Membrane bonding process for radiating plate with special-shaped structure and printed board

Abstract

The invention relates to a film bonding technology for a heat dissipation plate of a special-shaped structure and a printed board. The film bonding technology comprises the steps of S1 film bonding technology formulation, S2 bonding tool design, S3 tool production, S4 film carving data processing, S5 film carving, S6 film poking, S7 cold bonding, S8 tool positioning, S9 preheating, S10 hot pressing, S11 cooling, S12 tool dismounting and S13 processing. According to the invention, through a parameter formulating technology, formulated process parameters need to be combined with the force applied to the cold plate stress area of the special-shaped structure and the area in contact with the printed board during hot pressing, so that the force can meet the film adhesion pressure requirement, the adhesion assembly cannot be damaged in the hot pressing link, the heat dissipation board and the printed board are adhered together, and the adhesion peeling strength requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of film bonding technology, in particular to a film bonding technology for a heat dissipation plate with a special-shaped structure and a printed circuit board. Background Art

[0002] At present, the integration level of aerospace electronic equipment is getting higher and higher, and the energy density is getting higher and higher. One problem brought about by miniaturization, integration and modularization is that a large number of surface mount components and modules are integrated on the surface of the printed circuit board, which leads to a large heat flux of the printed circuit board.

[0003] When products are undergoing environmental stress screening, components may fail due to heat dissipation problems under high temperature conditions, so it is urgent to pursue a simple and effective heat dissipation method.

[0004] Installing heat sinks in printed circuit boards is one of the common methods. Commonly used heat sinks are all made of metal materials, with aluminum and copper being the most common; non-metallic materials include epoxy boards, glass, ceramics, and fluoroplastics. Circuit boards equipped with heat sinks have greatly improved thermal conductivity, dimensional stability, vibration resistance, and appearance protection. At the same time, the thermal expansion and contraction of components on the printed circuit board are alleviated, improving the reliability and service life of electronic equipment. Through the research of this project, the bonding process of special-shaped heat sinks is improved, and the bonding efficiency and bonding quality are improved.

[0005] In the current existing technology, most of the bonding methods for special-shaped heat sinks on the market use liquid adhesive bonding methods. The peeling strength and high temperature resistance of the components after bonding by this bonding method are not as good as those of film bonding. Summary of the invention

[0006] In view of the shortcomings of the above-mentioned existing production technology, the applicant provides a film bonding process for special-shaped heat sinks and printed circuit boards, thereby conducting a detailed analysis of the special-shaped structure, analyzing the stress-bearing area of ​​the material in the process formulation link, and formulating the optimal film bonding process parameters.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A film bonding process for a special-shaped heat sink and a printed circuit board includes the following operation procedures:

[0009] S1: Film bonding process development;

[0010] Study the dimensions of special-shaped structures, develop positioning methods and tooling, calculate the required pressure value based on the contact area between the heat sink and the printed circuit board, and develop film bonding process parameters;

[0011] S2: bonding tooling design;

[0012] By studying the heat sink structure and the dimensions of the printed circuit board, the basic structure of the bonding and positioning tooling was confirmed, and the tooling with anti-static, anti-collision and rapid positioning was comprehensively considered;

[0013] S3: tooling production;

[0014] According to the design dimensions of the tooling and the production clamping process, purchase the raw materials for tooling production and produce the tooling;

[0015] S4: film engraving data processing;

[0016] Convert the electronic data of cold plate production into a format that can be used by the film engraving machine, and edit and layout it; S5: film engraving;

[0017] Cut the KAPTON film according to the required size, and attach the cut KAPTON film to the engraving machine; load the corresponding edited data, and start the engraving machine to engrave the film.

