System and method for measuring static volume in material container

Abstract

To provide a device configured to discharge an assembly material onto an electronic substrate, a system for detecting the static volume in a material cartridge, and a method for detecting the static volume in the material cartridge.SOLUTION: A system to detect static volume in a material cartridge includes a mass flow meter to measure a volume of air delivered to the material cartridge. A controller is configured to specify a volume of assembly material in the material cartridge upon determining the volume of air in the material cartridge. A method to detect static volume in the material cartridge includes measuring a volume of air delivered to the material cartridge.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present application generally relates to an apparatus including a stencil printer and a dispenser for printing and depositing a viscous material, such as solder paste, onto an electronic substrate, such as a printed circuit board (PCB), and more particularly to a system and method for measuring the volume of a viscous material within a material container of the apparatus.

Background Art

[0002] When manufacturing a surface mount printed circuit board, a solder paste can be printed onto the circuit board using a stencil printer. Typically, a circuit board having a pattern of pads or some other conductive surface, onto which the solder paste will be deposited, is automatically fed into the stencil printer, and one or more small holes or marks (known as "fiducials") on the circuit board are used to properly align the circuit board with the stencil or screen of the stencil printer before printing the solder paste onto the circuit board. In some systems, an optical alignment system embodying an imaging or vision system is used to align the circuit board with the stencil.

[0003] In the above printer, when the circuit board is properly aligned with the stencil, the circuit board is raised up to the stencil and solder paste is discharged onto the stencil. A wiper blade (i.e., squeegee) traverses the stencil and extrudes the solder paste through the holes of the stencil onto the circuit board. As the squeegee moves across the stencil, the solder paste tends to spread out in front of the blade. This causes, desirably, mixing and shearing of the solder paste and results in the desired viscosity to easily fill the holes of the screen, i.e., the stencil. The solder paste is typically discharged onto the stencil from a standard cartridge. Thereafter, the stencil is separated from the circuit board, and most of the material remains on the circuit board due to the adhesion between the circuit board and the solder paste. The material remaining on the surface of the stencil is removed in a cleaning process before further circuit boards are printed.

[0004] Similarly, in another type of equipment used to manufacture surface mount printed circuit boards, a dispensing system can be used to dispense viscous materials onto the circuit board. There are several types of dispensing systems used to dispense precise amounts of liquid or paste for various applications. One such application is the assembly of integrated circuit chips and other electronic components onto the circuit board. In this application, an automated dispensing system is used to dispense dots of liquid epoxy or solder paste, or some other related material, onto the printed circuit board. The automated dispensing system can also be used to dispense lines of underfill material and encapsulants that can be used to mechanically secure components to the printed circuit board.

[0005] In a conventional dispensing system, the dispensing unit is attached to a moving assembly or gantry that uses a servo motor controlled by a computer system or controller to move the dispensing unit along three mutually perpendicular axes (x-axis, y-axis, and z-axis). To dispense liquid dots at desired positions on a printed circuit board or other substrate, the dispensing unit is moved along the horizontal x-axis and y-axis directions on the same plane until the dispensing unit is positioned above the desired location. The dispensing unit is then lowered along the vertically oriented z-axis direction until the dispensing unit and the nozzle / needle of the dispensing system are at the appropriate dispensing height above the electronic substrate. The dispensing unit dispenses a dot of liquid, then is raised along the z-axis, moved to a new position along the x-axis and y-axis, and lowered along the z-axis to dispense the next liquid dot. In applications such as encapsulation or underfill dispensing as described above, the dispensing unit is typically controlled to dispense a line of material as the dispensing unit is moved along the x-axis and y-axis along the desired path of the line. In some types of dispensing units, such as injection pumps, the z-axis movement before and after the dispensing operation may not be necessary.

[0006] The dispenser material cartridges provided in stencil printers and dispensers have a finite volume and are known to operate within a certain pressure range. For various reasons, it is desirable to know the amount of material in the cartridge. Also, problems arise in identifying the amount of material in the cartridge when it is found that the starting volume when the cartridge is new is less than 100% of the maximum volume of the cartridge, which is the starting point for measuring the material capacity of the cartridge. SUMMARY OF THE INVENTION

[0007] One aspect of the present disclosure relates to an apparatus configured to eject an assembly material onto an electronic substrate. In one embodiment, the apparatus includes a frame and a unit coupled to the frame. The unit is configured to deposit an assembly material onto the electronic substrate. The unit includes a material cartridge coupled to a pressure regulator, which is configured to supply pressurized air to the material cartridge at a desired pressure. The material cartridge is configured to contain the assembly material. The apparatus further includes a substrate support assembly coupled to the frame. The substrate support assembly is configured to support the electronic substrate. The apparatus further includes a controller configured to control the apparatus, including the unit, and a system configured to detect a static volume within the material cartridge. The system includes a mass flow meter configured to measure a volume of air delivered to the material cartridge. The controller is further configured to identify a volume of the assembly material within the material cartridge when a volume of air within the material cartridge is identified.

