PCB element mounting pressure control method, control device and equipment

Abstract

The embodiment of the invention provides a PCB element mounting pressure control method, control device and equipment, and the method comprises the steps: S1, obtaining the first parameter information of a to-be-mounted PCB, and enabling the first parameter information to comprise the elastic modulus E and the thickness T of the to-be-mounted PCB; s2, acquiring second parameter information of the to-be-mounted PCB, wherein the second parameter information is defined as component pin density rho of a unit area in a preset radius R0 region by taking a mounting point as a center; s3, calculating a dynamic pressure adjustment coefficient K based on the first parameter information and the second parameter information; s4, according to the layout characteristics of the PCB to be mounted, independent pressure regulation and control areas are divided, and reference pressure P0 is distributed to each area; and S5, dynamically controlling the output pressure P of the mounting head according to the K value of the area to which the mounting point belongs when the element mounting is executed. According to the method, micro-deformation of the PCB caused by uneven pressure can be remarkably reduced, and the mounting quality is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of PCB component mounting, and in particular to a PCB component mounting pressure control method, a control device and equipment. BACKGROUND

[0002] In the field of electronic manufacturing, PCB component mounting is a key process that determines product reliability. With the development of electronic devices towards miniaturization and high density, the widespread use of small size components and BGA, QFP and other multi-pin precision devices puts higher requirements on the precise control of mounting pressure. Insufficient mounting pressure can lead to virtual soldering of solder joints and increase in contact resistance, while excessive pressure can cause micro-deformation of the PCB, resulting in cracking of solder joints or damage to the component body, especially in ultra-thin PCBs or high-density integrated areas, such problems occur frequently, seriously affecting the long-term stability and production yield of electronic devices.

[0003] In the prior art, PCB first threshold component mounting pressure control mainly relies on experience setting or simple zoning pressure strategy. The traditional method usually uses a fixed pressure value to mount the entire board, or only roughly divides the pressure interval according to the component type, without fully considering the influence of PCB first threshold material, thickness, etc. on the mounting pressure, and without correlating the component distribution density with the regional deformation risk. For example, high-density mounting areas are more prone to micro-deformation under the same pressure due to small solder joint spacing and low local stiffness, but existing methods cannot adjust the pressure threshold specifically; components with pins across regions often experience uneven stress due to pressure differences in adjacent regions, leading to solder joint cracking. The above defects make it difficult for existing technologies to balance soldering reliability and component protection needs when mounting ultra-thin, high-density PCBs, and an intelligent pressure control method based on multi-dimensional parameter coupling is urgently needed to solve the above technical problems.

[0004] Therefore, it is of important engineering application value to develop a pressure control method that takes into account the physical properties of the first threshold PCB and the layout characteristics of the components to improve the mounting quality of high-end electronic devices. SUMMARY

[0005] The present application provides a PCB component mounting pressure control method, a control device and equipment. The method constructs a dynamic pressure adjustment coefficient K through coupling analysis of elastic modulus E, board thickness T and pin density p, and controls the pressure based on PCB layout characteristics to precisely match the deformation resistance and stress concentration characteristics of different regions, significantly reducing PCB micro-deformation caused by uneven pressure, and thus improving mounting quality.

[0006] In a first aspect, a PCB component mounting pressure control method is provided, the method comprising:

[0007] S1: Obtain first parameter information of a PCB to be mounted, the first parameter information including: elastic modulus E and thickness T of the PCB to be mounted;

[0008] S2: Obtain second parameter information of the PCB to be mounted, the second parameter information being defined as: element pin density per unit area in a region with a preset radius R0 centered on a mounting point;

[0009] S3: Based on the first parameter information and the second parameter information, calculate a dynamic pressure adjustment coefficient K, the calculation formula being:

[0010] K=F(E,T)×G(ρ),

[0011] wherein F(E,T) is a deformation resistance coefficient of the PCB to be mounted, and G(ρ) is a local stress concentration coefficient of the PCB to be mounted;

[0012] S4: According to layout characteristics of the PCB to be mounted, divide independent pressure regulation regions, and assign a reference pressure P0 to each region;

[0013] S5: When performing component mounting, dynamically control output pressure P of a mounting head according to the K value of a region to which a mounting point belongs.

[0014] It should be understood that, by means of the dynamic pressure adjustment model, the defects that the traditional uniform pressure strategy cannot take into account material characteristics and layout stress can be effectively solved, wherein the elastic modulus E and the thickness T quantify the bending resistance of the PCB body, the pin density ρ accurately reflects the local stress concentration risk, and the product relationship K value of the two ensures that sufficient pressure is applied to the high-rigidity region to ensure solder immersion, while the pressure is automatically reduced in the high-density component region to avoid micro-cracks.