[0018] As a further improvement of the above technical solution:

[0019] Tear off the KAPTON film along the outer shape, and use a sharp cone to clean the remaining slices inside the KAPTON film; separate the cleaned finished films with paper to avoid direct contact between the finished films;

[0020] S7: cold adhesive;

[0021] The production staff places the finished film on top of the bonding surface of the heat sink, inserts a syringe into the bonding surface and injects a small amount of adhesive until the cold plate and the film are completely bonded and flat;

[0022] S8: tooling positioning;

[0023] Confirm the bonding surface of the printed circuit board, take out the heat sink after cold bonding, put the printed circuit board and the heat sink into the tooling, and ensure that the four sides of the printed circuit board and the heat sink are embedded in the tooling;

[0024] S9: Preheating;

[0025] Take a piece of kraft paper and a high temperature resistant film, fold them in half, sandwich the bonding component in the middle, put the cold plate side up in the drying oven to heat;

[0026] S10: hot pressing;

[0027] Put the preheated bonding components into a vulcanizer for heating and pressurization;

[0028] S11: Cooling;

[0029] After hot pressing, the bonded components are removed from the vulcanizer and placed between two steel plates to cool.

[0030] Push out the bonding component from the hollowed-out portion on the reverse side of the tooling;

[0031] S13: Processing;

[0032] The production staff uses a blade or a sharp cone to clean the glue that overflows from the edge and cleans the surface with anhydrous ethanol.

[0033] Its further technical solution is:

[0034] In S2, the tooling accuracy is controlled within ±0.05mm.

[0035] In S3, when the production process changes steps, it is necessary to design a quick positioning and clamping tooling to ensure that the bonding tooling can be produced and completed quickly to ensure the overall progress of the bonding.

[0036] In S9, the high temperature resistant film is inside and ensure that there is no foreign matter in the kraft paper and the high temperature resistant film.

[0037] In S9, the film adhesion preheating temperature is 123°C and the preheating time is 5 minutes.

[0038] In S10, the film bonding hot pressing temperature is 135°C, the pressure is 0.5-1MPA, and the hot pressing time is 15min.

[0039] In S11, the cooling time is 5 minutes.

[0040] The beneficial effects of the present invention are as follows:

[0041] The present invention adopts parameter formulation technology to formulate process parameters that need to be combined with the force applied to the stress area of ​​the special-shaped cold plate and the contact area with the printed circuit board during hot pressing to meet the film bonding pressure requirements, thereby ensuring that the bonding components will not be damaged during the hot pressing process and that the heat sink and the printed circuit board are bonded together, and meeting the bonding anti-peel strength requirements.

[0042] The present invention effectively solves the problem that conventional film bonding process parameters may cause excessive or insufficient force on special-shaped heat sinks during bonding due to structural characteristics, resulting in bonding quality problems. By analyzing the special-shaped heat sinks, a set of special process parameter conversion methods are mastered, so that the produced bonding components will not damage the bonding plates and can also ensure their bonding strength, which significantly improves the bonding quality compared to conventional processes. DETAILED DESCRIPTION

[0043] The specific embodiments of the present invention are described below.

[0044] The film bonding process of the special-shaped heat sink and printed circuit board of this embodiment includes the following operation flow:

[0045] S1: Film bonding process development;

[0046] Study the dimensions of special-shaped structures, develop positioning methods and tooling, calculate the required pressure value based on the contact area between the heat sink and the printed circuit board, and develop film bonding process parameters;

[0047] S2: bonding tooling design;

[0048] By studying the heat sink structure and the dimensions of the printed circuit board, the basic structure of the bonding and positioning tooling was confirmed, and the tooling with anti-static, anti-collision and rapid positioning was comprehensively considered;

[0049] S3: tooling production;

[0050] According to the design dimensions of the tooling and the production clamping process, purchase the raw materials for tooling production and produce the tooling;

[0051] S4: film engraving data processing;

[0052] Convert the electronic data of cold plate production into a format that can be used by the film engraving machine, and edit and layout it; S5: film engraving;

[0053] Cut the KAPTON film according to the required size, and attach the cut KAPTON film to the engraving machine; load the corresponding edited data, and start the engraving machine to engrave the film.

[0054] Tear off the KAPTON film along the outer shape, and use a sharp cone to clean the remaining slices inside the KAPTON film; separate the cleaned finished films with paper to avoid direct contact between the finished films;

[0055] S7: cold adhesive;

[0056] The production staff places the finished film on top of the bonding surface of the heat sink, inserts a syringe into the bonding surface and injects a small amount of adhesive until the cold plate and the film are completely bonded and flat;

[0057] S8: tooling positioning;

[0058] Confirm the bonding surface of the printed circuit board, take out the heat sink after cold bonding, put the printed circuit board and the heat sink into the tooling, and ensure that the four sides of the printed circuit board and the heat sink are embedded in the tooling;

[0059] S9: Preheating;

[0060] Take a piece of kraft paper and a high temperature resistant film, fold them in half, sandwich the bonding component in the middle, with the cold plate facing up, and put them in a drying oven to heat;

[0061] S10: hot pressing;

[0062] Put the preheated bonding components into a vulcanizer for heating and pressurization;

[0063] S11: Cooling;

[0064] After hot pressing, the bonded components are removed from the vulcanizer and placed between two steel plates to cool.

