CN112929998B - Heating plate - Google Patents

Abstract

The present application discloses a heating plate, which is used for a lamination machine for manufacturing printed circuit boards. The heating plate includes: a substrate; The power supply is turned on to generate heat by using the flowing current; the shield layer covers the surface of the substrate on which the auxiliary thermal resistance strip is laid, and is used to protect the auxiliary thermal resistance strip; the auxiliary thermal resistance strip is constructed in a preset shape and laid on the substrate, The resistance distribution density of the auxiliary thermal resistance strips located in the central area of the substrate is smaller than the resistance distribution density of the auxiliary thermal resistance strips located in the peripheral area of the substrate. The heating plate provided by the application can effectively balance uneven heat radiation and improve the temperature consistency of each area of the heating plate.

Description

a heating plate

technical field

The present application relates to the technical field of circuit board manufacturing, in particular to a heating plate for a laminating machine.

Background technique

Printed circuit board, referred to as circuit board, is generally composed of copper foil, prepreg, inner layer and other components. It can also be called printed circuit board, printed circuit board, or PCB (printed circuit board) in English. Among them, copper foil is a negative electrolytic material, a thin, continuous metal foil deposited on the base layer of the circuit board, which acts as a conductor of the PCB. It easily adheres to the insulating layer, accepts the printed protective layer, and forms a circuit pattern after etching.

The main manufacturing equipment of printed circuit boards is a laminator, also known as a circuit board pressing machine. When manufacturing a circuit board, it needs to be heated and pressurized. Foil bonded molding. During the pressing process of multi-layer circuit boards, the semi-cured film undergoes a solid-liquid-solid transformation process under high temperature and high pressure. During this process, the resin in the film undergoes complex physical changes such as flow and shrinkage. The temperature is not uniform, the thickness of the semi-cured film is inconsistent, and the copper foil is tightly attached to the film, and the deformation coefficients of the two are inconsistent, which leads to uneven copper foil, poor quality of the circuit board, and even scrapping. Especially when the copper foil used on the outside is relatively thin, the quality defect of wrinkling is easy to occur during the lamination process.

Contents of the invention

Aiming at the deficiencies in the above technologies, the present application provides a heating plate capable of uniform heating.

The technical scheme that this application solves its technical problem adopts is:

A heating plate for a laminator for manufacturing printed circuit boards, the heating plate comprising:

Substrate;

The heating layer is laid on the substrate, the heating layer includes an auxiliary thermal resistance strip, and the auxiliary thermal resistance strip is used to connect with a power source to generate heat by using the current flowing;

A shield layer, covering the surface of the substrate on which the auxiliary thermal resistance strips are laid, for protecting the auxiliary thermal resistance strips;

The auxiliary thermal resistance strips are configured to be laid on the substrate in a predetermined shape, and the resistance distribution density of the auxiliary thermal resistance strips located in the central area of the substrate is smaller than that of the auxiliary thermal resistance strips located in the peripheral area of the substrate. resistance distribution density.

In one embodiment, the cross-sectional area of the auxiliary thermal resistance strips located in the central region of the substrate is larger than the cross-sectional area of the auxiliary thermal resistance strips located in the peripheral region of the substrate.

In one embodiment, the size of the auxiliary thermal resistance strips in the thickness direction of the heating plate is uniform, and the width of the auxiliary thermal resistance strips located in the central area of the substrate is larger than that of the auxiliary thermal resistance strips located in the peripheral area of the substrate. The width of the thermal resistance strip.

In one embodiment, the spacing of the auxiliary thermal resistance strips located in the central region of the substrate is greater than the spacing of the auxiliary thermal resistance strips located in the peripheral region.

In one of the embodiments, the spacing of the auxiliary thermal resistance strips located in the central area of the substrate is greater than the spacing of the auxiliary thermal resistance strips located in the peripheral area, and the cross-sectional area of each of the auxiliary thermal resistance strips is All consistent.

In one of the embodiments, the substrate is provided with an installation groove consistent with the direction of the preset shape of the auxiliary thermal resistance strip, and the auxiliary thermal resistance strip is embedded in the installation groove.

In one of the embodiments, the preset shape trend includes a serpentine trend, a zigzag trend or a zigzag trend.

In one of the embodiments, the number of the heating layers is two, which are respectively the first heating layer and the second heating layer, and the first heating layer and the second heating layer are respectively laid on two sides of the substrate. On the board surface, the number of the shield layers is two, which are respectively the first shield layer and the second shield layer, and the assembly sequence of the heating plate is the first shield layer, the first heating layer, A substrate, a second heating layer and a second shield layer.

