WO2021179519A1

WO2021179519A1 - Preparation method for high-precision multi-stage printed circuit board of intelligent unmanned aerial vehicle

Info

Publication number: WO2021179519A1
Application number: PCT/CN2020/105812
Authority: WO
Inventors: 王欣; 周刚; 曾祥福
Original assignee: 广东科翔电子科技股份有限公司
Priority date: 2020-03-10
Filing date: 2020-07-30
Publication date: 2021-09-16
Also published as: CN111246687A

Abstract

Disclosed is a preparation method for a high-precision multi-stage printed circuit board of an intelligent unmanned aerial vehicle. The preparation method is used for preparing an N-layer high-precision multi-stage printed circuit board for an intelligent unmanned aerial vehicle aviation equipment, wherein N is a natural number larger than 6. The preparation method comprises: a first step of manufacturing an inner layer core board (30); a second step of manufacturing layers L3 to L(N-2); a third step of manufacturing layers L2 to L(N-1); and a fourth step of manufacturing layers L1 to LN, wherein the layers L1 and LN are firstly manufactured, then the layer L1, an integral board formed by the layers L2 to L(N-1) manufactured in the third step, and the layer LN are sequentially stacked together for a laminating treatment, so as to laminate the layers L1 to LN together. According to the preparation method for a high-precision multi-stage printed circuit board of an intelligent unmanned aerial vehicle, a circuit board is prepared by firstly preparing the inner layer core board (30), and then preparing circuit layers in multiple steps and laminating the circuit layers; and the circuit board prepared by the preparation method has the advantages of having multiple layers, a thin plate thickness, a high precision, etc.

Description

High-precision multi-stage intelligent UAV printed circuit board preparation method

Technical field

The invention relates to the technical field of printed circuit boards, in particular to a method for preparing a high-precision multi-stage intelligent unmanned aerial vehicle printed circuit board.

Background technique

As aeronautical equipment, smart drones need to integrate more circuits with a lighter mass, while achieving more functions in a smaller area. Therefore, the high-precision multi-level intelligent UAV printed circuit board has the following characteristics: multiple layers, thin board thickness, strict size requirements, high hole filling and recession requirements, and strict line width tolerance requirements.

In the preparation process of the existing printed circuit board, on the one hand, since the core board is not allowed to be tangent to the concentric circles after the pressing, the core board is baked before the pressing to make the board surface The loss of water disperses and solidifies the resin on the surface of the board. Baking refers to heating and baking the core board in the baking room. A baking rack is generally set in the traditional baking room, and multiple core boards are stacked in sequence on the baking rack. In this traditional way of stacking multiple core boards in a baking chamber for baking, during the baking process, the baking degree of each core board is likely to be different, and the baking is uneven. On the other hand, during the etching process of the inner core of the printed circuit board, when the core is transported on the inner etching line, the corners of the core are easily scrapped, which increases the overall investment cost.

Summary of the invention

The invention provides a method for preparing a printed circuit board of a high-precision multi-stage intelligent drone with a large number of layers, a thin plate and a high precision.

In order to achieve the above objectives, the following technical solutions are implemented.

A method for preparing a high-precision multi-stage intelligent UAV printed circuit board. The preparation method is used to prepare an N-layer high-precision multi-stage printed circuit board for intelligent UAV aviation equipment, where N is greater than 6 The natural number of, the preparation method includes the following steps,

The first step: the production of the inner core board, including cutting, inner wet film, inner etching and post-processing of the core board;

The second step: the production of L3 to L(N-2) layers; the inner core board produced in the first step is conventionally produced for pre-processing and post-processing, before embedding and post-processing It also includes baking board treatment, stacking the inner core boards after finishing the post-process processing in sequence, and performing the pressing process to laminate L3 to L(N-2) together;

The third step: the production of the L2 to L(N-1) layer, the L2 and L(N-1) layers are first produced, the L2 and the L3 to L(N-2) layer monolithic board produced in the second step are combined with L(N-1) are stacked one by one, and the pressing process is performed to laminate L2 to L(N-1) together;

The fourth step: the production of L1 to LN, the L1 and LN layers are first produced, the L1, the L2 to L(N-1) layer monolithic board made in the third step and the LN are stacked in sequence, and the pressing process is performed , Laminate L1 to LN together.

