阅读说明：本技术 一种带有螺丝通孔应力缓冲、对准装置的pcb板及加工方法 (PCB with screw through hole stress buffering and aligning device and processing method ) 是由 吕瑞倩 于 2021-09-10 设计创作，主要内容包括：本发明提供了一种带有螺丝通孔应力缓冲、对准装置的PCB板及加工方法,包括偶数层设置的PCB板主体,所述PCB板主体上设有螺丝通孔,所述螺丝通孔与螺丝钉通过螺纹连接,所述螺丝通孔周围设有一圈锡条,所述锡条下侧设有震动缓冲装置,所述PCB板主体层数为8-34层,优选的,所述PCB板主体层数为8层,8层从上到下分别标记为L1-L8层,其中L2层和L7层为信号回流层面。当PCB板主体的震动缓冲装置受到外界作用力时,在缓冲弹片的作用下,PCB板主体在下凹瞬间并产生相反的弹力与外界作用力相抵消,从而将锡条弹回到原始的位置,避免锡条受力后直接断掉,或者开裂的情况。(The invention provides a PCB with a screw through hole stress buffering and aligning device and a processing method thereof, wherein the PCB comprises a PCB main body arranged in an even number of layers, the PCB main body is provided with screw through holes, the screw through holes are connected with screws through threads, a circle of tin bars are arranged around the screw through holes, a vibration buffering device is arranged at the lower side of the tin bars, the number of layers of the PCB main body is 8-34, preferably, the number of layers of the PCB main body is 8, the 8 layers are respectively marked as L1-L8 from top to bottom, and the L2 layer and the L7 layer are signal backflow layers. When the vibrations buffer of PCB board main part received external effort, under the effect of buffering shell fragment, PCB board main part was concave down in the twinkling of an eye and produced opposite elasticity and external effort and offset to bounce back primitive position with the tin bar, avoid directly breaking after the tin bar atress, perhaps the condition of fracture.)

1. The PCB with the screw through hole stress buffering and aligning device is characterized by comprising a PCB main body (1) which is arranged on an even number of layers, wherein screw through holes (10) are formed in the PCB main body (1), screws (3) penetrate through the screw through holes (10), a circle of convex ring tin bars (12) are arranged around the screw through holes (10), and a vibration buffering device (5) is arranged on the lower side of each convex ring tin bar (12).

2. The PCB board according to claim 1, wherein the number of layers of the PCB board body (1) is 8-34.

3. The PCB of claim 1, wherein the number of layers of the PCB body (1) is 8, and the 8 layers are respectively marked as L1-L8 from top to bottom, wherein the L2 layer and the L7 layer are signal reflow layers, the shock absorbing device (5) is disposed in the L2 layer and the L7 layer, and the elastic mechanism (4) is disposed inside the shock absorbing device (5).

4. The PCB board of claim 3, wherein the L8 layer comprises an insulating sub-layer and a trace sub-layer, and a layer of substrate green oil is disposed outside the trace sub-layer.

5. The PCB board according to claim 1, wherein the screw through hole (10) is provided with a Pad (11) at the periphery, the size and the shape of the Pad (11) are set according to the position of a wave soldering component, a restricted area is arranged between the Pad (11) at the periphery of the screw through hole (10) and a pin adjacent to the wave soldering component, and the screw through hole (10) is avoided at the restricted area.

6. The PCB board as claimed in claim 1, wherein the thickness of the shock absorbing device (5) is in the range of 1-20mils, the closest distance F between the shock absorbing device (5) and the edge of the PCB board body (1) is more than or equal to 20mils, and the closest distance G between the shock absorbing device (5) and the via hole with the non-GND property is more than or equal to 12 mils.

7. The PCB board as claimed in claim 6, wherein the upper side of the vibration buffering device (5) is provided with a screw through hole Pad copper leakage (8), and when a convex ring tin bar (12) is arranged on the screw through hole Pad copper leakage (8), the thickness of the screw through hole Pad copper leakage (8) is more than or equal to 10 mils; when the convex ring tin bar (12) is not arranged on the screw through hole Pad copper leakage (8), the thickness of the screw through hole Pad copper leakage (8) is more than or equal to 20 mils.

