Milling forming method and device for semi-soft board area of PCB (Printed Circuit Board) and PCB

Abstract

The invention relates to the technical field of PCB processing, and discloses a milling forming method and device for a semi-soft board area of a PCB and the PCB. The method comprises the following steps: firstly, analyzing a laminated structure of a PCB semi-soft board area to construct a laminated structure model, performing material removal processing by stages based on the model to form a reference processing surface, performing depth controlled processing to form a detection processing surface, and then acquiring residual thickness data at multiple positions and counting to determine a residual thickness representative value; and then batch processing is carried out after the processing depth parameter is adjusted. According to the method, the rigid layer can be selectively and accurately removed, the damage risk of the flexible layer is avoided, and the functional integrity of the semi-flexible board is effectively guaranteed.

Description

Technical Field

[0001] This invention relates to the field of PCB processing technology, and in particular to a method, apparatus, and PCB for milling and forming a semi-flexible area of ​​a PCB. Background Technology

[0002] As electronic products rapidly develop towards miniaturization, irregular shapes, and multifunctionality, printed circuit boards (PCBs) with semi-flexible areas (partially flexible and partially rigid) are increasingly widely used in various precision electronic devices due to their combination of structural support and flexible connection functions. As a result, the requirements for their processing accuracy, functional integrity, and production adaptability are also continuously increasing.

[0003] In the processing of semi-flexible PCB areas, the core requirement is to selectively remove the target rigid layer material while completely preserving the underlying flexible substrate and electrical connection structure. However, traditional processing techniques struggle to meet this requirement: traditional V-CUT processes can only achieve straight-line processing, cannot adapt to complex contours, and have low depth control accuracy, easily damaging the flexible layer; die stamping processes require customized molds, resulting in high costs and long lead times, and stamping stress can easily cause tearing or delamination of the flexible material; full-process milling completely severs the flexible connection structure, losing the core function of the semi-flexible PCB. Therefore, improvements to existing technologies are necessary. Summary of the Invention

[0004] This invention provides a method, apparatus, and PCB for milling and forming a semi-flexible PCB area to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for milling a semi-flexible area of ​​a PCB, comprising:

[0007] The stack-up structure of the PCB semi-flexible board area is analyzed to determine the location of the flexible layer to be retained and the thickness of the rigid layer to be removed in the PCB semi-flexible board area, so as to construct a stack-up structure model.

[0008] Based on the aforementioned stacked structure model, a first-stage material removal process is performed on the semi-flexible plate region to form a reference processing surface for depth control;

[0009] A second-stage depth-controlled machining process is performed on the reference machining surface to selectively remove the remaining rigid layer material, forming a detection machining surface for thickness measurement;

[0010] Excess thickness data are collected at multiple preset measurement locations on the surface being inspected and processed to construct an excess thickness dataset;

[0011] The excess thickness dataset is statistically processed to determine a representative value of the excess thickness, and the depth parameters for subsequent processing are adjusted based on the representative value of the excess thickness.

[0012] Based on the adjusted depth parameters, the semi-flexible plate area is subjected to batch depth-controlled removal processing to form a semi-flexible plate structure with a predetermined excess thickness.

[0013] Optionally, the analysis of the stack-up structure of the PCB semi-flexible board area includes:

[0014] Read the thickness parameters of the flexible layer, metal layer and rigid layer in the PCB semi-flexible board area, and define the retention interface of the flexible layer and the removal range of the rigid layer based on the thickness parameters.

[0015] Optionally, performing a second-stage depth-controlled machining on the reference machined surface to selectively remove remaining rigid layer material and form a detection machined surface for thickness measurement includes:

[0016] According to the preset processing path and processing depth, the semi-flexible plate area is cut to form a reference processing surface for use in the second stage of depth-controlled processing.

[0017] Optionally, performing a second-stage depth-controlled machining on the reference machined surface to selectively remove remaining rigid layer material and form a detection machined surface for thickness measurement includes:

[0018] The target excess thickness value is set based on the retained interface of the flexible layer;

[0019] The remaining rigid layer material is removed by milling with a limited machining depth to obtain a test-machined surface that meets the target remaining thickness value.

