RU2801761C1 - Method and apparatus for manufacturing printed circuit board - Google Patents

Abstract

FIELD: electronic engineering.

SUBSTANCE: devices for additive manufacturing of printed circuit boards (PCB) and devices for rapid 3D prototyping for automated production of PCB prototypes for electronic devices. The technical result is achieved by the fact that the device for manufacturing multilayer printed circuit boards (MPCB) includes a three-coordinate positioning device, on the lower part of which an object table is fixed for fixing PCB substrates with a heating element attached to the bottom of the object table. On the movement block along the Z axis of the three-coordinate positioning device, by means of a carriage unit, there are installed: two dosing heads, each containing a syringe with a fluid material, the piston of which is attached to a stepper motor by means of a rod, while one of the dosing heads contains a screw dispenser with a dosing nozzle for applying an electrically conductive fluid material to the PCB substrate, the other dosing head contains a pneumatic dispenser with a dosing nozzle for applying an insulating fluid material to the PCB substrate. The device contains a sensor for detecting the surface and measuring the heights of the PCB substrate fixed on the object table, as well as a control unit electrically connected to the three-coordinate positioning device, dosing heads, a heating element and a surface detection sensor, receiving instructions representing the path of the PCB template, and controlling the connected elements of the device in accordance with the instructions. The screw dispenser consists of a sleeve, into the body of which an internal cavity with a channel for screw rotation is pressed, in which the screw is coaxially installed, pressed into a rotating mount fixed to the stepper motor and pressed by a fixing cover, with gaskets placed between the internal cavity of the sleeve and the rotating screw fastening, as well as between the fixing cover and the rotating screw fastening. In the side of the sleeve, there is an opening through which an electrically conductive fluid material is supplied from the dosing head into its cavity by means of a connecting tube.

EFFECT: ensuring smoothness of the surface, uniformity of the film structure, uniformity of the shape and geometric dimensions of the film, adhesive strength, high speed of the manufacturing process.

2 cl, 4 dwg

Description

The invention relates to the field of technological equipment and technological processes of nano- and microelectronics, in particular to devices for additive manufacturing of printed circuit boards and devices for rapid 3D prototyping. The device is designed for automated production of printed circuit board prototypes for electronic devices.

From the existing prior art, the following technical solution is known for the manufacture of multilayer printed circuit boards, described in: US 20200315035 B2 (Nano Dimension Technologies, LTD) publ. 10/01/2020 "Manufacture of printed circuit boards and fpc with shielded traces and/or components using inkjet 3d printing". This technical solution relates to methods and compositions for direct printing of printed circuit boards having electromagnetically shielded tracks and/or components. In particular, the description relates to direct and continuous 3D printing of insulated tracks and/or components with metal shield sleeves or capsules. A method for manufacturing a printed circuit board (PCB) having an electromagnetically shielded track using an inkjet printer, comprising: providing an inkjet printing system comprising a first inkjet printing head of an insulating resin; a second printhead for inkjet printing the first metallic ink; a conveyor operatively associated with the first and second printheads, configured to transport the substrate to each of the first and second printheads; and a computer-aided manufacturing (CAM) module comprising: a data processor; non-volatile memory; and a set of executable instructions stored therein for receiving a PCB rendering file having an electromagnetically shielded track, and creating a file that is at least one substantially two-dimensional layer for printing a printed circuit board having an electromagnetically shielded track. The use of inkjet printing (namely, the raster method of topology formation) in this technical solution leads to the following disadvantages: uneven film surface (appearance of peaks on the film surface); inhomogeneity of the internal structure of the film; increase in electromagnetic losses of the finished product; small film thickness, the need to apply several layers to achieve the optimal thickness of the electrically conductive track.