In one embodiment, the substrate is in a square shape, and the auxiliary thermal resistance strips include a plurality of strips connected end to end and parallel to each other, and the plurality of strips are all parallel to one side of the substrate set up.

In one of the embodiments, the auxiliary thermal resistance strip is made in one piece.

In one embodiment, a cooling structure for rapidly cooling the heating plate is further provided on the substrate.

In one of the embodiments, the cooling structure includes a pipeline connected with a refrigerant, and when the heating plate stops heating after pressing, the pipeline passes through a refrigerant to cool the circuit board quickly; the tube The passage is formed in the base plate, and the cooling medium is cooling water or cooling oil.

Compared with the prior art, the present application has the beneficial effects that: the heating layer of the heating plate provided by the present application has auxiliary thermal resistance strips with a preset shape and direction, and the resistance distribution density of the auxiliary thermal resistance strips located in the middle area of the substrate is smaller than that located in the substrate. The resistance distribution density of the auxiliary thermal resistance strip in the surrounding area can effectively compensate the uneven temperature caused by the uneven heat radiation in the middle area of the heating plate and the surrounding area, improve the temperature consistency of each area of the heating plate, and ensure the processing of printed circuit boards quality.

Description of drawings

Fig. 1 is the schematic diagram of the three-dimensional explosion structure of the heating plate described in the present application;

Fig. 2 is a schematic cross-sectional structure diagram of the heating plate shown in Fig. 1;

Fig. 3 is a schematic top view of the heating layer of the heating plate in another embodiment of the present application;

Fig. 4 is a schematic top view of the heating layer of the heating plate in another embodiment of the present application;

Fig. 5 is a schematic diagram of a module structure of a laminator provided by an embodiment of the present application.

FIG. 6 is a schematic perspective view of the laminator shown in FIG. 5 .

Fig. 7 is a nine-point temperature test diagram of the heating plate shown in Fig. 3 .

Fig. 8 is the nine-point temperature test data of the heating plate shown in Fig. 7 .

FIG. 9 is a graph drawn from nine-point temperature data of the heating plate shown in FIG. 7 .

Fig. 10 is the nine-point temperature test data of the heating plate in the prior art.

FIG. 11 is a graph plotted from nine-point temperature data for the heating plate shown in FIG. 10 .

Detailed ways

In order to make the above purpose, features and advantages of the present application more obvious and understandable, the specific implementation manners of the present application will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only some structures related to the present application are shown in the drawings but not all structures. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

The terms "comprising" and "having" and any variations thereof in this application are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally further includes For other steps or units inherent in these processes, methods, products or apparatuses.

Reference herein to an "embodiment" means that a predetermined feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

The present application will be further described in detail below in conjunction with the accompanying drawings, so that those skilled in the art can implement it with reference to the description.

As shown in FIG. 1 and FIG. 2 , the present application provides a heating plate 100 for use in a laminator for manufacturing printed circuit boards. In an embodiment of the present application, the heating plate 100 includes shield layers ( 10 , 14 ), heating layers ( 11 , 13 ) and a substrate 12 . Wherein, the heating layer (11, 13) is laid on the board surface of the substrate, and the shield layer (10, 14) is placed on the outermost layer of the heating plate 100, covering the surface of the substrate on which the heating layer (11, 13) is laid, Used to protect the heating layers (11, 13). After the heating plate 100 is assembled, the heating layers ( 11 , 13 ) are arranged between the base plate 12 and the shield layer 10 .

In one embodiment, there is one heating layer, and the heating plate includes a substrate 12 , a shield layer 10 , and a heating layer 11 disposed between the substrate 12 and the shield layer 10 . In the scenario applied to a laminator, the number of heating plates is at least two, and the two heating plates are stacked on top of each other, with a multi-layer core board for manufacturing circuit boards sandwiched in between, wherein the base plate 12 of the heating plate is located on the outside, and the shield The layer 10 faces the multilayer core board, and the multilayer core board is heated by the heating layer 11 .