[0020] Optionally, the step of collecting excess thickness data at multiple preset measurement locations on the inspected and processed surface to construct an excess thickness dataset includes:

[0021] Thickness detection is performed at multiple uniformly distributed measurement locations in the semi-flexible board region to construct a residual thickness dataset covering the entire semi-flexible board region.

[0022] Optionally, the step of statistically processing the excess thickness dataset to determine a representative value of the excess thickness, and adjusting the depth parameters for subsequent processing based on the representative value of the excess thickness, includes:

[0023] The excess thickness dataset is sorted, and its median value is extracted as the representative value of the excess thickness. Based on the representative value of the excess thickness, the depth parameters of depth-controlled processing are adaptively adjusted.

[0024] Optionally, this also includes establishing a processing benchmark;

[0025] The establishment of processing benchmarks includes:

[0026] Generate a backing plate machining program to construct the machining reference plane;

[0027] The backing plate is machined into a flat surface to form a machining reference plane;

[0028] The coordinate system of the pad processing program is kept consistent with the coordinate system of the semi-flexible plate area processing program.

[0029] Optionally, processing the semi-flexible board area includes:

[0030] An inside-out planning approach is adopted, and a preset overlap is set between adjacent processing paths to ensure the consistency of processing depth in the semi-flexible board area.

[0031] Optionally, before performing statistical processing on the excess thickness dataset to determine the representative value of the excess thickness, the method further includes:

[0032] The excess thickness dataset is analyzed to determine the distribution trend of the excess thickness within the semi-flexible plate area;

[0033] If a thickness deviation is detected at the edge or in a local area, local compensation is performed on the corresponding processing path or processing depth.

[0034] The present invention also provides a PCB manufactured according to the milling forming method for the semi-flexible PCB region as described in any of the preceding claims.

[0035] The present invention also provides a milling forming apparatus for a semi-flexible PCB area, comprising:

[0036] The processing modeling unit is used to analyze the stacked structure of the PCB semi-flexible board area, determine the position of the flexible layer to be retained and the thickness of the rigid layer to be removed in the PCB semi-flexible board area, so as to construct the stacked structure model.

[0037] The processing execution unit is configured to perform a first-stage material removal process on the semi-flexible board region based on the stacked structure model to form a reference processing surface for depth control; and to perform a second-stage depth-controlled processing on the reference processing surface to selectively remove the remaining rigid layer material to form a detection processing surface for thickness measurement.

[0038] The measurement unit is used to collect excess thickness data at multiple preset measurement positions on the detected and processed surface, and to construct an excess thickness dataset;

[0039] The parameter adjustment unit is used to perform statistical processing on the excess thickness dataset, determine the representative value of the excess thickness, and adjust the depth parameters of subsequent processing based on the representative value of the excess thickness; the processing execution unit is also used to perform batch depth-controlled removal processing on the semi-flexible board area according to the adjusted depth parameters to form a semi-flexible board structure with a predetermined excess thickness.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This invention provides a milling method, apparatus, and PCB for semi-flexible PCB regions. By analyzing the stacked structure of the semi-flexible PCB region to construct a stacked structure model, material removal is performed in stages based on this model. First, a reference processing surface is formed, followed by depth-controlled processing to form a detection processing surface. Excess thickness data is collected from multiple locations and statistically determined to identify representative values. Then, processing depth parameters are adjusted before batch processing begins. This invention enables selective and precise removal of the rigid layer, avoiding the risk of damage to the flexible layer and effectively ensuring the functional integrity of the semi-flexible PCB.

[0042] The present invention has other features and advantages, which will be apparent from or will be set forth in detail in the accompanying drawings and the following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of a milling and forming method for a semi-flexible PCB area provided in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of the PCB semi-flexible board area involved in the milling and forming method of the PCB semi-flexible board area provided in an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram illustrating the control capabilities of a milling and forming method for a semi-flexible PCB area provided in an embodiment of the present invention.

[0047] Figure 4 This is a schematic diagram illustrating the inward-outward tool path sequence in a milling method for a semi-flexible PCB area provided in an embodiment of the present invention.

[0048] Figure 5 This is a structural block diagram of a milling and forming device for a semi-flexible PCB area provided in an embodiment of the present invention.