The closest to the claimed technical solution is US 20160014906 B2 (VOLTERA INC.), publ. 01/14/2016 "Device and method for printing printed circuit boards". This technical solution relates to methods and devices for printing electrical circuits. In particular:

1) a device for printing printed circuit boards, including:

- subject table;

- fastening mechanism for attaching the printed circuit board substrate to the stage;

- a heating element;

- a sensor for detecting and creating a topographic map, mounted on a three-axis positioning device that moves the dosing head in three axes of the direction of movement;

- a control unit for receiving instructions representing the trajectory of the circuit board template, configured to activate the three-axis positioning device and the dosing head in accordance with the instructions;

- a carriage assembly for holding at least one dosing head configured to apply a flowable printed circuit board material to a printed circuit board substrate, the dosing head including:

- piston;

- as well as a rod detachably connected to the piston;

wherein the piston is movable by the stem in a downward direction when the stem is connected to the piston to dispense fluid circuit board material from the dosing head;

- stepper motor to move the rod.

2) a method for printing multilayer printed circuit boards, which is performed using a device for printing printed circuit boards, including:

- placement of the printed substrate on a heated object table;

- building a topographic map of the surface of the printed substrate using a proximity sensor and printing the designed printed circuit board template using the direct deposition method, which includes a downward force mechanism inside the dosing head to dispense electrically conductive and insulating pastes through nozzles directly onto the substrate;

- as well as direct printing of conductive and insulating pastes in layers, thermally curing the printed layers through a heated stage and repeating this cycle of printing and curing until all relevant layers have been printed, forming the desired PCB layout.

The disadvantage of this technical solution is the method of dosing fluid materials: the syringe method of dosing, as well as the dosing head, which includes a piston connected to a rod. The stem has limits on the force of the generated pressure inside the dosing device, which leads to a limitation of the viscosity range of the dosed materials. Also, one of the important disadvantages of this invention is: excessive dripping of the material after printing is stopped, and unstable pressure inside the container of the dosing device, which leads to heterogeneity and unevenness of the printed track.

The technical result of the claimed invention is to provide the following parameters: surface smoothness; uniformity of the film structure; uniformity of the shape and geometric dimensions of the film; adhesive strength; high speed of the manufacturing process;

The technical result of the claimed invention is achieved as follows:

1) a method for manufacturing printed circuit boards, including:

- placement of the printed substrate on a heated object table;

- receipt in the control unit of the height map of the substrate of the printed circuit board;

- receipt in the control unit of instructions representing the trajectory of the printed circuit board template;

- control through the control unit of a three-coordinate positioning device to move the dosing device in accordance with the trajectory of the printed circuit board template;

- application under the control of the control unit from the dosing head of the fluid material of the printed circuit board on the substrate of the printed circuit board in accordance with the trajectory of the printed circuit board template;

- the flowable material of the printed circuit board is a conductor, insulator or solder;

characterized in that the method of manufacturing printed circuit boards includes:

- uniform supply of the fluid material of the printed circuit board to the outlet of the dosing head is carried out by rotating the screw, the rotation of which is provided by a stepper motor, and moving the fluid material of the printed circuit board along the grooves of the screw;

- interrupting the supply of fluid material of the printed circuit board to the outlet of the dosing head by rotating the screw, the rotation of which is provided by a stepper motor, in the opposite direction;

2) a method for manufacturing multilayer printed circuit boards, which is performed using a device for manufacturing printed circuit boards, including:

- placement of the printed substrate on a heated object table;

- receipt in the control unit of the height map of the substrate of the printed circuit board;

- receipt in the control unit of instructions representing the trajectory of the printed circuit board template;

- control through the control unit of a three-coordinate positioning device to move the dosing device in accordance with the trajectory of the printed circuit board template;

- application under the control of the control unit from the dosing head of the fluid material of the printed circuit board on the substrate of the printed circuit board in accordance with the trajectory of the printed circuit board template;

- the flowable material of the printed circuit board is a conductor, insulator or solder;

characterized in that the substrate is alternately applied with a fluid material, which is a conductor and an insulator, along the trajectory of a printed circuit board template, while the conductor is applied by rotating the screw, the rotation of which is provided by a stepper motor, and moving the fluid material of the printed circuit board along the grooves of the screw for manufacturing conductive tracks and vias, and the insulator, which is applied from a pneumatic dispenser, is an electrically insulating barrier between the layers of the conductor, with each layer being cured by heating the stage through a heating element fixed on the stage, and repeating this cycle of printing and curing until until all relevant layers have been printed.