8. A method of manufacturing a PCB board as claimed in any of claims 1 to 7 wherein the method comprises the steps of:

step S1, drilling screw through holes (10) on the PCB main body (1), and drilling 8 concave Pad holes around the screw through holes (10), wherein the concave Pad holes surround the screw through holes (10) and are uniformly arranged in a shape of Chinese character 'mi';

step S2, placing an elastic mechanism (8) in the concave Pad hole on the PCB main body (1), wherein the outermost side of the compressed state of the elastic mechanism (8) is flush with the outer surface of the PCB main body (1) so as not to influence the screw through hole (10) of the screw lock;

step S3, copper plating is carried out on the upper side of the concave Pad hole;

step S4: and a convex ring tin bar (12) is welded on the copper plating of the concave Pad hole, and the thickness of the convex ring tin bar (12) is consistent with that of the screw through hole cap, so that the screw (3) can automatically slide into the screw through hole (10) when the screw (3) is locked.

Technical Field

The invention relates to the field of PCBs (printed circuit boards), in particular to a PCB with a screw through hole stress buffering and aligning device and a processing method.

Background

Along with the continuous development of applications such as cloud data, AI, big data, consequently, the performance requirement to network server's calculation is higher and higher, network server's calculation performance's powerful comes from the mainboard, the support of electronic spare and accessory such as chip, consequently need with the quantity of precision part and BGA chip on the mainboard constantly increase, then when BGA chip and high-density electronic components installation are more and more intensive on the mainboard, the spatial layout of screw through-hole in the PCB board is seriously influenced again, on the other hand because server mainboard function is abundanter more and more, consequently need increase multiple outer plug-in card and external device and install on the service system mainboard, this makes screw through-hole quantity increase to 30-50, and then can lead to the screw to appear multiple bad phenomenon when locking attaches the silk through-hole: 1. the situation that the screw through hole is scratched and copper is twisted easily occurs in the locking process, and if the scratch and the copper twisting of the screw through hole occur, the screw through hole cannot be maintained and can only be directly scrapped.

2. Because the screw can produce the lock in the lock attaches the stress, if install BGA chip or electric capacity in the too high scope of lock attach stress in the PCB board, easily cause BGA chip or electric capacity tin condition of splitting.

Therefore, in view of the current situation of the prior art, it is an urgent need to develop a PCB board with a screw through hole stress buffering and aligning device and a processing method thereof.

Disclosure of Invention

In order to solve the problems that the circuit on the PCB is easily scratched by deviation when screws are installed, so that short circuit or failure is caused, and BGA and part tin cracks are caused by locking stress when the screws are installed in the prior art, the invention provides the PCB with the screw through hole stress buffering and aligning device and the processing method.

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a PCB board and processing method with screw through-hole stress buffering, aligning device, includes the PCB board main part that the even number layer set up, be equipped with the screw through-hole in the PCB board main part, pass the screw in the screw through-hole, be equipped with round tin bar around the screw through-hole, the tin bar downside is equipped with vibrations buffer, the inside semicircular shrinkage pool that is of vibrations buffer, vibrations buffer can meet when the collision stress in screw lock attaches stress and the transportation with it and offset to avoid the part tin to split the condition to appear.

Further, the number of layers of the main body of the PCB is 8-34, preferably, the number of layers of the main body of the PCB is 8, the 8 layers are respectively marked as L1-L8 layers from top to bottom, wherein the L2 layer and the L7 layer are signal reflux layers, the shock buffering devices are arranged in the L2 layer and the L7 layer, and an elastic mechanism is arranged inside the shock buffering devices.

Further, the L8 layer includes an insulating sublayer and a wiring sublayer, and a layer of substrate green oil is arranged on the outer side of the wiring sublayer.

Furthermore, a Pad is arranged on the periphery of the screw through hole, the size and the shape of the Pad are set according to the position of the wave soldering element, a limiting area is arranged between the Pad on the periphery of the screw through hole and a pin adjacent to the wave soldering element, and the screw through hole is avoided in the limiting area.

Furthermore, the thickness range of the vibration buffering device in the PCB main body is 1-20mils, the closest distance F between the vibration buffering device and the edge of the PCB main body is not less than 20mils, and the closest distance G between the vibration buffering device and the non-GND-property via hole is not less than 12 mils.