[0049] Reference numerals: 10, PCB semi-flexible board area; 11, flexible layer to be retained; 12, rigid layer to be removed; 21, processing modeling unit; 22, processing execution unit; 23, measurement unit; 24, parameter adjustment unit. Detailed Implementation

[0050] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0051] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0052] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0053] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0054] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0055] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0056] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0057] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0058] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0059] In traditional PCB depaneling processes, V-CUT can only process straight lines and the depth is difficult to control; stamping requires mold opening, which is costly and prone to stress damage; and full-process milling will destroy the continuity of flexible materials. In response to these shortcomings, this invention provides the following technical solution to solve the problem that existing technologies cannot accurately control the depth and retain the flexible function.

[0060] Please refer to the reference. Figure 1 and Figure 2 This invention provides a method for milling and shaping a semi-flexible PCB region 10, comprising:

[0061] S1. Analyze the stacked structure of the PCB semi-flexible board region 10 to determine the position of the flexible layer 11 to be retained and the thickness of the rigid layer 12 to be removed in the PCB semi-flexible board region 10, so as to construct a stacked structure model.

[0062] S2. Based on the stacked structure model, the first stage of material removal processing is performed on the semi-flexible plate area to form a reference processing surface for depth control.

[0063] S3. Perform a second-stage depth-controlled machining on the reference machining surface, selectively removing the remaining rigid layer material to form a detection machining surface for thickness measurement.

[0064] S4. Collect excess thickness data at multiple preset measurement positions on the inspected processing surface and construct an excess thickness dataset;

[0065] S5. Perform statistical processing on the excess thickness dataset to determine the representative value of the excess thickness, and adjust the depth parameters of subsequent processing based on the representative value of the excess thickness.

[0066] S6. Based on the adjusted depth parameters, perform batch depth-controlled removal processing on the semi-flexible board area to form a semi-flexible board structure with a predetermined excess thickness.

[0067] In this embodiment, by analyzing the stacked structure of the PCB semi-flexible board area 10, the spatial distribution and dimensional parameters of the flexible and rigid layers are clarified, and material removal is carried out in stages based on this. Furthermore, in the first stage, a portion of the rigid layer is quickly removed to form a reference surface, and in the second stage, the remaining rigid layer is precisely removed and a detection surface is reserved. Actual processing status data is obtained through multi-position thickness detection, and processing parameters are adjusted after statistical analysis to ensure that the rigid layer is completely removed and the flexible layer is not damaged during batch processing.

[0068] Based on the method provided in this embodiment, it is possible to process semi-flexible circuit board contours of any complex shape, breaking through the shape limitations of traditional processes; through precise depth control to avoid the risk of damage to flexible circuits, it significantly improves product yield and long-term reliability. Testing showed that the solution in this embodiment achieved a thickness CPK of 2.84 in the sample stage with no quality abnormalities; no mold opening is required, and products can be quickly switched through CNC programming, adapting to small-batch, multi-variety production modes, shortening the production cycle and reducing overall costs.

[0069] In some optional implementations, step S1 involves analyzing the stack-up structure of the PCB semi-flexible board region 10, including:

[0070] Read the thickness parameters of the flexible layer, metal layer and rigid layer in the PCB semi-flexible board area 10, and define the retention interface of the flexible layer and the removal range of the rigid layer based on the thickness parameters.

[0071] Understandably, the layered structure is fundamental to determining the depth and scope of processing. Existing technologies, lacking clear definition of each layer's thickness and interface location, are prone to processing deviations. The aforementioned steps precisely read the thickness parameters of each layer and define the retention and removal areas, providing accurate dimensional basis for subsequent staged processing and avoiding damage to flexible layers or residue of rigid layers caused by blind processing.

[0072] Specifically, based on the stack-up design characteristics of PCB semi-flexible boards, the actual thickness data of the flexible layer, metal layer and rigid layer are obtained by detection, and the upper surface of the flexible layer is used as the termination interface for the removal of the rigid layer. Combined with the total thickness of the rigid layer, the removal amount of each stage is determined, thereby ensuring that the processing only acts on the rigid layer area.

[0073] In some alternative implementations, a second-stage depth-controlled machining process is performed on the reference machined surface to selectively remove remaining rigid layer material, forming a detection machined surface for thickness measurement, including:

[0074] According to the preset processing path and processing depth, the semi-soft plate area is cut to form a reference processing surface for the second stage of depth-controlled processing.