[0008] Embodiments of the device can further include configuring the cartridge to comprise a cylindrical body having an open upper end and a tapered lower end with a relatively small opening for discharging the assembly material from the cartridge. The cartridge can further comprise a piston disposed within the cylindrical body, the piston applying pressure to the assembly material disposed within a chamber below the piston. The cartridge can further comprise a cap provided within the open end of the body to surround (close) the open end of the cartridge. The cap of the cartridge can be connected to a tube in fluid communication with a pressure regulator, and pressurized air can be supplied into the chamber above the piston to extrude the assembly material from the cartridge. A mass flow meter can be disposed between the pressure regulator and the cap of the cartridge. The mass flow meter is installed downstream of the pressure regulator and measures the flow rate of air through the tube over a calculated time interval, identifies the volume of the empty space within the chamber above the piston within the body of the cartridge, and can identify the volume of the assembly material within the chamber below the piston within the body of the cartridge. The lower end of the body can comprise a nozzle for metering out a controlled amount of the assembly material in a fixed quantity during use. The cartridge can be made of a transparent or translucent plastic material to enable visual knowledge of the amount of assembly material within the cartridge. The pressure regulator can comprise a control circuit connected to a controller, a first control valve, and a second control valve, the first control valve and the second control valve being connected to the control circuit. A source of air pressure can be connected to the pressure regulator by a solenoid valve connected to the controller. The controller can further be configured to determine an exchange schedule for the material cartridge and provide a notification.

[0009] Another aspect of the present disclosure relates to a system for detecting a static volume within a material cartridge. In one embodiment, the system includes a mass flow meter that measures the volume of air delivered to the material cartridge. A controller is configured to identify the volume of air within the material cartridge and thereby identify the volume of assembly material within the material cartridge.

[0010] Embodiments of the system can further include configuring the cartridge to include a cylindrical body having an open upper end and a tapered lower end having a relatively small opening for discharging assembly material from the cartridge. The cartridge can further include a piston disposed within the cylindrical body, the piston applying pressure to the assembly material disposed within a chamber below the piston. The cartridge can further include a cap provided within the open end of the body so as to surround the open end of the cartridge. The cap of the cartridge can be connected to a tube in fluid communication with a pressure regulator and can supply pressurized air into the chamber above the piston to extrude the assembly material from the cartridge. The mass flow meter can be disposed between the pressure regulator and the cap of the cartridge. The mass flow meter is installed downstream of the pressure regulator and measures the flow rate of air through the tube over a calculated time interval to identify the volume of free space within the chamber above the piston within the body of the cartridge and the volume of assembly material within the chamber below the piston within the body of the cartridge. The lower end of the body can include a nozzle for discharging a controlled amount of assembly material in a fixed amount during use. The cartridge can be made of a transparent or translucent plastic material to enable visually knowing the amount of assembly material within the cartridge. The pressure regulator can include a control circuit connected to the controller, a first control valve, and a second control valve, the first control valve and the second control valve being connected to the control circuit. A source of air pressure can be connected to the pressure regulator by a solenoid valve connected to the controller. The controller can further be configured to determine a replacement schedule for the material cartridge and provide a notification.

[0011] Yet another aspect of the present disclosure relates to a method for detecting a static volume within a material cartridge. In one embodiment, the method includes measuring the volume of air delivered to the material cartridge. A controller is configured to identify the volume of air within the material cartridge and then identify the volume of assembly material within the material cartridge.

[0012] Embodiments of the method can further include measuring the volume of air by a mass flow meter positioned between the material cartridge and a pressure regulator. The cartridge has a cylindrical body having an open upper end and a tapered lower end having a relatively small opening through which assembly material is discharged from the cartridge, and a piston disposed within the cylindrical body that applies pressure to the assembly material disposed within a chamber below the piston, and a cap provided within the open end of the body so as to surround the open end of the cartridge. The method can further include supplying pressurized air into the chamber above the piston to extrude the assembly material from the cartridge. The method can further include positioning the mass flow meter between the pressure regulator and the cap of the cartridge. The method can further include positioning the mass flow meter downstream of the pressure regulator to measure the flow rate of air through the tube over a calculated time interval, identify the volume of the empty space within the chamber above the piston within the body of the cartridge, and identify the volume of the assembly material within the chamber below the piston within the body of the cartridge.