In another embodiment, the heating plate 100 may also include two heating layers, namely the first heating layer 11 and the second heating layer 13 disposed on the upper and lower surfaces of the substrate 12 . The outermost layer of heating layer (11,13) is shield layer (10,14), and the quantity of shield layer is two, is respectively first shield layer 10, and second shield layer 14, heating plate 100 In order of composition, they are the first shield layer 10 , the first heating layer 11 , the substrate 12 , the second heating layer 13 , and the second shield layer 14 . Both the upper and lower surfaces of the heating plate 100 provided in this embodiment can be used for heating. In the specific scenario of being applied to a laminator, the heating plate 100 provided in this embodiment can be used as an intermediate plate, which is arranged on the upper and lower heating plates. In the middle, there is a gap between two adjacent heating plates with a multi-layer core plate interposed, and the number of centrally arranged heating plates can be one or more. The heating plate with double heating layers provided in this embodiment can be used in combination with the heating plate with single heating layer provided in the above embodiment. It is arranged in the middle, and a multi-layer core board is interposed between adjacent heating plates, and each multi-layer core board is heated by two adjacent heating plates on the upper and lower sides.

The first heating layer 11 and the second heating layer 13 have the same structure, and for the sake of brevity, only the first heating layer 11 is used as an example for illustration. Please refer to Fig. 3, the first heating layer 11 includes auxiliary thermal resistance strips 111, the two ends of the auxiliary thermal resistance strips 111 are connected to the power supply, after the power supply is turned on, there is a current flowing in the auxiliary thermal resistance strips 111, and the thermal effect of the current makes the auxiliary heating The resistance strip 111 generates heat, which further increases the temperature of the heating plate 100 . The auxiliary thermal resistance strips 111 are laid on the substrate 12 in a predetermined shape, and the resistance distribution density of the auxiliary thermal resistance strips 111 located in the central area of the substrate 12 is smaller than that of the auxiliary thermal resistance strips 111 located in the peripheral area of the substrate 12 . So set, in the case of the same current, the average heat generated per unit area by the auxiliary thermal resistance strips 111 located in the middle area is lower than the average heat generated by the auxiliary thermal resistance strips 111 in the peripheral area, which can balance the The more heat exchange between the surrounding area of the heating plate and the surrounding environment leads to more heat loss in the surrounding area, and the temperature drop is relatively large, which improves the uniformity of the temperature in each area of the heating plate. Conversely, if the auxiliary thermal resistance strips 111 are evenly distributed on the substrate 12, in the case of equal heating heat, since the heat exchange between the peripheral area of the substrate 12 and the surrounding environment is more active, the heat loss of the substrate 12 located in the middle area is slower, resulting in The temperature rise is higher than that of the peripheral area, and the temperature of the peripheral area is lower than that of the middle area, resulting in uneven temperature of the heating plate 100, and the produced printed circuit boards are of poor quality or even scrapped. Here, the resistance distribution density is understood as the total resistance value within a unit area of the substrate 12 , that is, the resistance distribution density is equal to the resistance value of the corresponding region/area of the corresponding region. It can be understood that the greater the density of resistance distribution, the greater the heat generated by the thermal effect of the current per unit area when the same current is passed.

For the convenience of manufacturing and temperature control, in this embodiment, the auxiliary thermal resistance strip 111 of the first heating layer 11 is a continuous strip conductor, and the two ends of the auxiliary thermal resistance strip 111 are used to connect the power supply. , the current at any position of the auxiliary thermal resistance bar 111 is the same. Specifically, the auxiliary thermal resistance strip 111 is made as one piece.

Further, since the auxiliary thermal resistance bar 111 is a conductor, it utilizes the flowing current to generate heat, in order to avoid electric leakage, there is also a heating layer (11, 13) between the adjacent substrate 12 and the shield layer (10, 14). Insulation layer 22, so as to effectively avoid leakage or series electricity between the heating layer and adjacent layers. Specifically, the first heating layer 11 is insulated from the first shield layer 10, the first heating layer 11 is also insulated from the substrate 12, the second heating layer 13 is insulated from the substrate 12, and the second heating layer 13 is insulated from the second heating layer 13. The two shield layers 14 are insulated. The insulation layer 22 includes an insulating structure covering the auxiliary thermal resistance strip 111 , that is to say, the surface of the auxiliary thermal resistance strip 111 is covered by the insulating structure, so that the auxiliary thermal resistance strip 111 is insulated from the outside. An optional insulating structure is insulating ceramics sintered on the periphery of the auxiliary thermal resistance bar 111 . In order to further strengthen the reliability of the insulation, the shield layer is also insulating. In one embodiment, the shield layer itself can be made of insulating material. In another embodiment, the surface of the shield layer facing the heating layer can also be coated with insulation. The protective layer, such as aluminum oxide, forms two layers of insulation protection to improve the safety and reliability of insulation protection. In another embodiment, the insulating layer 22 may also be disposed on the substrate 12 and on the shield layers 10 , 14 . Since the structures and materials of the first shield layer 10 and the second shield layer 14 may be the same, only one of them will be specifically described herein. Similarly, only one of the first heating layer 11 or the second heating layer 13 is described herein.