3) a device for the manufacture of printed circuit boards, including:

- subject table;

- fastening mechanism for attaching the printed circuit board substrate to the stage;

- a heating element associated with the stage of curing the flowable material of the printed circuit board after applying the flowable material of the printed circuit board to the substrate of the printed circuit board;

- a sensor for detecting the surface and creating a topographic map of the surface of the substrate, mounted on a three-coordinate positioning device capable of moving the dosing head in three axes of the direction of movement, with the possibility of supplying a fluid material of the printed circuit board to the surface of the printed circuit board substrate;

- a carriage assembly for holding a dosing head configured to apply a fluid printed circuit board material to a printed circuit board substrate, wherein the dosing head includes:

- piston;

- as well as a rod detachably connected to the piston;

wherein the piston is movable by the stem in a downward direction when the stem is connected to the piston to dispense fluid circuit board material from the dosing head;

- stepper motor for moving the rod;

- the device also includes a three-axis positioner for moving the dosing head relative to the substrate of the printed circuit board and a control unit for receiving instructions representing the trajectory of the printed circuit board template, configured to activate the three-axis positioning device and the dosing head in accordance with the instructions;

differs in that:

- the dosing head is connected by means of a connecting tube to a screw dispenser, which applies an electrically conductive fluid material of the printed circuit board along the path of the printed circuit template;

- a second dosing head is added to the device, connected by means of a connecting tube to a pneumatic dispenser, which applies an insulating fluid material.

The essence of the invention is illustrated by drawings, which show:

In FIG. 1 - block diagram of the device for the manufacture of printed circuit boards;

In FIG. 2 - device for the manufacture of printed circuit boards;

In FIG. 3 - dosing heads for the manufacture of multilayer printed circuit boards;

In FIG. 4 - screw dispenser.

A device for manufacturing a printed circuit board using three-dimensional printing (Fig. 1, 2) contains a three-coordinate positioning device 1, a module that combines two dosing heads 2, an object table 5, a heating element 6, a surface detection sensor 7, a control unit 8, two dosing heads (Fig. 1, 2) one with a screw dispenser (3) and the second with a pneumatic dispenser (4); dosing nozzles 10, carriage assembly for holding dosing heads 9, connecting tube 12, fluid material 13, container 14, piston 15, stem 16, connector 17, stepper motor 18 for auger and dosing head. The dosing head with a screw dispenser (3) (Fig. 3) contains (Fig. 4) a rotating fastening of the screw 11, gaskets 19, a screw 20, an outlet mounting hole 21, a fixing cover 22, a hollow sleeve having an internal cavity 23 and a housing 24, hole 25 for fixing the connecting tube 12. The dosing head with a pneumatic dispenser (4) (Fig. 3) contains a valve 26 through which pressure is applied by means of a compressor.

The operation of the PCB manufacturing apparatus is described below. Three-coordinate positioning device 1 (Fig. 2) has a stable design that provides rigidity and immobility of the device. An object table 5 is fixed to the lower part of the three-axis positioning device 1 in such a way as to isolate it from vibration loads created by the three-axis positioning device and dosing heads 2. The object table 5 is designed to fix the substrates. Attached to the bottom of the stage is a heating element 6 which provides temperature profiles for heating the substrate for the purpose of curing printed conductive or insulating tracks, solder paste and other functional elements. On the block of the three-coordinate positioning device 1, which is responsible for moving along the Z axis, using the supporting structure 9, dosing heads 2, a screw dispenser (3), a pneumatic dispenser (4) and a surface detection sensor 7 are installed. heads 2 along a given trajectory in order to form a printed circuit board template, as well as moving the surface detection sensor 7 in order to measure heights and build a topographic map of the substrate surface located on the object table. The control unit 8, which is electrically connected to the three-axis positioning device 1, the dosing heads 2, the stepper motor 18, the heating element 6 and the surface detection sensor 7, is responsible for the automation of the technological process, the exchange of information and the control of the connected elements of the device.

