CN214960168U - Heating assembly for heating plate - Google Patents

Abstract

The application discloses heating element for hot plate, heating element are used for heating the hot plate, and heating element is the slice, has a heating plane, includes: the resistor strip is used for being connected with a power supply to generate heat by utilizing the circulating current; the resistance strips extend along the trend of a preset shape in the heating plane, and the resistance distribution density of the resistance strips positioned in the middle area of the heating assembly is smaller than that of the resistance strips positioned in the peripheral area of the heating assembly. The application provides a heating element for hot plate improves the temperature uniformity in each region of hot plate.

Description

Heating assembly for heating plate

Technical Field

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

Background

Printed circuit boards, generally composed of copper foil, prepreg, and inner layer, may also be called printed circuit boards (pcbs).

The main manufacturing equipment of the printed circuit board is a laminating machine, which is also called a circuit board laminating machine and comprises a frame and a heating plate, wherein a laminating chamber is arranged in the frame, the heating plate is arranged in the laminating chamber, and the heating plate is connected with a hydraulic device. When the circuit board is manufactured, the inner core boards and the copper foil are bonded and molded through the semi-solidified rubber sheets at high temperature and high pressure through the temperature rise and pressurization process. In the process of laminating the multilayer circuit board, the semi-solidified film undergoes a solid-liquid-solid conversion process at high temperature and high pressure, and if the temperature of each area is not uniform in the pressing process, the semi-solidified film has inconsistent thickness, so that the copper foil is uneven, the quality of the circuit board is poor, and even the circuit board is scrapped.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects in the technology, the application provides the heating assembly for the heating plate, which can realize uniform temperature of each area of the heating plate in the temperature rising process.

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

a heating assembly for a heating plate for heating the heating plate for a laminator for manufacturing circuit boards, the heating assembly being in the form of a sheet having a heating plane, comprising:

a resistive strip for connection to a power source to generate heat from a circulating current;

the resistance strips extend along the trend of a preset shape in the heating plane, and the resistance distribution density of the resistance strips in the middle area of the heating assembly is smaller than that of the resistance strips in the peripheral area of the heating assembly.

In one embodiment, the resistor strip is a continuous strip, and two ends of the resistor strip are electrically connected with a power supply.

In one embodiment, the resistor strip is a one-piece component.

In one embodiment, the resistor strip is provided with an insulating layer on the periphery.

In one embodiment, the insulating layer is insulating ceramic sintered on the surface of the resistor strip.

In one embodiment, the cross-sectional area of the resistor strips in the central region of the heating assembly is larger than the cross-sectional area of the resistor strips in the peripheral region of the heating assembly.

In one embodiment, the resistor strips have a uniform dimension in the thickness direction of the heating member, and the width of the resistor strips in the central region of the heating assembly is greater than the width of the resistor strips in the peripheral region of the heating assembly.

In one embodiment, the spacing between the resistor strips in the central region of the heating assembly is greater than the spacing between the resistor strips in the peripheral region.

In one embodiment, the cross-sectional area of the resistor strip is not uniform throughout.

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

Compared with the prior art, the application has the beneficial effects that: the application provides a heating element for hot plate has the resistance strip of predetermineeing the shape trend, and the resistance distribution density that is located the regional resistance strip in heating member middle part is less than the resistance distribution density that is located the regional resistance strip of heating member periphery to compensate the inhomogeneous temperature that leads to of hot plate 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 perspective exploded view of a heating panel having a heating assembly provided in an embodiment of the present application;

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

figure 3 is a schematic top view of a heating assembly of a heating plate in another embodiment of the present application.

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, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within 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 particular 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.