[0013] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is shown in various figures is represented by like reference numerals. For clarity, not all components may be labeled in all of the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0015] This disclosure comprehensively relates to a material coating machine (referred to as a "stencil printer", "screen printer", "printer", or "printing machine" in this disclosure) and other equipment that is used in a surface mount technology (SMT) process line and is configured to apply an assembly material (e.g., solder paste, conductive ink, or encapsulation material) onto a substrate (e.g., a printed circuit board referred to as an "electronic substrate", "circuit board", "board", "PCB", "PCB substrate", "substrate", or "PCB board" in this disclosure), or perform other operations such as inspection, rework, or placement of electronic components onto the substrate. Specifically, embodiments of this disclosure are described below with reference to a stencil printer used for manufacturing a printed circuit board.

[0016] For purposes of illustration only and not limitation, the present disclosure will now be described in detail with reference to the accompanying drawings. The present disclosure is not limited to the details of construction and the arrangement of components set forth in the following description or shown in the drawings with respect to its application. The principles described herein may be used in other embodiments and may be practiced or carried out in various ways. Also, the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Any reference to examples, embodiments, components, elements, or acts of the systems and methods referred to herein in the singular is intended to include embodiments including a plurality thereof, and any reference to embodiments, components, elements, or acts in the plural is intended to include embodiments including only a single one thereof. References in the singular or plural are not intended to limit the systems or methods, their components, acts, or elements disclosed herein. Use of the terms "including," "comprising," "having," "containing," "involving," and variations thereof herein is meant to encompass the item listed preceded by the term and equivalents thereof and additional items. References to "or / and" are to be construed as inclusive such that any term described using "or / and" can indicate any one of the single, more than one, and all of the terms so described. Additionally, where there is inconsistency in the usage of terms between this document and documents incorporated herein by reference, the usage of terms in the incorporated documents is supplementary to the usage in this document, and where the inconsistency results in a contradiction, the usage in this document is valid.

[0017] For purposes of illustration, embodiments of the present disclosure will be described below with reference to a stencil printer used to print an assembly material such as solder paste onto a circuit board. However, those skilled in the art will understand that the embodiments of the present disclosure are not limited to a stencil printer that prints solder paste onto a circuit board, but can be used in other applications that require the dispensing of other adhesive assembly materials such as glue and encapsulants. For example, the apparatus can be used to print an epoxy for use as an underfill for a chip scale package. Further, the stencil printer according to the embodiments of the present disclosure is not limited to printing an assembly material onto a circuit board, but includes those used to print other materials onto various substrates such as semiconductor wafers. Also, the terms screen and stencil can be used interchangeably in the present disclosure to describe a device within the printer that defines the pattern to be printed on the substrate. In certain embodiments, the stencil printer can include a Momentum™ or Edison™ series stencil printer platform provided by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts. An exemplary stencil printer is generally designated by 5 in FIG. 1. In this embodiment, the stencil printer 5 is an Edison™ series stencil printer platform provided by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts.

[0018] Referring to FIG. 2, a stencil printer according to an embodiment of the present disclosure is generally indicated at 10. As shown, the stencil printer 10 has a frame 12 that supports the components of the stencil printer. The components of the stencil printer can include, among other things, a controller 14, a display 16, a stencil 18, and a print head or print head assembly. The print head or print head assembly is generally indicated at 20 and is configured to apply solder paste in a manner described in more detail below.

[0019] As shown in FIG. 2 and as will be described below, the stencil and the print head assembly can be connected to the frame 12 as appropriate or otherwise connected. In one embodiment, the print head assembly 20 can be mounted on a print head assembly gantry 22, and the print head assembly gantry 22 can be mounted on the frame 12. By the print head assembly gantry 22, the print head assembly 20 can be moved in the y-axis direction under the control of the controller 14 and can apply pressure to the print head assembly by engaging with the stencil 18. In certain embodiments, the print head assembly 20 can be placed above the stencil 18 and can descend in the z-axis direction to contact the stencil and seal against the stencil.

