A PCB laser group hole jump machining method and system based on thermal recovery constraint

Abstract

The application discloses a PCB laser group-hole jump processing method and system based on thermal recovery constraint, and the method comprises the following steps: selecting target holes in a PCB group-hole area according to PCB group-hole data; extracting hole parameters of each target hole, reading board material parameters and laser parameters of the PCB; calculating single-hole energy, thermal influence radius and thermal recovery time of the target hole; judging whether there is a thermal interference relationship between any two target holes; establishing a minimum processing time interval and an energy compensation model when the thermal recovery constraint is not met; generating a jump processing path based on the minimum processing time interval or the energy compensation model; and performing laser processing according to the jump processing path. The method can obviously reduce local thermal accumulation in high-density PCB group-hole laser processing, reduce hole wall carbonization, resin ablation, hole edge melting, hole diameter drift and copper foil warping, and improve the hole diameter consistency and hole wall quality of micro blind holes and high-density interconnection holes.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology for circuit boards, specifically to a method and system for laser-assisted hole skipping processing of PCBs based on thermal recovery constraints. Background Technology

[0002] With the development of AI servers, high-speed communication, advanced packaging, and high-density interconnect designs, PCB hole structures are trending towards smaller hole diameters, denser hole spacing, and a greater number of local holes. Traditional mechanical drilling is limited by tool diameter, tool wear, hole wall quality, and processing efficiency, making laser drilling an important method for micro-hole processing.

[0003] However, laser processing involves high energy density. If the traditional sequential path (such as...) is followed... Figure 4 As shown in the figure, continuous machining of adjacent holes using a serpentine or shortest path can lead to thermal effects between adjacent holes, causing problems such as hole wall carbonization, resin ablation, hole diameter drift, copper foil warping, interlayer damage, and decreased reliability.

[0004] For example, holes in PCBs and carrier boards include through-holes, blind vias, micro-blind vias, buried vias, conductive vias, and heat dissipation holes. Micro-blind vias in high-density interconnect structures typically have smaller diameters and smaller spacing. As wiring density and I / O density increase, hole processing relies more and more on lasers. Existing laser processing paths typically employ coordinate order, row-column order, serpentine paths, shortest path, or fixed jump-hole paths. These paths are superior in motion efficiency, but they do not fully consider the differences in thermal impact caused by variations in hole diameter, energy input, dielectric thickness, material thermal sensitivity, and copper layer distribution at different hole locations.

[0005] In high-density clustered hole regions, after a previous hole is laser-processed, a heat-affected zone (HAZ) forms around the hole due to the surrounding medium, resin, glass fiber, and copper foil. If the next hole is nearby and processed immediately, the HAZs of the two holes will overlap. Repeated occurrence of this process will lead to localized heat accumulation and loss of processing quality control. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a PCB laser group hole skipping processing method and system based on thermal recovery constraints. Without significantly reducing processing efficiency, the processing sequence and processing interval are reasonably arranged according to the thermal influence state of each hole, avoiding local heat accumulation caused by continuous heating of adjacent or near-adjacent holes.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Firstly, a method for laser-assisted hole skipping processing of PCBs based on thermal recovery constraints is provided, comprising the following steps: Based on the PCB hole data, select the target hole in the PCB hole area; Extract the hole parameters for each target hole, including at least the hole position coordinates, hole diameter, and hole spacing; Read the PCB board material parameters and laser parameters; Based on the hole parameters, plate parameters, and laser parameters, calculate the single-hole energy and heat-affected radius of the target hole. R i and heat recovery time t i ; Based on thermal influence radius R i and heat recovery time t i Combined with hole spacing L ij Determine whether there is thermal interference between any two target holes; For a pair of target holes that have thermal interference, establish a minimum processing time interval. Δt ij,min And the energy compensation model when the thermal recovery constraint is not satisfied; Based on minimum processing time interval Δt ij,min Alternatively, an energy compensation model can generate a skip processing path; Laser processing is performed according to the described skip processing path.

[0008] The method of this invention is not simply to "process PCB holes with laser", but to propose a group hole skipping path planning and processing control method with single hole thermal influence radius and thermal recovery time as constraints.

[0009] This PCB laser via skip processing method can significantly reduce local heat accumulation in high-density PCB via laser processing when processing micro-holes and vias in PCBs (HDI boards, IC carrier boards, packaging substrates and high-density interconnect boards). It also reduces hole wall carbonization, resin ablation, hole edge melting, hole diameter drift and copper foil warping, and improves the hole diameter consistency and hole wall quality of micro-blind vias and high-density interconnect vias.