Further, a screw through hole Pad copper leakage is formed in the upper side of the vibration buffering device, and when a convex ring tin bar is arranged on the screw through hole Pad copper leakage, the thickness of the screw through hole Pad copper leakage is larger than or equal to 10 mils; when the protruding ring tin bar is not arranged on the screw through hole Pad copper leakage, the thickness of the screw through hole Pad copper leakage is larger than or equal to 20mils, and the maximum strength of the PCB main body is ensured and cracks are avoided through the arrangement of the upper side limiting area.

Further, the method is divided into the following steps:

step S1, drilling screw through holes on the PCB main body, and drilling 8 concave Pad holes around the screw through holes, wherein the concave Pad holes surround the screw through holes and are uniformly distributed in a shape of Chinese character mi;

s2, placing an elastic mechanism in the concave Pad hole on the PCB main body, wherein the outermost side of the elastic mechanism in a compressed state is flush with the outer surface of the PCB main body, so that screw through holes are not influenced when screws are locked on the screws, the elastic mechanism adopts a buffer elastic sheet, the buffer elastic sheet has 200-DEG C-resistant and conductive properties, the number of the buffer elastic sheets is a plurality, when the PCB main body is vibrated, a buffer device instantly reacts under the action of the buffer elastic sheet, so that the PCB main body generates opposite elastic force at the moment of sinking, the convex tin bar is rebounded to the original position, and the situation that the tin bar is directly broken or cracked after being stressed is avoided;

step S3, copper plating is carried out on the upper side of the concave Pad hole;

step S4: the convex ring tin bar is welded on the copper plating of the concave Pad hole, the thickness of the convex ring tin bar is consistent with that of the screw through hole cap, so that when the screw is locked, the screw can automatically slide into the screw through hole, the convex ring tin bar is divided into the upper convex tin bar and the lower convex tin bar, the convex ring tin bar is used as an alignment device, when the screw is aligned to the middle of the screw through hole, the screw can automatically slide into the screw through hole in the middle position, and therefore surrounding tin bars or parts are prevented from being touched, and meanwhile the situation that the screw is locked after being aligned to the screw is avoided.

According to the technical scheme, the invention has the following advantages:

the scheme provides a PCB with a screw through hole stress buffering and aligning device and a processing method, and the PCB is provided with a PCB main body which is arranged in an even number layer, the PCB main body is provided with screw through holes, then the screw through holes are connected with screws through threads, a circle of tin bars are arranged around the screw through holes, then a vibration buffering device is arranged at the lower side of the tin bars, wherein the inside of the vibration buffering device is a semicircular concave hole, and the vibration buffering device buffers when the PCB main body meets the stress of locking the screw through holes and in the transportation process, so that the tin cracking of parts is avoided;

through placing elastic mechanism in the spill Pad hole in PCB board main part, when the vibrations buffer of PCB board main part received external effort, under the effect of buffering shell fragment, PCB board main part is concave in the twinkling of an eye and produce opposite elasticity and external effort and offset down to kick-back primitive position with the tin bar, avoid directly breaking after the tin bar atress, perhaps the condition of fracture.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

Fig. 1 is a sectional view of a main body of a PCB panel in accordance with an embodiment of the present invention.

FIG. 2 is a partial schematic view of FIG. 1 in accordance with an embodiment of the present invention.

Fig. 3 is a schematic diagram of a PCB in an embodiment of the invention.

Fig. 4 is a schematic view of a raised-ring solder strip according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of the location distribution of the resilient mechanism in an embodiment of the present invention.

In the drawings, 1-the PCB board body; 2-convex tin bar; 3-screws; 4-an elastic mechanism; 5-a shock-absorbing device; 6-case tray screw posts; 7-a chassis tray; 8, copper leakage of the through hole Pad of the screw; 9-protruding tin bar downwards; 10-screw through hole; 11-Pad; 12-raised ring tin bar.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present embodiment, and it is apparent that the embodiments described below are only a part of embodiments of the present invention, and not all embodiments. 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 scope of protection of this patent.