[0075] Generally speaking, directly performing depth-controlled machining will result in low efficiency and make it difficult to guarantee the flatness of the machined surface.

[0076] In this embodiment, based on the rigid layer thickness determined by the stacked structure model, the machining depth of the first stage (removing the surface copper and part of the rigid intermediate thick layer) is set. A conventional milling cutter is used to cut along a preset path. By controlling the cutting parameters, the reference machining surface formed after machining is ensured to be flat, providing a stable machining reference for the subsequent second stage to accurately remove the remaining rigid layer, thus solving the problem that efficiency and accuracy cannot be achieved in a single machining stage.

[0077] Through the first and second stages of processing, excess rigid layer material can be removed accurately and quickly, shortening the overall processing cycle and forming a flat reference surface. This ensures the consistency of accuracy in subsequent depth-controlled processing and avoids depth deviations caused by uneven initial surfaces.

[0078] In some alternative implementations, a second-stage depth-controlled machining process is performed on the reference machined surface to selectively remove remaining rigid layer material, forming a detection machined surface for thickness measurement, including:

[0079] The target excess thickness value is set according to the interface of the flexible layer; the remaining rigid layer material is removed by milling with a limited machining depth to obtain a test machining surface that meets the target excess thickness value.

[0080] Understandably, since some rigid layer remains after the first stage of processing, subsequent removal operations need to be more precise to avoid affecting the flexible function of the semi-flexible board, while also reserving a test surface for thickness verification. Therefore, in subsequent operations, a target thickness value (based on the requirement to retain the flexible layer) must first be set, and then a milling method with a limited depth must be used to ensure that the remaining rigid layer is completely removed without touching the flexible layer, thereby solving the problem of balancing precise depth control and inspection requirements.

[0081] For example, in actual operation, using the flexible layer retention interface as a reference, a target excess thickness value is set (i.e., the distance between the inspection machining surface and the flexible layer retention interface). A dedicated fixed shank two-flute flat-bottom C end mill (e.g., Ф2.1×5.0×Ф3.175×38.1×C0.4) is selected. By strictly controlling the milling depth and flatness, the rigid layer material remaining on the reference machining surface is accurately removed, forming a flat inspection machining surface. This ensures that the underlying flexible substrate and copper are not damaged, achieving accurate removal of the remaining rigid layer and a flat inspection machining surface that meets the accuracy requirements for subsequent excess thickness measurement. This effectively avoids the risk of flexible layer damage and ensures the flexible function and electrical connection performance of the semi-flexible board.

[0082] In some optional implementations, excess thickness data is collected at multiple preset measurement locations on the inspected processing surface to construct an excess thickness dataset, including:

[0083] Thickness detection is performed at multiple uniformly distributed measurement locations in the semi-flexible board region to construct a residual thickness dataset covering the entire semi-flexible board region.

[0084] It is understandable that data from a single measurement location cannot reflect the overall thickness distribution of the semi-flexible board area, and local deviations can easily lead to batch processing defects. In this embodiment, based on the geometry and size of the semi-flexible board area, multiple evenly distributed measurement locations (such as the nine-point method) are rationally planned to detect the thickness data at each location, and all detection data are integrated to form a thickness dataset, ensuring the comprehensiveness and representativeness of the data and avoiding judgment biases caused by limitations in measurement locations.

[0085] Based on this, the obtained excess thickness data can truly reflect the overall processing status of the semi-flexible plate area, providing accurate and comprehensive data support for subsequent statistical analysis and parameter adjustment, and reducing the risk of batch non-conformity caused by the failure to detect local excess thickness deviations.

[0086] In some optional implementations, statistical processing is performed on the excess thickness dataset to determine a representative value for the excess thickness, and the depth parameters for subsequent processing are adjusted based on this representative value, including:

[0087] The residual thickness dataset is sorted, and its median value is extracted as the representative value of residual thickness. Based on the representative value of residual thickness, the depth parameters of depth-controlled processing are adaptively adjusted.

[0088] Because outliers may exist in the excess thickness dataset, directly using the mean is easily affected by interference, while the median value can more stably reflect the central tendency of the data. In this embodiment, the collected excess thickness dataset is sorted by numerical value, and the median value is selected as the representative value of the excess thickness that can represent the overall excess thickness level of the region. This representative value is compared with the preset target excess thickness value, the deviation is calculated, and the milling depth parameters are adaptively adjusted accordingly to ensure that the excess thickness of subsequent machining accurately matches the target requirements.