[0010] Furthermore, the process includes online quality inspection and feedback correction steps after laser processing to obtain the hole diameter deviation, hole opening carbonization range, hole wall quality, or temperature changes after laser processing, and to update the thermally affected radius of subsequent target holes. R i Heat recovery time t i And energy compensation models.

[0011] Furthermore, for continuous laser processing or equivalent continuous laser processing, the input model for single-hole energy...E i The expression is as follows: E i = or i ×P i × t i , In the formula, or i For energy coupling efficiency, P i The average power of the laser. t i The duration of action or dwell time for a single target hole; For pulsed laser processing, the input model for single-hole energy E i The expression is as follows: E i = or i ×e i × n i , In the formula, e i For single-pulse energy, n i To act on the first i The number of pulses per target aperture.

[0012] Furthermore, the thermal influence radius R i Indicates the first i After laser processing of one target hole, the thermal radius of influence on the processing quality of adjacent target holes along the PCB board surface direction. R i The computational model is expressed as follows: R i = D i / 2+ R 0 ×a( G i )×c( C i )×( E i / E 0 ) α × ( H 0 / H i )β , In the formula, D i The diameter of the target hole; R 0 The reference thermal influence radius; a( G i ) is the correction factor for the thermal sensitivity level of the PCB material; c( C i ) represents the copper layer distribution correction factor for the PCB; E 0 As a reference single-hole energy input, E i Energy per pore; H 0 α is the reference medium thickness; α is the energy correction index; β is the thickness correction index.

[0013] Furthermore, heat recovery time t i Indicates the first i After the target hole is machined, the time required for its heat-affected zone to recover to the state that allows adjacent holes to be machined is called the heat recovery time. t i The computational model is expressed as follows: t i = t 0 × b(G i ) × q(C i ) ×( R i / R 0 ) 2 ×( H i / H 0 ) γ , in, t 0 As the baseline thermal recovery time, b(G i ) This is the thermal recovery correction factor for the PCB material. q(C i ) γ is the thermal recovery correction factor corresponding to the copper layer distribution of the PCB; γ is the thickness recovery index.

[0014] Furthermore, when the thermally affected radii of two target holes overlap, a thermal interference relationship is determined, and a thermal interference degree is established based on the degree of overlap of the thermally affected areas.I ij Minimum processing time interval Δt ij,min With thermal interference I ij Linear correlation; when L ij When the sum of the thermal influence radii of adjacent target holes is greater than or equal to the sum of their thermal influence radii, I ij A value of 0 indicates no additional heat recovery waiting time.

[0015] Furthermore, when processing cannot be performed under the constraint of production line cycle time and the minimum processing time interval cannot be completely waited for, the laser energy of the subsequent target hole is compensated. The energy compensation model is expressed as follows: E j ' = E j ×[1 - k × I ij ×max(0, 1 - Δt actual / Δt ij,min )], in, E j ' For the compensated single-hole energy input, k For compensation coefficient, Δt actual This is the actual interval time. I ij For thermal interference, E i This represents the energy at a single pore.

[0016] Furthermore, the method for generating skip-processing paths includes the following steps: Construct a thermal interference map of the PCB via area; Set jump processing path constraints based on the aforementioned thermal interference map; Establish the path cost function; When adopting a batch-based skip strategy, for a regular matrix array of holes, the hole positions of the group holes are divided into multiple batches. When the thermal interference between the hole positions in each batch is low, the batches are revisited for supplementary processing. When adopting a local rearrangement strategy, if the next target hole does not meet the thermal recovery constraint, an alternative hole position is searched within the candidate window. The candidate window consists of the K future hole positions or unprocessed hole positions within the same group of holes. The hole position with the lowest path cost function and that meets the thermal recovery constraint is selected as the next processing target hole.

[0017] Secondly, a PCB laser group hole skipping processing system based on thermal recovery constraints is provided to realize the PCB laser group hole skipping processing method based on thermal recovery constraints as described above. The system includes the following modules: The hole data acquisition module is used to import hole parameters, plate parameters, and laser parameters; The thermal parameter calculation module is used to calculate the single-hole energy and thermal influence radius of the target hole. R i and heat recovery time t i ; The thermal interference relationship construction module is used to determine whether there is a thermal interference relationship between any two target holes; The thermal recovery constraint generation module is used to establish the minimum processing time interval. Δt ij,min And the energy compensation model when the thermal recovery constraint is not satisfied; The jump path planning module generates jump-type processing paths; Laser processing control module, used to control the laser of the mechanism; The quality feedback correction module is used to obtain the aperture deviation, orifice carbonization range, orifice wall quality or temperature change after laser processing, and update the thermally affected radius of subsequent target holes. R i Heat recovery time t i And energy compensation models.

[0018] Thirdly, a non-transitory computer-readable storage medium is provided, the non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the PCB laser group hole skipping processing method based on thermal recovery constraints as described above.

