CN112929998B

CN112929998B - Heating plate

Info

Publication number: CN112929998B
Application number: CN202110260583.1A
Authority: CN
Inventors: 沈金明; 府震华; 孔清; 时文岗
Original assignee: Yancheng Jiateng Electromechanical Co ltd
Current assignee: Yancheng Jiateng Electromechanical Co ltd
Priority date: 2021-03-10
Filing date: 2021-03-10
Publication date: 2023-03-31
Anticipated expiration: 2041-03-10
Also published as: TW202236901A; CN112929998A

Abstract

The application discloses hot plate for make printed circuit board's laminator, the hot plate includes: a substrate; the heating layer is laid on the substrate and comprises auxiliary heating resistance strips, and the auxiliary heating resistance strips are used for being connected with a power supply to generate heat by utilizing circulating current; the protective cover layer covers the surface of the substrate on which the auxiliary thermal resistance strips are laid and is used for protecting the auxiliary thermal resistance strips; the auxiliary thermal resistance strips are constructed into a preset shape and laid on the substrate, and the resistance distribution density of the auxiliary thermal resistance strips positioned in the middle area of the substrate is smaller than that of the auxiliary thermal resistance strips positioned in the peripheral area of the substrate. The application provides a hot plate can balance the heat radiation inhomogeneous effectively, improves the temperature uniformity in each region of hot plate.

Description

Heating plate

Technical Field

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

Background

A printed circuit board, abbreviated as a circuit board, generally includes elements such as a copper foil, a prepreg, and an inner layer, and may also be referred to as a Printed Circuit Board (PCB). Wherein the copper foil is an anionic electrolytic material, a thin, continuous metal foil deposited on the substrate layer of the circuit board, which acts as a conductor for the PCB. It is easy to adhere to the insulating layer, receive the printing protective layer, form the circuit pattern after corroding.

The main manufacturing equipment of the printed circuit board is a laminating machine, also called a circuit board laminating machine, and the inner layer core boards and the copper foils are bonded and molded at high temperature and high pressure through semi-cured films after the processes of heating and pressurizing are carried out when the circuit board is manufactured. In the process of laminating the multilayer circuit board, the semi-cured film undergoes a solid-liquid-solid conversion process at high temperature and high pressure, resin in the film undergoes complex physical changes such as flowing and shrinking, if the temperature of each area is not uniform in the pressing process, the semi-cured film has inconsistent thickness, the copper foil is tightly attached to the film, the difference of the deformation coefficients of the copper foil and the film is inconsistent, and further the copper foil is uneven, the quality of the circuit board is poor, and even the circuit board is scrapped. Particularly, when the copper foil used outside is relatively thin, the quality defect of wrinkling is easily generated in the pressing process.

Disclosure of Invention

Aiming at the defects in the technology, the heating plate capable of heating uniformly is provided.

The technical scheme adopted by the application for solving the technical problem is as follows:

a heater plate for a lamination press used in manufacturing printed circuit boards, the heater plate comprising:

a substrate;

the heating layer is laid on the substrate and comprises auxiliary heating resistance strips, and the auxiliary heating resistance strips are used for being connected with a power supply to generate heat by utilizing circulating current;

the protective cover layer covers the surface of the substrate on which the auxiliary thermal resistance strips are laid and is used for protecting the auxiliary thermal resistance strips;

the auxiliary thermal resistance strips are constructed into a preset shape and laid on the substrate, and the resistance distribution density of the auxiliary thermal resistance strips in the middle area of the substrate is smaller than that of the auxiliary thermal resistance strips in the peripheral area of the substrate.

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

In one embodiment, the auxiliary thermal resistance strips have a uniform size in the thickness direction of the heating plate, and the width of the auxiliary thermal resistance strips in the central region of the substrate is greater than the width of the auxiliary thermal resistance strips in the peripheral region of the substrate.

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

In one embodiment, the pitch of the auxiliary thermal resistance strips in the central region of the substrate is greater than the pitch of the auxiliary thermal resistance strips in the peripheral region, and the cross-sectional areas of the auxiliary thermal resistance strips are uniform.

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

In one embodiment, the predetermined shape comprises a serpentine shape, a zigzag shape or a zigzag shape.