[0065] Push out the bonding component from the hollowed-out portion on the reverse side of the tooling;

[0066] S13: Processing;

[0067] The production staff uses a blade or a sharp cone to clean the glue that overflows from the edge and cleans the surface with anhydrous ethanol.

[0068] In S2, the tooling accuracy is controlled within ±0.05mm.

[0069] In S3, when the production process changes steps, it is necessary to design a quick positioning and clamping tooling to ensure that the bonding tooling can be produced and completed quickly to ensure the overall progress of the bonding.

[0070] In S9, the high temperature resistant film is inside and ensure that there is no foreign matter in the kraft paper and the high temperature resistant film.

[0071] In S9, the film adhesion preheating temperature is 123°C and the preheating time is 5 minutes.

[0072] In S10, the film bonding hot pressing temperature is 135°C, the pressure is 0.5-1MPA, and the hot pressing time is 15min.

[0073] In S11, the cooling time is 5 minutes.

[0074] The process of bonding the special-shaped heat sink and printed circuit board according to the present invention has the following process route:

[0075] S1 film bonding process formulation → S2 bonding tooling design → S3 tooling production → S4 film engraving data processing → S5 film engraving → S6 film stamping → S7 cold bonding → S8 tooling positioning → S9 preheating → S10 hot pressing → S11 cooling → S12 tooling disassembly → S13 processing.

[0076] Specific:

[0077] Film bonding process formulation: After receiving the boards to be bonded, the process personnel will study their structural dimensions, formulate suitable positioning methods and tooling based on the uneven force characteristics of the special-shaped heat sink, calculate the required pressure value based on the contact area between the special-shaped heat sink and the printed circuit board, and formulate film bonding process parameters.

[0078] Bonding tooling design: By studying the heat sink structure and the dimensions of the printed circuit board, the basic structure of the bonding and positioning tooling is confirmed. The tooling is considered to be anti-static, anti-collision and capable of rapid positioning, and the tooling accuracy is controlled within ±0.05mm.

[0079] Tooling production: Based on the design of the tooling's dimensions and the production clamping process, the tooling production raw materials are purchased. When the production process changes, it is necessary to design a quick positioning and clamping tooling to ensure that the bonding tooling can be quickly produced to ensure the overall progress of the bonding.

[0080] Engraving data processing: convert the electronic data of cold plate production into a format that can be used by the engraving machine, and edit and layout it.

[0081] Film engraving: Cut the KAPTON film according to the required size, and attach the cut KAPTON film to the film engraving machine; load the corresponding edited data, and start the film engraving machine to engrave the film.

[0082] Film stamping: Take the engraved KAPTON film off the engraving machine, tear off the KAPTON film along the outer shape, and use a sharp cone to clean the remaining slices inside the KAPTON film; separate the cleaned finished films with paper to avoid direct contact between the finished films.

[0083] Cold bonding: The production staff places the finished film on top of the bonding surface of the heat sink, inserts a syringe into the bonding surface and injects a small amount of adhesive until the cold plate and the film are completely bonded and fit flat.

[0084] Tool positioning: confirm the bonding surface of the printed circuit board, take out the heat sink that has been cold-bonded, put the printed circuit board and the heat sink into the tooling, and ensure that all four sides of the printed circuit board and the heat sink are embedded in the tooling.

[0085] Preheating: Take a piece of kraft paper and a high temperature resistant film, stack them in half (the high temperature resistant film is inside and make sure there is no foreign matter in the kraft paper and the high temperature resistant film), sandwich the bonding component in the middle, with the cold plate facing up, and put it in a drying oven for heating; the conventional film bonding preheating temperature is 123℃, and the preheating time is 5 minutes.