[0019] An execution device includes a processor and a memory, the processor being coupled to the memory; the memory is used to store a program; the processor is used to execute the program in the memory, causing the execution device to perform the PCB laser group hole skipping processing method based on thermal recovery constraints as described above.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. The PCB laser group hole skipping processing method calculates the heat-affected radius of each target hole in the PCB group hole area individually. R i and heat recovery time t iThis method generates a skip-processing path based on thermal recovery constraints, preventing adjacent thermally interfering holes from being processed continuously or meeting the minimum thermal recovery time. When the thermal recovery time cannot be met, compensation is made for laser power, pulse number, repetition frequency, dwell time, focal position, or number of processing operations. This significantly reduces local heat accumulation in high-density PCB group hole laser processing, reducing hole wall carbonization, resin ablation, hole edge melting, hole diameter drift, and copper foil warping, and improving the hole diameter consistency and hole wall quality of micro blind holes and high-density interconnect holes. 2. Compared with global waiting for cooling, this PCB laser group hole skip-processing method can balance processing efficiency under local thermal recovery constraints. 3. Compared with fixed skip holes, it can adaptively adjust according to hole diameter, energy, thickness, material thermal sensitivity, and copper layer distribution. 4. This method can be embedded in existing PCB laser drilling equipment, CAM path planning software, or host computer control systems. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating a PCB laser group hole skipping processing method based on thermal recovery constraints according to the present invention. Figure 2 This is a schematic diagram illustrating the relationship between the heat-affected radius and thermal interference of the present invention; Figure 3 This is a schematic diagram of the calculation model for the heat-affected radius and heat recovery time of the present invention; Figure 4 This is a schematic diagram of the conventional sequential processing in the prior art, where adjacent holes are continuously heated; Figure 5 This is a schematic diagram of the skip processing path of the present invention, showing dispersed heating under thermal recovery constraints; Figure 6 This is a schematic diagram of the architecture and data flow of the PCB laser group hole skipping processing system based on thermal recovery constraints according to the present invention. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: A method for skip-type laser hole processing of PCBs based on thermal recovery constraints is provided, combined with... Figure 1 As shown, it includes the following steps: S100: Import PCB hole data; S200: Based on the PCB hole data, select target holes in the PCB hole region; extract the hole parameters for each target hole, including at least the hole position coordinates ( xi , y i ), aperture D i and hole spacing L ij ; S300: Reads PCB board material parameters and laser parameters; S400: Calculate the single-hole energy of the target hole based on the hole parameters, plate parameters, and laser parameters. S500: Further calculate the heat-affected radius R i and heat recovery time t i ; S600: Constructing thermal interference relationships: based on thermal influence radius R i and heat recovery time t i Combined with hole spacing L ij Determine whether there is thermal interference between any two target holes; S700: Generate thermal recovery constraint: For a pair of target holes with thermal interference, establish a minimum processing time interval. Δt ij,min And the energy compensation model when the thermal recovery constraint is not satisfied; S800: Based on minimum processing time interval Δt ij,min Alternatively, an energy compensation model can generate a skip processing path; S900: Perform laser processing according to the described skip processing path; S1000: Online quality inspection: Obtains hole diameter deviation, hole opening carbonization range, hole wall quality, or temperature change after laser processing; S1100: Feedback Correction Model: Updates the thermal influence radius of subsequent target holes. R i Heat recovery time t i And energy compensation models.

[0024] This PCB laser-assisted multi-hole skipping processing method calculates the thermal impact radius of each target hole within the PCB multi-hole area individually. R i and heat recovery time t iBased on thermal recovery constraints, a skip processing path is generated to prevent adjacent thermally interfering holes from being processed continuously or to meet the minimum thermal recovery time. When the thermal recovery time cannot be met, compensation is made for laser power, pulse number, repetition frequency, dwell time, focal position, or number of processing times. This can significantly reduce local heat accumulation in high-density PCB group hole laser processing, reduce hole wall carbonization, resin ablation, hole edge melting, hole diameter drift, and copper foil warping, and improve the hole diameter consistency and hole wall quality of micro blind holes and high-density interconnect holes.

[0025] This PCB laser-assisted skip-hole drilling method, compared to global waiting for cooling, can balance processing efficiency under the constraint of local thermal recovery. Compared to fixed skip-hole drilling, it can adaptively adjust according to hole diameter, energy, thickness, material thermal sensitivity, and copper layer distribution. It can be embedded into existing PCB laser drilling equipment, CAM path planning software, or host computer control systems.