In one embodiment, the quantity of zone of heating is two, is first zone of heating and second zone of heating respectively, first zone of heating with the second zone of heating is laid respectively two faces of base plate, the quantity of protecting the cover layer is two, is first protecting the cover layer and second protecting the cover layer respectively, the equipment order of hot plate does in proper order first protecting the cover layer, first zone of heating, base plate, second zone of heating and second protecting the cover layer.

In one embodiment, the substrate is square, the auxiliary thermal resistance strips comprise a plurality of strip-shaped strips which are connected end to end and are parallel to each other, and the strip-shaped strips are arranged in parallel with one side edge of the substrate.

In one embodiment, the auxiliary thermal resistance strips are integrally formed.

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

In one embodiment, the cooling structure comprises a pipeline communicated with a refrigerant, and the pipeline is communicated with the refrigerant to rapidly cool the circuit board under the condition that the heating plate stops heating after pressing is finished; the pipeline is formed in the substrate, and the refrigerant is cooling water or cooling oil.

Compared with the prior art, the application has the beneficial effects that: the application provides a zone of heating of hot plate has the supplementary hot resistance strip of predetermineeing the shape trend, is located the regional resistance distribution density who assists the hot resistance strip in base plate middle part and is less than the resistance distribution density who assists the hot resistance strip that is located the peripheral region of base plate to compensate the inhomogeneous temperature that leads to of hot plate middle part region and peripheral region heat radiation effectively inhomogeneous, improve the uniformity of each regional temperature of hot plate, guarantee printed circuit board's processing quality.

Drawings

Fig. 1 is a schematic perspective exploded view of a heating panel according to the present application;

FIG. 2 is a schematic cross-sectional view of the heating plate shown in FIG. 1;

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

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

fig. 5 is a schematic structural diagram of a module of a laminator according to an embodiment of the present disclosure.

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

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

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

FIG. 9 is a graph plotted against nine point temperature data for the heater plate shown in FIG. 7.

FIG. 10 is nine point temperature test data for a prior art heater plate.

FIG. 11 is a graph plotted against nine point temperature data for the heater plate shown in FIG. 10.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. It should be further noted that, for the convenience of description, only some of the structures related to the present application are shown in the drawings, not all of the structures. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

The terms "comprising" and "having," as well as any variations thereof, in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a predetermined feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the 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 explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The present application will now be described in further detail with reference to the accompanying drawings, whereby one skilled in the art can, with reference to the description, make an implementation.

As shown in fig. 1 and 2, the present application provides a heating plate 100 for a laminator used to manufacture printed circuit boards. In an embodiment of the present application, the heating plate 100 includes a shield layer (10, 14), a heating layer (11, 13), and a substrate 12. Wherein, the heating layers (11, 13) are laid on the plate surface of the base plate, the shielding layers (10, 14) are arranged on the outermost layer of the heating plate 100 and cover the surface of the base plate on which the heating layers (11, 13) are laid for protecting the heating layers (11, 13). After the heating plate 100 is assembled, the heating layers (11, 13) are disposed between the base plate 12 and the shield layer 10.

In one embodiment, the number of heating layers is one, and the heating plate includes a base plate 12, a shield layer 10, and a heating layer 11 disposed between the base plate 12 and the shield layer 10. In the scenario of application to a laminator, the number of heating plates is at least two, the two heating plates are stacked on each other, a multilayer core board for manufacturing a circuit board is sandwiched in the middle, wherein the substrate 12 of the heating plates is located at the outer side, the shield 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 2 heating layers, i.e., a first heating layer 11 and a second heating layer 13, which are disposed on the upper and lower plate surfaces of the substrate 12. The outermost layers of the heating layers (11, 13) are provided with two protective cover layers (10, 14), which are respectively a first protective cover layer 10 and a second protective cover layer 14, and the heating plate 100 is sequentially provided with the first protective cover layer 10, the first heating layer 11, the substrate 12, the second heating layer 13 and the second protective cover layer 14 according to the composition sequence. Both the upper and lower surfaces of the heating plate 100 provided in this embodiment can be used for heating, and in a specific scenario applied to a laminator, the heating plate 100 provided in this embodiment can be used as a middle plate, and is disposed between the upper and lower heating plates, and a gap is formed between the two adjacent heating plates to sandwich a multilayer core plate, and the number of the heating plates disposed in the middle may be 1, or may be multiple. The heating plate of the double heating layers that this embodiment provided can be used with the combination of the heating plate of the single heating layer that above-mentioned embodiment provided, and the heating plate setting of single heating layer is at the upper and lower both ends of heating plate stack, and the heating plate setting of double heating layer is in the middle, presss from both sides between the adjacent heating plate and establishes the multilayer core, and every multilayer core carries out the heating of upper and lower two sides by two adjacent heating plates.