[0015] In combination with the first aspect, in some implementations of the first aspect, the calculation formula of the deformation resistance coefficient F(E,T) in the step S3 is:

[0016] F(E,T)=α·(E / E ref ) m ·(T / T ref ) n ,

[0017] wherein E ref is a reference elastic modulus, T ref is a standard thickness, the index m∈[0.4,0.6], n∈[0.9,1.1], and α is a normalization coefficient.

[0018] It should be understood that the power function design of the deformation resistance coefficient effectively captures the nonlinear characteristics of the mechanical properties of the board. The formula, through the flexible adjustment of the index n, makes the pressure output curve highly consistent with the actual deformation threshold of the PCB, especially successfully eliminating the risk of delamination between boards in rigid-flex combined boards.

[0019] In combination with the first aspect, in some implementations of the first aspect, the calculation formula of the local stress concentration coefficient G(ρ) in step S3 is:

[0020] G(ρ) = β - γ·ln(ρ + c),

[0021] where γ is an attenuation coefficient, and c is a density offset constant.

[0022] It should be understood that the natural logarithm function design of the local stress concentration coefficient balances the pressure reduction demand of the high-density area and the reliability of the solder wetting in the low-pressure area. The attenuation characteristics of the logarithmic function ensure that the pressure coefficient K decreases gently when the pin density increases, avoiding the cold welding problem caused by sudden changes in pressure. At the same time, the introduction of the density offset constant c effectively solves the calculation singularity problem of isolated small components, making the pressure output stable in a reasonable range.

[0023] In combination with the first aspect, in some implementations of the first aspect, the calculation formula of the preset radius R0 in step S2 is:

[0024] R0 = R base +k·(Tref-T),

[0025] where R base is a reference radius, and k is a board thickness compensation coefficient.

[0026] It should be understood that the adaptive calculation rule of the preset radius R0 breaks through the limitations of traditional fixed detection areas, can accurately capture the propagation range of edge deformation of the board, and focuses on local high stress points. This design significantly improves the deformation monitoring efficiency and avoids invalid data interference.

[0027] In combination with the first aspect, in some implementations of the first aspect, the division rule of the independent pressure regulation area in step S4 includes:

[0028] The mechanical reinforcement structure boundary of the to-be-mounted PCB board is preferentially used as the partition boundary;

[0029] If there is no mechanical reinforcement structure area, the pin density jump gradient of the to-be-mounted PCB board is used for division:

[0030] If the difference Δρ of the ρ values of adjacent areas is greater than a first threshold value, a new regulation area is generated.

[0031] It should be understood that based on the composite partition strategy of physical boundary (mechanical reinforcement structure) and electrical characteristics (pin density jump), the spatial matching of the pressure regulation zone and the actual anti-deformation ability of the PCB is realized.

[0032] In combination with the first aspect, in some implementations of the first aspect, for the BGA packaging element, the calculation range of p covers 3 times the solder ball pitch outward.

[0033] In combination with the first aspect, in some implementations of the first aspect, the method comprises an optimization step:

[0034] Detect the quality of the solder joints after mounting and mark the fault position;

[0035] When the defect rate of the same area is greater than a second threshold, correct the K value according to the defect type;

[0036] The corrected K value is applied to the same area of the subsequent PCB to be mounted in the same batch.

[0037] In combination with the first aspect, in some implementations of the first aspect, the method further comprises:

[0038] After mounting a single circuit board, record the actual mounting pressure of each area and store it in a database to provide a data basis for subsequent optimization of the mounting process.

[0039] The second aspect provides a control device, which comprises a processor and a memory, the processor is coupled with the memory, the memory is used to store computer programs or instructions, and the processor is used to execute the computer programs or instructions in the memory, so that any implementation manner of the first aspect is executed.

[0040] The third aspect provides a device, which comprises the control device of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 A PCB element mounting pressure control method implementation flowchart is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0042] The terminology used in the following description merely for the purpose of describing particular embodiments and is not intended to limit the application. As used in this description and the accompanying claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "or" as used herein refers to any or all possible combinations of one or more of the associated listed items.

[0043] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Thus, the appearances of the phrases "in one embodiment" or "in some embodiments" or "in other embodiments" or "in still other embodiments" or similar phrases in various places throughout this specification are not necessarily all referring to the same embodiment, unless otherwise expressly specified. The terms "including," "comprising," "having," and variations thereof are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "coupled" and "connected," and variations thereof, are intended to encompass a connection between two or more elements, which is sufficed only by the direct connection between these elements, but can also be evidenced by an indirect connection between these elements through other elements.

