CN112372365B

CN112372365B - Milling deburring method for circuit board

Info

Publication number: CN112372365B
Application number: CN202011183351.2A
Authority: CN
Inventors: 许校彬; 徐涛
Original assignee: Huizhou Techuang Electronic Technology Co ltd
Current assignee: Huizhou Techuang Electronic Technology Co ltd
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2022-07-15
Anticipated expiration: 2040-10-29
Also published as: CN112372365A

Abstract

The invention discloses a milling deburring method for a circuit board, which comprises the following steps: acquiring liquid nitrogen; raising the pressure value of the liquid nitrogen by using a pressurizing device; installing a spraying device connected with a pressurizing device on the milling mechanism; adjusting the spraying direction of the spraying device to be within 15-35 degrees of an included angle between the spraying direction of the spraying device and the extending direction of the milling cutter; spraying liquid nitrogen into a preset milling path area where a milling cutter of the milling mechanism is in contact with the circuit board by using a spraying device; and milling the circuit board in the preset milling path area by using a milling cutter of the milling mechanism. According to the method for milling and deburring the circuit board, liquid nitrogen is sprayed towards the tail end of the milling cutter at an angle of 15-35 degrees, so that the milling cutter can generate broken chips in the continuous process of the circuit board of the milling cutter under the vaporization effect of the liquid nitrogen, and burr-free milling is achieved, the problem that burrs are generated in the process of machining and forming the circuit board made of polytetrafluoroethylene materials is avoided from the source, the milling efficiency is improved, and the machining cost is reduced.

Description

Milling deburring method for circuit board

Technical Field

The invention relates to the technical field of circuit board processing, in particular to a milling and deburring method for a circuit board.

Background

The polytetrafluoroethylene circuit board, that is the PTFE material circuit board of saying often, because material characteristic reason has produced a large amount of flocculent burrs in the outline machining process, and this kind of burr can't be polished, can only use the blade piece by piece to repair the burr after milling machine processing finishes, and is consuming time serious, a large amount of extravagant human costs. The PTFE burr problem severely impacts the processing cost and efficiency of the profile, as well as the flow rate of the product. The PTFE burrs are undoubtedly the biggest pain points of the appearance process, so the problem that the appearance processing burrs of the PTFE sheet plate are urgent is solved.

However, the traditional milling process cannot form an effective solution or thought to solve the problem of burr retention of the polytetrafluoroethylene circuit board in the machining and forming process, which affects the appearance integrity of the whole circuit board, and the retained burr needs to be repaired manually by using a blade block by block after the milling machine is finished in a manual mode, so that the time consumption is serious, the labor cost is greatly wasted, and the processing cost is increased.

Disclosure of Invention

Therefore, a circuit board milling and deburring method is needed to solve the technical problem of how to avoid burr retention in the process of processing and forming the circuit board.

A milling and deburring method for a circuit board comprises the following steps:

acquiring liquid nitrogen;

increasing the pressure value of the liquid nitrogen by using a pressurizing device;

installing a spraying device connected with the pressurizing device on a milling mechanism;

adjusting the spraying direction of the spraying device to be between 15 and 35 degrees of an included angle between the spraying direction of the spraying device and the extending direction of the milling cutter;

the liquid nitrogen is sprayed into a preset milling path area where a milling cutter of the milling mechanism is in contact with a circuit board by using the spraying device;

and milling the circuit board in the preset milling path area by using a milling cutter of the milling mechanism.

In one embodiment, the step of mounting the jetting device connected to the pressurizing device on the milling mechanism comprises:

and arranging two injection devices connected with the pressurizing device, and symmetrically installing the two injection devices on the milling mechanism.

In one embodiment, the step of adjusting the jetting direction of the jetting device to an angle between 15 degrees and 35 degrees with the extending direction of the milling cutter comprises:

the spraying direction of the spray head of each spraying device faces to the tail end of the milling cutter, and the included angle between the spraying direction and the extending direction of the milling cutter is 15-35 degrees.

In one embodiment, the spraying direction of the spray head of each spraying device faces to the tail end of the milling cutter, and the included angle between the spraying direction and the extending direction of the milling cutter is 20-30 degrees.

In one embodiment, the spraying direction of the spray head of each spraying device faces to the tail end of the milling cutter, and the included angle between the spraying direction and the extending direction of the milling cutter is 26 degrees.

In one embodiment, a plurality of the injection devices connected with the pressurizing device are arranged, the injection devices are respectively installed on a milling mechanism, the injection devices are respectively arranged around a milling cutter at intervals, the injection direction of a spray head of each injection device faces to the tail end of the milling cutter, and the included angle between the injection direction and the extension direction of the milling cutter is between 20 and 30 degrees.

In one embodiment, after the step of milling the circuit board in the preset milling path area by using the milling cutter of the milling mechanism, the method further comprises the following steps:

collecting the broken chips generated in the process of milling the circuit board,

and recovering and treating the broken chips.

In one embodiment, the step of collecting chippings generated during milling of the circuit board comprises: after the milling cutter mills the circuit board, the circuit board is erected, the vibrating machine is used for vibrating the circuit board, the broken chips are vibrated and fall off from the circuit board, the broken chips separated from the circuit board fall on a milling plane of the milling platform, and the scraper is used for scraping the broken chips on the milling plane into a collecting box.

In one embodiment, the step of recovering the crushed chips comprises:

extruding the broken cuttings by using a rolling device to obtain circuit board extrusion waste residues; performing filtrate operation on the circuit board extrusion waste residues through a filtrate part of the movable grid; drying the circuit board extrusion waste residue after filtrate operation by a drying part of the movable grid to obtain circuit board drying waste residue; and carrying out centrifugal crushing treatment operation on the dried circuit board drying waste residue by using a centrifugal crushing device to obtain circuit board waste residue particles.

In one embodiment, the rolling speed of the rolling device is 3-6 m/min.

The method for milling and deburring the circuit board sprays liquid nitrogen towards the tail end of the milling cutter under an angle of 15-35 degrees, under the vaporization action of liquid nitrogen, the milling cutter, the main shaft chuck and the circuit board below the tail end of the milling cutter are rapidly cooled, so that the temperature rise speed of the milling cutter is reduced in the milling process, the temperature rise of the milling cutter in the milling process is avoided, the temperature rise of the circuit board is avoided, the temperature of a contact area of the milling cutter and the circuit board is lower when the circuit board is milled and processed by the milling cutter, the characteristics of the circuit board are changed by external factors, so that the milling cutter can generate broken chips in the process of continuously milling the circuit board, thereby achieving burr-free milling, therefore, the problem that burrs are generated in the processing and forming process of the polytetrafluoroethylene circuit board is avoided from the source, the milling efficiency is improved, and the processing cost is reduced.

Drawings

FIG. 1 is a schematic structural diagram of a milling cooling device of a milling machine in one embodiment;

FIG. 2 is a schematic diagram of an exemplary milling cooling device of an embodiment;

FIG. 3 is a schematic view of a partial structure of a milling cooling device of a milling machine according to an embodiment;

FIG. 4 is a schematic view of a portion of a milling cooling device of a milling machine according to another embodiment;

FIG. 5 is an enlarged schematic view of portion A of the embodiment shown in FIG. 4;

FIG. 6 is a schematic diagram illustrating a portion of a milling cooling device of a milling machine according to an embodiment;

FIG. 7 is a schematic view of a portion of a milling cooling device of a milling machine according to another embodiment;

FIG. 8 is a flow chart of the steps of a method for milling and deburring a circuit board according to one embodiment;

fig. 9 is a flow chart of the steps of a milling deburring method for a circuit board in another embodiment.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanying figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, but are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

As shown in fig. 8, in an embodiment, the method for milling and deburring the circuit board includes the following steps: step S101: and obtaining liquid nitrogen. Step S102: and raising the pressure value of the liquid nitrogen by using a pressurizing device. Step S103: and installing the spraying device connected with the pressurizing device on the milling mechanism. Step S104: and spraying the liquid nitrogen into a preset area where the milling cutter of the milling mechanism is contacted with the circuit board by using the spraying device. According to the circuit board milling deburring method in the embodiment, the obtained liquid nitrogen is pressurized, so that the liquid nitrogen can keep a higher pressure value to be output, the pressurized liquid nitrogen is sprayed out by using the spraying device arranged on the milling mechanism, the liquid nitrogen is sprayed into the preset area where the milling cutter of the milling mechanism is in contact with the circuit board, the ambient temperature is reduced by using the principle that the liquid nitrogen absorbs energy when being converted from a liquid state to a gas state, and the purpose of reducing the temperature in the preset area where the milling cutter is in contact with the circuit board is achieved, so that the follow-up milling cutter generates broken chips when milling the circuit board, the purpose of generating no burrs on the milled circuit board is achieved, the milling efficiency is improved, and the processing cost is reduced.

To further illustrate each step in the above embodiments, the steps in the above embodiments will now be described in detail, illustrating the principles of each step and further preferred embodiments of the step.

Step S101: and acquiring liquid nitrogen.