The heating plate 100 provided by this application controls the heating heat located in different areas of the substrate 12 through the auxiliary thermal resistance strip 111 with a preset shape, thereby balancing the uneven temperature caused by uneven heat radiation in different areas, and can improve the heating plate. The temperature is uniform and consistent to ensure the production quality and yield of printed circuit boards.

The following describes how the heating plate processes printed circuit boards. The printed circuit board is mainly composed of copper foil, prepreg, inner layer and other core boards stacked in order, and a layer of prepreg is set between adjacent copper foils. change, thereby bonding multiple layers of copper foil together. The heating plate 100 includes at least two, and there are multi-layer core boards that need to be laminated in the middle. Of course, multiple heating plates can also be stacked on top of each other, and multi-layer core boards are laid between adjacent heating plates 100. Multiple printed circuit boards can be pressed together by applying pressure. The central heating plate 100 is provided with two heating layers 11, 13 for heating the multi-layer core boards on both sides.

In the case that the heating plate stops heating after pressing, in order to reduce the temperature as soon as possible, it is convenient to disassemble the printed circuit board. In an embodiment, the substrate 12 is also provided with a cooling structure for rapidly cooling the heating plate 100 . The cooling structure includes a pipeline 122 , specifically, the pipeline 122 is formed in the base plate 12 . In FIG. 1 and FIG. 2 , only one of the pipelines is numbered 122 for simplicity of illustration. The pipeline 122 can contain cooling water or cooling oil, through which the cooling water or cooling oil can effectively reduce the temperature of the heating plate, further reducing the temperature of the circuit board. Because the peripheral area of the substrate 12 is in contact with the external environment, the heat is dissipated faster and the temperature drops faster, while the central area is weaker in exchange with the outside and the temperature drops slower, in order to balance the uneven heat loss. Preferably, the pipeline 122 in the base plate 12 has more pipelines in the middle area than in the peripheral area, so as to speed up the heat loss of the heating plate 100 in the middle area, so that in the cooling process, the temperature of the heating plate is relatively high. Uniformity, to prevent the quality problems of printed circuit boards caused by the uneven temperature of the substrate during the cooling process. Preferably, the pipeline 122 is formed in the base plate 12, and the pipeline 122 can also be provided separately. The substrate 12 is made of aluminum, and the effective use of aluminum is not only beneficial to heat dissipation but also light in weight.

Continuing to refer to FIG. 3 , the first heating layer 11 includes a positive electrode 114 and a negative electrode 112 , one end of the auxiliary thermal resistance strip 111 is connected to the positive electrode 114 , and the other end is connected to the negative electrode 112 . In a specific application process, the positive electrode 114 and the negative electrode 112 are powered on, the current flows in the auxiliary thermal resistance bar 111 , and heat is generated due to the thermal effect of resistance. The type of the power supply may be a DC power supply or an AC power supply, preferably a DC power supply. After the auxiliary thermal resistance strip 111 is electrified, heat energy will be generated. The power supply control method of the auxiliary thermal resistance strip 111 can specifically be to change the current value or voltage value of power supply, or to control the time period of power supply. The material of the auxiliary thermal resistance strip 111 can be a material with a high thermal resistance, such as iron, steel, chromium, manganese, ceramics and the like.

In the embodiment shown in FIG. 3 , the spacing between the auxiliary thermal resistance strips 111 of preset shape and direction laid on the central region of the substrate 12 is greater than that between the auxiliary thermal resistance strips 111 of preset shape and direction laid on the peripheral region of the substrate 12 spacing between. In this embodiment, the auxiliary thermal resistance strip 111 has a uniformly distributed resistance, wherein the uniformly distributed resistance means that the resistance value of the auxiliary thermal resistance strip 111 of any unit length is the same. In a specific embodiment, the auxiliary thermal resistance strip 111 The cross-sectional area is the same everywhere. Wherein, the substrate 12 is square, such as a rectangle or a square, and the peripheral area and the middle area of the substrate 12 are understood as extending along a direction of the substrate, such as the length (width) direction, and the two ends positioned in the length direction (width) are peripheral areas, The middle part of both ends is the middle region.