[0026] Furthermore, the hole parameters, plate parameters, and laser parameters are all system inputs, while single-hole energy, heat-affected radius, heat recovery time, hole spacing, thermal interference, minimum time interval, etc. are all intermediate quantities. The skip processing path and compensation processing parameters (correcting power, pulse number, frequency, dwell time, etc. when waiting is insufficient) are all outputs.

[0027] Wherein, the hole position coordinates ( x i , y i Sources include CAM, drilling files, Gerber files, machine machining tasks, or manual input; hole diameter. D i Target dimensions include micro-blind holes, through holes, and heat dissipation holes; the plate parameters include dielectric thickness. H i Material heat sensitivity rating G i and copper layer distribution parameters C i The thickness of the medium can be obtained from the stack-up design, the plate database or the thickness measurement results. The material thermal sensitivity level is determined by Tg, Td, resin content, thermal conductivity, carbonization threshold, etc. The copper layer distribution parameters include data such as copper coverage around the target hole, copper thickness, copper ring, and copper layer position. The laser parameters (laser processing parameters) include power, pulse energy, pulse number, frequency, dwell time, and focal position.

[0028] Furthermore, for continuous laser processing or equivalent continuous laser processing, the input model for single-hole energy... E i The expression is as follows: E i = or i×P i × t i , In the formula, or i For energy coupling efficiency, P i The average power of the laser. t i The duration of action or dwell time for a single target hole; For pulsed laser processing, the input model for single-hole energy E i The expression is as follows: E i = or i ×e i × n i , In the formula, e i For single-pulse energy, n i To act on the first i The number of pulses per target hole.

[0029] If the average power is known P i With repetition frequency f i Then it can be adopted e i = P i / f i Perform the conversion; if there are multiple scans or multiple hole-opening processes, then n i It can be the sum of the number of pulses, or the accumulation of the energy inputs from each pulse.

[0030] Material thermal sensitivity rating G i This is used to characterize the sensitivity of PCB dielectric materials to temperature rise, carbonization, ablation, thermal deformation, and interlayer damage under laser irradiation. Material thermal sensitivity rating. G i It can be directly provided from the process database, or in some implementations it can be calculated from material parameters.

[0031] S i = w 1 · F Tg +w 2·F Td +w 3 ·F CTE +w 4 ·F resin +w 5 ·F k +w 6 ·F damage , In the formula, S i For thermal sensitivity rating, w 1 to w 6 As weight; F Tg , F Td , F CTE , F resin , F k , F damage These are normalization factors for glass transition temperature, thermal decomposition temperature, coefficient of thermal expansion, resin content, thermal conductivity, and damage threshold, respectively.

[0032] According to thermal sensitivity rating S i Materials can be classified into low-thermosensitive G1, medium-thermosensitive G2, and high-thermosensitive G3. An exemplary classification is shown in Table 1 below; the actual threshold is determined by the material system.

[0033] Table 1: Classification of Thermosensitive Grades

[0034] Furthermore, combined Figure 3 As shown, the heat-affected radius R i Indicates the first i The thermal radius that affects the processing quality of adjacent target holes in the direction of the PCB board surface after laser processing of one target hole. R i This includes not only the radius of the target hole itself, but also the thermal expansion distance beyond the edge of the hole.

[0035] thermal influence radius R i The computational model is expressed as follows: Ri = D i / 2+ R 0 ×a( G i )×c( C i )×( E i / E 0 ) α × ( H 0 / H i ) β , In the formula, D i The diameter of the target hole; R 0 The reference thermal influence radius; a( G i ) is the correction factor for the thermal sensitivity level of the PCB material; c( C i ) represents the copper layer distribution correction factor for the PCB; E 0 As a reference single-hole energy input, E i Energy per pore; H 0 The reference dielectric thickness is α; the energy correction index is α; and the thickness correction index is β. α can be taken from 0.3 to 0.8, and β can be taken from 0.2 to 1.0; the specific values ​​can be calibrated according to different PCB materials, laser wavelengths, pulse widths, and hole types.

[0036] Furthermore, heat recovery time t i Indicates the first i After a target hole is machined, the time required for its heat-affected zone to recover to the state permitted for machining adjacent holes. The permitted state can be defined as a temperature below a safe temperature threshold. T safe Or the risk of pore wall carbonization, pore diameter deviation, or interlayer damage is lower than the preset threshold.

[0037] Heat recovery time t i The computational model is expressed as follows: t i = t 0 × b(G i ) × q(C i) ×( R i / R 0 ) 2 ×( H i / H 0 ) γ , in, t 0 As the baseline thermal recovery time, b(G i ) This is the material thermal recovery correction factor for the PCB. q(C i ) γ is the thermal recovery correction factor corresponding to the copper layer distribution of the PCB; γ is the thickness recovery index. γ can be taken from 0.5 to 2.0, and the actual value can be calibrated based on thermal imager measurements, temperature sensors, finite element thermal simulations, or hole quality inspection results.