Specifically, liquid ammonia is stored in a liquid nitrogen tank, and is obtained from the liquid nitrogen tank. The reason for using liquid ammonia here is to utilize the property of liquid ammonia, which has a low boiling point, and which can be instantaneously changed from a liquid state to a gaseous state, and the change of the liquid state to the gaseous state can absorb energy, thereby lowering the temperature of the peripheral object. In this embodiment, the liquid nitrogen tank is a self-pressurizing tank, that is, the liquid nitrogen tank itself can pressurize the liquid ammonia to maintain the liquid state of the liquid ammonia. From another point of view, it is understood that liquid nitrogen is obtained, and in fact, the liquid nitrogen is obtained by liquefying nitrogen in a gaseous state. However, the market is mature today, and liquid ammonia is available on the market, and liquid nitrogen is obtained without the need for special pressurization of gaseous nitrogen. However, from a technical point of view, liquid ammonia is obtained by technical means when there is no ready-made liquid nitrogen in the market, contained in a tank of liquid ammonia.

In one embodiment, after obtaining the liquid ammonia, the output of the liquid ammonia is quantitatively controlled and output to the pressurizing device at a preset flow rate. In this embodiment, through setting up flow controller at the output of liquid ammonia case, control the output quantity of liquid ammonia per second for the liquid ammonia of input pressure device is in the flow range value that predetermines. Therefore, the amount of liquid ammonia finally reaching the milling cutter and the circuit board can be controlled. On the one hand, the use cost of the liquid ammonia can be controlled, on the other hand, the output quantity of the liquid ammonia can be properly adjusted according to the sizes of different milling cutters and the thicknesses of circuit boards, the purposes of cooling and burr reduction can be achieved, meanwhile, the cost of milling operation can be reduced, resources are saved, and unnecessary waste is avoided.

Step S102: and raising the pressure value of the liquid nitrogen by using a pressurizing device.

Specifically, the liquid nitrogen is exported from the output of liquid nitrogen case after, owing to broken away from the pressurization system of liquid nitrogen case self, the pressure value of liquid nitrogen, the compression ratio example that also is the liquid nitrogen can reduce, pressurize the liquid nitrogen of following liquid nitrogen case output through pressure device once more this moment, can make finally satisfy predetermined pressure value from shower nozzle spun liquid nitrogen, also satisfy predetermined jet velocity promptly, reach the controllable condition of output of liquid nitrogen, make finally the cooling to milling cutter and circuit board controllable.

In one embodiment, after step S102, the method further includes the steps of: utilize pressure measurement device to detect the pressure value of the output of liquid nitrogen case, the pressure value of pressure device input, the pressure value of pressure device output respectively for satisfy between each pressure value and predetermine the pressure value condition: the pressure value of the output end of the liquid nitrogen box is greater than that of the input end of the pressurizing device, and the pressure value of the output end of the liquid nitrogen box is smaller than that of the output end of the pressurizing device; and when the preset pressure value conditions cannot be met among the pressure values, sending out a warning signal to remind a user. In this embodiment, through the pressure value of analysis liquid nitrogen in the circulation in-process, judge whether can satisfy the cooling requirement of predetermineeing when liquid nitrogen is spout from the shower nozzle, reach the purpose of cooling milling cutter and circuit board. It can be understood that when can not satisfy the pressure value condition of predetermineeing between each pressure value, it shows that liquid nitrogen is in a certain link of circulation in-process and goes wrong, and this problem will directly result in liquid nitrogen can not satisfy when the shower nozzle blowout and predetermine the cooling requirement, consequently need solve the problem of liquid nitrogen output pressure value, also need shut down and detect liquid nitrogen case or pressure device and whether break down promptly.

In one embodiment, the warning signal is a light signal, a sound signal and/or a vibration signal. That is, when the preset pressure value condition cannot be satisfied between the pressure values, a light signal, a sound signal and/or a vibration signal is emitted. Therefore, the user can be reminded in an obvious and direct mode that the machine needs to be stopped to detect whether the liquid nitrogen tank or the pressurizing device has faults or not. The problem that burrs of a circuit board after the milling cutter is machined cannot be thoroughly solved due to the fact that liquid nitrogen cannot meet the preset cooling requirement when being sprayed out of the spray head is also avoided.

Step S103: and installing the spraying device connected with the pressurizing device on the milling mechanism.

Specifically, the injection device is used for injecting liquid nitrogen from the liquid nitrogen box to the milling mechanism and the circuit board after the liquid nitrogen passes through the pressurizing device. Because the milling cutter is arranged on the milling mechanism, the injection device is arranged on the milling mechanism, and the milling cutter and the circuit board can be comprehensively cooled in time according to the operation route of the milling cutter on the milling mechanism. In this embodiment, install injection apparatus on milling mechanism through detachable mode to the maintenance to injection apparatus's installation and later stage is convenient. In addition, the installation position of the spraying device needs to be adjacent to the milling cutter of the milling mechanism, and particularly the spray head of the spraying device needs to be adjacent to the milling cutter and can adjust the spraying direction of the spray head, namely the spray head of the spraying device can adjust the most preferable spraying direction according to the type of the milling cutter, the thickness of the circuit board and the like, so that the liquid nitrogen can quickly and effectively reduce the temperature of the milling cutter and the circuit board.

Step S104: and spraying the liquid nitrogen into a preset area where a milling cutter of the milling mechanism is contacted with the circuit board by using the spraying device.

Specifically, the generation area of the circuit board burr is the area where the milling cutter contacts the circuit board, that is, the cutting position after the circuit board is cut by the milling cutter. This area requires liquid nitrogen for cooling, but not other areas of the circuit board. Therefore, the liquid nitrogen needs to be intensively sprayed to the preset area by using the spraying device, so that the liquid nitrogen absorbs heat when the liquid is converted into a gaseous state, and the purpose of cooling the preset area is achieved. It should be noted that, because the milling cutter is made of metal, the circuit board is made of PTFE polytetrafluoroethylene, and the heat conductivity of the milling cutter and the circuit board are different, it is obvious that the heat conductivity of the circuit board is lower than that of the milling cutter, and the milling cutter can reach the lowest temperature when liquid nitrogen is released. At the same time, the ptfe reaches the lowest temperature at which liquid nitrogen is released, and reaches the same temperature by heat transfer when the temperature varies between substances without changing the state of the substance (phase change, such as solid-liquid-gas phase).

In one embodiment, after the step of injecting the liquid nitrogen into the preset contact area between the milling cutter of the milling mechanism and the circuit board by using the injection device, the method further comprises the following steps: and a temperature detector is arranged on the milling mechanism, and the temperature value in the preset area is obtained in real time. In the embodiment, the temperature in the preset area is detected in real time through the temperature detector, so that the temperature range with the best deburring effect can be obtained after long-time milling operation. The optimal deburring is that the circuit board and the milling cutter are cooled during the milling process, so that broken chips are generated when the milling cutter cuts the circuit board, and the broken chips are directly separated from the circuit board without remaining on the circuit board to cause burr generation.

Further, after the step of detecting the temperature in the preset area in real time by the temperature detector, the method further comprises the steps of: and adjusting the flow and the injection speed of the injection device for injecting the liquid nitrogen according to the acquired temperature value in the preset area so as to achieve the optimal cooling effect. In this embodiment, when the liquid nitrogen is obtained in step S101, the output amount of the liquid ammonia per second may be controlled by setting the flow controller at the output end of the liquid ammonia tank, so that the liquid ammonia input to the pressurizing device is within the preset flow range value. In this way, in the present embodiment, by detecting the temperature in the preset region in real time, it becomes controllable to adjust the flow rate and the injection speed of the liquid nitrogen injected by the injection device. The optimal cooling effect is that the circuit board after milling does not generate burrs at a preset temperature is taken as a standard, the circuit board and the circuit board are mapped with each other, namely the temperature when the burrs are not generated in the milling process is the optimal temperature, and the burrs are not generated in the milling process at the optimal temperature. Therefore, the temperature in the preset area is detected in real time through the temperature detector, and the flow and the injection speed of the injection device for injecting the liquid nitrogen are adjusted according to the obtained temperature value in the preset area, so that the optimal cooling effect is achieved.

In order to further improve the efficiency of milling and deburring the circuit board, as shown in fig. 9, in an embodiment, the milling machine milling temperature reduction device is further implemented and operated by a circuit board milling and deburring method, and the circuit board milling and deburring method includes the following steps: step S201: and acquiring liquid nitrogen. Step S202: and raising the pressure value of the liquid nitrogen by using a pressurizing device. Step S203: and installing the spraying device connected with the pressurizing device on the milling mechanism. Step S204: adjusting the spraying direction of the spraying device to be within 15-35 degrees of an included angle between the spraying direction of the spraying device and the extending direction of the milling cutter. Step S205: and spraying the liquid nitrogen into a preset milling path area where a milling cutter of the milling mechanism is in contact with the circuit board by using the spraying device. Step S206: and milling the circuit board in the preset milling path area by using a milling cutter of the milling mechanism. In the circuit board milling and deburring method of the embodiment, after the temperature of the contact area of the milling cutter and the circuit board is reduced, the milling cutter can generate broken chips in the continuous process of milling the circuit board, so that the burr-free milling is realized, and the problem that burrs are generated in the process of machining and forming the polytetrafluoroethylene circuit board is avoided from the source.