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 will be described as an example. Referring to fig. 3, the first heating layer 11 includes an auxiliary thermal resistance strip 111, two ends of the auxiliary thermal resistance strip 111 are connected to a power supply, and after the power supply is turned on, a current flows through the auxiliary thermal resistance strip 111, and the current thermal effect causes the auxiliary thermal resistance strip 111 to generate heat, so that the temperature of the heating plate 100 is raised. The auxiliary thermal resistance strips 111 are configured to be 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 region of the substrate 12 is smaller than the resistance distribution density of the auxiliary thermal resistance strips 111 located in the peripheral region of the substrate 12. With the arrangement, under the condition that the current magnitude is consistent, the average heat generated by the auxiliary thermal resistance strips 111 in the middle area per unit area is lower than the average heat generated by the auxiliary thermal resistance strips 111 in the peripheral area per unit area, so that the conditions that the heat loss of the peripheral area is more and the temperature is reduced more due to more heat exchange between the peripheral area of the heating plate and the surrounding environment can be balanced, and the uniformity of the temperature of each area of the heating plate is improved. On the contrary, if the auxiliary thermal resistance strips 111 are uniformly distributed on the substrate 12, under the condition of equal heating heat, the heat exchange between the peripheral area of the substrate 12 and the surrounding environment is more active, the heat dissipation of the substrate 12 in the central area is slower, which leads to the temperature rise in the peripheral area and the temperature in the peripheral area being lower than that in the central area, resulting in the temperature non-uniformity of the heating plate 100, and the quality of the produced printed circuit board is poor or even scrapped. Here, the resistance distribution density is understood to be a total resistance value in a unit area of the plate surface of the substrate 12, that is, the resistance distribution density is equal to a resistance value of the corresponding region/an area of the corresponding region. It will be appreciated that the greater the density of the resistive profile, the greater the amount of heat generated by the thermal effect of the current per unit area, given the same current.

For convenience of manufacturing and temperature control, in the present embodiment, the auxiliary heating resistor strips 111 of the first heating layer 11 are continuous strip conductors, two ends of the auxiliary heating resistor strips 111 are used for connecting a power supply, and after the power supply is connected, the current at any position of the auxiliary heating resistor strips 111 is the same. Specifically, the auxiliary thermal resistance strip 111 is integrally formed.

Further, since the auxiliary thermal resistance strips 111 are conductors, heat is generated by the flowing current, and in order to avoid electric leakage, an insulating layer 22 is further arranged between the heating layers (11, 13) and the adjacent substrate 12 and shield layers (10, 14), so that electric leakage or electric crosstalk between the heating layers and the adjacent layers is effectively avoided. Specifically, the first heater layer 11 is insulated from the first shield layer 10, the first heater layer 11 is also insulated from the substrate 12, the second heater layer 13 is insulated from the substrate 12, and the second heater layer 13 is insulated from the second shield layer 14. The insulating layer 22 includes an insulating structure coated on the auxiliary heat resistor strip 111, that is, the surface of the auxiliary heat resistor strip 111 is covered with the insulating structure, so that the auxiliary heat resistor strip 111 is insulated from the outside. An alternative insulating structure is an insulating ceramic sintered at the outer periphery of the auxiliary resistive heating strips 111. In order to further enhance the reliability of insulation, the protective cover layer is also insulated, in one embodiment, the protective cover layer itself may be made of an insulating material, and in another embodiment, the surface of the protective cover layer facing the heating layer may also be coated with an insulating protective layer, such as alumina, so as to form two layers of insulating protection, thereby improving the safety and reliability of the insulating protection. In another embodiment, insulating layer 22 may also be disposed on substrate 12 and on shield layers 10, 14. Since the first and second shielding layers 10, 14 may be identical in structure and material, only one of them will be described in detail herein. Likewise, only one of the first heating layer 11 or the second heating layer 13 is described herein.