The preparation method of the high-precision multi-stage intelligent drone printed circuit board of the present invention prepares the circuit board by first preparing the inner core board, and then preparing the circuit layer in multiple steps and pressing the circuit board. The advantage of high precision. Specifically, after the inner core board is made, the L3 to L(N-2) layers are made and pressed together to form an integral board, and then the L2 layer and the L(N-1) layer are combined with the L3 to L(N-2) layer. -2) Laminate together to form an integrated board, and finally L1 and LN layers and L2 to L(N-1) are pressed together to form an integrated printed circuit board. This preparation method can prepare the thickness and precision of the board. The high multi-layer board meets the circuit board requirements of the intelligent UAV aviation equipment field.

Further, the inner layer etching process is carried out by the inner layer etching line for thin plate transfer, and the inner layer etching line is a precision-shaped side reel. Because the thickness of the high-precision circuit board is thin, the thickness of the inner core board is only 0.08mm when the inner core board is etched. The traditional inner etching line is used for etching and transmission, which is very easy to form a card board, and then lead to the scrap of the board. Through long-term observations of the inventor, it has been found that the main reason for the thin board is that the corners of the board tend to fall in the gap of the reel during the conveying process to form the board. In the present invention, the inner layer etching line adopts precision side reel to reduce the gap between the end reel, which will not affect the production of the circuit, and effectively solves the problem that the board corners in the prior art are easy to fall into the gap and cause the board to be jammed.

Further, the inner layer etching line includes a plurality of transmission shafts distributed in parallel, and each transmission shaft is provided with a plurality of intermediate rollers for conveying thin plates and end rollers located at both ends of the transmission shaft. The thickness of the end row reels is greater than the thickness of the middle row reels, and the rows of reels on the adjacent transmission shafts are dislocated. The arrangement of the dislocation reel on the adjacent conveying shafts provides better support for the inner core plate. At the same time, the end reel is thicker than the middle reel, so that the two at the same end The gap between adjacent rows of reels is reduced, effectively avoiding the board corners from falling into the gaps of the end reels.

Further, the end reel is made of PVC material with a thickness of 8mm, and the gap between the two end reels at the same end of the adjacent transmission shaft is 1mm. Under the condition of ensuring the transmission support effect, it can effectively ensure that there will be no occurrence. The jam phenomenon saves raw material costs and labor costs, and effectively ensures that the process is stable during the long-term etching process.

Further, the post-process processing in the first step includes AOI detection, PE punching and browning processing.

Further, the baking sheet processing in the second step above is to perform baking sheet and expansion and shrinkage control processing on the core board in a layered baking sheet manner. The layered baking sheet is adopted. The layered baking sheet can be used to place the core board in layers, and each core board is heated evenly, so that the temperature uniformity of the core board baking board is good, and the stability of the baking board is improved, thereby reducing The amount of expansion and contraction of the small core board.

Further, the baking process is to sequentially place the core plates in a baking device for baking. The baking device includes a baking chamber, and the baking chamber is provided with a multilayer baking rack arranged at intervals. The baking rack includes a baking tray and a supporting structure, the supporting structure is installed in the baking chamber, and the baking tray is installed on the supporting structure for placing and baking the core board. The setting of multi-layer baking racks in the baking chamber makes multiple core boards placed on different layers of baking trays to ensure that the core boards on each baking tray are evenly heated during the baking process, so that the board is heated evenly. The internal water is dispersed and the board surface resin is cured uniformly, which improves the stability of the core board and reduces the expansion and contraction of the core board.