In this embodiment, the preset shape of the auxiliary thermal resistance strip 111 is a serpentine shape, which may also be called a "bow" shape. Please refer to Fig. 3, in the present embodiment, the substrate 12 is square, can be rectangular or square, and the auxiliary thermal resistance strip 111 comprises a plurality of strips that are first connected and parallel to each other. One side is arranged in parallel, and the distance between the strips located in the middle area is greater than the distance between the strips located in the peripheral area. Wherein, the substrate 12 has two mutually parallel adjacent sides adjacent to the above-mentioned sides. Along the extension direction of the adjacent sides, the substrate 12 is sequentially divided into a peripheral area, a central area, and a peripheral area. The peripheral areas located at both ends are symmetrical to each other. In the extending direction of the side length, the ratio of the width of the central region to the length of the adjacent side is 30%-60%. The peripheral area and the middle area are understood as along an extension direction of the substrate 12, such as the length (width) direction, the two ends located in the length direction (width) are the peripheral area, the part between the two ends is the middle area, and the periphery The region and the middle region are arranged in sequence along the length direction. If the entire area of the substrate 12 is set to 100%, the proportion of the central area is between 30% and 60%, and the proportions of each peripheral area on the left and right sides of the central area are respectively between 35% and 20%. between. Further, please refer to FIG. 3 , the connecting portion between adjacent strips is in an arc shape, thereby reducing the temperature accumulation caused by the sharp transition of the strips.

The inventors of the present application simulated experiments and found that if the auxiliary thermal resistance strips 111 are evenly arranged, the measured temperature on the surface of the substrate 12 is a hilly network temperature line with a high center and low sides. And the temperature in the middle is significantly higher than the surrounding temperature, roughly showing a parabolic change. In order to more accurately realize the temperature consistency of each area of the substrate 12, further, along the length extension direction of the adjacent sides, the strips in the middle area are set such that the distance between the strips in the middle area increases first and then Decreasing change, and the increasing and decreasing ranges are the same, that is, the increasing and decreasing strips are symmetrical to each other, and the optional increasing and decreasing ranges are 0.2cm, 0.3cm, 0.4cm, 0.5cm, 0.8cm. When the incremental distance is selected as 0.5cm, the temperature change of the heating plate tends to be consistent, and the temperature in each area is more uniform.

In other embodiments, please refer to FIG. 4 , the preset shape of the auxiliary thermal resistance strip 111' may also be zigzag. The difference between this embodiment and the above implementation is only that the preset shape and orientation of the auxiliary thermal resistance strips are different, and the same structures use the same reference numerals, which will not be repeated here. Specifically, the substrate 12 is in a square shape, and the auxiliary thermal resistance strip 111' running in a zigzag shape can also be referred to as a coiled auxiliary thermal resistance strip. The belt is in the shape of an open mouth. Specifically, the auxiliary thermal resistance strip 111' lays a first circle along a constant distance from the outer contour of the substrate, roughly surrounds a circle but does not close it, and lays a second circle at a constant distance from the first circle, and then in the same manner Lay the third circle until the middle of the substrate 12. It can be directly connected to the power supply from the middle, or it can continue to be laid from the middle of the substrate 12 to the surrounding area, until it reaches the edge of the substrate 12. Turn on the power. The auxiliary thermal resistance strips in each circle are continuous, and the spacing between adjacent auxiliary thermal resistance strips is not completely consistent, and the spacing between the auxiliary thermal resistance strips located in the middle area is greater than that of the auxiliary thermal resistance strips located in the peripheral area. In this embodiment, the central region refers to a region within a preset distance from the geometric center of the substrate, and the peripheral region refers to a peripheral edge of the substrate, which is roughly ring-shaped. Specifically, the middle region is a square region centered on the geometric center of the substrate 12 , the outer contour of the square region is similar to the outer contour of the substrate 12 , and the area of the middle region accounts for 30%-50% of the area of the substrate 12 . Preferably, as for the spacing of the auxiliary thermal resistance strips, when viewed from the geometric center of the substrate to the outer contour of the substrate, the distance between adjacent square ring-shaped strips changes in a decreasing manner, and the decreasing range gradually decreases. The decreasing range of the distance between the square annular bands located in the middle area is 2mm-10mm, and the decreasing range of the distance between the square annular bands located in the peripheral area is 0.1mm-0.5mm. Furthermore, rounded transitions are used at the intersection of the two sides of the auxiliary thermal resistance strip to avoid temperature accumulation caused by right angles. The auxiliary thermal resistance strips in the direction of the back shape can lay auxiliary thermal resistance strips of different densities according to the distance between the substrate and the surrounding environment, which can more effectively compensate for the high temperature in the middle of the substrate and the surrounding temperature due to the large heat exchange between the surrounding area of the heating plate and the environment. low problem. In another embodiment, the auxiliary thermal resistance strips 111 may also be arranged in a zigzag direction.