The application provides a hot plate 100, through the supplementary hot resistance strip 111 of predetermineeing the shape trend, the control is located the heating heat in the different regions of base plate 12 to the temperature that the balance leads to because the thermal radiation of different regions is inhomogeneous, can improve the even uniformity of temperature of hot plate, guarantees printed circuit board's production quality and yield.

How the heating plate processes the printed circuit board will be described below. The printed circuit board is mainly characterized in that copper foils, semi-solidified films, inner layers and other core boards are sequentially paved and stacked, one layer of semi-solidified film is arranged between adjacent copper foils, and the semi-solidified films are subjected to phase change under the action of temperature, so that multiple layers of copper foils are bonded together. The heating plate 100 includes at least two multi-layer core plates to be laminated, and a plurality of the multi-layer core plates may be stacked on top of each other, and the multi-layer core plates are laid between adjacent heating plates 100, so that a plurality of printed circuit boards can be laminated by one-time high-temperature pressurization. The centrally arranged heating plate 100 is provided with two

heating layers

11, 13 for heating the multilayer core plates on both sides.

In the case that the heating plate stops heating after the pressing is finished, the temperature is lowered as quickly as possible, thereby facilitating the detachment of the printed circuit board. In an embodiment, the substrate 12 is further provided with a cooling structure for rapidly cooling the heating plate 100. The cooling structure includes a pipe 122, and particularly, the pipe 122 is formed in the substrate 12. In fig. 1 and 2, only one of the pipes is designated by reference numeral 122 for simplicity of illustration. The pipe 122 can contain cooling water or cooling oil, and the heating plate is effectively cooled by the cooling water or cooling oil, so as to further reduce the temperature of the circuit board. Since the peripheral region of the substrate 12 is in contact with the external environment, heat dissipation is fast and temperature reduction is fast, while the central region is in contact with the external environment, temperature reduction is slow, in order to balance the non-uniformity of heat dissipation. Preferably, the number of the pipes in the central area of the pipe 122 in the substrate 12 is greater than that in the peripheral area, so as to accelerate the heat dissipation of the heating plate 100 in the central area, make the temperatures of all parts of the heating plate uniform in the cooling process, and prevent the quality problem of the printed circuit board caused by the non-uniform temperatures of all parts of the substrate in the cooling process. Preferably, the pipe 122 is formed in the base plate 12, and the pipe 122 may be separately provided. The substrate 12 is made of aluminum, and the aluminum material is effective in heat dissipation and light in weight.

With continued reference to fig. 3, the first heating layer 11 includes a positive electrode 114 and a negative electrode 112, and the auxiliary thermal resistance strip 111 has one end connected to the positive electrode 114 and the other end connected to the negative electrode 112. In a specific application process, the positive electrode 114 and the negative electrode 112 are powered on, and current flows in the auxiliary thermal resistance strip 111 to generate heat due to resistance thermal effect to generate heat energy. The type of power supply may be a dc power supply or an ac power supply, preferably a dc power supply. The auxiliary thermal resistance strips 111 generate heat energy when energized. The energization control manner of the auxiliary thermal resistance strip 111 may specifically be to change the magnitude of the current value or the voltage value of the energization, or to control the time period of the energization. The material of the auxiliary thermal resistance strip 111 may be a material with a high thermal resistance value, such as iron, steel, chromium, manganese, ceramic, etc.

In the embodiment shown in fig. 3, the spacing between the auxiliary heat resistance strips 111 having the predetermined shape and arranged in the central region of the substrate 12 is larger than the spacing between the auxiliary heat resistance strips 111 having the predetermined shape and arranged in the peripheral region of the substrate 12. In this embodiment, the auxiliary thermal resistance strips 111 have uniformly distributed resistances, wherein uniformly distributed resistances are understood to mean that the resistance values of the auxiliary thermal resistance strips 111 per unit length are the same, and in a specific embodiment, the cross-sectional areas of the auxiliary thermal resistance strips 111 are uniform throughout. Where the substrate 12 is square, such as rectangular or square, the peripheral region and the central region of the substrate 12 are understood to be along an extending direction of the substrate, such as the length (width) direction, and the two end portions located in the length (width) direction are peripheral regions, and the central portion of the two end portions is a central region.