[0044] In electronic manufacturing, the first threshold component mounting of PCB is a key process to determine the reliability of the product. Under the trend of miniaturization and high density of electronic devices, the widespread application of small size components and multi-pin precision devices puts forward higher requirements for mounting pressure control. Insufficient pressure can easily cause virtual welding of solder joints, and excessive pressure can cause first threshold PCB first threshold micro-deformation, leading to solder joint cracking or component damage, especially in ultra-thin plates and high-density areas. The existing technology relies on experience or simple zoning strategy, and uses fixed pressure mounting, without fully considering parameters such as first threshold PCB first threshold material, thickness and component distribution density. This leads to problems such as difficulty in adjusting the pressure threshold in high-density areas, uneven stress on pins across regions, etc., and cannot balance the welding reliability and component protection needs of ultra-thin and high-density first threshold PCBs. Therefore, an intelligent control scheme that couples multiple dimensional parameters is urgently needed.

[0045] Embodiments of the present application provide a PCB component mounting pressure control method, control device and equipment, which can effectively solve the above problems.

[0046] The technical solutions provided by the embodiments of the present application will be described below with reference to the accompanying drawings.

[0047] The technical solutions provided by the embodiments of the present application will be described below with reference to the accompanying drawings.Figure 1 A PCB component mounting pressure control method implementation flowchart is provided for the embodiments of the present application. In some examples, the method comprises:

[0048] S1: Obtain first parameter information of a PCB to be mounted, the first parameter information comprising: elastic modulus E and thickness T of the PCB to be mounted;

[0049] S2: Obtain second parameter information of the PCB to be mounted, the second parameter information being defined as: the component pin density per unit area in a region with a preset radius R0 centered on a mounting point;

[0050] S3: Based on the first parameter information and the second parameter information, calculate a dynamic pressure adjustment coefficient K, the calculation formula being:

[0051] K = F(E, T) × G(p),

[0052] wherein F(E, T) is a deformation resistance coefficient of the PCB to be mounted, and G(p) is a local stress concentration coefficient of the PCB to be mounted;

[0053] S4: According to the layout characteristics of the PCB to be mounted, divide independent pressure regulation regions, and assign a reference pressure P0 to each region;

[0054] S5: When performing component mounting, dynamically control the output pressure P of the mounting head according to the K value of the region to which the mounting point belongs.

[0055] In some examples, the calculation formula of the deformation resistance coefficient F(E, T) in step S3 is:

[0056] F(E, T) = a · (E / E ref ) m · (T / T ref ) n ,

[0057] wherein E ref is a reference elastic modulus, T ref is a standard thickness, the exponents m ∈ [0.4, 0.6], n ∈ [0.9, 1.1], and a is a normalization coefficient.

[0058] In a possible implementation, in the mounting preparation stage, the board material model in the PCB design file is read, and the elastic modulus value in the pre-stored database is matched. If a new model is encountered, the elastic modulus value is estimated based on the substrate composition and the supplier's data book, and the error is controlled within ±3%.

[0059] In some examples, the calculation formula of the local stress concentration coefficient G(p) in step S3 is:

[0060] G(p) = β - γ - ln(p + c),

[0061] wherein, γ is an attenuation coefficient, and c is a density offset constant.

[0062] In some examples, the calculation formula of the preset radius R0 in the step S2 is as follows:

[0063] R0 = R base + k - (Tref - T),

[0064] wherein, R base is a reference radius, and k is a plate thickness compensation coefficient.

[0065] In some examples, the division rule of the independent pressure regulation area in the step S4 comprises:

[0066] the mechanical reinforcement structure boundary of the to-be-mounted PCB board is preferentially used as the partition boundary;

[0067] if there is no mechanical reinforcement structure area, the to-be-mounted PCB board is divided according to the pin density jump gradient:

[0068] if the difference Δp of the ρ values of adjacent areas is greater than a first threshold value, a new regulation area is generated.

[0069] In a possible implementation, when the area of the ultra-thin connector with metal reinforcement ribs is processed (a typical scenario: T = 0.8 mm, and a USB-C interface is arranged at the plate edge 5 mm), the R0 calculation value is automatically expanded to 12 mm (compensation for the deformation diffusion effect of the thin plate), which completely covers the connector pin area and the adjacent weak rigidity area. At the same time, the reinforcement rib is preferentially used as the physical boundary to isolate the plate edge area, and the deformation is blocked from being transmitted to the main plate.