To further illustrate each step in the milling and deburring method for circuit boards of the above embodiments, the steps of the above embodiments will now be described in detail, and the principle of each step and further preferred implementation steps of the step will be explained.

Step S201: and obtaining liquid nitrogen.

Specifically, liquid ammonia is stored in and taken out from a liquid nitrogen tank. The reason for using liquid ammonia here is to utilize the property of liquid ammonia, which has a low boiling point, that is instantaneously transformed from a liquid state to a gaseous state, and that the transformation of the liquid state to the gaseous state absorbs energy, thereby lowering the temperature of the peripheral object. In this embodiment, the liquid nitrogen tank is a self-pressurizing tank, that is, the liquid nitrogen tank itself can pressurize the liquid ammonia to maintain the liquid state of the liquid ammonia. From another point of view, it is understood that liquid nitrogen is obtained, and in fact, the liquid nitrogen is obtained by liquefying nitrogen in a gaseous state. However, the market is mature today, and liquid ammonia is available on the market, and liquid nitrogen is obtained without the need for special pressurization of gaseous nitrogen. However, from a technical point of view, when there is no liquid nitrogen available on the market in the liquid ammonia tank, the liquid ammonia is obtained by technical means.

Step S202: and increasing the pressure value of the liquid nitrogen by using a pressurizing device.

In one embodiment, after step S202, the method further includes the steps of: utilize pressure measurement device to detect the pressure value of the output of liquid nitrogen case, the pressure value of pressure device input, the pressure value of pressure device output respectively for satisfy between each pressure value and predetermine the pressure value condition: the pressure value of the output end of the liquid nitrogen box is greater than that of the input end of the pressurizing device, and the pressure value of the output end of the liquid nitrogen box is smaller than that of the output end of the pressurizing device; and when the preset pressure value conditions cannot be met among the pressure values, sending out a warning signal to remind a user. In this embodiment, through the pressure value of analysis liquid nitrogen in the circulation in-process, judge whether can satisfy the cooling requirement of predetermineeing when liquid nitrogen is spout from the shower nozzle, reach the purpose of cooling milling cutter and circuit board. It can be understood that when can not satisfy the pressure value condition of predetermineeing between each pressure value, explain that liquid nitrogen is in some link of circulation in-process and go wrong, and this problem will directly result in the liquid nitrogen can not satisfy the predetermined cooling requirement when the shower nozzle blowout, consequently need solve the problem of liquid nitrogen output pressure value, also whether needs shut down to detect liquid nitrogen case or pressure device break down promptly.

In one embodiment, the warning signal is a light signal, a sound signal and/or a vibration signal. That is, when the preset pressure value condition cannot be satisfied between the pressure values, a light signal, a sound signal and/or a vibration signal is emitted. Therefore, the user can be reminded in an obvious and direct mode that the machine needs to be stopped to detect whether the liquid nitrogen tank or the pressurizing device has faults or not. The problem that burrs of a circuit board after the milling cutter is machined cannot be thoroughly solved due to the fact that liquid nitrogen cannot meet the preset cooling requirement when sprayed out from the spray head is also avoided.

Step S203: and installing the spraying device connected with the pressurizing device on the milling mechanism.

Specifically, the injection device is used for injecting liquid nitrogen from the liquid nitrogen box to the milling mechanism and the circuit board after the liquid nitrogen passes through the pressurizing device. Because the milling cutter is arranged on the milling mechanism, the injection device is arranged on the milling mechanism, and the milling cutter and the circuit board can be comprehensively cooled in time according to the operating route of the milling cutter on the milling mechanism. In this embodiment, install injection apparatus on milling mechanism through detachable mode to the maintenance to injection apparatus's installation and later stage is convenient. In addition, the installation position of the spraying device needs to be adjacent to the milling cutter of the milling mechanism, and particularly the spray head of the spraying device needs to be adjacent to the milling cutter and can adjust the spraying direction of the spray head, namely the spray head of the spraying device can adjust the most preferable spraying direction according to the type of the milling cutter, the thickness of the circuit board and the like, so that the liquid nitrogen can quickly and effectively reduce the temperature of the milling cutter and the circuit board.

Step S204: adjusting the spraying direction of the spraying device to be within 15-35 degrees of an included angle between the spraying direction of the spraying device and the extending direction of the milling cutter.

Specifically, the liquid nitrogen is sprayed to the angle range of the milling cutter and the circuit board, and the cooling effect can be influenced. Supposing that if most of liquid nitrogen is sprayed to the milling cutter and the small part of liquid nitrogen is sprayed to the circuit board, the cooling effect of the circuit board is poor, and burrs can still be generated; similarly, if most of the liquid nitrogen is sprayed to the circuit board and a small part of the liquid nitrogen is sprayed to the milling cutter, the cooling effect of the milling cutter is poor, and in the milling process, the heat generated by the milling cutter can still be conducted to the circuit board to increase the temperature of the circuit board in the contact area between the milling cutter and the circuit board, so that although the temperature of the circuit board is initially reduced, the milling cutter can still generate burrs after the circuit board is heated in a grounding mode in the later period. Therefore, the injection angle of liquid nitrogen is important. In this embodiment, the spraying direction of the spraying device is adjusted to be within an angle of 15 to 35 degrees with the extending direction of the milling cutter. That is, in the virtual space, the extending direction of the injection device is a first line, the extending direction of the milling cutter is a second line, and the angle formed by the intersection of the first line and the second line is between 15 degrees and 35 degrees. This angle is expressed in fig. 2 as ≦ θ. Like this, under the angle between 15 degrees to 35 degrees, can equalize the volume that liquid nitrogen sprays the back and distribute circuit board and milling cutter, on the one hand can the cooling circuit board, on the other hand also can reduce the temperature of milling cutter, both all can reach the cooling purpose, make temperature between them not produce mutual interference, namely because circuit board and milling cutter all are cooled down, the temperature difference that produces between the two is less, heat of conduction each other is lower, especially the temperature of milling cutter can not influence the temperature of circuit board, so the circuit board is in the back of milling, do not have the burr and produce, milling efficiency and milling effect have been improved.

In order to enable the milling cutter and the circuit board to be cooled by liquid nitrogen well and achieve burr-free milling, in one embodiment, the spraying direction of the spray head faces to the tail end of the milling cutter, and an included angle between the spraying direction and the extending direction of the milling cutter is 20-30 degrees. Preferably, the spray direction of the spray head is towards the end of the milling cutter and the angle between the spray direction and the extension direction of the milling cutter is between 26 degrees. At the moment, a better milling effect is achieved. As shown in the following table:

test number	Angle theta	End temperature of milling cutter	Temperature of circuit board	Type of chip	Burr effect
						1	15 degree	-123.4℃	-123.3℃	Chipping and crushing chips	Is good
2	18 degree	-121.3℃	-121.5℃	Chipping and crushing chips	Good effect
						3	20 degree	-120.6℃	-120.7℃	Disintegrating chips	Is excellent in
4	22 degree	-120.8℃	-120.2℃	Chipping and crushing chips	Is excellent in
						5	24 degrees	-119.2℃	-119.8℃	Chipping and crushing chips	Is excellent
6	26 degree	-119.5℃	-119.6℃	Chipping and crushing chips	Is superior to
						7	30 degree	-118.6℃	-118.3℃	Disintegrating chips	Is excellent
8	33 degree	-116.8℃	-116.4℃	Disintegrating chips	Is excellent
						9	35 degree	-112.3℃	-112.2℃	Chipping and crushing chips	Is excellent in

As shown in the above table, after the spraying direction of the spray head is adjusted, the temperature of the tail end of the milling cutter and the temperature of the circuit board are respectively detected by using the temperature measuring instrument, and after a plurality of tests, when the spraying direction of the spray head faces the tail end of the milling cutter and the angle of the included angle between the spraying direction and the extending direction of the milling cutter is between 26 degrees, both the milling cutter and the circuit board can be well cooled by liquid nitrogen, crumbling chips are generated during milling of the circuit board, no burr is generated, and the milling surface is smoother than other spraying angles.

In one embodiment, two injection devices connected with the pressurizing device are provided, the two injection devices are symmetrically arranged on a milling mechanism, the injection direction of a spray head of each injection device faces to the tail end of the milling cutter, and the included angle between the injection direction and the extension direction of the milling cutter is between 20 and 30 degrees. Preferably, the injection direction of each spray head faces to the end of the milling cutter, and the included angle between the injection direction and the extension direction of the milling cutter is 26 degrees. It can be understood that through setting up two injection apparatus, two injection apparatus respectively spray the liquid nitrogen to milling cutter jointly in two relative directions, can be so that the cooling rate of milling cutter end and circuit board is faster, and the cooling effect is better.