Further, the baking tray is a circular baking tray, the baking tray is composed of a plurality of groups of round pieces of different sizes, each round piece is distributed in a concentric shape, and each round piece is made of metal material The cross-section of the circular piece is circular, the diameter of the circular cross-section of the circular piece is 3mm, and the distance between adjacent circular pieces is 5cm. Each round piece of different sizes is a circular baking pan formed by concentrically distributed distribution. After the core board is placed on the baking pan, during the baking process, the upper and lower heating is consistent, and the uniformity is good. A circular baking pan with multiple circular pieces made of metal material distributed in a concentric structure is adopted. The heat transfer speed of the metal material is fast and stable. The distance between adjacent circular pieces is 5cm, so that each circular piece The distance is equal, the distribution is uniform and stable, and the heat in the baking chamber can be evenly transferred to the core board, so that the water in the board is dispersed and the resin on the board is cured uniformly, which effectively avoids the uneven baking caused by the traditional multi-layer stacking baking.

Further, the number of the circular parts is at least 6 groups, and the specific number of the circular parts depends on the size of the core plate and the size of the baking chamber. At least 6 groups of circular parts are provided to effectively ensure that each group is round. The pieces are evenly distributed to form a stable baking tray, so that the core board is stable after being placed on the baking tray.

Further, the metal material is any one of stainless steel, copper, or aluminum, and may also be other common heat transfer metal materials.

Further, the supporting structure includes at least two intersecting supporting bars, both ends of the supporting bars are respectively connected to the inner wall of the baking chamber, and the inner wall of the baking chamber in contact with the end of the supporting bar is provided with a support Support grooves with matching strips. The support bar is used to support the circular piece, and the support groove is used to support and fix the support bar, so that the support structure is stable and installed in the baking chamber.

Further, the support bar has a square support bar with a width of 1 cm, a thickness of 1 cm, and a 1 cm×1 cm square structure, which not only has a stable structure, but also has less consumables and is easy to install.

Further, the baking temperature in the baking chamber is 160° C., and the baking time is 4 hours, which makes the core board baking process more stable and has better effects, and further reduces the amount of expansion and contraction of the core board during baking.

Compared with the prior art, the method for preparing the high-precision multi-stage intelligent UAV printed circuit board of the present invention has the following beneficial effects:

After the inner core board of the present invention is completed, the L3 to L(N-2) layers are made and pressed together to form an integral board, and then the L2 layer and the L(N-1) layer are combined with the L3 to L(N- 2) Laminate together to form an integrated board, and finally L1 and LN layers and L2 to L(N-1) are pressed together to form an integrated printed circuit board. This preparation method can prepare the thickness of the board with high precision. The multi-layer board meets the requirements of the circuit board in the field of intelligent UAV aviation equipment.

The expansion and contraction control method of the printed circuit board core board of the present invention adopts a layered baking plate. The layered baking plate can be used to place the core boards in layers, and each core board is heated evenly up and down, thereby making the core board baking board The temperature uniformity is good, which improves the stability of the baking sheet, thereby reducing the expansion and contraction of the core board.

Description of the drawings

Figure 1 is a schematic diagram of the L3 to L10 laminated board in the preparation method of the high-precision multi-stage intelligent UAV printed circuit board of the present invention;

Figure 2 is a schematic diagram of the L2 to L11 laminated board in the method for preparing the high-precision multi-stage intelligent drone printed circuit board according to the present invention;

Fig. 3 is a schematic diagram of the L1 to L12 laminated board in the method for preparing the printed circuit board of the high-precision multi-stage intelligent drone of the present invention;

Fig. 4 is a schematic plan view of the baking rack in the preparation method of the high-precision multi-stage intelligent drone printed circuit board of the present invention;

Figure 5 is a partial schematic diagram of the baking chamber in the preparation method of the high-precision multi-stage intelligent drone printed circuit board of the present invention;

Fig. 6 is a schematic diagram of the structure of the inner layer etching line in the preparation method of the high-precision multi-stage intelligent drone printed circuit board of the present invention.

Detailed ways

Hereinafter, the method for preparing the printed circuit board of the high-precision multi-stage intelligent drone of the present invention will be further described in detail with reference to specific embodiments and drawings.

