a single or multi-layer composite material plate with a softening temperature below 300 degrees Celsius; a guide through hole is first drilled at the target through hole to provide plasma and chip discharge space for the target through hole enlargement rotary drilling; During the process of rotary cutting and reaming drilling of the target through hole, a negative pressure space channel for the discharge of debris from rotary cutting and reaming drilling of the target through hole is provided below the guide through hole. The method for setting up the negative pressure space channel is as follows: a fixture plate is placed below the plate, and a negative pressure through hole is pre-machined on the fixture plate. The negative pressure through hole is connected to the guide through hole. The fixture plate is placed on the drilling platform honeycomb plate, and the drilling platform honeycomb plate is connected to the negative pressure equipment system. Then, a negative pressure is formed in the drilling platform honeycomb plate to adsorb and fix the fixture plate and the plate, thereby forming a negative pressure in the negative pressure through hole, allowing airflow to pass through the guide through hole. The airflow flows from above the plate towards the negative pressure through hole on the fixture plate.

15. A device for laser drilling through holes, characterized in that: It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed, implements the steps of the method as claimed in any one of claims 1 to 13.

16. A device for laser drilling through holes, characterized in that: It includes a machine base, a laser, and a laser drilling device as described in claim 15, wherein the laser drilling device is electrically connected to the laser. The machine platform is used to place the processing materials; The laser is used to generate the processing beam; The laser drilling device is used to control the laser to operate according to the steps of the method described in any one of claims 1 to 13, so as to complete the laser processing of the plate.

Images