Further, a plurality of injection devices connected with the pressurizing device are arranged, the injection devices are respectively installed on the milling mechanism, the injection devices are respectively arranged around the milling cutter at intervals, the injection direction of a spray head of each injection device faces to the tail end of the milling cutter, and the included angle between the injection direction and the extension direction of the milling cutter is between 20 and 30 degrees. Preferably, the injection direction of each spray head faces to the end of the milling cutter, and the included angle between the injection direction and the extension direction of the milling cutter is 26 degrees. It can be understood that through setting up a plurality of injection apparatus, a plurality of injection apparatus spray the liquid nitrogen to milling cutter jointly, can be so that the cooling rate of milling cutter end and circuit board is faster, and the cooling effect is better for the effect of burring can both satisfy the requirement when the angle is between 20 degrees to 30 degrees.

Step S205: and spraying the liquid nitrogen into a preset milling path area where a milling cutter of the milling mechanism is in contact with the circuit board by using the spraying device.

Specifically, the burr generating region of the circuit board is a region where the milling cutter contacts the circuit board, that is, a cutting position after the circuit board is cut by the milling cutter. The area needs liquid nitrogen for cooling, but not other areas of the circuit board. Therefore, the liquid nitrogen needs to be intensively sprayed to the preset area by using the spraying device, so that the liquid nitrogen absorbs heat when the liquid is converted into a gaseous state, and the purpose of cooling the preset area is achieved.

In one embodiment, after the step of injecting the liquid nitrogen into the preset contact area between the milling cutter of the milling mechanism and the circuit board by using the injection device, the method further comprises the following steps: and a temperature detector is arranged on the milling mechanism, and the temperature value in the preset area is obtained in real time. In the embodiment, the temperature in the preset area is detected in real time through the temperature detector, so that the temperature range with the best deburring effect can be obtained after long-time milling operation. The optimal deburring is to cool the circuit board and the milling cutter during the milling process, so that the milling cutter can generate broken chips when cutting the circuit board, and the broken chips can be directly separated from the circuit board without remaining on the circuit board to cause burr generation.

Further, after the step of detecting the temperature in the preset area in real time by the temperature detector, the method further comprises the steps of: and adjusting the flow and the injection speed of the injection device for injecting the liquid nitrogen according to the acquired temperature value in the preset area so as to achieve the optimal cooling effect. In this embodiment, when the liquid nitrogen is obtained in step S201, the output amount of the liquid ammonia per second may be controlled by setting a flow controller at the output end of the liquid ammonia tank, so that the liquid ammonia input to the pressurizing device is within the preset flow range value. In this way, in the present embodiment, by detecting the temperature in the preset region in real time, it becomes controllable to adjust the flow rate and the injection speed of the liquid nitrogen injected by the injection device. The optimal cooling effect is that the circuit board after milling does not generate burrs at a preset temperature is taken as a standard, the circuit board and the circuit board are mapped with each other, namely the temperature when the burrs are not generated in the milling process is the optimal temperature, and the burrs are not generated in the milling process at the optimal temperature. Therefore, the temperature in the preset area is detected in real time through the temperature detector, and the flow and the injection speed of the injection device for injecting the liquid nitrogen are adjusted according to the obtained temperature value in the preset area, so that the optimal cooling effect is achieved.

Step S206: and milling the circuit board in the preset milling path area by using the milling cutter of the milling mechanism.

Specifically, through the steps, the milling cutter and the circuit board of the milling mechanism are cooled, particularly the circuit board is cooled, when the milling cutter of the milling mechanism works, the cooled circuit board is milled along the preset milling path area, the milling cutter can continuously break up cutting scraps, and the effect of the burr-free milled circuit board can be achieved, so that the production requirement is met. The preset milling path area refers to a feed path to be milled on the circuit board by the milling cutter, and the feed of the milling cutter on the circuit board is completed by operating the milling mechanism according to a milling target by a worker.

Further, after the step of milling the circuit board in the preset milling path area by using the milling cutter of the milling mechanism, the method further comprises the following steps: collecting the broken cuttings generated in the process of milling the circuit board, and recovering and treating the broken cuttings. Specifically, the step of collecting the crumbled chips generated in the process of milling the circuit board comprises the following steps: after the circuit board is milled by the milling cutter, the circuit board is erected, the vibrating machine is used for vibrating the circuit board, the broken chips are vibrated and fall off from the circuit board, the broken chips separated from the circuit board fall on a milling plane of the milling platform, and the scraper is used for scraping the broken chips on the milling plane into a collecting box. That is to say, the circuit board to be milled is taken out from the production line and placed on the milling plane by the manipulator, and the manipulator clamps the circuit board to be milled by using the clamping device at the moment, so that the circuit board is placed to have the phenomena of movement deviation and the like. After the milling is finished, the milled circuit board is turned for 90 degrees by the mechanical arm, so that the circuit board is erected on the milling plane, the vibrating machine works and vibrates the circuit board to vibrate the crumbled chips to fall off from the circuit board, the crumbled chips separated from the circuit board fall on the milling plane of the milling platform, and finally the mechanical arm is utilized to scrape the crumbled chips on the milling plane to a collecting box along a driving scraper, so that the recovery of the crumbled chips is finished. The whole process of the process is mechanized, the burr-free milling operation is realized, and meanwhile, the broken chips are automatically recovered, so that the situation that the milled plane does not have broken chips when the circuit board is milled every time can be ensured, the influence of the broken chips on the smoothness of the milling operation, namely the circuit board, is avoided, the efficiency of the milling operation is improved, and the accuracy of the milling operation, namely the milling operation, is improved.

Further, the step of recycling the chipped and crushed chips includes: extruding the broken cuttings by using a rolling device to obtain circuit board extrusion waste residues; performing filtrate operation on the circuit board extrusion waste residues through a filtrate part of the movable grid; drying the circuit board extruded waste residues after the filtrate operation by a drying part of the movable grid to obtain circuit board dried waste residues; and carrying out centrifugal crushing treatment operation on the dried circuit board drying waste residues by using a centrifugal crushing device to obtain circuit board waste residue particles.

It can be understood that after the broken chips are vibrated and fall off from the circuit board and are collected in the collecting box, the broken chips absorb a large amount of moisture in the air due to the temperature rise, so that the water content of the circuit board waste residue mainly containing the broken chips is higher. In this embodiment, the circuit board waste is subjected to the pressing operation by the rolling device, that is, the circuit board waste is taken out from the collection box and put in the rolling device for the pressing operation. Preferably, the rolling device comprises at least two oppositely arranged pressing wheels, the pressing wheels are arranged below the collecting box, a throwing door is arranged at the bottom of the collecting box, and circuit board waste residues in the collecting box fall into the rolling device when the throwing door is opened. After the circuit board waste residues pass through the collecting box, the throwing door is opened, the circuit board waste residues in the collecting box fall into the rolling device below the collecting box, and most of moisture in the circuit board waste residues can be removed by extruding the circuit board waste residues through the two oppositely arranged pressing wheels.

The circuit board waste residue after the pinch roller extrusion continues to fall into the removal net that sets up under the pinch roller, and the removal net includes filtrating portion and stoving portion, and filtrating portion sets up under the pinch roller, and the stoving portion is connected with filtrating portion. The filter liquor portion is used for further filtering the solution contained in the circuit board waste residue after being extruded by the pressing wheel, and meanwhile, the water extruded out of the rolling device is filtered into the waste water tank through the filter liquor portion, so that the waste water is conveniently subjected to centralized treatment, and the environmental protection property of waste water treatment is improved.

The movable grids are equivalent to a grid conveyor belt and can move back and forth at a uniform speed, circuit board waste residues filtered by the filter liquor part move to the drying part from the filter liquor part along with the movement of the movable grids, and the circuit board waste residues are dried by the drying part to remove residual moisture in the circuit board waste residues. It should be noted that the drying part comprises a grid conveyor belt arranged on the surface and an electric heating element arranged in the drying part, and the electric heating element can perform electric heating through connecting a motor so as to dry the waste residue, remove the residual moisture in the waste residue and achieve a better dewatering effect.

In this embodiment, centrifugal grinding device includes feed inlet, centrifugal rubbing crusher constructs and first discharge gate, and the feed inlet sets up under the one end that the filtrating portion was kept away from to the drying portion, and the input of centrifugal rubbing crusher constructs is connected with the frame of feed inlet, and first discharge gate is connected with centrifugal rubbing crusher's output. It can be understood that after the drying operation is completed in the drying part, the circuit board waste residues continue to move along with the movement of the moving grids, finally fall into a feed port arranged right below one end, far away from the filtrate part, of the drying part, the centrifugal crushing mechanism is connected with the feed port, and the circuit board waste residues enter the centrifugal crushing mechanism through the feed port. It can be understood that, centrifugal rubbing crusher constructs including the casing cover, driving motor, main shaft and crushing blade, the main shaft is installed on the casing cover, crushing blade locates on the main shaft, driving motor fixed mounting covers at the casing, driving motor's output and main shaft fixed connection, the main shaft is the hollow shaft, crushing blade is the helix form and arranges on the main shaft, driving motor's the direction of rotation is the same with the helix that crushing blade arranged soon, crushing blade not only can be with comminuted when rotatory, can also produce propulsive force, with kibbling material by feed inlet propelling movement to discharge gate, make the inside of whole machine keep clean. In addition, the dried circuit board waste residues are processed by the centrifugal crushing mechanism to finally obtain dry particles in a fine sand state, so that the quality of the circuit board waste residues is reduced, a good weight reduction effect is achieved, the circuit board waste residues are conveniently processed, and the processing cost is greatly reduced.