In this embodiment, the predetermined shape of the auxiliary thermal resistance strips 111 is a serpentine shape, which may also be referred to as a "bow" shape. Referring to fig. 3, in the embodiment, the substrate 12 is square, and may be rectangular or square, the auxiliary thermal resistance strips 111 include a plurality of strip-shaped strips which are connected end to end and are parallel to each other, the plurality of strip-shaped strips are all parallel to one side edge of the substrate 12, and the distance between the strip-shaped strips in the middle area is greater than the distance between the strip-shaped strips in the peripheral area. The substrate 12 has two adjacent sides parallel to each other adjacent to the above-mentioned side, along the extending direction of the adjacent sides, the substrate 12 is sequentially a peripheral area, a middle area, and a peripheral area, the peripheral areas at the two ends are symmetrical to each other, and in the extending direction of the length of the adjacent sides, the width of the middle area accounts for 30% -60% of the length of the adjacent sides. The peripheral region and the central region are understood to be peripheral regions at both ends in the length direction (width) and central regions at a portion between the both ends along an extending direction of the substrate 12, such as the length (width) direction, the peripheral regions and the central regions being arranged in order along the length direction. If the entire area of the substrate 12 is set to 100%, the occupation ratio of the central area ranges from 30% to 60%, and the occupation ratio of each of the peripheral areas on the left and right sides of the central area ranges from 35% to 20%, respectively. Further, referring to fig. 3, the connecting portion between the adjacent strip-shaped bands is in an arc shape, so that the temperature accumulation caused by the sharp transition of the strip-shaped bands is reduced.

The inventor of the present application finds, through experimental simulation, that if the auxiliary thermal resistance strips 111 are uniformly arranged, the measured temperature on the surface of the substrate 12 is a hill-shaped mesh temperature line with a high middle part and low sides. And the temperature of the middle part is obviously higher than that of the periphery, and changes in a roughly parabolic manner. In order to more accurately realize the temperature uniformity of each region of the substrate 12, further, along the length extending direction of the adjacent sides, the strip-shaped belt of the middle region is set as follows: the distance between the strip belts positioned in the middle area changes in an increasing mode and then in a decreasing mode, the increasing and decreasing change amplitude is the same, namely the strip belts presenting the increasing change and the strip belts presenting the decreasing change are mutually symmetrical, and the selectable increasing and decreasing amplitude is 0.2cm,0.3cm,0.4cm,0.5cm and 0.8cm. When the incremental distance is selected to be 0.5cm, the temperature change at each position of the heating plate tends to be consistent, and the temperature of each area is more uniform.

In other embodiments, referring to fig. 4, the predetermined shape of the auxiliary thermal resistance strips 111' may also be a zigzag shape. The difference between this embodiment and the above implementation is only that the preset shapes of the auxiliary thermal resistance strips are different, and the same reference numerals are used for the same structures, which are not described again. Specifically, the substrate 12 is a square auxiliary thermal resistor 111' with a zigzag shape, which may also be called a coiled auxiliary thermal resistor, and includes a plurality of circles of square annular strips connected end to end, and each square annular strip is in an unclosed square shape. Specifically, the auxiliary thermal resistance strips 111' are laid along a first circle at a constant distance from the outer contour of the substrate, and are generally laid around the first circle without being closed, and laid along a second circle at a constant distance from the first circle, and then laid along a third circle in the same manner until reaching the middle of the substrate 12, so that the power supply can be directly led out from the middle, and the auxiliary thermal resistance strips can be continuously laid from the middle of the substrate 12 to the peripheral area for one circle, and laid until reaching the edge of the substrate 12, so that the power supply can be conveniently switched on from the outer edge. The auxiliary thermal resistance strips of each circle are continuous, the distance between the adjacent auxiliary thermal resistance strips is not completely consistent, and the distance between the auxiliary thermal resistance strips positioned in the middle area is larger than that of the auxiliary thermal resistance strips positioned in the peripheral area. In this embodiment, the central region refers to a region within a predetermined distance from the geometric center of the substrate, and the peripheral region refers to a substantially annular region at the peripheral edge of the substrate. Specifically, the middle region is a square-row region centered on the geometric center of the substrate 12, the outer contour of the square-row 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, the distance between the adjacent square annular bands is gradually decreased when viewed from the geometric center of the substrate to the outer contour of the substrate, and the decreasing width is gradually decreased. The decreasing amplitude of the distance between the square annular bands located in the central region is 2mm to 10mm, and the decreasing amplitude of the distance between the square annular bands located in the peripheral region is 0.1mm to 0.5mm. Furthermore, the intersection of the two edges of the auxiliary thermal resistance strip adopts fillet transition, so that the temperature aggregation caused by right angles is avoided. The auxiliary heating resistor strips with the square-shaped trend can be laid according to the distance between the substrate and the surrounding environment, and the problems that the temperature of the middle part of the substrate is high and the surrounding temperature is low due to the fact that the peripheral area of the heating plate exchanges heat with the environment more are effectively compensated. In another embodiment, the auxiliary thermal resistance strips 111 may also be arranged in a zigzag shape.