1 to FIG. 6, a non-limiting embodiment of the present invention, a high-precision multi-stage intelligent UAV printed circuit board preparation method, the preparation method is used to prepare 12 for intelligent UAV aviation equipment For a high-precision multi-layer printed circuit board, where 12 is a natural number greater than 6, this embodiment takes a 12-layer board as an example for description. The preparation method includes the following steps:

The first step: the production of the inner core board 30, including cutting, inner wet film, inner etching and post-processing of the core board 30. FR4 with a thickness of 0.08mm is selected as the core board 30. The post-processing includes AOI. Inspection, PE punching and browning treatment;

The second step: the production of the L3 to L10 layers; the inner core plate 30 produced in the first step is subjected to the pre-processing and post-processing of the plugging hole and the post-processing process according to the conventional production. The plugging hole adopts aluminum sheet plug hole: double hole The noodles need to be oiled. After plugging the first piece of baking sheet, do the slice confirmation. It is divided into BGA area and non-BGA area. The area with plug hole fullness ≥ 90% is BGA area, and 90%> plug hole fullness ≥ 80% is non-BGA Area; before plugging and buried holes and post-process processing, it also includes baking plate processing, which is used to control and reduce the expansion and contraction of the core plate 30. The pre-process processing includes: X-ray gong edge → edging → drilling → black hole →Board electrical treatment, X-ray gong-side shooting adopts ±2mil sub-board, drilling: 1 piece/1 stack, using double-edged drill, hole thickness control ≤25μm, drilling life ≤1500 drills, limited to one grinding; The minimum point of the hole copper is 15μm, the surface copper is 20-35μm, and the range is controlled within 6μm. It is made of VCP, the current coefficient is 9ASF, the time is 90 minutes, and the full surface copper is measured. Post-process processing includes edge grinding → line exposure, development and etching → AOI → high-pressure water washing → browning treatment: the inner core board 30 after the post-process treatment is stacked in sequence, and the pressing process is performed, and L3 to L10 are laminated Put together, the layers are bonded with PP sheets during pressing, and sliced after pressing;

The third step: the production of L2 to L11 layers, first make L2 and L11 layers, stack L2, the L3 to L10 layer monolithic board made in the second step, and L11 in turn, and perform the pressing process, the L2 to L11 L11 is laminated together; the production process includes X-ray gong edge → edging → copper reduction browning → laser → drilling → black hole → hole-filling plate electricity → circuit exposure, development and etching → AOI → high-pressure water washing → browning → Stack the board → press-fit. Specific control includes controlling surface copper 7-9μm after copper reduction and browning, controlling the thickness of bottom copper to prevent delamination, laser drilling: 1. Laser aperture: +/-25um; 2. When laser is +/-2mil sub-factor Board; 3. The alignment degree of the first piece of the outer layer of the laser slice blind hole overlap hole, it is required to meet the specification requirements. After laser sampling, use a hundredfold mirror to check whether there is any laser residue in the copper at the bottom of the blind hole. The same method is used to fill the holes, using a hundred-fold lens to observe the hole filling depressions. Observe more than 10 blind holes at each point. Because of the observation with a hundred-fold lens, there is no need to scrap the section and the speed is fast. The principle is that the uniformity of copper reduction during laser irradiation, the difference in copper reduction between the board surface and the board surface due to the difference in immersion concentration, is likely to have residual glue at the bottom during laser irradiation, and when filling holes, vertical hole filling is used to fill the plate. The surface spray and copper plating uniformity will also affect the degree of depression of the hole filling.