In another embodiment, the resistance of the auxiliary thermal resistance strips 111 is uneven, and the cross-sectional area of the auxiliary thermal resistance strips located in the central region of the substrate 12 is larger than that of the auxiliary thermal resistance strips 111 located in the peripheral region of the substrate 12 . It can be understood that the thicker the auxiliary thermal resistance strip 111 is, the smaller its resistance is, and the smaller the thermal effect of the current is, the resistance strip 111 in the central area is set to be thicker than the auxiliary thermal resistance strip 111 in the peripheral area, so that the same current is generated in the central area There is less heat, which can balance the uneven temperature of the heating plate caused by the uneven heat radiation in the peripheral area and the central area of the heating plate.

In a specific embodiment, the cross-section of the auxiliary thermal resistance strip 111 is square, the size of the auxiliary thermal resistance strip 111 in the thickness direction of the substrate 12 is consistent, and the width of the auxiliary thermal resistance strip 111 located in the middle area of the substrate 12 is larger than that of the auxiliary thermal resistance strip 111 located in the substrate 12. The width of the auxiliary thermal resistance strip 111 in the peripheral area, so that the auxiliary thermal resistance strip 111 per unit length covers the board surface of the substrate 12 in the middle area of a larger area, and the area heated by the direct contact between the substrate 12 and the auxiliary thermal resistance strip 111 increases , to suppress temperature fluctuations on the surface of the substrate 12 caused by the spacing of the auxiliary thermal resistance strips 111 . Moreover, the heating structure formed by laying the auxiliary thermal resistance strips 111 is generally sheet-shaped, with uniform thickness, and the contact area with the substrate 12 is used for direct conduction heating, which further improves the uniformity of the heating temperature. Further, the resistance of the unit length of the auxiliary thermal resistance strip 111 located in the middle area is lower than the resistance of the unit length of the auxiliary thermal resistance strip 111 located in the peripheral area, which can reduce the heat generated by the unit length of the auxiliary thermal resistance strip 111 in the central area, Further balance for less heat loss in the central area.

In the heating process, since the substrate 12 is an aluminum plate with good thermal conductivity, the heat generated in the peripheral area will inevitably radiate to the central area, so the temperature in the central area is also affected by the heat generated by the auxiliary thermal resistance strip 111 in the peripheral area. Therefore, , not only the difference in heat exchange between the peripheral area and the central area and the external environment should be considered, but also the mutual heat auxiliary heat influence between the peripheral area and the central area of the substrate 12 should be considered. Considering the above problems, this embodiment further sets the spacing between the auxiliary thermal resistance strips 111 located in the central area of the substrate 12 to be greater than the spacing of the auxiliary thermal resistance strips 111 in the peripheral area of the substrate 12 . It is also possible to further increase the spacing between the auxiliary thermal resistance strips 111 on the basis of using auxiliary thermal resistance strips with a cross-sectional area lower than that of the peripheral area in the central region. In this way, increasing the distance between adjacent strips of the auxiliary thermal resistance strips 111 in the central region can balance the influence of the thermal auxiliary heat in the peripheral region on the temperature of the substrate 12 in the central region.

The base plate 12 is provided with an installation groove consistent with the preset shape of the auxiliary thermal resistance strip 111 , the auxiliary thermal resistance strip 111 is embedded in the installation groove, and then covered with the protective cover 10 (or 14 ). In order to facilitate processing and manufacturing. The size of the auxiliary thermal resistance strips 111 in the thickness direction of the heating plate 100 is uniform, and the width of the auxiliary thermal resistance strips 111 located in the central region of the substrate is greater than the width of the auxiliary thermal resistance strips 111 located in the peripheral region of the substrate 12 . Correspondingly, the depths of the mounting grooves are consistent everywhere, and the width of the mounting grooves located in the central region of the substrate 12 is greater than the width of the mounting grooves located in the peripheral region of the substrate 12 . Therefore, when opening the installation groove on the substrate 12, it is only necessary to control the width of the installation groove (the width of the auxiliary thermal resistance strip), which is convenient for processing and manufacturing.

The heating layer of the heating plate 100 provided by the present application is an auxiliary thermal resistance strip with a preset shape and orientation, and the orientation or the distance between the orientations of the auxiliary thermal resistance strip can be adaptively arranged according to the size of the heating plate, thereby effectively reducing The unbalanced heat loss of the heating plate in the central area and the peripheral area leads to the risk of uneven temperature, which further improves the temperature consistency of the heating plate 100 throughout the heating process.