[0038] Furthermore, combined Figure 2 As shown, when the thermally affected radii of two target holes overlap, a thermal interference relationship is determined, and a thermal interference degree is established based on the degree of overlap of the thermally affected areas. I ij Minimum processing time interval Δt ij,min With thermal interference I ij Linear correlation; when L ij When the sum of the thermal influence radii of adjacent target holes is greater than or equal to the sum of their thermal influence radii, I ij A value of 0 indicates no additional heat recovery waiting time.

[0039] Specifically, the hole spacing between the i-th target hole and the j-th target hole L ij Calculate using the following formula: L ij =sqrt(( x i - x j ) 2 +( y i - y j ) 2 ), in,( x i , y i )and( xj , y j ) are the coordinates of the two target holes in the PCB machining coordinate system.

[0040] When the thermally affected radii of two holes overlap, it is determined that there is a thermal interference relationship between them: if L ij < R i + R j ,but P i and P j There is thermal interference. This judgment can be used to construct a thermal interference map, with the target hole as a node and hole pairs with thermal interference relationships as edges.

[0041] Thermal interference can be further defined. I ij : I ij = max(0, ( R i + R j - L ij ) / ( R i + R j )); I ij The value ranges from 0 to 1. I ij The larger the value, the greater the overlap between the heat-affected zones of the two holes, making them less suitable for continuous processing.

[0042] Furthermore, for two target holes that have a thermal interference relationship... P i and P j Minimum processing time interval can be established. D t ij,min Its model is as follows: Δt ij,min =max( t i , t j )× I ij δ , Wherein, δ is the thermal interference nonlinear correction index, which can be taken from 0.8 to 1.5; when δ=1, the minimum processing time interval is linearly related to the degree of thermal interference.

[0043] Expanding the above equation, we get: Δt ij,min =max(( t i , t j )×[1- L ij / ( R i + R j )] δ , when L ij ≥ R i + R j hour, I ij A value of 0 means no additional heat recovery waiting time will be added.

[0044] If directionality is considered, an asymmetric model can be used: Δ t i →j,min= t i × I ij δ , The above formula indicates that after processing P i Further processing P j The minimum required waiting time is mainly determined by P i The heat recovery time is determined by this.

[0045] Furthermore, when processing cannot be performed under the constraint of production line cycle time and the minimum processing time interval cannot be completely waited for, the laser energy of the subsequent target hole is compensated. The energy compensation model is expressed as follows: E j ' = E j ×[1 - k × I ij ×max(0, 1 - Δt actual / Δt ij,min )], in,E j ' For the compensated single-hole energy input, k For compensation coefficient, Δt actual This is the actual interval time. I ij For thermal interference, E i This represents the energy at a single pore.

[0046] Energy compensation can be achieved by reducing laser power, reducing the number of pulses, reducing single pulse energy, changing the repetition frequency, shortening the dwell time, adjusting the focal position, or increasing the number of processing steps.

[0047] Furthermore, to enhance engineering feasibility, in addition to formulaic models, lookup table and interpolation models can also be used. The equipment controller can pre-store data based on experimental calibration. R i and t i The parameter table is shown in Table 2 below.

[0048] Table 2: R i and t i Parameter table

[0049] When the input parameters lie between adjacent intervals in the table, linear interpolation, bilinear interpolation, multidimensional interpolation, or piecewise fitting can be used to determine the parameters. R i and t i This method is suitable for deployment of embedded controllers, PLCs, motion control cards, or device software.

[0050] Furthermore, combined Figure 4 and Figure 5 As shown, the goal of the skip-processing path is to maximize processing efficiency while avoiding continuous processing of holes due to thermal interference. This invention can be implemented using methods such as graph models, batch partitioning, greedy search, heuristic path optimization, constraint programming, or local rearrangement.

[0051] The method for generating skip-processing paths includes the following steps: (1) Construct a thermal interference map of the PCB via area; Let the set of target holes in the PCB hole cluster region be represented as V={P1,P2,...,P...} N}.like P i and P j satisfyL ij < R i + R j Then a thermal interference edge e is established between the two. ij Thus, the thermal interference map G is obtained. T =(V,E T ).

[0052] Thermal interference maps can be used to quickly determine which holes should not be machined immediately after a certain hole location has been machined, and which holes can be prioritized for skipping.

[0053] (2) Set jump processing path constraints based on the thermal interference map; Let the processing path be π = {P1, P2, ..., P}. N}, p k For the k-th target hole to be processed, the path should satisfy one of the following constraints: I pk ,p {k+1} ≤I th , That is, the thermal interference between two holes processed in succession is below the threshold.