Referring to fig. 1 and 2, fig. 1 is a schematic perspective exploded view illustrating a heating plate using a heating assembly according to an embodiment of the present application, and fig. 2 is a schematic sectional view illustrating the heating plate of fig. 1. As shown in fig. 1 and 2, a heating plate 100, a laminator for manufacturing printed circuit boards. The heating plate 100 includes a shield layer (10, 14), a heating element (11, 13), and a base plate 12. Wherein, the heating components (11, 13) are laid on the plate surface of the substrate, and the shielding layers (10, 14) are arranged on the outermost layer of the heating plate 100 and cover the surface of the substrate on which the heating components (11, 13) are laid for protecting the heating components (11, 13). After the heating plate 100 is assembled, the heating elements (11, 13) are disposed between the substrate 12 and the shield layer 10. Specifically, the heating element is in the form of a sheet, forming a heating plane, sandwiched between the substrate 12 and the shield layer 10.

In one embodiment of the heating element, the heating plate has only one heating element, i.e., the heating plate includes a substrate 12, a shielding layer 10, and a heating element 11 disposed between the substrate 12 and the shielding layer 10. In the scenario of being applied to the laminator, the number of the heating plates is at least two, the two heating plates are stacked on each other, a multi-layer core board for manufacturing the circuit board is sandwiched between the two heating plates, wherein the substrate 12 of the heating plates is located at the outer side, the shield layer 10 faces the multi-layer core board, and the multi-layer core board is heated by the heating assembly 11.

In another implementation scenario of the heating plate, referring to fig. 1, the heating plate 100 may also include 2 heating elements, namely a first heating element 11 and a second heating element 13, respectively, which are respectively laid on the upper and lower plate surfaces of the substrate 12, the outermost layers of the heating elements (11, 13) are shielding layers (10, 14), namely a first shielding layer 10 and a second shielding layer 14, respectively, and the heating plate 100 sequentially comprises the first shielding layer 10, the first heating element 11, the substrate 12, the second heating element 13, and the second shielding layer 14 according to the order of composition. The upper and lower surfaces of the heating plate 100 provided in this embodiment can both be used for heating, and can be used as an intermediate plate, and is disposed between the upper and lower heating plates, and two gaps for sandwiching the multilayer core plate are formed between the two adjacent heating plates, and the number of the heating plates disposed in the center may be 1, or may be multiple.

The two heating assemblies 11, 13 are similar in structure, and for the sake of brevity, only the first heating assembly 11 will be described below. Referring to fig. 3, the heating assembly 11 includes a resistor 111, two ends of the resistor 111 are connected to a power supply, and after the power supply is turned on, a current flows in the resistor 111, and a thermal effect of the current causes the resistor 111 to generate heat, so as to raise the temperature of the heating plate 100. The resistor strips 111 extend along the preset shape trend in the heating plane, and the resistor strip 111 in the central area of the heating member has a lower resistance distribution density than the resistor strip 111 in the peripheral area of the heating member. Taking the example of application to the heating plate 100, the resistor strips 11 are configured to be laid on the substrate 12 in a predetermined shape, and the resistor strips 11 located in the central region of the substrate 12 have a lower resistance distribution density than the resistor strips 111 located in the peripheral region of the substrate 12. With such an arrangement, when the current levels are the same, the average heat generated per unit area of the resistor strips 111 located in the central region is lower than the average heat generated per unit area of the resistor strips 111 located in the peripheral region, so that the situation that the temperature is lower than the central region due to the fact that the peripheral region of the heating plate 100 exchanges much heat with the surrounding environment can be balanced, and the uniformity of the temperature of the heating plate can be improved. On the contrary, if the resistor strips are uniformly distributed on the substrate 12, under the condition of equal heating heat, since the heat exchange between the peripheral region of the heating plate 100 and the surrounding environment is more active, the heat dissipation of the heating plate in the central region is slower, the temperature of the heating plate is increased to the peripheral region, and the temperature of the peripheral region is lower than that of the central region, so that the temperature of the heating plate 100 is not uniform, and the quality of the produced printed circuit board is poor or even scrapped. Here, the resistance distribution density is to be understood as a total resistance value per unit area of the heating plane plate surface of the heating member, that is, the resistance distribution density is the resistance value of the corresponding region/the area of the corresponding region. It can be understood that the larger the distribution density of the resistance, the more the heating value of the heating effect of the current is increased by the same current.