Continuing to refer to FIG. 3 , the heating plate 100 further includes a temperature measuring unit 113 . The temperature measurement unit 113 is used to measure the temperature of the heating plate 100 , so as to feed back the temperature to the main controller 300 of the laminator 500 , so that the main controller 300 can form a closed-loop control of heating according to the temperature of the heating plate 100 .

The heating plate 100 provided in this application can be used in the manufacture of printed circuit boards, including flexible circuit boards and traditional rigid circuit boards. The total resistance of the auxiliary thermal resistance strip 111 is 0.1Ω-10Ω, preferably 1.5Ω, 2.5Ω.

In order to further illustrate the more uniform heating temperature effect of the heating plate provided in the present application, the application also provides nine-point temperature test data of the heating plate shown in FIG. 3 . Figure 7 shows a nine-point temperature test chart of the heating plate. Specifically, 9 different points are used to detect temperature data, and the heating layout of the heating plate is divided according to the nine grids, and the 9 temperature detection points are respectively set in each grid. The temperature of the heating process was collected, and after the experiment, the temperature data was shown in Figure 8, and the data shown in Figure 8 was graphed to obtain the temperature data curve shown in Figure 9. From the temperature data curve fitted in Figure 9, it can be seen that the temperatures of the 9 points at the same time are basically the same, and the temperature curves of the 9 points are almost overlapped, so it can be intuitively concluded that the temperature of each area of the heating plate is uniform during the heating process .

As a comparison, Figures 10 to 11 show the temperature data of the existing heating plate. As a control group, the heating layer of the existing heating plate adopts evenly distributed heating rods, the spacing of each heating rod is the same, and the heating rods are roughly cylindrical. The same 9-point temperature test was used to obtain the temperature test data shown in Figure 10, and the data shown in Figure 10 was graphed to obtain the temperature data curve shown in Figure 11. It can be seen from Figure 11 that the greater the temperature difference of the nine temperature test points of the heating plate as the heating time goes on, the greater the degree of dispersion, and the poorer temperature uniformity. Therefore, the heating plate provided by the present application has a more consistent heating temperature.

A laminator 500 employing the above-described heating plate is shown in FIGS. 5 and 6 . The laminator 500 is applicable to the production of printed circuit boards. In this embodiment, the laminator 500 includes a frame body 520 , a hydraulic unit 200 , a main control box 510 , a main controller 300 and a plurality of heating plates 100 . Wherein, the main controller 300 is arranged in the main control box 510 , and the main controller 300 is used for controlling the hydraulic pressure signal of the laminator 500 and the heating signal for controlling the laminator 500 . A plurality of heating boards 100 are stacked on top of each other, and there is a space between adjacent heating boards 100 for placing multilayer core boards for manufacturing printed circuit boards. In a specific application, the main controller 300 can be a traditional PC computer. The hydraulic unit 200 includes a hydraulic cylinder 210 and a hydraulic control device 220 for controlling the hydraulic cylinder 210. The hydraulic control device 220 is used to receive a hydraulic pressure signal from the main controller 300 and control the movement of the hydraulic cylinder 210 according to the hydraulic pressure signal. Wherein the hydraulic cylinder 210 is a hydraulic oil cylinder. The heating plate 100 is the heating plate described in any of the above-mentioned embodiments herein, and is used for receiving a heating signal from the main controller 300 and controlling the heating of the heating plate 100 according to the heating signal. Wherein, the heating signal is the heating current.

The specific heating process of the laminator 500 is as follows: the main line 400 provides a reliable power signal to the transformer 403 , and the transformer 403 converts the input voltage signal into a voltage signal required by the hydraulic unit 200 and provides it to the hydraulic control device 220 . The main controller 300 can output specific heating control methods or control curves to the heating plate 100, and the heating plate 100 can be heated according to the control methods or temperature curves according to changes in current or voltage. Preferably, the temperature measurement unit 113 can feed back the real-time temperature of the heating plate 100 to the main controller 300 , and the main controller 300 adjusts the control mode or control curve according to the real-time temperature, thereby forming a closed-loop control on the heating plate 100 .

Since the resistance value of the auxiliary thermal resistance strip 111 is relatively small, roughly between 0.1Ω-10Ω, in order to prevent short circuit caused by excessive voltage, the transformer 403 includes a step-down circuit, which is used to reduce the voltage to a safe range and prevent the auxiliary heat from flowing through. The current of the resistance bar 111 is too large, resulting in a short circuit.