[0089] Please refer to Figure 3 The aforementioned steps eliminate abnormal interference data and accurately reflect the overall thickness status of the region; precise control of the thickness is achieved through parameter adjustment to ensure the consistency of the thickness of batch processed products. After verification, the thickness CPK of the sample stage can reach 2.84, and the process stability is excellent.

[0090] Unevenness of the backing plate or inconsistency of the coordinate system during the processing can lead to PCB board positioning deviation and fluctuations in processing depth.

[0091] To address the issues of inaccurate positioning and depth deviation, and to provide a fundamental guarantee for precise machining, some optional implementation methods also include establishing machining benchmarks.

[0092] Specifically, establishing a machining datum includes: generating a pad machining program to construct the machining datum plane; machining the pad to form the machining datum plane; and ensuring that the coordinate system of the pad machining program is consistent with the coordinate system of the semi-soft plate area machining program to ensure consistency in machining position and machining depth.

[0093] In this embodiment, a backing plate processing program is generated to match the semi-flexible board area processing program. A Φ2.4 standard milling cutter is used to perform planar processing on the backing plate, and the cutters overlap by half a milling cutter diameter to ensure the flatness of the backing plate. The processing size of the backing plate is 2 inches larger than that of the production board. At the same time, the coordinate system of the backing plate processing program and the semi-flexible board area processing program is kept consistent, so that the PCB board is accurately positioned on the reference plane, ensuring the consistency of processing position and depth.

[0094] Based on the aforementioned steps, a flat and uniform processing benchmark is established, which effectively eliminates processing errors caused by uneven pads and coordinate deviations; ensures accurate PCB board positioning, significantly improves the consistency of processing position and depth, and lays a stable foundation for subsequent depth-controlled processing.

[0095] Traditional processing path planning can easily lead to edge material deformation or insufficient processing overlap, affecting depth consistency. Therefore, to avoid the aforementioned problems, in some optional embodiments, when processing the semi-flexible board area, the following methods are included:

[0096] An inside-out planning approach is adopted, and a preset overlap is set between adjacent processing paths to ensure the consistency of processing depth in the semi-flexible board area.

[0097] Please refer to Figure 4 In this embodiment, when planning the machining path of the semi-flexible plate area, an inward-outward tooling sequence is adopted to reduce the deformation of the edge material caused by stress during machining. A preset overlap (such as 80% overlap ratio) is set between adjacent machining paths to ensure that the milling cutter has no blind spots, avoids rigid layer residue or machining depth deviation caused by path gaps, and ensures that the machining depth of the entire semi-flexible plate area is uniform and consistent, effectively reducing the impact of material deformation on accuracy during machining. The overlapping coverage of adjacent paths avoids machining blind spots, ensures consistent machining depth in the semi-flexible plate area, and improves product surface quality and dimensional accuracy.

[0098] In some optional implementations, before performing statistical processing on the excess thickness dataset to determine the representative value of the excess thickness, the following steps are also included:

[0099] Analyze the excess thickness dataset to determine the distribution trend of excess thickness within the semi-flexible plate region;

[0100] If a thickness deviation is detected at the edge or in a local area, local compensation is performed on the corresponding processing path or processing depth.

[0101] It is understandable that even with uniform processing parameters, thickness deviations may still occur at the edges or in certain areas of the semi-soft plate due to factors such as material properties and tool wear. Adjusting the parameters directly according to the overall representative value will not solve the local defects.

[0102] In this embodiment, statistical analysis of the excess thickness dataset is performed to determine the variation trend of the excess thickness in the semi-flexible plate area (such as thicker edges, thinner local areas, etc.) based on the data distribution characteristics. When the excess thickness of the edge or local area is detected to exceed the allowable deviation range, the corresponding machining path (such as optimizing the tool feed density) or machining depth parameters (such as increasing / decreasing the local milling depth) are adjusted for the specific area to achieve accurate compensation for local deviations, avoid the expansion of local defects, and thus improve the overall uniformity of the excess thickness in the semi-flexible plate area, further ensuring the stability and consistency of product quality.

[0103] Based on the above embodiments, this invention provides a PCB manufactured by milling the PCB semi-flexible board region 10 according to any of the above methods.