[0086] Hot pressing: Place the preheated bonding components into a vulcanizer for heating and pressurization; conventional film bonding hot pressing temperature is 135°C, pressure is 0.5-1MPA, and hot pressing time is 15min.

[0087] Cooling: After hot pressing, remove the bonded component from the vulcanizer and place it between two steel plates to cool for 5 minutes.

[0088] Disassemble the tooling: Take out the cooled bonding component and push it out from the hollow part on the back of the tooling.

[0089] Treatment: The production staff uses a blade or a sharp cone to clean the glue overflowing from the edge; use anhydrous ethanol to clean the surface.

[0090] Through the above process flow, the optimal film bonding process parameters can be easily formulated.

[0091] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A film bonding process for a special-shaped heat sink and a printed circuit board, characterized in that: The following operation procedures are included: S1: Film bonding process development; Study the dimensions of special-shaped structures, develop positioning methods and tooling, calculate the required pressure value based on the contact area between the heat sink and the printed circuit board, and develop film bonding process parameters; S2: bonding tooling design; By studying the heat sink structure and the dimensions of the printed circuit board, the basic structure of the bonding and positioning tooling was confirmed, and the tooling with anti-static, anti-collision and rapid positioning was comprehensively considered; S3: tooling production; According to the design dimensions of the tooling and the production clamping process, purchase the raw materials for tooling production and produce the tooling; S4: film engraving data processing; Convert the electronic data of cold plate production into a format that can be used by the film engraving machine, and edit and layout it; S5: film engraving; Cut the KAPTON film according to the required size, and attach the cut KAPTON film to the engraving machine; load the corresponding edited data, and start the engraving machine to engrave the film. S6: poke membrane; Take the engraved KAPTON film from the engraving machine, tear off the KAPTON film along the outer shape, and use a sharp cone to clean the remaining slices inside the KAPTON film; separate the cleaned finished films with paper to avoid direct contact between the finished films; S7: cold adhesive; The production staff places the finished film on top of the bonding surface of the heat sink, inserts a syringe into the bonding surface and injects a small amount of adhesive until the cold plate and the film are completely bonded and flat; S8: tooling positioning; Confirm the bonding surface of the printed circuit board, take out the heat sink after cold bonding, put the printed circuit board and the heat sink into the tooling, and ensure that the four sides of the printed circuit board and the heat sink are embedded in the tooling; S9: Preheating; Take a piece of kraft paper and a high temperature resistant film, fold them in half, sandwich the bonding component in the middle, put the cold plate side up in the drying oven to heat; S10: hot pressing; Put the preheated bonding components into a vulcanizer for heating and pressurization; S11: Cooling; After hot pressing, the bonded components are removed from the vulcanizer and placed between two steel plates to cool. S12: disassembly tooling; Take out the cooled bonding component and push it out from the hollowed-out part on the back of the tooling; S13: Processing; The production staff uses a blade or a sharp cone to clean the glue that overflows from the edge and cleans the surface with anhydrous ethanol.

2. The process for bonding a special-shaped heat sink to a printed circuit board according to claim 1, characterized in that: In S2, the tooling accuracy is controlled within ±0.05mm.

3. The process for bonding a special-shaped heat sink to a printed circuit board according to claim 1, characterized in that: In S3, when the production process changes steps, it is necessary to design a quick positioning and clamping tooling to ensure that the bonding tooling can be produced and completed quickly to ensure the overall progress of the bonding.

4. The process for bonding a special-shaped heat sink to a printed circuit board according to claim 1, characterized in that: In S9, the high temperature resistant film is inside and ensure that there is no foreign matter in the kraft paper and the high temperature resistant film.

5. The process for bonding a special-shaped heat sink to a printed circuit board according to claim 1, characterized in that: In S9, the film adhesion preheating temperature is 123°C and the preheating time is 5 minutes.

6. The process for bonding a special-shaped heat sink to a printed circuit board according to claim 1, characterized in that: In S10, the film bonding hot pressing temperature is 135°C, the pressure is 0.5-1MPA, and the hot pressing time is 15min.

7. The process for bonding a special-shaped heat sink to a printed circuit board according to claim 1, characterized in that: In S11, the cooling time is 5 minutes.