As shown in fig. 1-3, the present invention provides a PCB with a screw through hole stress buffering and aligning device and a processing method thereof, including a PCB main body 1 disposed in an even number of layers, each layer of the PCB main body 1 further includes: the number of the signal layers and the number of the return circuit reference layers are double, the thicker the PCB main body 1 is, the more the number of the layers can be made, and the number of the layers of the PCB main body is 8-34.

Example 1: as shown in fig. 2: the number of layers of the PCB main body 1 is 8, the 8 layers are respectively marked as L1-L8 layers from top to bottom, wherein the L2 layer and the L7 layer are signal backflow layers, the PCB main body 1 is provided with a screw through hole 10, a screw 3 passes through the screw through hole 10, the periphery of the screw through hole 10 is provided with Pad11, Pad11 (the Pad in the PCB main body is a welding Pad, is a part where the PCB main body and a component pin are mutually welded and consists of a copper foil and a hole, the copper foil is exposed and cannot be covered by a solder mask) is arranged in size and shape according to the position of a wave soldering component, a limiting area is arranged between the peripheral Pad of the screw through hole 10 and a pin adjacent to the wave soldering component, the screw through hole is avoided in the limiting area, a circle of convex ring tin bar 12 is arranged around the screw through hole 10, a vibration buffer device 5 is arranged on the lower side of the convex ring tin bar 12, wherein the vibration buffer device 5 is arranged in the L2 layer and the L7 layer, an elastic mechanism 4 is arranged in the vibration buffering device 5;

the L7 layer includes GND return layer C and insulating sublayer, wherein GND return layer's material is mainly copper, and copper content is 90%, and GND return layer is as signal return path, namely return current, and when high-speed digital signal transmission, the flow direction of signal is from driver along the transmission line transmission to the load in the PCB board main part, and then returns driver end along ground or power through the shortest path by the load, and this return signal on ground or power is called signal return path, and all signals need to have the return path.

The L8 layer includes an insulating sub-layer B and a routing sub-layer D, where the insulating sub-layer B is made of a sheet insulating material: after insulation is laminated, semi-cured epoxy resin is extruded to start flowing and solidifying, and the multilayer circuit board is bonded together, so that a layer of reliable insulator is formed;

the routing sublayer D is a layer which is arranged on the bottom layer of the PCB main body 1 and used for routing and can be observed on the outer surface of the PCB main body 1, wherein the routing sublayer is a circuit of which the whole copper surface is finished by etching to obtain a design draft, and is also a copper wire of the PCB main body which is generally seen.

The outer side of the wiring sublayer D is provided with a layer of substrate green oil E, wherein the substrate green oil E is a liquid photoinduced solder resist, is an acrylic oligomer, is used as a protective layer, is coated on a circuit and a base material of a printed circuit board which do not need to be welded, or is used as a solder resist, aims to protect a formed circuit pattern for a long time, and is at least 10mils away from the edge of a PCB main body, so that the situation that the edge of the PCB is curled due to friction and the like is avoided.

The thickness range of the vibration buffering device 5 in the PCB main body 1 is 1-20mils, the vibration buffering device 5 is arranged in L2 and/or L7, the closest distance F between the vibration buffering device 5 and the edge of the PCB main body 1 is not less than 20mils, the closest distance G between the vibration buffering device 5 and a via hole with a non-GND attribute is not less than 12mils, a screw through hole Pad copper leakage 8 is arranged between the vibration buffering device 5 and the convex ring tin bar 12, a convex ring tin bar 12 is arranged on the screw through hole Pad copper leakage 8, the thickness of the screw through hole Pad copper leakage 8 is not less than 10mils, a non-convex ring tin bar 12 is arranged on the screw through hole Pad copper leakage 8, and the thickness of the screw through hole Pad copper leakage 8 is not less than 20 mils.

The processing method of the device comprises the following steps:

step S1, drilling screw through holes 10 on the PCB board main body 1, and drilling 8 concave Pad holes around the screw through holes 10, wherein the concave Pad holes surround the screw through holes 10 and are uniformly distributed in a shape of Chinese character mi;

step S2, placing an elastic mechanism 8 in the concave Pad hole on the PCB body 1, wherein the outermost side of the compressed state of the elastic mechanism 8 is flush with the outer surface of the PCB body 1, so that the screw through hole 10 of the screw lock is not influenced;

step S3, copper plating is carried out on the upper side of the concave Pad hole;

step S4: and a convex ring tin bar 12 is welded on the copper plating of the concave Pad hole, and the thickness of the convex ring tin bar 12 is consistent with that of the screw through hole cap, so that the screw 3 can automatically slide into the screw through hole 10 when the screw 3 is locked.