For convenience of manufacture and temperature control, in the present embodiment, the resistor strip 111 of the first heating assembly 11 is a continuous strip conductor, and both ends of the resistor strip 111 are used for connecting a power supply, and after the power supply is connected, the current is the same at all positions of the resistor strip 111. Preferably, the resistor track 111 is integrally formed as one piece.

Further, since the heating element is a conductor, heat is generated by a current flowing through the heating element, and the insulating layer 22 is provided on the outer periphery of the resistor strip 111 to prevent leakage current. Thereby realize insulating between heating element and adjacent base plate and the guard shield layer to avoid effectively taking place electric leakage or string electricity between heating element and the adjacent layer. The insulating layer 22 is an insulating material coated on the resistor strip 111, that is, the surface of the resistor strip 111 is covered with the insulating material, so that the resistor strip 111 is insulated from the outside. An alternative insulating material is an insulating ceramic sintered around the resistor track 111. In order to further enhance the reliability of the insulation, the shield layer is also insulated, in one embodiment, the shield layer may be made of an insulating material, and in another embodiment, an insulating protection layer, such as alumina, is also disposed outside the insulating layer, so as to form two layers of insulating protection with the insulating layer 22, thereby improving the safety and reliability of the insulating protection.

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

With continued reference to fig. 3, the first heating element 11 includes a positive electrode 114 and a negative electrode 112, and the resistive 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, the positive electrode 114 and the negative electrode 112 are powered, and current flows in the resistor strip 111, so that heat is generated 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. When the resistor strip 111 is energized, heat energy is generated. The energization control manner of the resistor strip 111 may specifically be to change the value of the current or the voltage, or to control the on-off time period of the energization. The material of the resistor strip 111 may be a material with a high thermal resistance, such as iron, steel, chromium, manganese, ceramic, etc. In the embodiment shown in fig. 3, the spacing between the pre-shaped electrically resistive tracks 111 in the central region of the heating element is greater than the spacing between the pre-shaped electrically resistive tracks 111 in the peripheral regions of the heating element. In this embodiment, the resistor strips 111 have a uniform distribution of resistance, wherein a uniform distribution of resistance is understood to mean that the resistance values of any unit length of the resistor strips 111 are the same. In a particular embodiment, the resistive track 111 has a non-uniform cross-sectional area throughout. The peripheral region and the central region of the heating member are defined as the peripheral regions at both ends in the length direction (width) along an extending direction of the heating member, such as the length direction (width direction), and the central regions at the middle parts of both ends are the central regions, and the peripheral regions and the central regions are sequentially arranged along the length direction. In this embodiment, the predetermined shape of the resistor strips 111 is a serpentine shape, which may also be referred to as a "bow" shape. Specifically, referring to fig. 3, the radiation resistor strips 111 are substantially parallel strip-shaped strips connected end to end, and the connection portion between adjacent strip-shaped strips is in an arc shape, so that the temperature concentration caused by the sharp transition of the strip-shaped strips is reduced. And the distances between the adjacent strip belts are different, and the distance between the middle area is larger than the distance between the strip belts at the two end areas.

In another embodiment, the resistance across the resistor strips 111 is non-uniform, with the cross-sectional area of the resistor strips located in the central region of the heating member being greater than the cross-sectional area of the resistor strips 111 located in the peripheral region of the heating member. It will be appreciated that the thicker the resistive track 111, the lower its resistance and the lower the thermal effect of the current, the thicker the resistive track 111 in the central region is, and the thicker the resistive track 111 in the peripheral region is, so that the same current generates less heat per unit area in the central region, which can balance the uneven heating plate temperature caused by uneven heat radiation in the peripheral and central regions of the heating plate.