[0020] The stencil printer 10 can also have a conveyor system having rails (not shown) for transporting a printed circuit board (which may be referred to as a "printed wiring board", a "substrate", or an "electronic substrate" in the present disclosure) to a printing position within the stencil printer. The rails may be referred to as a "tractor feed mechanism" in the present disclosure. The tractor feed mechanism is configured to feed, load, or otherwise deliver a circuit board to a working area of the stencil printer, which may be referred to as a "print nest" in the present disclosure, and to unload the circuit board from the print nest.

[0021] In addition, referring to FIG. 3, the stencil printer 10 has a support assembly 28 that supports a circuit board 29 (shown in dashed lines). The support assembly 28 raises and fixes the circuit board so that the circuit board is stable during the printing operation. In certain embodiments, the substrate support assembly 28 can further include a specific substrate support system, such as a rigid support, a plurality of pins, or a flexible tool, etc. The substrate support system is positioned below the circuit board when the circuit board is in the printing position. A part of the substrate support system can be used to support the internal region of the circuit board to prevent bending or warping of the circuit board during the printing operation.

[0022] In one embodiment, the print head assembly 20 can be configured to receive solder paste from a dispenser, such as a solder paste cartridge, etc., which provides the solder paste to the print head assembly during the printing operation. Instead of a cartridge, other methods of supplying solder paste may be utilized. For example, the solder paste can be manually deposited between the blades or from an external source. In addition, in certain embodiments, the controller 14 can be configured to use a personal computer having a suitable operating system, such as the Microsoft Windows® operating system provided by Microsoft Corporation, and use application-specific software to control the operation of the stencil printer 10. The controller 14 can be network-connected to a master controller used to control a production line for manufacturing circuit boards.

[0023] In one configuration, the stencil printer 10 operates as follows. The circuit board 29 is loaded into the stencil printer 10 using a conveyor rail. The support assembly 28 raises and fixes the circuit board 29 to the printing position. Then, the print head assembly 20 is lowered in the z-axis direction until the blade of the print head assembly contacts the stencil 18 with a desired pressure. Then, the print head assembly 20 is moved in the y-axis direction across the stencil 18 by the print head assembly gantry 22. The print head assembly 20 deposits solder paste onto the circuit board 29 through the holes in the stencil 18. When the print head assembly completely traverses the stencil 18 across the holes, the print head assembly is lifted from the stencil and the circuit board 29 is lowered back onto the conveyor rail. The circuit board 29 is released and conveyed from the stencil printer 10, whereby a second circuit board can be loaded into the stencil printer. To print on the second circuit board 29, the print head assembly is lowered in the z-axis direction to contact the stencil and is moved across the stencil 18 in a direction opposite to that used for the first circuit board.

[0024] An imaging system 30 can be provided for the purpose of aligning the stencil 18 with the circuit board 29 before printing and inspecting the circuit board after printing. In one embodiment, the imaging system 30 can be disposed between the stencil 18 and the support assembly 28 on which the circuit board is supported. The imaging system 30 is coupled to an imaging gantry 32 for moving the imaging system. In one embodiment, the imaging gantry 32 can be coupled to the frame 12, has a beam extending between the side rails of the frame 12, and provides a back-and-forth movement to the imaging system 30 above the circuit board 29 in the y-axis direction. The imaging gantry 32 can further include a carriage device for housing the imaging system 30 and is configured to move along the length of the beam in the x-axis direction. The structure of the imaging gantry 32 used for moving the imaging system 30 is known in the solder paste printing art. The imaging system 30 is positioned at an arbitrary position below the stencil 18 and above the circuit board 29 such that images of predetermined areas of the circuit board or the stencil can be taken respectively.

[0025] After applying the solder paste to the circuit board one or more times, excess solder paste can accumulate at the bottom of the stencil 18, and a stencil wiper assembly generally indicated at 34 can move under the stencil to remove the excess solder paste. In other embodiments, the stencil 18 may move above the stencil wiper assembly.

[0026] FIG. 4 schematically shows a dispensing system generally designated 40 in accordance with one embodiment of the present disclosure. The dispensing system 40 is used to dispense a viscous material (e.g., an adhesive, a potting compound, an epoxy, a solder paste, an underfill material, etc.) or a semi-viscous material (e.g., a soldering flux, etc.) onto an electronic substrate 42 such as a printed circuit board or a semiconductor wafer. The dispensing system 40 may alternatively be used for other applications such as applying automotive gasket material, or in certain medical applications, or for applying conductive ink, etc. It should be understood that the reference to viscous or semi-viscous materials is intended to be exemplary and non-limiting as used in the present disclosure. In one embodiment, the dispensing system 40 includes a first dispensing unit and a second dispensing unit generally designated 44 and 46, respectively, and a controller 48 that controls the operation of the dispensing system. It should be understood that the dispensing units 44, 46 may also be referred to as dispensing pumps and / or dispensing heads in the present disclosure. Although two dispensing units 44, 46 are shown, it should be understood that a single dispensing unit or multiple dispensing units may be used.