The fourth step: the production of L1 to L12, the L1 and L12 layers are made first, the L1, the L2 to L11 layer monolithic board made in the third step and the L12 are stacked in sequence, and the lamination process is carried out, and the L1 to L12 Laminating together, the production process includes X-ray gong edge → edging → copper reduction and browning → laser → drilling → black hole → hole-filling plate electricity → circuit exposure, development and etching → AOI → impedance test → solder plug hole → Solder mask → text → impedance test → gold forming → over reflow soldering → electrical test → pressure baking → final inspection. Specific control: After electroplating, cut the hole copper, take the pinch point opposite to the low potential position, and measure the hole copper according to the 6-point measurement method; circuit: the resistance value of the first piece needs to be measured, the impedance value and BGA specifications are the priority control, and the impedance is controlled second Line width and minimum line width, quality measurement: 1. After etching, the peeling strength of copper foil must be measured (≥1.0512/mm (single point minimum)); 2. After etching, the tensile strength of the pad must be measured (≥10MPa (1.10mm circle)形PAD)); 3. The bottom of the line measurement line, the top of the BGA and SMD measurement line; plug hole: aluminum plug hole 1, plug hole depth ≥ 70%, no cracks extending to the hole, no copper leakage inside the plug hole, It is not allowed to plug the hole with plug and print method. 2. Use special plug hole ink, and it is not allowed to plug the hole with surface oil; test after solder mask: 1. Thermal stress test (288*10 seconds*5 times, immersion tin) without falling off; 2. No fall off after 5 times of reflow soldering; 3. 10% H2SO4 resistance, 5% 12aOH resistance test, 10mi12 no oil rejection; 4. Hardness test ≥ 5H, use 5HB pencil for hardness test; molding production: 1. Molding tolerance Strictly control according to ±0.1mm; 2. The program is divided into rough milling and fine milling once each, the first piece is taken from the diagonal base plate, and 4 axes are measured according to MI drawings; 3. All shipments are measured with two-dimensional full measurement; 4. There are two 3.6mm PTH holes on the edge of the board, no burrs are allowed; shipping inspection: 1. Full inspection of the dent and thickness (soldering resistance to soldering resistance) at the time of shipment; 2. All samples are shipped with two dimensions Full measurement size; 3. Ion pollution test, solderability test, insulation test, thermal stress test are required to be done according to customer specifications.

1 to 6, a non-limiting embodiment of the present invention, the high-precision multi-stage intelligent UAV printed circuit board preparation method of the present invention first prepares the inner core board 30, and then prepares the circuit layer and presses it in multiple steps The integrated method for circuit board preparation has the advantages of multiple layers, thin board thickness and high precision. Specifically, after the inner core board 30 is manufactured, the L3 to L10 layers are first fabricated and pressed together to form an integrated board, and then the L2 and L11 layers are laminated with L3 to L10 to form the integrated board, and finally The L1 layer and the L12 layer are pressed together with L2 to L11 to form an integrated printed circuit board. This preparation method can prepare a multi-layer board with a thickness and high precision, and meets the requirements of a circuit board in the field of intelligent UAV aviation equipment.

Referring to FIG. 6, a non-limiting embodiment of the present invention, the inner layer etching process is carried out by the inner layer etching line for thin plate transfer, and the inner layer etching line is a precision-shaped side reel. Because the thickness of the high-precision circuit board is relatively thin, when the inner core board 30 is etched, the board thickness is only 0.08mm. The traditional inner etching line is used for etching and transmission, which is very easy to form a card board, and then lead to the scrap of the board. Through long-term observations of the inventor, it has been found that the main reason for the thin board is that the corners of the board tend to fall in the gap of the reel during the conveying process to form the board. In the present invention, the inner layer etching line adopts a precision side reel, which reduces the gap between the end reel 50, which does not affect the production of the circuit, and effectively solves the problem that the board corners in the prior art are easy to fall into the gap and cause the board to be stuck. .

Referring to FIG. 6, a non-limiting embodiment of the present invention, the inner layer etching line includes a plurality of parallel transmission shafts 40, each transmission shaft 40 is provided with a plurality of intermediate rows 69 for conveying thin plates and located The end rollers 50 at the two ends of the transmission shaft 40 have a thickness greater than the thickness of the middle roller 69, and the rows of rollers on the adjacent transmission shafts 40 are distributed in a misaligned manner. The dislocation and distribution of the row reels on the adjacent transmission shafts 40 provide better support for the transmission of the inner core plate 30. At the same time, the end row reels 50 are thicker than the middle row reels 69, so that they are located at the same end. The gap between the two adjacent row reels of the bottom part is reduced, which effectively prevents the board corners from falling into the gap of the end part row reels 50. The end reel 50 is made of PVC material and has a thickness of 8mm. The gap between the two end reels 50 at the same end of the adjacent transmission shaft 40 is 1mm. Under the condition of ensuring the transmission support, it can effectively ensure that it will not appear. The jam phenomenon saves raw material costs and labor costs, and effectively ensures that the process is stable during the long-term etching process.