In another embodiment, the resistance is not uniform throughout the auxiliary thermal resistance strips 111, and the cross-sectional area of the auxiliary thermal resistance strips located in the central region of the substrate 12 is larger than the cross-sectional area 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 strips 111, the lower the resistance thereof, and the lower the current heating effect, the thicker the central region of the resistance strips 111 is set to be than the peripheral region of the auxiliary thermal resistance strips 111, so that the same current generates less heat in the central region, and the uneven temperature of the heating plate caused by the uneven heat radiation in the peripheral region and the central region of the heating plate can be balanced.

In an embodiment, the cross section of the auxiliary thermal resistance strips 111 is square, the size of the auxiliary thermal resistance strips 111 in the thickness direction of the substrate 12 is uniform, the width of the auxiliary thermal resistance strips 111 in the middle area of the substrate 12 is greater than the width of the auxiliary thermal resistance strips 111 in the peripheral area of the substrate 12, so that the auxiliary thermal resistance strips 111 per unit length cover the plate surface of the substrate 12 in the middle area of a larger area, the area of the substrate 12 heated by direct contact with the auxiliary thermal resistance strips 111 is increased, and the situation that the temperature wave fluctuates on the plate surface of the substrate 12 due to the distance between the auxiliary thermal resistance strips 111 is suppressed. Moreover, the heating structure formed by laying the auxiliary heating resistor strips 111 is integrally flaky, the thickness is uniform, the contact area with the substrate 12 is used for direct conduction heating, and the uniformity of the heating temperature is further improved. Further, the resistance of the auxiliary thermal resistance strips 111 in the unit length in the central region is smaller than the resistance of the auxiliary thermal resistance strips 111 in the unit length in the peripheral region, so that the heat generated by the auxiliary thermal resistance strips 111 in the unit length in the central region can be reduced, and the condition of less heat loss in the central region is further balanced.

In the heating process, since the substrate 12 is made of an aluminum plate and has good thermal conductivity, the heat generated in the peripheral region is necessarily radiated to the central region, and therefore, the temperature in the central region is also increased by the heat generated by the auxiliary thermal resistance strips 111 in the peripheral region, and therefore, not only the difference in heat exchange between the peripheral region and the central region and the external environment, but also the mutual heat auxiliary influence between the peripheral region and the central region of the substrate 12 is considered. In view of the above, the present embodiment further sets the pitch between the auxiliary thermal resistance strips 111 located in the central region of the substrate 12 to be greater than the pitch of the auxiliary thermal resistance strips 111 located in the peripheral region of the substrate 12. The distance between the auxiliary thermal resistance strips 111 can be further increased on the basis that the auxiliary thermal resistance strips with the cross-sectional areas lower than those of the peripheral regions are adopted in the middle region. In this way, the distance between adjacent stripe stripes of the auxiliary thermal resistance stripes 111 in the central region is increased, and the influence of the peripheral region thermal auxiliary heat on the temperature of the substrate 12 in the central region can be balanced.

The substrate 12 is provided with an installation groove having a shape 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 the protection cover 10 (or 14) is covered on the auxiliary thermal resistance strip 111. The processing and manufacturing are convenient. The auxiliary heat resistor strips 111 have a uniform size in the thickness direction of the heating plate 100, and the width of the auxiliary heat resistor strips 111 in the central region of the substrate is greater than the width of the auxiliary heat resistor strips 111 in the peripheral region of the substrate 12. Correspondingly, the depth of each mounting groove is consistent, and the width of the mounting groove in the middle area of the substrate 12 is larger than that of the mounting groove in the peripheral area of the substrate 12. Therefore, when the mounting groove is formed in the substrate 12, only the width of the mounting groove (the width of the auxiliary thermal resistance strip) needs to be controlled, and the processing and the manufacturing are convenient.