[0104] By using the above method, the 10 rigid layers in the semi-flexible PCB area can be selectively and precisely removed, while retaining the complete flexible layer and electrical connection structure. This allows the PCB product to simultaneously possess the structural stability of the rigid area and the flexibility of the semi-flexible area, with its structural characteristics directly corresponding to the technical parameters of the processing method.

[0105] Based on this, the semi-flexible board area of ​​this PCB has a flexible shape and good thickness consistency (CPK can reach 2.84), and there are no quality problems such as flexible layer damage or delamination; the product yield is high and the long-term reliability is strong, which is in line with the development trend of miniaturization and irregular shape of modern electronic products.

[0106] Please refer to Figure 5 Based on the above embodiments, this embodiment of the invention also provides a milling forming apparatus for a PCB semi-flexible board area 10, comprising:

[0107] The processing modeling unit 21 is used to analyze the stacked structure of the PCB semi-flexible board area 10, determine the position of the flexible layer 11 to be retained in the PCB semi-flexible board area 10, and the thickness of the rigid layer 12 to be removed, so as to construct a stacked structure model.

[0108] The processing execution unit 22 is used to perform a first-stage material removal process on the semi-flexible board region based on the stacked structure model to form a reference processing surface for depth control; and to perform a second-stage depth-controlled processing on the reference processing surface to selectively remove the remaining rigid layer material to form a detection processing surface for thickness measurement.

[0109] Measurement unit 23 is used to collect excess thickness data at multiple preset measurement positions on the inspected processing surface and construct excess thickness dataset;

[0110] The parameter adjustment unit 24 is used to perform statistical processing on the excess thickness dataset, determine the representative value of the excess thickness, and adjust the depth parameters of subsequent processing based on the representative value of the excess thickness; the processing execution unit 22 is also used to perform batch depth-controlled removal processing on the semi-flexible board area according to the adjusted depth parameters to form a semi-flexible board structure with a predetermined excess thickness.

[0111] In this embodiment, the processing modeling unit 21 reads the thickness parameters of the flexible layer, metal layer, and rigid layer in the PCB semi-flexible board area 10, defines the interface for retaining the flexible layer and the range for removing the rigid layer, and constructs an accurate stacked structure model to provide a data foundation for processing execution. The processing execution unit 22 is equipped with a conventional milling cutter and a dedicated fixed-shank two-flute flat-bottom C end mill. In the first stage, the copper surface and part of the rigid intermediate thick layer are quickly removed according to the preset path and depth to form a flat reference processing surface. In the second stage, a limited-depth milling method is used to accurately remove the remaining rigid layer and form a detection processing surface. The measurement unit 23 collects the remaining thickness data at a uniformly distributed preset position (such as the nine-point method) to construct a full-area remaining thickness dataset. The parameter adjustment unit 24 sorts and statistically analyzes the dataset, extracts the median value as the representative value of the remaining thickness, and adjusts the depth parameters after comparing with the target remaining thickness value. The processing execution unit 22 completes batch processing according to the adjusted parameters, and the units form a closed-loop collaboration.

[0112] In summary, the device provided in this embodiment can achieve integrated control of the entire process of PCB semi-flexible board area 10 processing. The collaborative operation of each unit ensures processing accuracy. The CPK of the sample stage verification can reach 2.84, with no quality abnormalities such as flexible layer damage. The processing execution unit 22 is adapted to different milling cutters and processing stages. Combined with the dynamic optimization of the parameter adjustment unit 24, it can adapt to the processing of any complex irregular contour, thereby improving production flexibility.

[0113] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not be construed as limiting the scope of protection of this application. Any technical solutions resulting from equivalent structural or procedural substitutions or modifications made based on the essential concept of this application and utilizing the content described in the text and drawings of this application, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of protection of this application.