The substrate 12 is provided with an installation groove having a shape consistent with the preset shape of the resistor strip 111, the resistor strip 111 is embedded into the installation groove, and the protection cover 10 (or 14) is covered thereon. The processing and manufacturing are convenient. The resistor strips 111 have a uniform size in the thickness direction of the heating panel 100, and the width of the resistor strips 111 located in the central region of the heating block is greater than the width of the resistor strips 111 located in the peripheral region of the heating block. Correspondingly, the mounting grooves are consistent in depth, 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 resistor strip) needs to be controlled, and the processing and the manufacturing are convenient.

In other embodiments, the predetermined shape of the resistor strip 111 may also be a zigzag shape or a zigzag shape. The resistance strips 111 in the zigzag trend are laid in a first circle along the outer contour of the substrate 12 at a constant distance, are roughly wound in a circle but are not closed, are laid in a second circle at a constant distance from the first circle, are laid in a third circle in the same way until the middle of the substrate 12 can be directly led out from the middle to be connected with a power supply, and can also be laid in a circle from the middle of the substrate 12 to the peripheral area until the edge of the substrate is laid, so that the power supply is conveniently switched on. The resistor strips of each circle are continuous, the distance between the adjacent resistor strips is different, and the distance between the resistor strips positioned in the middle area is larger than that of the resistor strips positioned in the peripheral area. Preferably, the spacing of the resistor strips increases in sequence from the outer edge to the middle.

The application provides a heating element 11 (or 13) of hot plate 100 for having the resistance strip 111 of predetermineeing the shape trend, can arrange the resistance strip trend or move towards the interval between according to the size of hot plate and adaptability to reduce effectively that the heat that is located the hot plate of middle part region and peripheral zone loses the unbalanced risk that leads to the temperature is 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 of the resistor strip 111 is 0.1 Ω -10 Ω, preferably 1.5 Ω, 2.5 Ω.

After the heating and pressing are completed, the temperature of the heating plate 100 is lowered as quickly as possible, thereby facilitating the detachment of the printed circuit board. The base plate 12 is also 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 by 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 may contain cooling water or cooling oil, and the adjacent first and second heating assemblies 11 and 13 are effectively cooled by the cooling water or cooling oil.

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 (10)

1. A heating assembly for a heating plate for heating the heating plate of a laminating machine for manufacturing circuit boards, the heating assembly being in the form of a sheet having a heating plane, comprising:

a resistive strip for connection to a power source to generate heat from a circulating current;

the resistance strips extend along the trend of a preset shape in the heating plane, and the resistance distribution density of the resistance strips in the middle area of the heating assembly is smaller than that of the resistance strips in the peripheral area of the heating assembly.

2. The heating assembly of claim 1 wherein said resistive track is a continuous strip, said resistive track having ends electrically connected to a power source.

3. The heating assembly of claim 2, wherein the resistive track is a one-piece member.

4. The heating assembly of claim 1, wherein the resistive track is provided with an insulating layer on its periphery.

5. The heating element of claim 4, wherein the insulating layer is an insulating ceramic sintered to the surface of the resistor strip.

6. The heating assembly of claim 1, wherein a cross-sectional area of the resistive track in a central region of the heating assembly is greater than a cross-sectional area of the resistive track in a peripheral region of the heating assembly.

7. The heating element of claim 6, wherein said resistive track has a uniform dimension across the thickness of said heating element, and wherein said resistive track has a greater width in a central region of said heating element than in a peripheral region of said heating element.

8. The heating assembly of claim 1, wherein a pitch of the resistor strips in a central region of the heating assembly is greater than a pitch of the resistor strips in the peripheral region.

9. The heating assembly of claim 8, wherein the resistive track has a non-uniform cross-sectional area throughout.

10. The heating element of claim 1, wherein the predetermined shape comprises a serpentine, zig-zag or zig-zag.

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