In order to ensure that the rolling device achieves a better dehydration effect on the circuit board waste residue and improve the environmental protection and safety of the circuit board waste residue treatment, in one embodiment, the rolling speed of the rolling device is 3-6 m/min. It can be understood that if the rolling speed of the rolling device is too low, circuit board waste residues are easy to adhere to the surface of the pressing wheel, so that the operation of the rolling device is affected. If the rolling speed of the rolling device is too high, the solution of the circuit board waste residue is easy to splash in the rolling process, so that the operation environment is adversely affected, and meanwhile, the extruded waste liquid is inconvenient to collect. In the embodiment, the rolling speed of the rolling device is 3-6 m/min, so that the rolling device can achieve a good dehydration effect on the circuit board waste residue, and the circuit board waste residue cannot be adhered to the surface of the pressing wheel in the rolling process, so that the treatment efficiency of the circuit board waste residue is improved. Meanwhile, the extruded waste liquid is convenient to collect, and the environmental protection and safety of the waste residue treatment of the circuit board are improved.

In order to increase the weight reduction rate of the circuit board waste residue, in one embodiment, the drying operation temperature is 75-85 ℃. It can be understood that if the temperature of the drying operation is too low, the residual moisture in the circuit board waste residue cannot be removed well, so that the weight reduction rate of the circuit board waste residue is low, the processing of the circuit board waste residue is not facilitated, and the processing cost is increased easily. If the temperature of the drying operation is too high, the waste residue of the circuit board is easy to cause coking or fire, thereby generating a safety problem. In the embodiment, the drying operation temperature is 75-85 ℃, and experimental detection shows that residual moisture in the circuit board waste residue can be effectively removed at the drying operation temperature of 75-85 ℃, so that a good weight reduction effect is achieved, and the operation safety can be ensured.

Further, the drying operation time is 1 hour to 1.5 hours. It can be understood that if the baking operation time is too short, the residual moisture in the circuit board waste residue cannot be removed well, so that the weight reduction rate of the circuit board waste residue is low, the circuit board waste residue is not easy to treat, and the treatment cost is increased easily. If the baking operation is carried out for too long time, the waste residues of the circuit board are easy to cause coking or fire, thereby generating safety problems. In this embodiment, the drying operation time is 1 hour to 1.5 hours, and experimental detection shows that the drying operation time is 1 hour to 1.5 hours at a temperature of 75 ℃ to 85 ℃, so that residual moisture in the circuit board waste residue can be removed more effectively, and the weight reduction rate of the circuit board waste residue is improved.

In one embodiment, the moving speed of the moving grid is 2m/min to 4 m/min. It can be understood that the mobile grid is equivalent to a grid conveyor belt and can reciprocate at a uniform speed, circuit board waste residues filtered by the filtering part move to the drying part from the filtering part along with the motion of the mobile grid, and the circuit board waste residues are dried by the drying part to remove residual moisture in the film residues. When the circuit board waste residue moves to the drying part along with the mobile network, the mobile grid can be stopped and made at any time so as to be convenient for fully baking the circuit board waste residue, after the baking operation is completed, the mobile grid is continuously started, and the baked circuit board waste residue is conveyed to the centrifugal crushing device for centrifugal crushing operation. In addition, the solution produced in the rolling process directly falls into the moving grid and is filtered into the wastewater tank through the filtrate part of the moving grid. In the embodiment, the moving speed of the moving grid is 2 m/min-4 m/min, the processing speed of the circuit board waste residue by the rolling device can be effectively matched, the solution generated in the rolling process is prevented from falling on the rolled circuit board waste residue, the circuit board waste residue achieves a good dehydration effect, and meanwhile, the processing efficiency of the circuit board waste residue can be improved.

In one embodiment, the rotation speed of the centrifugal crushing device is 3000 r/min-4000 r/min. It can be understood that if the rotating speed of the centrifugal crushing device is too low, the centrifugal crushing device can easily crush the circuit board waste residue incompletely or has poor uniformity, and cannot achieve a good crushing effect, so that the subsequent treatment of the circuit board waste residue particles is not facilitated. If the rotation speed of the centrifugal grinding device is too high, the temperature of the device is easily too high and the device is easily worn excessively. In the embodiment, the rotating speed of the centrifugal crushing device is 3000 r/min-4000 r/min, and through experimental detection, when the rotating speed is 3000 r/min-4000 r/min, uniform and dry fine sand-shaped circuit board waste residue particles can be obtained, so that the quality of the circuit board waste residue particles is effectively reduced, and a better weight reduction effect is achieved. Meanwhile, the waste residues of the circuit board can be conveniently treated, and the treatment cost is greatly reduced.

In one embodiment, the comminution blades of the centrifugal comminution apparatus are detachably arranged on the main shaft of the centrifugal comminution apparatus. It should be noted that, centrifugal rubbing crusher constructs including the casing cover, driving motor, main shaft and crushing blade, the main shaft is installed on the casing cover, crushing blade locates on the main shaft, driving motor fixed mounting is covered at the casing, driving motor's output and main shaft fixed connection, the main shaft is the hollow shaft, crushing blade is the helix form and arranges on the main shaft, driving motor's direction of rotation and the helix that crushing blade arranged are the same to the direction of rotation, crushing blade not only can be with comminuted when rotatory, can also produce the propulsive force, with kibbling material by feed inlet propelling movement to discharge gate, make the inside of whole machine keep clean. In this embodiment, crushing blade detachably among the centrifugal reducing mechanism sets up on centrifugal reducing mechanism's main shaft, and through the quantity of control crushing blade, can control the crushing fineness of circuit board waste residue to guarantee to push circuit board waste residue granule to the ejection of compact, make the circuit board waste residue smash into even fine sand form granule simultaneously, and then conveniently handle circuit board waste residue, the treatment cost that significantly reduces.

In an embodiment, the circuit board milling and deburring method is also applied and operated through a milling and cooling device of a milling machine, namely, the circuit board milling and deburring method is operated through the milling and cooling device of the milling machine to achieve the purpose of reducing the temperature of an area where the milling cutter is in contact with a circuit board, so that the milling cutter can generate broken cuttings in the continuous process of milling the circuit board of the milling cutter to achieve burr-free milling, and the problem that burrs are generated in the process of machining and forming the polytetrafluoroethylene circuit board is avoided from the source.

The milling and cooling device of the milling machine is mainly applied to CNC (computerized numerical control) forming of the PTFE material circuit board, the temperature of a milling cutter in the cutting process of the milling machine and the temperature of the PTFE material circuit board are reduced by conveying the milling cutter to a spray head through a pressurized liquid nitrogen device, effective broken cuttings are generated in a milling area when the milling cutter mills the PTFE material circuit board, and the burr-free forming effect of the edge of the cut PTFE material circuit board is achieved.

Specifically, referring to fig. 1 and fig. 2, the present invention provides a milling cooling device 10 for a milling machine, where the milling cooling device 10 is used for processing a circuit board 90, and the milling cooling device 10 includes: the milling mechanism 100 and the temperature reducing mechanism 200, the temperature reducing mechanism 200 includes an injection device 210, a liquid nitrogen tank 220 and a pressurizing device 230, the injection device 210 is installed on the milling mechanism 100, an output end of the liquid nitrogen tank 220 is communicated with an input end of the pressurizing device 230, and an output end of the pressurizing device 230 is communicated with an input end of the injection device 210. The injection device 210 includes an infusion tube 211 and a head 212, the infusion tube 211 communicates with an output end of the pressurizing device 230, and the head 212 communicates with an output end of the infusion tube 211. The infusion tube 211 and the spray head 212 are mounted on the milling mechanism 100, the spray head 212 is adjacent to the milling cutter 101 of the milling mechanism 100, the spraying direction of the spray head 212 faces to the tail end of the milling cutter 101, and the included angle theta between the spraying direction and the extending direction of the milling cutter 101 is between 15 and 35 degrees.

According to the milling cooling device 10 of the milling machine, liquid nitrogen is sprayed towards the tail end of the milling cutter at an angle of 15-35 degrees, and under the vaporization action of the liquid nitrogen, the milling cutter 101, the spindle chuck and the circuit board 90 below the tail end of the milling cutter 101 are rapidly cooled, so that on one hand, the temperature rising speed of the milling cutter 101 in the milling process is reduced, the temperature rising of the milling cutter 101 in the milling process is avoided, the temperature rising of the circuit board 90 is avoided due to the fact that the temperature of the milling cutter 101 is increased and is conducted to the circuit board 90, on the other hand, when the circuit board 90 is processed by milling by the milling cutter 101, the temperature of the area where the milling cutter 101 is in contact with the circuit board 90 is lower, the characteristic of the circuit board 90 is changed by external factors, the milling cutter 101 can generate broken chips in the continuous process of the milling cutter circuit board 90, the purpose of burr-free milling is achieved, and the problem that burrs are generated in the processing and forming process of the polytetrafluoroethylene material 90 is avoided from the source, the milling efficiency is improved, and the processing cost is reduced.