[0070] In some examples, for a BGA packaging element, the calculation range of ρ covers 3 times the solder ball pitch of the BGA packaging element.

[0071] In some examples, the method comprises an optimization step:

[0072] After mounting, the quality of the solder joints is detected, and the fault position is marked;

[0073] When the defect rate of the same area is greater than a second threshold value, the K value is corrected according to the defect type;

[0074] The corrected K value is applied to the same area of the to-be-mounted PCB board in the same batch.

[0075] In a possible implementation, when the virtual welding rate of a certain area exceeds the second threshold value, the K value is increased by 1.15 times to enhance the solder filling force; if cracking is detected, the K value is decreased to release stress.

[0076] In some examples, the method further comprises:

[0077] After the single circuit board is mounted, the actual mounting pressure of each area is recorded and stored in a database to provide a data basis for subsequent optimization of the mounting process.

[0078] Embodiments of the present application provide a control device, which comprises a processor and a memory, the processor is coupled with the memory, the memory is used to store computer programs or instructions, and the processor is used to execute the computer programs or instructions in the memory, so that the method as described in any of the preceding embodiments is executed.

[0079] Embodiments of the present application also provide a device, which comprises the control device as described in the above embodiments.

[0080] The above is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above embodiment, but any equivalent modification or change made by the ordinary skilled in the art according to the disclosed content of the present application shall be included in the protection scope recorded in the claims.

Claims

1. A method of controlling the mounting pressure of a PCB board component, characterized by, The method comprises: S1: obtaining first parameter information of a to-be-mounted PCB board, the first parameter information comprising: elastic modulus E and board thickness T of the to-be-mounted PCB; S2: obtaining second parameter information of the to-be-mounted PCB board, the second parameter information being defined as: element pin density per unit area in a region with a preset radius R0 centered on a mounting point; S3: based on the first parameter information and the second parameter information, calculating a dynamic pressure adjustment coefficient K, the calculation formula being: K = F(E, T) × G(ρ), wherein F(E, T) is a deformation resistance coefficient of the to-be-mounted PCB board, and G(ρ) is a local stress concentration coefficient of the to-be-mounted PCB board; S4: dividing an independent pressure regulation region according to layout characteristics of the to-be-mounted PCB board, and assigning a reference pressure P0 to each region; S5: during component mounting, dynamically controlling the output pressure P of a mounting head according to the K value of the region to which the mounting point belongs.

2. The method of claim 1, wherein, The calculation formula of the deformation resistance coefficient F(E, T) in the step S3 is: F(E,T) = a • (E / E ref ) m • (T / T ref ) n , wherein E ref is the reference modulus of elasticity, T ref is the standard thickness, the indices m e [0.4, 0.6], n e [0.9, 1.1], and a is a normalization coefficient.

3. The method of claim 1, wherein, The calculation formula of the local stress concentration coefficient G(ρ) in the step S3 is: G(ρ) = β - γ·ln(ρ + c), wherein γ is an attenuation coefficient, and c is a density offset constant.

4. The method of claim 1, wherein, The calculation formula of the preset radius R0 in the step S2 is: R0 = R base + k - (Tref - T), where R base is the reference radius, and k is a plate thickness compensation factor.

5. The method of claim 1, wherein, The division rule of the independent pressure regulation region in the step S4 comprises: preferably, a mechanical reinforcement structure boundary of the to-be-mounted PCB board is used as a division line; if there is no mechanical reinforcement structure region, the to-be-mounted PCB board is divided according to a pin density jump gradient: if the difference Δρ of the ρ values of adjacent regions is greater than a first threshold value, a new regulation region is generated.

6. The method of claim 5, wherein, For a BGA packaged component, the calculation range of ρ covers 3 times the solder ball pitch of the component.

7. The method of claim 1, wherein, The method comprises an optimization step: after mounting, detecting the quality of the solder joints and marking the fault positions; when the defect rate of the same region is greater than a second threshold value, correcting the K value according to the defect type; the corrected K value is applied to the same region of the to-be-mounted PCB board in the same batch subsequently.

8. The method of claim 1, wherein, The method further comprises: after completing the mounting of a single circuit board, recording the actual mounting pressure of each region and storing it in a database, thereby providing a data basis for subsequent optimization of the mounting process.

9. A control device characterized by comprising: The device comprises a processor and a memory, the processor being coupled to the memory, the memory being used to store computer programs or instructions, and the processor being used to execute the computer programs or instructions in the memory, so that the method in any one of claims 1 to 8 is executed.

10. An apparatus, comprising: The device comprises a control device as claimed in claim 9.

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