In a specific embodiment, the main controller 300 adjusts the temperature curve of the heating plate 100 by controlling the on and off of the current. The heating plate 100 has a target temperature curve, which rises first and then stabilizes at a set temperature value, including a rising temperature section and a stable temperature section. The temperature rises along the target temperature curve. When the temperature is higher than the target temperature curve, the current of the auxiliary thermal resistance strip 111 is cut off. When the temperature is detected to be lower than the target temperature curve, the auxiliary thermal resistance strip 111 is connected to make the auxiliary thermal resistance strip 111 energized. , thereby heating up.

In another embodiment, the main controller 300 adjusts the temperature of the heating plate by controlling the magnitude of the current. Specifically, when the temperature of the heating plate is higher than the optimal target temperature curve, reduce the current of the auxiliary thermal resistance strip 111, thereby reducing the heat generated by the auxiliary thermal resistance strip 111, and the heat loss of the heating plate is greater than that of the auxiliary thermal resistance strip 111. The heat, and thus the temperature drops, gradually approaches the target temperature curve. When it is detected that the temperature is lower than the target temperature curve, the current flowing in the auxiliary thermal resistance bar 111 is increased to heat up, and the temperature of the heating plate is raised to gradually rise to the target temperature curve.

Although the embodiment of the present application has been disclosed as above, it is not limited to the application listed in the description and the embodiment, it can be applied to various fields suitable for the present application, and it can be easily understood by those familiar with the field Further modifications are to be expected, so the application is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (10)

1. a heating plate, a lamination machine for manufacturing circuit boards, is characterized in that, the heating plate comprises: Substrate; The heating layer is laid on the substrate, the heating layer includes an auxiliary thermal resistance strip, and the auxiliary thermal resistance strip is used to connect with a power source to generate heat by using the current flowing; A shield layer, covering the surface of the substrate on which the auxiliary thermal resistance strips are laid, for protecting the auxiliary thermal resistance strips; The auxiliary thermal resistance strips are configured to be laid on the substrate in a predetermined shape, and the resistance distribution density of the auxiliary thermal resistance strips located in the central area of the substrate is smaller than that of the auxiliary thermal resistance strips located in the peripheral area of the substrate. The distribution density of resistance; The base plate is also provided with a cooling structure for rapid cooling of the heating plate; the cooling structure includes a pipeline communicated with the refrigerant, and when the pressing is completed and the heating plate stops heating, the pipeline Cooling medium is passed to quickly cool the circuit board; the pipeline is formed in the base plate, and the number of pipelines in the central area of the base plate is more than that in the peripheral area of the base plate. 2. The heating plate according to claim 1, wherein the cross-sectional area of the auxiliary thermal resistance strip located in the central region of the substrate is larger than the cross-sectional area of the auxiliary thermal resistance strip located in the peripheral region of the substrate area. 3. The heating plate according to claim 2, characterized in that, the size of the auxiliary thermal resistance strips in the thickness direction of the heating plate is uniform, and the width of the auxiliary thermal resistance strips located in the middle region of the substrate is larger than that located in the The width of the auxiliary thermal resistance strip in the peripheral area of the substrate. 4. The heating plate according to any one of claims 1 to 3, wherein the spacing of the auxiliary thermal resistance strips located in the central region of the substrate is greater than that of the auxiliary thermal resistance strips located in the peripheral region spacing. 5. The heating plate according to claim 1, characterized in that, the spacing of the auxiliary thermal resistance strips located in the central region of the substrate is greater than the spacing of the auxiliary thermal resistance strips located in the peripheral area, and the auxiliary thermal resistance strips are located in the peripheral area. The cross-sectional area of the thermal resistance strip is uniform everywhere. 6. The heating plate according to claim 1, wherein the substrate is provided with a mounting groove consistent with the preset shape of the auxiliary thermal resistance strip, and the auxiliary thermal resistance strip is embedded in the installed in the slot. 7. The heating plate according to claim 1, characterized in that, the preset shape direction includes a serpentine direction, a zigzag direction or a zigzag direction. 8. The heating plate according to claim 1, characterized in that, the number of the heating layers is two, respectively the first heating layer and the second heating layer, the first heating layer and the second heating layer Layers are respectively laid on the two board surfaces of the substrate, the number of the shield layers is two, which are the first shield layer and the second shield layer respectively, and the assembly sequence of the heating plate is the first shield layer and the second shield layer respectively. A shield layer, a first heating layer, a substrate, a second heating layer, and a second shield layer. 9. The heating plate according to claim 1, wherein the substrate is in a square shape, and the auxiliary thermal resistance strips include a plurality of strips that are first connected and parallel to each other, and the plurality of strips are each It is arranged parallel to one side of the substrate. 10. The heating plate according to claim 9, characterized in that, the auxiliary thermal resistance strip is made in one piece.

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