Claims

1. A method for milling and shaping a semi-flexible area of ​​a PCB, characterized in that, include: The stack-up structure of the PCB semi-flexible board area is analyzed to determine the location of the flexible layer to be retained and the thickness of the rigid layer to be removed in the PCB semi-flexible board area, so as to construct a stack-up structure model. Based on the aforementioned stacked structure model, a first-stage material removal process is performed on the semi-flexible plate region to form a reference processing surface for depth control; A second-stage depth-controlled machining process is performed on the reference machining surface to selectively remove the remaining rigid layer material, forming a detection machining surface for thickness measurement; Excess thickness data are collected at multiple preset measurement locations on the surface being inspected and processed to construct an excess thickness dataset; Perform statistical processing on the excess thickness dataset to determine a representative value of the excess thickness, and adjust the depth parameters of subsequent processing based on the representative value of the excess thickness; Based on the adjusted depth parameters, the semi-flexible plate area is subjected to batch depth-controlled removal processing to form a semi-flexible plate structure with a predetermined excess thickness.

2. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, The analysis of the stack-up structure in the PCB semi-flexible board area includes: Read the thickness parameters of the flexible layer, metal layer and rigid layer in the PCB semi-flexible board area, and define the retention interface of the flexible layer and the removal range of the rigid layer based on the thickness parameters.

3. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, The second-stage depth-controlled machining of the reference machined surface, selectively removing remaining rigid layer material to form a detection machined surface for thickness measurement, includes: According to the preset processing path and processing depth, the semi-flexible plate area is cut to form a reference processing surface for use in the second stage of depth-controlled processing.

4. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, The second-stage depth-controlled machining of the reference machined surface, selectively removing remaining rigid layer material to form a detection machined surface for thickness measurement, includes: The target excess thickness value is set based on the retained interface of the flexible layer; The remaining rigid layer material is removed by milling with a limited machining depth to obtain a test-machined surface that meets the target remaining thickness value.

5. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, The process involves collecting excess thickness data at multiple preset measurement locations on the inspected and processed surface to construct an excess thickness dataset, including: Thickness detection is performed at multiple uniformly distributed measurement locations in the semi-flexible board region to construct a residual thickness dataset covering the entire semi-flexible board region.

6. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, The step of statistically processing the excess thickness dataset to determine a representative value for excess thickness, and adjusting the depth parameters for subsequent processing based on the representative value for excess thickness, includes: The excess thickness dataset is sorted, and its median value is extracted as the representative value of the excess thickness. Based on the representative value of the excess thickness, the depth parameters of the depth-controlled processing are adaptively adjusted.

7. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, This also includes establishing processing standards; The establishment of processing benchmarks includes: Generate a backing plate machining program to construct the machining reference plane; The backing plate is machined into a flat surface to form a machining reference plane; The coordinate system of the pad processing program is kept consistent with the coordinate system of the semi-flexible plate area processing program.

8. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, Processing the semi-flexible board area includes: An inside-out planning approach is adopted, and a preset overlap is set between adjacent processing paths to ensure the consistency of processing depth in the semi-flexible board area.

9. The milling forming method for the semi-flexible PCB area according to claim 1, characterized in that, Before performing statistical processing on the excess thickness dataset to determine the representative value of the excess thickness, the method further includes: The excess thickness dataset is analyzed to determine the distribution trend of the excess thickness within the semi-flexible plate area; If a thickness deviation is detected at the edge or in a local area, local compensation is performed on the corresponding processing path or processing depth.

10. A PCB, characterized in that, It is manufactured according to the milling forming method of the PCB semi-flexible board area as described in any one of claims 1 to 9.

11. A milling and forming apparatus for a semi-flexible PCB area, characterized in that, include: The processing modeling unit is used to analyze the stacked structure of the PCB semi-flexible board area, determine the position of the flexible layer to be retained and the thickness of the rigid layer to be removed in the PCB semi-flexible board area, so as to construct the stacked structure model. The processing execution unit is configured to perform a first-stage material removal process on the semi-flexible board region based on the stacked structure model to form a reference processing surface for depth control; and to perform a second-stage depth-controlled processing on the reference processing surface to selectively remove the remaining rigid layer material to form a detection processing surface for thickness measurement. The measurement unit is used to collect excess thickness data at multiple preset measurement positions on the detected and processed surface, and to construct an excess thickness dataset; The parameter adjustment unit is used to perform statistical processing on the excess thickness dataset, determine the representative value of the excess thickness, and adjust the depth parameters of subsequent processing based on the representative value of the excess thickness. The processing execution unit is also used to perform batch depth-controlled removal processing on the semi-flexible board area according to the adjusted depth parameters to form a semi-flexible board structure with a predetermined excess thickness.

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