The milling mechanism 100 is a device loaded with a milling cutter 101, also referred to as the entire mechanism in the industry as a milling machine. Is a rotary tool for milling machining having one or more cutter teeth. The method is mainly used for processing planes, steps, grooves, forming surfaces, cutting off workpieces and the like on a milling machine. In this embodiment, the milling mechanism 100 mainly utilizes the milling cutter 101 to cut the circuit board, for example, to cut the circuit board with a large area in the whole speed into a plurality of small circuit boards, and to cut off excess material blocks at the edge of the circuit board, for example, to shape the appearance of the circuit board. The milling mechanism generally includes a driving motor, a spindle chuck and a milling cutter, the driving motor drives the spindle to rotate, the spindle drives the spindle chuck to rotate, the spindle chuck clamps the milling cutter, and the milling cutter is simply driven to rotate. When the milling cutter contacts the surface of the circuit board, the milling cutter rotating at high speed finishes the milling operation of the circuit board.

In order to facilitate the milling operation of the worker more accurately or facilitate the worker to observe the milling operation condition of the milling machine, in an embodiment, the milling cooling device of the milling machine further comprises an observation lamp, the observation lamp is mounted on the milling mechanism, the irradiation direction of the observation lamp faces the tail end of the milling cutter, and the observation lamp is used for irradiating the milling area of the milling cutter. Specifically, should observe lamps and lanterns include support, sleeve, chargeable cell panel, link, support frame, connection casing, lamp plate, LED wick, rotatory handle, two-way screw rod, sliding plate, slide bar, cylinder chuck, arc groove, movable rod, shaft coupling, clearing hole and rolling bearing, and the support mounting can adopt spiro union, joint or the mode of pegging graft to connect on milling the mechanism for example. Connect the casing and be connected through the bolt with rotatory handle, the output shaft of rotatory handle is connected through the shaft coupling with two-way screw rod, two-way screw rod runs through in the sliding plate inside and mesh mutually and is connected, be equipped with the cylinder chuck on the sliding plate, through rotatory this rotatory handle, rotatory handle passes through the shaft coupling and drives two-way screw rod and rotate, two-way screw rod acts on the sliding plate, make the relative two-way screw rod of sliding plate remove, it presss from both sides tightly or keeps away from the arc groove to drive the cylinder chuck, can realize the clamp of link and loosen, convenient quick change to new LED wick. The sliding plate runs through and has the slide bar, and the slide bar both ends all with be connected casing welded connection, are equipped with the clearing hole on connecting the casing, and the clearing hole runs through has the link, connects and fixedly is equipped with rolling bearing on the casing. The connecting frame is provided with an arc groove corresponding to the cylindrical chuck, the connecting frame is embedded with the movable rod in sliding connection, and the other end of the movable rod is welded with the connecting shell. The connecting shell is connected with the lamp panel through bolts, and an LED lamp wick is embedded in the lamp panel. The connecting frame is connected with the support in a welded mode, the support is connected with the supporting frame in a welded mode, and the supporting frame is connected with the connecting frame in a welded mode. The support passes through bolt fixed connection with the sleeve, and the sleeve is connected through the bolt with chargeable cell panel. So, during the use, through rotatory this rotatory handle, rotatory handle passes through the shaft coupling and drives two-way screw rod and rotate, and two-way screw rod acts on the sliding plate for the relative two-way screw rod of sliding plate removes, drives the cylinder chuck and presss from both sides tightly or keep away from the arc groove, can realize the tight and loosen of clamp to the link, convenient quick change to new LED wick. Therefore, the observation lamp is convenient for workers to observe the milling operation condition of the milling machine, and can effectively replace the LED lamp wick in time when the LED lamp wick is damaged, so that the working efficiency and the continuity of the work are improved.

The cooling mechanism 200 is used for cooling the milling cutter 101, the spindle chuck, and the circuit board 90 below the end of the milling cutter 101. Cooling mechanism 200 in this application utilizes the nitrogen gas composition to account for air 78%, and is colorless, odorless, and non-corrosiveness is incombustible, and the temperature is extremely low, and is inactive, does not support characteristics such as burning, can make the milling machine of this application mill and cut heat sink can go on at the interior space. Since liquid nitrogen is at atmospheric pressure, the temperature is 196 ℃ below zero, which is far lower than the temperature in air, and the boiling point of liquid nitrogen is low, the liquid nitrogen is instantly transformed from liquid state to gaseous state, and basically, the liquid nitrogen is vaporized when boiling is not seen, so the principle of the cooling mechanism 200 is that pressurized liquid ammonia is instantly vaporized into ammonia gas during injection, and energy is absorbed during the transformation from liquid state to gaseous state, thereby reducing the temperature of the peripheral region contacted by the liquid ammonia during vaporization, especially the object contacted with the liquid ammonia, and rapidly reducing the temperature of the object.

The essence of the cutting process of the milling cutter is a deformation process in which the material to be cut is subjected to shear slip by the pressing action of the cutting edge and the rake face of the milling cutter. Under the action of the cutting force of the milling cutter, the cut area of the material firstly generates compressive elastic deformation, and after the shear stress exceeds the yield limit of the material, the internal crystal lattice of the material slides, namely, plastic deformation is generated on a shearing plane. The cutter moves forward continuously, the cutting force is increased, stress concentration is generated, and the material shearing stress near the cutting edge exceeds the strength limit and is peeled. The cutting layer is plastically deformed and is peeled off in the vicinity of the cutting edge, thereby performing a cutting action. The deformed and stripped material flows out along the chip groove of the front cutter face under the squeezing action of the front cutter face of the milling cutter, and then chips are generated.

Since the material to be cut is different, the cutting conditions are different, and the deformation during the cutting process is different, the chips formed are also various. Common cutting types are nodular chips, broken chips, ribbon chips, unit chips. The type of the cutting chip is determined by the stress-strain characteristic and the plastic deformation degree of the material, if the processing conditions are the same, the material with high plasticity is not easy to break and is easy to form strip-shaped cutting chips, while the hard and brittle material can generate brittle fracture almost without plastic deformation, and the obtained cutting chips are in irregular fine particles. That is, under the same processing conditions, as the plasticity of the material becomes lower, the transformation process of the chip shape is as follows: unit chip → band chip → nodular chip → chip. For burr reduction, the four chips are ordered in terms of profitability: the unit chip < band chip < nodular chip < chipping chip, so the tendency to shift the chip type from unit chip to chipping chip is the tendency of burr improvement.

The crystal of PTFE polytetrafluoroethylene can generate unit-shaped shearing sliding when stressed in a crystallization area, so that the PTFE has the characteristics of poor mechanical property, easy creep, no wear resistance and the like. Even if the temperature is as low as-196 ℃, the PTFE material can still keep 5% of elongation, and the temperature of the PTFE material in the shape processing process is not lower than room temperature, so burrs generated in the processing process of the PTFE plate are the inherent mechanical characteristics of the PTFE material, namely the easy creep. In addition, the plastic deformation of a PTFE cutting area is increased by heat generated by friction between a cutting edge of the milling cutter and chips in the shape machining process, so that unit or strip-shaped chips are easily generated in the milling process, the milling cutter cannot normally cut off the chips along with the aggravation of tool winding and poor chip removal caused by the strip-shaped chips, and non-metal PTFE burrs are inevitably generated on the shape machining path. In contrast, the common FR-4 material with low plasticity has the advantages that the chip edge is broken chips in the shape processing process, namely, the broken chips are fine powder particles, the edge of the plate is smooth and has no burr after the shape is milled, and the milling cutter has no cutter winding phenomenon. Therefore, it is confirmed that the cause of the generation of the burrs is related to the polytetrafluoroethylene, and the burrs can be removed by the treatment according to the characteristics of the polytetrafluoroethylene.

Since the root of the PTFE burrs is the creep-susceptible property of the PTFE material, the improvement is necessarily directed to reducing the creep deformation of the PTFE material during the contour machining process, i.e., reducing the plastic deformation of the cut region of the plate during the cutting process of the milling cutter, and the most desirable effect is to change the chips generated during the machining process from strip-shaped or unit-shaped chips to broken chips, so that the PTFE burrs can be easily solved.

The heat generated by the friction between the cutting edge of the milling cutter and the cutting chips in the shape processing process of the polytetrafluoroethylene circuit board increases the plastic deformation of the PTFE cutting area, so that the temperature is reduced by uninterruptedly and finely spraying liquid nitrogen to the milling cutter aiming at the high temperature problem in the friction process. Liquid nitrogen is at atmospheric pressure and at a temperature of-196 c, and because of the high temperature in air, and the low boiling point of liquid nitrogen, it is essentially vaporized when you cannot see it. Meanwhile, the nitrogen accounts for 78% of the air, and is colorless, odorless, non-corrosive, non-combustible and extremely low in temperature. Nitrogen is inactive and does not support combustion. The liquid nitrogen is instantly vaporized into nitrogen gas in the injection process, the nitrogen gas exists in the air and the nitrogen gas does not support combustion, so the method can be used indoors and is very safe. Therefore, the temperature of the spindle chuck and the milling cutter can be reduced, the cutting capacity in the milling process is guaranteed, the milling cutter can continuously break chips, and the burr-free milling is achieved to meet the production requirement.