4 and 5, a non-limiting embodiment of the present invention, the baking plate processing in the second step is to use a layered baking plate to perform baking plate and expansion and shrinkage control processing on the core plate 30. It adopts the layered baking plate method. The layered baking plate can be used to place the core plates 30 in layers. Each core plate 30 is evenly heated up and down, so that the temperature uniformity of the core plate 30 is good, and the stability of the baking plate is improved. , Thereby reducing the amount of expansion and contraction of the core board 30.

4 and 5, a non-limiting embodiment of the present invention, the baking process is to sequentially place the core plate 30 in a baking device for baking, the baking device includes a baking chamber 10, the baking The baking temperature in the baking chamber 10 is 160° C., and the baking time is 4 hours, so that the baking process of the core board 30 is more stable, the effect is better, and the amount of expansion and contraction of the core board 30 during baking is further reduced. The baking chamber 10 is provided with multiple layers of baking racks 20 arranged at intervals. The baking rack 20 includes a baking tray 22 and a supporting structure 21. The supporting structure 21 is installed in the baking chamber 10. The baking tray 22 is installed on the supporting structure 21 for placing and baking the core board 30. The multi-layer baking racks 20 arranged at intervals in the baking chamber 10 are arranged so that multiple core plates 30 are respectively placed on the baking trays 22 of different layers to ensure that the cores on the baking trays 22 are The board 30 is evenly heated, so that the water in the board is dispersed and the resin on the board is cured uniformly, and the stability of the core board 30 is improved, thereby reducing the amount of expansion and contraction of the core board 30.

4 and 5, a non-limiting embodiment of the present invention, the baking tray 22 is a circular baking tray 22, the baking tray 22 is composed of a plurality of groups of round pieces of different sizes, each round The pieces are distributed in concentric circles, each round piece is made of metal material, the cross section of the round piece is round, the diameter of the round section of the round piece is 3mm, and the distance between adjacent round pieces is 5cm. The circular pieces of different sizes are distributed in a concentric shape to form a circular baking tray 22. After the core plate 30 is placed on the baking tray 22, during the baking process, the upper and lower heating is consistent, and the uniformity is good. The circular baking pan 22 formed by a plurality of circular pieces made of metal material distributed in a concentric structure is adopted. The heat transfer speed of the metal material is fast and stable. The distance between adjacent circular pieces is 5cm, so that each circular piece The distance between them is the same and the distribution is even and stable. The heat in the baking chamber 10 can be evenly transferred to the core board 30, so that the water in the board is dispersed and the resin on the board is cured uniformly, which effectively avoids the baking failure caused by traditional multi-layer stacking baking. All phenomenon.

4 and 5, a non-limiting embodiment of the present invention, the number of the circular members is at least 6 groups, the specific number of circular members depends on the size of the core plate 30 and the size of the baking chamber 10 At least 6 groups of circular parts are provided to effectively ensure that the circular parts of each group are evenly distributed to form a stable baking tray 22, so that the core plate 30 is stable after being placed on the baking tray 22.

4 and 5, a non-limiting embodiment of the present invention, the metal material is any one of stainless steel, copper, or aluminum, and may also be other common heat transfer metal materials.

4 and 5, a non-limiting embodiment of the present invention, the support structure 21 includes at least two intersecting support bars, both ends of the support bars are connected to the inner wall of the baking chamber 10, and the baking The inner wall of the chamber 10 in contact with the end of the support bar is provided with a support groove matched with the support bar. The support bar is arranged to support the circular piece, and the support groove is set to support and fix the support bar, so that the support structure 21 is stably installed in the baking chamber 10.

4 and 5, a non-limiting embodiment of the present invention, the support bar has a square support bar with a width of 1 cm and a thickness of 1 cm. The support bar has a square structure of 1 cm×1 cm, which is not only stable in structure, but also less consumable. It is easy to install at the same time.