[0027] The ejection system 40 can also include a frame 50 having a base or support 52 for supporting an electronic substrate, an ejection unit gantry 54 movably coupled to the frame to support and move the ejection units 44, 46, and a weighing device or scale 56 for weighing the amount of viscous material, for example, as part of a calibration procedure, and providing weight data to the controller 48. Other transfer mechanisms such as a conveyor system (not shown) or a moving beam can be used in the ejection system 40 to control the loading of the electronic substrate 42 into the ejection system and the unloading of the electronic substrate 42 from the ejection system. The gantry 54 can be moved using a motor under the control of the controller 48 to position the ejection units 44, 46 at a predetermined position above the electronic substrate 42. The ejection system 40 can include a display unit 58 connected to the controller 48 for displaying various information to the operator. An optional second controller for controlling the ejection units may be provided. Also, each ejection unit 44, 46 can be configured to have a z-axis sensor, for example, a laser, that detects the height at which the ejection unit is disposed above the electronic substrate 42 or above a feature mounted on the electronic substrate. The z-axis sensor is coupled to the controller 48 and relays the information obtained by the sensor to the controller.

[0028] Before performing the ejection operation, as described above, the electronic substrate 42, e.g., a printed circuit board, must be aligned or otherwise matched with the ejection units 44 and / or 46 of the ejection system 40. The ejection system 40 further includes a vision system 60, which in one embodiment is coupled to a vision system gantry 62 that is movably coupled to the frame 50 to support and move the vision system. In another embodiment, the vision system 60 may be provided on the gantry 54 used to move the ejection units 44, 46. As described above, the vision system 60 is utilized to collate the positions of landmarks, targets, or reference points known as reference portions on the electronic substrate 42. Once the position is identified, the controller 48 can be programmed to operate the movement of one or more of the ejection units 44, 46 to eject material onto the electronic substrate 42.

[0029] The systems and methods of the present disclosure may relate to ejecting material onto an electronic substrate 42, e.g., a printed circuit board. The description of the systems and methods provided in the present disclosure refers to an exemplary electronic substrate (e.g., a printed circuit board) supported on the support 52 of the ejection system 40. In one embodiment, the ejection operation can be controlled by a controller 48 that can include a computer system configured to control the material ejection unit. In another embodiment, the controller 48 may be operated by an operator. The controller 48 is configured to operate the movement of the vision system gantry 62 to move the vision system 60 and acquire one or more images of the electronic substrate 42. The controller 48 is further configured to operate the movement of the gantry 54 to move the ejection units 44, 46 and perform the ejection operation.

[0030] The methods disclosed in the present disclosure further support the use of various types of ejection units, including but not limited to auger pumps, piston pumps, time and pressure pumps, and jet pumps.

[0031] In one embodiment, an exemplary dispensing system described in the present disclosure can be embodied as a Camalot (trademark) dispensing system, such as a Prodigy (trademark) dispenser sold by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts.

[0032] Each system, e.g., the stencil printer 10 and the dispensing system 40, comprises one or more assembly material paste cartridges for dispensing assembly materials such as solder paste, adhesives, encapsulants, epoxies, and underfill materials. As described above, the stencil printer 10 typically prints solder paste onto an electronic substrate, e.g., the circuit board 29. The print head gantry 20 is configured to include at least one cartridge configured to hold an assembly material and dispense it onto the stencil 18. A sensor associated with the controller 14 detects the amount of assembly material on the stencil 18 before a stencil wiping operation is performed. Similarly, as further described above, the dispensing system 40 dispenses an assembly material at an exact location on the electronic substrate 42. Each dispensing unit 44, 46 includes a cartridge configured to hold an assembly material and dispense it onto the electronic substrate 42. Such cartridges are known to have a finite volume and operate within a certain pressure range to dispense material from the cartridge. For various reasons, it is important to monitor the amount of assembly material contained within the cartridge, and in particular, to know when to replace a cartridge that is running out of assembly material.