The PCB board main body 1 is respectively provided with a SolderMaskLayer (the SolderMaskLayers are solder-resisting layers) at two sides, and the SolderMaskLayers are present to prevent the PCB from being adhered with tin at the position where the PCB is not coated with the tin when the PCB is subjected to wave soldering.

The screws 3 are M3\ M4\ M5 models commonly used by the server, wherein M3 is the screws 3 with the diameter of 3mm, approximately 30 screws with different models are arranged in the server, and an electric screw driver is adopted to carry out manual locking and attaching to fix the mainboard in the case.

Screw hole 10 above the PCB board main part 1 that the screw hole corresponds, chassis tray screw post diameter that is used for fixing the PCB board main part is 0.5mm less than the diameter of screw hole 10 trompil, chassis tray screw post diameter is whole to be defined by structural engineer, guarantee that the screw hole 10 trompil of PCB board main part matches with the screw is coincide, wherein the drilling error of screw hole 10 is 0- +6mils, wherein chassis tray screw post attribute is GND, ground connection is connected with quick-witted case and ground.

Case tray screw post 6: in the case of the server, the main board is placed in the case, the main board is fixed by locking screw through holes 10 through screws, the number of case tray screw posts in the server is 30-40, the case tray screw posts 6 have the function of supporting the main board, screw threads are arranged in the case tray screw posts and are locked with the screw threads of the screws, and preferably, the case tray screw posts are made of copper and are connected with the case.

Case tray 7: after the mainboard is installed into the case, the mainboard is locked on the case tray through case tray screw posts and is fixed, and then the tray and the mainboard are put together on the server system case, so that the installation is prevented from touching parts on the PCB.

The screw through hole Pad is exposed in copper 8: the screw cap exposes the regional contact of copper with the mainboard, can be better with GND through quick-witted case tray screw post be connected to the ground, the regional diameter size of exposing the copper of screw through-hole upside a week is: screw cap +7mm (the head of the screw is the screw cap).

Upper convex tin bar 2: and (3) carrying out tinning treatment on the copper exposed area at the outer edge of the screw through hole, wherein the size of the upper convex tin bar is in a certain proportion to the radius of the screw through hole, such as: the screw through-hole radius is 1.5mm, and the width 2mm of protruding tin bar goes up, and the height of protruding tin bar is unanimous with the screw cap thickness of screw, and is preferred, through increasing PCBA steel mesh thickness, guarantees to have sufficient last tin volume, guarantees that the height of protruding tin bar is 1.2 times of screw cap on the assurance.

Semi-circular concave Pad hole: the diameter of the concave Pad hole is 1.5mm, the depth is 20% of the plate thickness, and the elastic mechanism 4 is convenient to mount to generate effective buffering force.

The groove wall of the concave Pad hole is designed by copper plating or tin plating, the thickness of the copper plating is required to be 1.0mil-2.0mils, and the concave groove wall is arranged right below the convex ring tin bar.

Elastic mechanisms 4 are placed in the semicircular concave Pad holes, and the elastic mechanisms 4 can form reverse acting force for buffering when the PCB main body is locked with screw through holes through screws and stress is generated in the transportation process.

The elastic mechanism 4 can be a spring plate, and the spring plate has the properties of 200-degree high temperature resistance and electric conduction.

Downward convex tin bar 9: the same convex ring tin bars are arranged below the screw through holes 10 of the PCB body 1, the lower convex tin bars 9 are arranged, so that screws 3 can be aligned to screw posts of the chassis tray conveniently, and the width and height of the lower convex tin bars 9 are the same as those of the upper convex tin bars 2.

The terms "upper", "lower", "outside", "inside", and the like in the description and claims of the present invention and the above-described drawings (if any) are used for distinguishing relative positions without necessarily being construed qualitatively. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.