[0054] Or: T(p) {k+1} )-T(p k )≥Δt pk ,p {k+1} ,min, That is, when thermal interference exists, the processing time of the post-processed hole position meets the minimum thermal recovery time interval.

[0055] (3) Establish the path cost function; To balance motion efficiency and thermal recovery quality, a path cost function is established: Cost(i,j) =λ1·( L ij / L 0 )+λ2· I ij +λ3·( W ij / τ0)+λ4· Q j , in, L ij The distance between the holes is represented here, relative to the distance traveled. I ij For thermal interference, W ij This is the waiting time caused by insufficient heat recovery. Q jFor the hole location quality risk score, λ1 to λ4 are the weighting coefficients.

[0056] Waiting time item W ij It can be represented as: W ij =max(0, Δt ij,min - Δt actual ), When the actual interval is insufficient W ij If the value is positive, path planning will avoid selecting that hole or trigger a wait / compensation.

[0057] (4) When adopting a batch-based skip strategy, for a regular matrix array of holes, the hole positions are divided into multiple batches. When the thermal interference between the hole positions in each batch is low, the batches are revisited for supplementary processing. The batch division is determined by... R i , t i , L ij and I ij The decision is not based on fixed coordinate rules.

[0058] Select a group of holes with a lower risk of thermal interference from the unprocessed holes as the current batch; Process according to the movement distance or the local shortest path within the current batch; After processing is completed, check whether the holes that have thermal interference with the processed holes meet the thermal recovery time. Holes that meet the constraints are added to the next batch; holes that do not meet the constraints are postponed or parameter compensation is performed. Repeat the process until all target holes are machined.

[0059] (5) When adopting a local rearrangement strategy, if the next target hole does not meet the thermal recovery constraint, an alternative hole position is searched in the candidate window; the candidate window is the unprocessed hole position in the future K hole positions or the same group of holes, and the hole position with the lowest path cost function and meeting the thermal recovery constraint is selected as the next processing target hole.

[0060] This local rearrangement method facilitates modification based on the existing CAM path without completely reconstructing the global path, making it suitable for device-side software upgrades.

[0061] Furthermore, in steps 1000 and 1100, the heat-affected radius of subsequent holes can be updated in the following manner. R i Heat recovery time t i : R i，new = R i ×(1+ m R ×Δ Q i ), t i，new = t i ×(1+ m τ ×Δ Q i ), Where, Δ Q i This is a risk deviation index for hole quality. m R and m τ This is the feedback correction coefficient. When carbonization or excessively large pore size is detected, the system increases the heat-affected radius or heat recovery time, or reduces the energy input to subsequent pore sites.

[0062] Example 2: A PCB laser group hole skipping processing system based on thermal recovery constraints is provided to realize the PCB laser group hole skipping processing method based on thermal recovery constraints as described above.

[0063] Combination Figure 6 As shown, the system includes the following modules: The hole data acquisition module is used to import hole parameters, plate parameters, and laser parameters; The thermal parameter calculation module is used to calculate the single-hole energy and thermally affected radius of the target hole. R i and heat recovery time t i ; The thermal interference relationship construction module is used to determine whether there is a thermal interference relationship between any two target holes; The thermal recovery constraint generation module is used to establish the minimum processing time interval. Δt ij,min And the energy compensation model when the thermal recovery constraint is not satisfied; The jump path planning module generates jump-type processing paths; Laser processing control module, used to control the laser of the mechanism; The quality feedback correction module is used to obtain the aperture deviation, orifice carbonization range, orifice wall quality or temperature change after laser processing, and update the thermally affected radius of subsequent target holes. R i Heat recovery time t i And energy compensation models.

[0064] Example 3: A non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores computer instructions, the computer instructions causing the computer to execute the PCB laser group hole skipping processing method based on thermal recovery constraints as described above.

[0065] An execution device includes a processor and a memory, the processor being coupled to the memory; the memory is used to store a program; the processor is used to execute the program in the memory, causing the execution device to perform the PCB laser group hole skipping processing method based on thermal recovery constraints as described above.

[0066] Furthermore, it may also include processing equipment, which may include a laser, an optical path system, a galvanometer scanning system, an XY motion platform, a controller (processor), a memory, a vision positioning device, an aperture detection device, a temperature detection device, and a human-machine interface. The controller (processor) executes the program in the memory to realize the above-mentioned thermal recovery constraint modeling, jump path planning, and laser processing control.

[0067] This invention can be implemented as a software algorithm module for PCB laser processing equipment, or as independent CAM path optimization software, host computer control program, motion controller program, or embedded control program.

[0068] Input interfaces: CAM files, drilling files, Gerber files, equipment task files, material databases, and process parameter databases.

[0069] Output interfaces: skip processing path, hole processing sequence, laser parameter table, waiting time table, abnormal hole list.