In one embodiment, the cooling mechanism further comprises a flow controller, and the flow controller is arranged between the liquid nitrogen tank and the pressurizing device. Specifically, the flow controller is arranged at the output end of the liquid nitrogen box, and the liquid nitrogen box is communicated with the pressurizing device through the flow controller. The flow controller is used for quantitatively controlling the output of the liquid ammonia and outputting the liquid ammonia to the pressurizing device at a preset flow. Therefore, the amount of liquid ammonia finally reaching the milling cutter and the circuit board can be controlled. On the one hand, the use cost of the liquid ammonia can be controlled, on the other hand, the output quantity of the liquid ammonia can be properly adjusted according to the sizes of different milling cutters and the thicknesses of circuit boards, the cost of milling operation can be reduced while the purposes of reducing temperature and burrs are achieved, resources are saved, and unnecessary waste is avoided.

As shown in fig. 3, 4, 5 and 6, in order to adjust the spraying angle of the spraying head 212, in one embodiment, the milling mechanism 100 is provided with an angle adjusting block 110 adjacent to the milling cutter 101, and the spraying head 212 is rotatably connected with the angle adjusting block 110. Thus, the nozzle 212 rotates along the rotation center of the angle adjusting block 110. Further, the nozzle 212 includes a connection block 216 and an injection cylinder 217, the connection block 216 is rotatably connected to the angle adjustment block 110, the injection cylinder 217 is connected to the connection block 216, and the injection cylinder 217 is communicated with the output end of the infusion tube 211 through the connection block 216 and the angle adjustment block 110. Thus, the liquid ammonia in the liquid nitrogen tank 220 can be injected to the milling cutter 101, the spindle chuck and the area such as the circuit board 90 below the tail end of the milling cutter 101 through the angle adjusting block 110, the connecting block 216 and the injection cylinder 217 under the pressurization of the pressurizing device 230, and thus the injection cylinder 217 can be accurately oriented in a rotation adjusting mode, the liquid ammonia is not wasted, and the temperature of the area such as the milling cutter 101, the spindle chuck and the area such as the circuit board 90 below the tail end of the milling cutter 101 can be reduced to the minimum, so that the generation of burrs can be avoided.

In one embodiment, the milling mechanism is further provided with a transparent observation protection plate, and the transparent observation protection plate is arranged above the spray head. Preferably, a transparent viewing shield is provided around each spray head. Transparent observation guard plate is used for keeping apart user and liquid ammonia, prevents that liquid ammonia from sputtering to user's face and eyes from causing the injury. Further, the transparent observation protection plate is a plate-shaped structure made of a transparent material, such as a glass material, a plastic material and the like. In one embodiment, the transparent observation protection plate is vertically positioned on the projection of the circuit board, and the projection of the nozzle on the circuit board is covered, that is to say, the transparent observation protection plate comprises the nozzle in the covering area, so that the nozzle can generate liquid ammonia sputtering or the liquid ammonia sputtering generated when the nozzle sprays liquid ammonia to the circuit board can be shielded by the transparent observation protection plate. Therefore, the transparent observation protection plate can be used for realizing the isolation protection of an operation user.

Further, the transparent observation protection plate is also provided with a convex lens. The position of the convex lens corresponds to the position of the nozzle, and each nozzle is correspondingly provided with one convex lens. Preferably, the transparent viewing prevention plate is integrally provided with the convex lens. In this embodiment, the convex lens has a spherical surface. So, can enlarge the visual angle of spouting accurate and this region of circuit board through this convex lens, whether the spray angle of observation nozzle that can be more obvious is in predetermineeing the within range, detects the nozzle and can spout the region to waiting to mill with liquid ammonia completely to can conveniently operate the spray angle of adjustment nozzle, improve the make full use of liquid ammonia.

In order to realize that the liquid ammonia in the liquid nitrogen tank 220 can be injected to the milling cutter 101, the spindle chuck and the circuit board 90 below the end of the milling cutter 101 through the angle adjusting block 110, the connecting block 216 and the injection cylinder 217 under the pressurization of the pressurization device 230, in an embodiment, the milling mechanism 100 is provided with a pipe joint 120 adjacent to the angle adjusting block 110, the inner end of the pipe joint 120 is communicated with the connecting block 216 and the angle adjusting block 110, and the outer end of the pipe joint 120 is communicated with the output end of the liquid conveying pipe 211. In this way, a liquid flow path is formed from the pipe joint 120 to the connection block 216, and the liquid ammonia is pressurized by the pressurizing device 230, passes through the liquid transfer pipe 211, the pipe joint 120, the angle adjusting block 110, and the connection block 216, is finally ejected from the ejection cylinder 217, and is finally ejected to the region such as the milling cutter 101, the spindle chuck, and the circuit board 90 below the end of the milling cutter 101. Further, the nozzle 212 further comprises a hose 218, the angle adjusting block 110 is provided with a first pipe passage 111, the connecting block 216 is provided with a second pipe passage 219, the hose 218 is respectively accommodated in the first pipe passage 111 and the second pipe passage 219, one end of the hose 218 is communicated with the inner end of the pipe joint 120, and the other end of the hose 218 is communicated with the input end of the injection cylinder 217. In this way, since the flexible tube 218 is made of a flexible material and can be bent freely, the flexible tube 218 can ensure the normal circulation of liquid ammonia during the rotation of the connection block 216 relative to the angle adjustment block 110, that is, during the adjustment of the injection angle of the injection cylinder 217.

As shown in fig. 6 and 7, in an embodiment, the injection cylinder 217 is provided with a tapered channel 2171, a portion of the tapered channel 2171 adjacent to the connecting block 216 is an input end, a portion of the tapered channel 2171 adjacent to the end of the injection cylinder 217 is an output end, also called an injection port, and an opening area of the input end is larger than that of the output end. The tapered passage 2171 communicates with the second tube passage 219. Thus, the opening area of the input end is large, so that more liquid nitrogen can be contained, and after the liquid nitrogen is input into the tapered channel 2171 through the second tube channel 219, the liquid nitrogen is ejected from the output end with the small opening area, so that the outward ejection distance of the liquid nitrogen is further, and the liquid nitrogen can be accurately ejected to the milling cutter 101, the spindle chuck, the circuit board 90 below the tail end of the milling cutter 101 and other areas.

In order to realize the multi-angle rotation of the connecting block 216 relative to the angle adjusting block 110, in one embodiment, the connecting block 216 has an abdicating notch 221, and the rotating portion 112 of the angle adjusting block 110 is received in the abdicating notch 221. Thus, due to the receding of the receding notch 221, the rotating portion 112 of the angle adjusting block 110 can rotate relative to the receding notch 221. In this embodiment, the rotating portion 112 of the angle adjusting block 110 is a circular structure. Further, the connecting block 216 abuts against two opposite side walls of the abdicating notch 221 on two opposite surfaces of the angle adjusting block 110, respectively. In this way, the connecting block 216 will wrap the rotating portion 112 of the angle adjusting block 110, so that the whole structure is more compact, and the connecting block 216 will not move along the extending direction of the rotating shaft during the rotating process, thereby facilitating the stable adjustment of the angle of the connecting block 216 relative to the angle adjusting block 110.

Further, the nozzle 212 further includes a positioning pin 222, the angle adjusting block 110 is provided with a positioning channel 113, two opposite side walls of the connection block 216 at the abdicating notch 221 are respectively provided with a positioning notch 223, and the positioning pin 222 sequentially penetrates through one positioning notch 223, the positioning channel 113 and the other positioning notch 223 and then is respectively connected with the angle adjusting block 110 and the connection block 216. The alignment pin 222 provides a rotational support for rotation between the angle adjustment block 110 and the attachment block 216 so that the attachment block 216 can rotate relative to the angle adjustment block 110 about the axis of the alignment pin 222. At the same time, the positioning pin 222 also serves as a connection fixing function, so that the connecting block 216 is stably limited on the angle adjusting block 110. In this way, by adjusting the tightness of the positioning pin 222, the angle of the connecting block 216 relative to the angle adjusting block 110 can be correspondingly adjusted, and the injection direction of the injection cylinder 217 can also be indirectly adjusted, since the injection direction of the injection head 212 faces the end of the milling cutter 101 and the included angle θ between the injection direction and the extension direction of the milling cutter 101 is a measurable value, the tightness of the positioning pin 222 can be adjusted according to the size of the included angle θ in the adjustment process, so that the injection direction of the injection head 212 is stable and reliable, and the milling processing efficiency is improved.