The application provides a hot plate 100's zone of heating is for having the supplementary hot resistance strip of predetermineeing the shape trend, can arrange the supplementary hot resistance strip trend or move towards interval between according to the size of hot plate adaptability to reduce effectively and be located the heat of the regional hot plate of middle part and peripheral zone and scatter and disappear unbalanced the risk that leads to the temperature inhomogeneous, further improve the heating process hot plate 100 temperature uniformity everywhere.

With continued reference to FIG. 3, the heating plate 100 further includes a temperature measuring unit 113. The temperature measuring unit 113 serves to measure the temperature of the heating plate 100, thereby feeding back the temperature to the main controller 300 of the laminator 500, so that the main controller 300 can form closed-loop control of heating according to the temperature of the heating plate 100.

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

To further illustrate the effect of the heating plate provided by the present application on more uniform heating temperature, the present application also provides nine-point temperature test data of the heating plate shown in fig. 3. Fig. 7 shows a nine-point temperature test chart of the heating plate. Specifically, 9 different points are adopted to detect temperature data, the heating layout of the heating plate is divided according to the nine-square grid, and the 9 temperature detection points are respectively and correspondingly arranged in each grid. The temperature during the heating process is collected, and after experiments, the temperature data is as shown in fig. 8, and the data shown in fig. 8 is plotted graphically to obtain a temperature data curve shown in fig. 9. It can be seen from the fitted temperature data curve of fig. 9 that the temperatures of 9 points at the same time are substantially the same, and the temperature curves of 9 points are almost overlapped, so that the uniform and consistent temperatures of all areas of the heating plate in the heating process can be intuitively obtained.

As a control group, fig. 10 to 11 show temperature data of the conventional heating plate. As a control, the conventional heating plate employs uniformly distributed heating rods, each heating rod has the same pitch, and the heating rods are substantially cylindrical. Similarly, the 9-point temperature test was used to obtain the temperature test data shown in fig. 10, and the data shown in fig. 10 was plotted graphically to obtain the temperature data curve shown in fig. 11. As can be seen from fig. 11, the greater the difference between the temperatures of the 9 temperature test points of the heating plate with the lapse of heating time, the greater the dispersion degree, and the poorer the temperature uniformity. Therefore, the heating plate provided by the application has more uniform heating temperature.

Fig. 5 and 6 show a laminator 500 employing the heating plate described above. Laminator 500 can be used to produce 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 a main controller 300 is provided in the main control box 510, the main controller 300 for controlling a hydraulic pressure signal of the laminator 500 and for controlling a heating signal of the laminator 500. A plurality of heating plates 100 are stacked on one another, and a space for placing a multi-layer core board for manufacturing a printed circuit board is provided between the adjacent heating plates 100. In a specific application, the main controller 300 may be a conventional PC computer. The hydraulic unit 200 includes a hydraulic cylinder 210 and a pilot operated device 220 for controlling the hydraulic cylinder 210, wherein the pilot operated device 220 is configured to receive a hydraulic pressure signal from the main controller 300 and control the hydraulic cylinder 210 to move according to the hydraulic pressure signal. Wherein the hydraulic cylinder 210 is a hydraulic cylinder. The heating plate 100 is a heating plate according to any of the above embodiments, and is configured to receive a heating signal from the main controller 300 and control the heating plate 100 to heat according to the heating signal. Wherein the heating signal is a heating current.

The specific heating process of laminator 500 is: the main line 400 supplies 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 supplies the voltage signal to the hydraulic control device 220. The main controller 300 may output a specific control manner or control curve of heating to the heating plate 100, and the heating plate 100 may heat according to the control manner or temperature curve according to a change of current or voltage. Preferably, the temperature measuring unit 113 may 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 the control curve according to the real-time temperature, thereby forming a closed-loop control on the heating plate 100.

Since the resistance of the auxiliary thermal resistor strip 111 is small, approximately between 0.1 Ω and 10 Ω, in order to prevent short circuit caused by excessive voltage, the transformer 403 includes a step-down circuit for reducing the voltage to a safe range and preventing excessive current flowing through the auxiliary thermal resistor strip 111 from causing short circuit.