[0070] Feedback interfaces include: aperture detection data, pore wall carbonization data, temperature data, platform position feedback, and laser energy feedback.

[0071] Example 4: This example uses the processing of micro blind vias on an HDI board as an example to further illustrate the processing method in Example 1.

[0072] A localized area on an HDI board contains multiple micro-blind vias with diameters of 50-80 μm, spacing of 80-150 μm, and dielectric thickness of approximately 40-60 μm. The laser type is either ultraviolet or picosecond laser. After importing the drilling file, the system identifies this area as a cluster of vias.

[0073] The system calculates the single-hole energy input for each micro-blind hole. E i And read the material's heat sensitivity rating from the sheet metal database. G i and medium thickness Hi The heat-affected radius is then determined using formulas or by looking up tables. R i and heat recovery time t i For hole spacing less than R i + R j Based on the hole positions, the system establishes a thermal interference relationship and generates a skip-processing path.

[0074] During processing, the system first processes holes that are far apart from each other, and then revisits adjacent holes. Compared with traditional row-column sequential processing, this approach can reduce the risk of hole wall carbonization and hole diameter enlargement caused by heating of consecutive adjacent holes.

[0075] The specific calculation process is as follows: Table 3 below shows several hole locations and their related parameters.

[0076] Table 3: Calculation Example Values

[0077] Let R0 = 30 μm, E0 = 0.50 mJ, H0 = 50 μm, τ0 = 20 ms, α = 0.5, β = 0.5, and γ = 1.0. G1 corresponds to a(G) = 0.9 and b(G) = 1.0; G2 corresponds to a(G) = 1.2 and b(G) = 1.4; for simplicity, the copper layer correction factor is taken as 1.

[0078] The heat-affected zone diameter of the target hole P1 is: R1 = 60 / 2 + 30 × 1.2 × (0.50 / 0.50) 0.5 ×(50 / 50) 0.5 =66μm, The thermal recovery time of the target hole P1 is: τ1 = 20 × 1.4 × (66 / 30) 2 ×(50 / 50) 1.0 =135.52ms, The heat-affected zone diameter of the target hole P2 is: R2 = 60 / 2 + 30 × 1.2 × (0.55 / 0.50) 0.5 ×(50 / 50) 0.5 ≈67.75μm, The thermal recovery time of the target hole P2 is: τ2 = 20 × 1.4 × (67.75 / 30) 2 ≈142.8ms The hole spacing L between P1 and P2 12 =85μm, while R1+R2=133.75μm, therefore P1 and P2 have a thermal interference relationship.

[0079] The thermal interference between P1 and P2 is: I 12 =(133.75-85) / 133.75≈0.364, The minimum processing time interval between P1 and P2 is: Δt 12,min =max(135.52,142.8)×0.364≈51.98ms, Therefore, after machining P1, the system does not directly machine P2, but jumps to P3 or other holes with lower thermal interference, and returns to machine P2 only after P2 meets the thermal recovery constraint of about 52 ms.

[0080] For carrier materials such as ABF and BT, the pore size is smaller and the pore density is higher, requiring higher standards for pore wall quality, pore bottom residue, and interlayer reliability. The system can handle materials with a thermal sensitivity rating of G. i Set to G2 or G3, and introduce copper coverage C. i As a correction parameter.

[0081] When the copper coverage in a certain area is high, the system adjusts c(C) according to the calibration table. i ) and q(C i If the copper layer increases the thermal expansion range, then increase R. i If the copper layer facilitates thermal recovery, then the τ period will be shortened. i The above adjustments are achieved through the process calibration table.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A PCB laser-based skip-hole processing method based on thermal recovery constraints, characterized in that, Includes the following steps: Based on the PCB hole data, select the target hole in the PCB hole area; Extract the hole parameters for each target hole, including at least the hole position coordinates, hole diameter, and hole spacing; Read the PCB board material parameters and laser parameters; Based on the hole parameters, plate parameters, and laser parameters, calculate the single-hole energy and heat-affected radius of the target hole. R i and heat recovery time τ i ; Based on thermal influence radius R i and heat recovery time τ i Combined with hole spacing L ij Determine whether there is thermal interference between any two target holes; For a pair of target holes that have thermal interference, establish a minimum processing time interval. Δt ij,min And the energy compensation model when the thermal recovery constraint is not satisfied; Based on minimum processing time interval Δt ij,min Alternatively, an energy compensation model can generate a skip processing path; Laser processing is performed according to the described skip processing path.

2. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, The laser processing procedure also includes online quality inspection and feedback correction steps, which obtain the hole diameter deviation, hole opening carbonization range, hole wall quality, or temperature change after laser processing, and update the heat-affected radius of subsequent target holes. R i Heat recovery time τ i And energy compensation models.

3. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, For continuous laser processing or equivalent continuous laser processing, the input model for single-hole energy is... E i The expression is as follows: E i = η i ×P i × t i ， In the formula, η i For energy coupling efficiency, P i The average power of the laser. t i The duration of action or dwell time for a single target hole; For pulsed laser processing, the input model for single-hole energy E i The expression is as follows: E i = η i ×e i × n i ， In the formula, e i For single-pulse energy, n i To act on the first i The number of pulses per target hole.

4. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, thermal influence radius R i Indicates the first i After laser processing of one target hole, the thermal radius of influence on the processing quality of adjacent target holes along the PCB board surface direction. R i The computational model is expressed as follows: R i = D i / 2+ R 0 ×a( G i )×c( C i )×( E i / E 0 ) α × ( H 0 / H i ) β , In the formula, D i The diameter of the target hole; R 0 The reference thermal influence radius; a( G i ) is the correction factor for the thermal sensitivity level of the PCB material; c( C i ) represents the copper layer distribution correction factor for the PCB; E 0 As a reference single-hole energy input, E i Energy per pore; H 0 The reference medium thickness is α; α is the energy correction index. β is the thickness correction index.

5. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, Heat recovery time τ i Indicates the first i After the target hole is machined, the time required for its heat-affected zone to recover to the state that allows adjacent holes to be machined is called the heat recovery time. τ i The computational model is expressed as follows: τ i = τ 0 × b(G i ) × q(C i ) ×( R i / R 0 ) 2 ×( H i / H 0 ) γ ， in, τ 0 As the baseline thermal recovery time, b(G i ) This is the thermal recovery correction factor for the PCB material. q(C i ) γ is the thermal recovery correction factor corresponding to the copper layer distribution of the PCB; γ is the thickness recovery index.

6. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, When the thermally affected radii of two target holes overlap, a thermal interference relationship is determined, and a degree of thermal interference is established based on the degree of overlap of their thermally affected areas. I ij Minimum processing time interval Δt ij,min With thermal interference I ij Linear correlation; when L ij When the sum of the thermal influence radii of adjacent target holes is greater than or equal to the sum of their thermal influence radii, I ij A value of 0 indicates no additional heat recovery waiting time.

7. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, When processing cannot proceed under the constraints of production line cycle time and the minimum processing interval cannot be waited for, laser energy compensation for subsequent target holes is performed. The energy compensation model is expressed as follows: E j ' = E j ×[1 - κ × I ij ×max(0, 1 - Δt actual / Δt ij,min )], in, E j ' For the compensated single-hole energy input, κ For compensation coefficient, Δt actual This is the actual interval time. I ij For thermal interference, E i This represents the energy at a single pore.

8. The PCB laser group hole skipping processing method based on thermal recovery constraint according to claim 1, characterized in that, The method for generating skip-processing paths includes the following steps: Construct a thermal interference map of the PCB via area; Set jump processing path constraints based on the aforementioned thermal interference map; Establish the path cost function; When adopting a batch-based skip strategy, for a regular matrix array of holes, the hole positions of the group holes are divided into multiple batches. When the thermal interference between the hole positions in each batch is low, the batches are revisited for supplementary processing. When adopting a local rearrangement strategy, if the next target hole does not meet the thermal recovery constraint, an alternative hole position is searched within the candidate window. The candidate window consists of the K future hole positions or unprocessed hole positions within the same group of holes. The hole position with the lowest path cost function and that meets the thermal recovery constraint is selected as the next processing target hole.

9. A PCB laser group hole skipping processing system based on thermal recovery constraints, used to implement the PCB laser group hole skipping processing method based on thermal recovery constraints as described in any one of claims 1 to 8, characterized in that, The system includes the following modules: The hole data acquisition module is used to import hole parameters, plate parameters, and laser parameters; The thermal parameter calculation module is used to calculate the single-hole energy and thermal influence radius of the target hole. R i and heat recovery time τ i ; The thermal interference relationship construction module is used to determine whether there is a thermal interference relationship between any two target holes; The thermal recovery constraint generation module is used to establish the minimum processing time interval. Δt ij,min And the energy compensation model when the thermal recovery constraint is not satisfied; The jump path planning module generates jump-type processing paths; Laser processing control module, used to control the laser of the mechanism; The quality feedback correction module is used to obtain the aperture deviation, orifice carbonization range, orifice wall quality or temperature change after laser processing, and update the thermally affected radius of subsequent target holes. R i Heat recovery time τ i And energy compensation models.

10. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that cause the computer to perform the PCB laser group hole skipping processing method based on thermal recovery constraints as described in any one of claims 1 to 8.

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