In order to prevent the flexible tube 218 from being compressed during the rotation of the rotating portion 112 of the angle adjusting block 110 relative to the connecting block 216, in one embodiment, the first tube passage 111 and the second tube passage 219 are respectively communicated with the relief notch 221. In this way, the space formed by the first tube passage 111, the second tube passage 219 and the abdicating notch 221 can accommodate the part of the hose 218 exposed at the joint of the angle adjusting block 110 and the connecting block 216, and when the part of the hose 218 is accommodated in the space formed by the first tube passage 111, the second tube passage 219 and the abdicating notch 221, even if the rotating part 112 of the angle adjusting block 110 contacts the hose 218 during the rotation relative to the connecting block 216, the hose 218 still has a large space, so that the hose 218 is difficult to be pressed to block, and the injection of liquid ammonia is affected. Furthermore, the angle adjusting block 110 is correspondingly provided with an avoiding notch 114 at the rotating part 112, and the avoiding notch 114 is communicated with the avoiding notch 221. In this way, through the opening of the avoiding notch 114, the part of the hose 218 exposed at the connection position of the angle adjusting block 110 and the connecting block 216 has a larger space, so that the hose 218 can be better protected, and the liquid ammonia can be stably sprayed in the milling process.

In order to enable the spray cylinder 217 to rapidly cool and cool the milling cutter 101, the spindle chuck and the area of the circuit board 90 below the tail end of the milling cutter 101 in unit time, in one embodiment, the spray direction of the spray head 212 faces the tail end of the milling cutter 101, and the included angle of ≧ theta between the spray direction and the extension direction of the milling cutter 101 is between 20 degrees and 30 degrees. Preferably, the angle of ≦ θ is 25 degrees. At this angle, the liquid ammonia injected from the injection cylinder 217 is mostly injected into the milling cutter 101, the spindle chuck, and the area of the circuit board 90 below the end of the milling cutter 101, and takes most of the temperature when it is vaporized, thereby rapidly cooling the area of the milling cutter 101, the spindle chuck, and the area of the circuit board 90 below the end of the milling cutter 101 in a unit time. Therefore, the milling cutter can generate effective broken cuttings in a milling area when milling the PTFE material circuit board, and the burr-free forming effect of the edge of the PTFE material circuit board after being cut is achieved.

In one embodiment, the milling machine milling cooling device further comprises a milling platform, a vibrating machine, a mechanical arm and a collecting box, wherein the milling mechanism is installed on the milling platform, the milling platform is provided with a milling plane, a circuit board to be milled is placed on the milling plane, the mechanical arm and the collecting box are respectively installed and arranged on the milling platform, the vibrating machine is installed on the mechanical arm, the mechanical arm is provided with a clamping device, the clamping device is used for clamping the circuit board to be milled, and the clamping device is further used for overturning the milled circuit board by 90 degrees so that the circuit board can stand on the milling plane. The vibrating machine is used for working when the circuit board is erected on the milling plane so as to vibrate the circuit board and vibrate and drop broken chips from the circuit board. The manipulator is further provided with a scraper which is used for abutting against the milling plane and scraping the broken chips on the milling plane to the collecting box.

According to the milling machine milling cooling device with the milling platform, the vibrating machine, the mechanical arm and the collecting box, when the milling machine milling cooling device works, the circuit board to be milled is taken out from a production line and placed on a milling plane through the mechanical arm, and the mechanical arm clamps the circuit board to be milled through the clamping device, so that the circuit board is placed and the phenomena of movement deviation and the like are achieved. After the milling is finished, the milled circuit board is turned over by 90 degrees by the manipulator, so that the circuit board is erected on a milling plane, the vibrating machine works and vibrates the circuit board to vibrate the crumbled chips from the circuit board to fall off, the crumbled chips separated from the circuit board fall on the milling plane of the milling platform, and finally the manipulator drives the scraper to scrape the crumbled chips on the milling plane into the collecting box, so that the crumbled chips are recovered. The whole process of the process is mechanized, the burr-free milling operation is realized, and meanwhile, the broken chips are automatically recovered, so that the situation that the milled plane does not have broken chips when the circuit board is milled every time can be ensured, the influence of the broken chips on the smoothness of the milling operation, namely the circuit board, is avoided, the efficiency of the milling operation is improved, and the accuracy of the milling operation, namely the milling operation, is improved.

All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above examples only show some embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. A milling and deburring method for a circuit board is characterized by comprising the following steps:

acquiring liquid nitrogen;

adjusting the spraying direction of the spraying device to be within 15-35 degrees of an included angle between the spraying direction of the spraying device and the extending direction of a milling cutter of the milling mechanism;

milling the circuit board in the preset milling path area by using a milling cutter of the milling mechanism;

standing the circuit board, vibrating the circuit board by using a vibrator, vibrating and dropping broken chips from the circuit board, dropping the broken chips separated from the circuit board on a milling plane of a milling platform, and scraping the broken chips on the milling plane into a collection box by using a scraper;

extruding the broken cuttings by using a rolling device to obtain circuit board extrusion waste residues;

performing filtrate operation on the circuit board extrusion waste residues through a filtrate part of the movable grid;

drying the circuit board extrusion waste residue after filtrate operation through the drying part of the movable grid to obtain circuit board drying waste residue;

carrying out centrifugal crushing treatment operation on the dried circuit board drying waste residues by using a centrifugal crushing device to obtain circuit board waste residue particles;

the milling and deburring method of the circuit board is realized by a milling and cooling device of a milling machine, and the milling and cooling device of the milling machine comprises the following steps: the liquid nitrogen spraying device is installed on the milling mechanism, the output end of the liquid nitrogen box is communicated with the input end of the pressurizing device, the output end of the pressurizing device is communicated with the input end of the spraying device, the spraying device comprises a liquid conveying pipe and a spray head, the liquid conveying pipe is communicated with the output end of the pressurizing device, the spray head is communicated with the output end of the liquid conveying pipe, the liquid conveying pipe and the spray head are installed on the milling mechanism, the spray head is adjacent to a milling cutter of the milling mechanism, the spraying direction of the spray head faces the tail end of the milling cutter, and the included angle between the spraying direction and the extending direction of the milling cutter ranges from 15 degrees to 35 degrees;

the milling mechanism is provided with an angle adjusting block adjacent to the milling cutter, and the spray head is rotationally connected with the angle adjusting block; the spray head comprises a connecting block and an injection cylinder, the connecting block is rotationally connected with the angle adjusting block, the injection cylinder is connected with the connecting block, and the injection cylinder is communicated with the output end of the infusion tube through the connecting block and the angle adjusting block; the milling mechanism is provided with a pipe joint adjacent to the angle adjusting block, the inner end of the pipe joint is communicated with the connecting block and the angle adjusting block, and the outer end of the pipe joint is communicated with the output end of the infusion tube; the spray head further comprises a hose, the angle adjusting block is provided with a first pipe channel, the connecting block is provided with a second pipe channel, the hose is contained in the first pipe channel and the second pipe channel respectively, one end of the hose is communicated with the inner end of the pipe joint, and the other end of the hose is communicated with the input end of the injection cylinder; the injection cylinder is provided with a conical channel, the part of the conical channel adjacent to the connecting block is an input end, the part of the conical channel adjacent to the tail end of the injection cylinder is an output end, the opening area of the input end is larger than that of the output end, and the conical channel is communicated with the second pipe channel; the connecting block is provided with a yielding notch, and the rotating part of the angle adjusting block is accommodated in the yielding notch; two opposite side walls of the connecting block and the abdicating notch are respectively abutted against two surfaces back to the back of the angle adjusting block; the nozzle also comprises a positioning pin, the angle adjusting block is provided with a positioning channel, two opposite side walls of the connecting block and the abdicating notch are respectively provided with a positioning notch, and the positioning pin is sequentially penetrated through the positioning notch, the positioning channel and the other positioning notch and then is respectively connected with the angle adjusting block and the connecting block; the first tube passage and the second tube passage are respectively communicated with the abdicating notch.

2. A circuit board milling and deburring method as claimed in claim 1, wherein said step of mounting said injector means connected to said pressurizing means on a milling mechanism comprises:

3. The circuit board milling and deburring method of claim 2, wherein the step of adjusting the jetting direction of the jetting device to an angle between 15 degrees and 35 degrees with the extending direction of the milling cutter comprises:

4. A circuit board milling and deburring method as claimed in claim 3, wherein the spraying direction of the spray head of each spraying device faces to the end of the milling cutter and the included angle between the spraying direction and the extending direction of the milling cutter is 20-30 degrees.

5. A circuit board milling and deburring method as claimed in claim 4, wherein the spraying direction of the spray head of each spraying device faces to the tail end of the milling cutter, and the included angle between the spraying direction and the extending direction of the milling cutter is 26 degrees.

6. A circuit board milling and deburring method as claimed in claim 1, wherein a plurality of said jet devices connected to said pressurizing device are provided, said plurality of said jet devices are respectively mounted on a milling mechanism, said plurality of said jet devices are respectively arranged at intervals around a milling cutter, the jet direction of the nozzle of each said jet device is directed toward the end of said milling cutter and the angle between said jet direction and the extending direction of said milling cutter is from 20 degrees to 30 degrees.

7. The circuit board milling and deburring method according to claim 1, wherein the rolling speed of the rolling device is 3 m/min-6 m/min.