[0033] Referring to FIG. 5, in one embodiment, an exemplary material container or cartridge is generally designated by 70. As shown, the cartridge 70 includes a generally cylindrical body 72 having an open upper end 74 and a tapered lower end 76 having a relatively small opening for discharging assembly material from the cartridge. The cartridge 70 can be made of a suitable transparent or translucent plastic material so that an operator can visually know how much assembly material is in the cartridge. The material cartridge 70 further includes a piston 78 disposed within the cylindrical body, and the piston is provided to divide the body 72 of the cartridge into an upper chamber 80 and a lower chamber 82. The piston 78 is further provided to apply pressure to the assembly material disposed within the lower chamber 82.

[0034] The material cartridge 70 further includes a cap or stopper 84 provided within the open upper end 74 of the body to surround the open end of the body 72 of the cartridge. Although not shown, the lower end 76 of the body 72 of the cartridge 70 can include a nozzle or some other component for discharging a controlled amount of assembly material in a fixed amount. For example, in a stencil printer such as the stencil printer 10, the cartridge is configured to discharge an assembly material, such as solder paste, between squeegee blades of a print head assembly, such as the print head assembly 20. In another example, in a dispensing system such as the dispensing system 40, the cartridge is configured to deliver the assembly material to a dispensing unit(s), such as the dispensing units 44, 46.

[0035] The cap 84 of the cartridge 70 is connected to a tube 86 that supplies pressurized gas, such as air, into the body 72 of the cartridge to apply the pressurized gas into the upper chamber 80 above the piston 78 and to push the assembly material out of the cartridge through the lower end 76. The tube 86 is connected to a pressure regulator 88 that maintains the desired pressure applied to the gas delivered to the upper chamber 80 above the piston 78 within the body 72 of the cartridge 70. In one embodiment, by way of example, air is delivered from a source of compressed air at 100 pounds per square inch (psi) (about 690 kPa) to the pressure regulator 88, and the pressure regulator is configured to reduce the air pressure to a desired pressure, such as 60 psi (about 413 kPa), when delivering air through the tube 86 to the upper chamber 80 above the piston 78 within the body 72 of the cartridge 70. It should be understood that the pressure regulator 88 can be configured to deliver the desired pressure to the cartridge.

[0036] The purpose of supplying air pressure to the upper chamber 80 above the piston 78 is to push the material out of the lower chamber 82 of the body 72 of the cartridge. Thus, the assembly material within the lower chamber 82 below the piston 78 is replaced by the air within the upper chamber 80 above the piston as the material is discharged from the cartridge 70 by moving the piston downward through the body 72 of the cartridge.

[0037] As shown, in one embodiment, a system for detecting the static volume within material cartridge 70 includes a mass flow meter 90 installed downstream of a pressure regulator 88 in fluid communication with a tube 86 to measure the flow rate of air through the tube. Note that the mass flow meter 90 can be installed upstream of the regulator 88 and is within the scope of the present disclosure. In one embodiment, the flow rate is measured over a calculated time interval to determine the volume of the empty space within the cartridge 70 occupied by air as the air enters the upper chamber 80 above the piston 78 within the body 72 of the cartridge. By measuring the volume of air delivered into the upper chamber 80 above the piston 78 of the cartridge 70, the volume of the assembly material within the lower chamber 82 below the piston of the body 72 of the cartridge is determined. Thus, an accurate determination of the amount of material within the cartridge 70 can be provided.

[0038] Referring to FIG. 6, in one embodiment, the pressure regulator 88 embodies an electro-pneumatic pressure regulator that includes a control circuit 92 coupled to a controller, such as controller 14, 48, a first control valve 94, and a second control valve 96, and the first control valve and the second control valve are coupled to the control circuit. An air pressure supply source is connected to the pressure regulator 88 by a solenoid valve 98 coupled to a controller, such as controller 14, 48. This configuration is such that pressurized air enters the pressure regulator 88 through the solenoid valve 98 and is adjusted by the first control valve 94 and the second control valve 96 of the pressure regulator to produce pressurized air at a desired pressure. A controller, such as controller 14, 48, provides control information to the solenoid valve 96 for delivering air to the pressure regulator 88 and to the control circuit 92 of the pressure regulator for delivering pressurized air at a desired pressure through the tube 86 to the cartridge 70. The mass flow meter 90 is positioned between the pressure regulator 88 and the cartridge 70. In one embodiment, the pressure regulator 88 can be a digital electronic pressure regulator.