In one embodiment, the main controller 300 adjusts the temperature profile of the heating plate 100 by controlling the on/off of the current. The heating plate 100 has a target temperature curve, the target temperature curve is first raised and then stabilized at a set temperature value, and includes a raised temperature section and a stabilized temperature section, the main controller 300 controls the temperature of the heating plate 100 to rise along the target temperature curve by controlling the on/off of the current, when the temperature is higher than the target temperature curve, the current of the auxiliary heating resistor strip 111 is cut off, and when the detected temperature is lower than the target temperature curve, the auxiliary heating resistor strip 111 is connected to electrify the auxiliary heating resistor strip 111, so as to heat and raise the temperature.

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, the current of the auxiliary heating resistor strip 111 is reduced, so that the heating heat of the auxiliary heating resistor strip 111 is reduced, and the heat loss of the heating plate is greater than the heating heat of the auxiliary heating resistor strip 111, so that the temperature is reduced and gradually approaches the target temperature curve. When the detected temperature is lower than the target temperature curve, the current flowing in the auxiliary heating resistor strip 111 is increased, so that heating is performed, the temperature of the heating plate is increased, and the temperature is gradually increased to the target temperature curve.

While the embodiments of the present application have been disclosed above, it is not limited to the applications listed in the description and the embodiments, which are fully applicable in a variety of fields suitable for this application, and further modifications will be readily apparent to those skilled in the art, and it is therefore not intended to be limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims

1. A heater plate for a laminating machine for manufacturing circuit boards, the heater plate comprising:

a substrate;

the auxiliary thermal resistance strips are constructed into a preset shape and laid on the substrate, and the resistance distribution density of the auxiliary thermal resistance strips in the middle area of the substrate is smaller than that of the auxiliary thermal resistance strips in the peripheral area of the substrate;

the base plate is also provided with a cooling structure for rapidly cooling the heating plate; the cooling structure comprises a pipeline communicated with a refrigerant, and the pipeline is communicated with the refrigerant to rapidly cool the circuit board under the condition that the heating plate stops heating after pressing is finished; the pipes are formed in the substrate, and the number of pipes of the pipes in the central area of the substrate is greater than that in the peripheral area of the substrate.

2. The heating plate of claim 1, wherein a cross-sectional area of the auxiliary resistive heating strips at a central region of the substrate is larger than a cross-sectional area of the auxiliary resistive heating strips at a peripheral region of the substrate.

3. The heating plate of claim 2, wherein the auxiliary resistor strips have a uniform size in the thickness direction of the heating plate, and the width of the auxiliary resistor strips is greater in a central region of the substrate than in a peripheral region of the substrate.

4. The heating plate of any of claims 1 to 3, wherein the pitch of the auxiliary heat resistance strips in the central region of the substrate is greater than the pitch of the auxiliary heat resistance strips in the peripheral region.

5. The heating plate of claim 1, wherein the auxiliary heat resistor strips are spaced at a greater interval in the central region of the substrate than in the peripheral region, and the auxiliary heat resistor strips have a uniform cross-sectional area throughout.

6. The heating plate as claimed in claim 1, wherein a mounting groove is provided on the base plate to be aligned with the predetermined shape of the auxiliary heating resistor strip, and the auxiliary heating resistor strip is inserted into the mounting groove.

7. The heating plate as claimed in claim 1, wherein the predetermined shape comprises a serpentine shape, a zigzag shape or a zigzag shape.

8. The heating plate of claim 1, wherein the number of the heating layers is two, respectively a first heating layer and a second heating layer, the first heating layer and the second heating layer are respectively laid on both faces of the substrate, the number of the shielding layers is two, respectively a first shielding layer and a second shielding layer, and the assembly sequence of the heating plate is the first shielding layer, the first heating layer, the substrate, the second heating layer and the second shielding layer in this order.

9. The heating plate of claim 1, wherein the base plate is square, the auxiliary resistive heating strips comprise a plurality of strips connected end to end and parallel to each other, and the plurality of strips are arranged parallel to one side of the base plate.

10. The heating plate according to claim 9, wherein the secondary thermal resistance strips are integrally formed.