Dosing heads 2 (Fig. 2) include a screw dispenser (3) and a pneumatic dispenser (4) connected to them, respectively, by means of connecting tubes. The screw dispenser (Fig. 4) consists of: the outer part of the sleeve 24, into which the inner cavity 23 is pressed, which makes it possible to achieve a flat upper surface at an angle of 90 degrees during manufacture. In the side of the sleeve there is an opening 25, into which a connecting tube 12 is inserted for supplying fluid material 13 from the dosing device 2 into the cavity of the sleeve 23, from below there is an outlet mounting hole 21 for installing the dosing nozzle 10 (Fig. 3); a channel is formed in the sleeve for the rotation of the screw 20, the dimensions are selected taking into account the minimum tolerance in relation to the screw 20; auger 20 is made of hardened steel, on the surface of the lower part of the auger a thread is carved at a given angle with an experimentally selected pitch for dosing a given portion of fluid material 13; the auger is pressed into the rotating screw mount 11, which is fixed by means of a connecting element 17 (Fig. 3) to the stepper motor 18 (Fig. 3) to ensure the rotation of the auger 20; the screw 20 and the surface of the sleeve 23, 24 are placed coaxially; the mechanism uses two gaskets 19: one lower one is necessary to prevent the paste from the inner surface of the sleeve 23 from getting on the rotating mechanism, and the second upper one is to reduce the friction of metal parts among themselves; after installing the gaskets in the sleeve, the fastening of the screw 20 is pressed by the fixing cover 22 to achieve tightness during the operation of the dosing device; as a result, the auger rotates freely and without jamming in the sleeve channel, the tightness of the sleeve is not violated. The screw dispenser 3 (Fig. 3) provides precise dosing of a viscous fluid material with a volume of 0.5 nl from the inner cavity of the sleeve 23 (Fig. 4) into the outlet mounting hole 21 (Fig. 4) connected to the dosing nozzle 10 (Fig. 3 ) with a diameter of 100 microns, that is, the screw blades 20 (Fig. 4), rotating under the action of a stepper motor 18 (Fig. 3), capture the fluid material 13 and push it in the direction of the dosing nozzle. When the stepper motor 18 is rotated clockwise, the screw 20 rotates downward, which entails the dosing of the fluid material 13, when the stepper motor 18 is rotated counterclockwise, the screw 20 moves upward, and the fluid material 13 is accordingly drawn back.

Pneumatic dispenser (4) is designed for application of dielectric pastes. This device is a high performance solution for dispensing low viscosity liquids. The pneumatic dispenser (4) contains a closing valve 26 with an internal return spring. When a pressure of about 5 kg/m² is supplied from the compressor, valve 26 with a spring moves, thereby squeezing the material through the nozzle onto the substrate. The release of air pressure causes the internal spring to return to its original position and close the valve 26, stopping the flow of material. The size of the dose and the speed of its extrusion are regulated by the size of the nozzle, the pressure of the liquid and the duration of the opening of the valve 26.

The method for applying a fluid material for a multilayer board consists in alternately applying a fluid material, which is a conductor and an insulator, along the path of a printed circuit board template, while the conductor is applied by rotating the screw, the rotation of which is provided by a stepper motor, and moving the fluid material of the printed circuit board along the grooves of the screw for the manufacture of conductive tracks and vias, and the insulator, which is applied from a pneumatic dispenser, is an electrically insulating barrier between the layers of the conductor, with each layer being cured by heating the stage through a heating element fixed on the stage, and repeating this cycle of printing and curing until all matching layers have been printed.