[0039] In one embodiment, the system can be configured to allow a user to input a known operating pressure within a process program used by a controller of the assembly device, such as controller 14 or controller 48, for a manual regulator. The system can be further configured to use a digital regulator, whose indicated pressure is known, in the process to identify a flow rate set based on the time of the compressed gas at a known temperature. In one example, the known temperature of the compressed air is 25 °C. The system can include a suitable temperature sensor for measuring the temperature of the compressed gas. When the free volume of the cartridge is known, the free volume can be subtracted from the total volume of the cartridge to identify the actual volume. This method can be performed when the discharge of the material is complete (refilling).

[0040] The calculated time interval is predetermined for the size of the cartridge. In one example for a 600 gram cartridge, the calculated time interval can be 2 seconds or less. However, the time interval should be long enough to ensure that the material exits the cartridge. Cartridges of different sizes, such as 1200 gram cartridges, can be used as well. The material cartridges commonly used in the discharge system will be very small and will have a very short sample time.

[0041] In one embodiment, information about how much assembly material is used within the cartridge and the period during which the assembly material is used can be determined by a controller (e.g., controllers 14, 48). This information can be shared with a manufacturing execution system (MES) or customer database associated with the assembly equipment. This information can be used to optimize the performance of the assembly equipment. For example, it is possible to determine a time frame for cartridge replacement, calculate the storage capacity of the replacement cartridge, and the like. In one specific example, a notification system can be implemented to provide replacement and inventory updates. Since the consumption amount is determined in real time, it is possible to optimize the storage of the cartridge and the timely delivery to the assembly apparatus.

[0042] A method for detecting the static volume within a material cartridge includes measuring the volume of air delivered to the material cartridge. The controller is configured to identify the volume of the assembly material within the material cartridge when identifying the volume of air within the material cartridge. The method includes measuring the volume of air using a mass flow meter positioned between the material cartridge and a pressure regulator. As described above, the mass flow meter can be positioned in front of the pressure regulator. In one embodiment, the method further includes supplying pressurized air into the chamber above the piston to extrude the assembly material from the cartridge and positioning the mass flow meter between the pressure regulator and the cap of the cartridge. Specifically, the method further includes positioning the mass flow meter downstream of the pressure regulator, measuring the flow rate of air through the pipe over a calculated time interval, identifying the volume of the empty space within the chamber above the piston within the body of the cartridge, and identifying the volume of the assembly material within the chamber below the piston within the body of the cartridge.

[0043] As a more advanced method, it can include sampling the volume of air at the start of automatic dispensing (refilling), then recording the mass flow rate at a given PSI, and extrapolating the amount of material dispensed during the automatic dispensing process (refilling).

[0044] Leak detection can also be identified by monitoring the mass air flow rate before and after automatic dispensing (before and after refilling), which should be zero if there is no leak.

[0045] Various controllers such as controllers 14 and 48 can perform the various operations described above. Using data stored in associated memory and / or storage devices, controllers 14, 48 can also execute one or more instructions stored on one or more non-transitory computer-readable media that controllers 14, 48 can include and / or be coupled to, resulting in the generation of manipulated data. In some examples, controllers 14, 48 may include one or more processors or other types of controllers. In one example, controllers 14, 48 are at least one processor or include at least one processor. In other examples, controllers 14, 48 use application-specific integrated circuits tuned to perform specific operations, in addition to or instead of a general-purpose processor, to perform at least some of the operations described above. As illustrated by these examples, examples according to the present disclosure can perform the operations described in the present disclosure using many specific combinations of hardware and software, and the present disclosure is not limited to any specific combination of hardware and software components. Examples of the present disclosure may include a computer program product configured to perform the methods, processes, and / or operations described above. The computer program product can be or include one or more controllers and / or processors configured to execute instructions for performing the methods, processes, and / or operations described above.

[0046] As described above, some aspects of at least one embodiment have been set forth, but it will be understood that various variations, modifications, and improvements will readily occur to those skilled in the art. Such variations, modifications, and improvements are intended to be part of this disclosure and are intended to be within the scope of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

1. 1. An apparatus configured to dispense assembly material onto an electronic substrate, comprising: A frame, a unit coupled to the frame, the unit configured to deposit an assembly material onto the electronic substrate, the unit comprising a material cartridge coupled to a pressure regulator, the pressure regulator configured to deliver pressurized air at a desired pressure to the material cartridge, the material cartridge configured to contain an assembly material; a substrate support assembly coupled to the frame and configured to support the electronic substrate; a controller configured to control the apparatus including the unit; a system for detecting a static volume within the material cartridge, the system comprising a mass flow meter for measuring a volume of air delivered to the material cartridge; Equipped with The controller is further configured to determine a volume of assembly material in the material cartridge upon determining a volume of air in the material cartridge. Device.