In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" , "Bottom", "Inner", "Outer" and other indications of the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present invention and simplifying the description, but not indicating or implying the pointed device Or the element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more than two, unless otherwise specifically defined.

In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. , Or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in the present invention can be understood according to specific situations.

The above-mentioned embodiments are only specific embodiments of the present invention, and their descriptions are more specific and detailed, but they should not be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these obvious alternative forms belong to the protection scope of the present invention.

Claims

A preparation method of a high-precision multi-stage intelligent UAV printed circuit board is characterized in that: the preparation method is used to prepare an N-layer high-precision multi-stage printed circuit board for intelligent UAV aviation equipment, wherein N is a natural number greater than 6, and the preparation method includes the following steps:

The first step: the production of the inner core board, including cutting, inner wet film, inner etching and post-processing of the core board;

The second step: the production of L3 to L(N-2) layers; the inner core board produced in the first step is conventionally produced for pre-processing and post-processing, before embedding and post-processing It also includes baking board treatment, stacking the inner core boards after finishing the post-process processing in sequence, and performing the pressing process to laminate L3 to L(N-2) together;

The third step: the production of the L2 to L(N-1) layer, the L2 and L(N-1) layers are first produced, the L2 and the L3 to L(N-2) layer monolithic board produced in the second step are combined with L(N-1) are stacked one by one, and the pressing process is performed to laminate L2 to L(N-1) together;

The fourth step: the production of L1 to LN, the L1 and LN layers are first produced, the L1, the L2 to L(N-1) layer monolithic board made in the third step and the LN are stacked in sequence, and the pressing process is performed , Laminate L1 to LN together.
The method for preparing a high-precision multi-stage smart drone printed circuit board according to claim 1, wherein the inner layer etching process is carried out by the inner layer etching line for thin plate transmission, and the inner layer etching line is made of precision Type side row reel.
The method for preparing a high-precision multi-stage smart drone printed circuit board according to claim 2, wherein the inner layer etching line includes a plurality of parallel transmission shafts, and each transmission shaft is provided with multiple transmission shafts. A middle row reel for conveying the thin plate and end reels located at both ends of the conveying shaft, the thickness of the end reel is greater than the thickness of the middle reel, and the rows of reels on the adjacent conveying shafts are dislocated.
The method for preparing a high-precision multi-stage smart drone printed circuit board according to claim 3, wherein the gap between the two end reels at the same end of the adjacent transmission shaft is 1 mm.
The method for preparing a high-precision multi-stage smart drone printed circuit board according to claim 4, wherein the post-process processing in the first step includes AOI detection, PE punching and browning processing.
The method for preparing a high-precision multi-stage smart drone printed circuit board according to any one of claims 1 to 5, wherein the baking plate in the second step is processed by using a layered baking plate The core board is baked and expanded and contracted.
The method for preparing a printed circuit board for a high-precision multi-stage intelligent drone according to claim 6, wherein the baking step is to sequentially place the core board in a baking device for baking, and the baking The device includes a baking chamber, the baking chamber is provided with multiple layers of baking racks arranged at intervals, the baking rack includes a baking tray and a support structure, the support structure is installed in the baking chamber, the baking tray Installed on the supporting structure, used to place and bake the core board.
The method for preparing a high-precision multi-stage intelligent drone printed circuit board according to claim 7, wherein the baking tray is a circular baking tray, and the baking tray is composed of multiple groups of different sizes. Consisting of circular pieces, each circular piece is distributed in a concentric circle shape, each circular piece is made of metal material, the cross section of the circular piece is circular, and the circular cross-sectional diameter of the circular piece is 3mm , The distance between adjacent circular pieces is 5cm.
The method for preparing a high-precision multi-stage smart drone printed circuit board according to claim 8, wherein the number of the circular parts is at least 6 groups.
The method for preparing a printed circuit board for a high-precision multi-stage intelligent drone according to claim 9, wherein the supporting structure includes at least two intersecting supporting bars, and both ends of the supporting bars are connected to the baking sheet respectively. The inner wall of the baking chamber is connected, and the inner wall of the baking chamber in contact with the end of the support bar is provided with a support groove matched with the support bar.