To ensure the precision of dispensing fluid material 13, fluid material 13 is fed into the screw dispenser (3) and pneumatic dispenser (4) from the syringe 14 with fluid material 13 through the connecting tube 12. The supply of fluid material 13 is carried out by a piston mechanism. The piston mechanism for supplying fluid material 13 includes a syringe 14 with fluid material 13, a syringe piston 15, a rod 16. The syringe piston 15 is attached to the rod 16, the rod 16 is attached to the stepper motor 18 using the connecting element 17. When the stepper motor 18 rotates along clockwise, the rod 16 moves down, which entails the movement of the piston 15 along the syringe 14 in the downward direction, as a result of which the fluid material 13 is supplied from the syringe 14 with the fluid material 13 through the connecting tube 12 to the screw dispenser (3) or the pneumatic dispenser ( 4). When the stepper motor 18 rotates counterclockwise, the piston 15 in the syringe 14 moves upwards, the fluid material 13 is drawn back from the screw dispenser (3) or pneumatic dispenser (4).

Claims (10)

1. A device for the manufacture of multilayer printed circuit boards, including a three-coordinate positioning device, on the lower part of which an object table is fixed for fixing printed circuit board substrates with a heating element attached to the bottom of the object table, on the Z-axis movement unit of the three-coordinate positioning device using a carriage assembly installed: - two dosing heads, each of which contains a syringe with fluid material, the piston of which is attached to the stepper motor by means of a rod, while one of the dosing heads contains a screw dispenser with a dosing nozzle for applying an electrically conductive fluid material to the printed circuit board substrate, connected by means of a connecting tube with syringe of the dosing head, wherein the screw in the dosing unit is connected to a stepper motor, the other dosing head contains a pneumatic dosing device with a dosing nozzle for applying an insulating fluid material to the printed circuit board substrate, containing a valve with an internal return spring, shifted when pressure is applied by a compressor, the capacity of which is connected by means of connecting tube with a syringe of the second dosing head, - a sensor for detecting the surface and measuring the heights of the printed circuit board substrate fixed on the object table, the device further includes a control unit electrically connected to a three-axis positioning device, dosing heads, a heating element and a surface detection sensor, receiving instructions representing the trajectory of the printed circuit board template, and controlling the connected elements of the device in accordance with the instructions, while the screw dosing device consists of a sleeve, into the body of which an internal cavity is pressed with a channel for the rotation of the screw, in which the screw is coaxially installed, pressed into a rotating mount fixed to the stepper motor and pressed by the fixing cover, with gaskets placed between the inner cavity of the sleeve and the rotating mount of the screw, as well as between the fixing cover and a rotating fastening of the screw, in the side of the sleeve there is an opening through which an electrically conductive fluid material is supplied from the dosing head into its cavity by means of a connecting tube. 2. A method for manufacturing multilayer printed circuit boards, which is performed using the device for manufacturing multilayer printed circuit boards according to claim 1, including: - fixing the printed circuit board substrate on the object table, - receipt in the control unit of the height map of the substrate of the printed circuit board, - receipt in the control unit of instructions representing the trajectory of the printed circuit board template, - control through the control unit of a three-axis positioning device for moving the dosing heads and the surface detection sensor relative to the printed circuit board substrate fixed on the heating table, along three axes of the direction of movement in accordance with the trajectory of the printed circuit template; - application under the control of the control unit from the dosing heads of the fluid material of the printed circuit board on the substrate of the printed circuit board in accordance with the trajectory of the printed circuit board template; at the same time, an electrically conductive fluid material is alternately applied to the printed circuit board substrate for the manufacture of conductive tracks and vias of the printed circuit board and insulating fluid material, which is an electrically insulating barrier between the layers of conductors, the electrically conductive fluid material is applied through the dosing nozzle of the screw dispenser by rotating the screw, provided by the rotation of the stepper motor clockwise, and moving the electrically conductive fluid material along the troughs of the screw towards the metering nozzle, the interruption of the supply of the electrically conductive fluid material is carried out by rotating the screw in the opposite direction, provided by counterclockwise rotation of the stepper motor, the insulating fluid material is applied through the metering nozzle of the pneumatic dispenser by opening valve with an internal return spring pressure applied by a compressor, the interruption of the supply of insulating fluid material is carried out by closing the valve, the return of the internal spring to its original position when the air pressure in the pneumatic dispenser tank drops, each layer deposited on the substrate is cured by heating the object table by means of a heating element attached to its bottom, and repeating this cycle of printing and curing until all relevant layers of the multilayer printed circuit board have been printed.