2. 10. The apparatus of claim 1, wherein the cartridge comprises a cylindrical body having an open upper end and a tapered lower end, the lower end having a relatively small opening through which assembly material is ejected from the cartridge.

3. 3. The apparatus of claim 2, wherein the cartridge further comprises a piston disposed within the cylindrical body, the piston applying pressure to an assembly material disposed in a chamber below the piston.

4. The device of claim 3 , wherein the cartridge further comprises a cap disposed within the open end of the body so as to enclose the open end of the cartridge.

5. 5. The apparatus of claim 4, wherein the cap of the cartridge is connected to a tube in fluid communication with the pressure regulator to provide pressurized air in a chamber above the piston to expel assembly material from the cartridge.

6. The apparatus of claim 5 , wherein the mass flow meter is disposed between the pressure regulator and the cartridge.

7. 6. The apparatus of claim 5, wherein the mass flow meter is located downstream of the pressure regulator and measures the flow rate of air through the tube over a calculated time interval to determine a volume of free space in the chamber above the piston in the body of the cartridge and thereby to determine a volume of assembly material in the chamber below the piston in the body of the cartridge.

8. The device of claim 2 , wherein the lower end of the body is provided with a nozzle that, during use, dispenses a controlled amount of assembly material.

9. 3. The device of claim 2, wherein the cartridge is made from a transparent or translucent plastic material to allow visual knowledge of the amount of assembly material in the cartridge.

10. 2. The apparatus of claim 1, wherein the pressure regulator comprises a control circuit coupled to the controller, a first control valve, and a second control valve, the first control valve and the second control valve being coupled to the control circuit.

11. The apparatus of claim 10 , wherein a source of air pressure is connected to the pressure regulator by a solenoid valve coupled to the controller.

12. The apparatus of claim 1 , wherein the controller is further configured to determine a replacement schedule for the material cartridge and to provide notification.

13. 1. A system for detecting a static volume within the material cartridge, comprising: a mass flow meter that measures the volume of air delivered to the material cartridge; Equipped with a controller configured to determine a volume of assembly material in the material cartridge upon determining a volume of air in the material cartridge; system.

14. 14. The system of claim 13, wherein the cartridge comprises a cylindrical body having an open upper end and a tapered lower end, the lower end having a relatively small opening through which assembly material is ejected from the cartridge.

15. 15. The system of claim 14, wherein the cartridge further comprises a piston disposed within the cylindrical body, the piston applying pressure to an assembly material disposed within a chamber below the piston.

16. The system of claim 15 , wherein the cartridge further comprises a cap disposed within the open end of the body to enclose the open end of the cartridge.

17. 17. The system of claim 16, wherein the cap of the cartridge is connected to a tube in fluid communication with the pressure regulator to provide pressurized air in a chamber above the piston to expel assembly material from the cartridge.

18. The system of claim 17 , wherein the mass flow meter is disposed between the pressure regulator and the cartridge.

19. 18. The system of claim 17, wherein the mass flow meter is located downstream of the pressure regulator and measures the flow rate of air through the tube over a calculated time interval to determine a volume of free space in the chamber above the piston in the body of the cartridge and thereby to determine a volume of assembly material in the chamber below the piston in the body of the cartridge.

20. The system of claim 14 , wherein the lower end of the body includes a nozzle that, during use, dispenses a controlled amount of assembly material.

21. The system of claim 14 , wherein the cartridge is made from a transparent or translucent plastic material to allow visual knowledge of the amount of assembly material in the cartridge.

22. 14. The system of claim 13, wherein the pressure regulator comprises a control circuit coupled to the controller, a first control valve, and a second control valve, the first control valve and the second control valve being coupled to the control circuit.

23. 23. The system of claim 22, wherein a source of air pressure is connected to the pressure regulator by a solenoid valve coupled to the controller.

24. The system of claim 13 , wherein the controller is further configured to determine a replacement schedule for the material cartridge and to provide notification.

25. 1. A method for detecting a static volume within the material cartridge, comprising: Measuring the volume of air delivered to the material cartridge; Including, the controller is configured to determine a volume of assembly material in the material cartridge upon determining a volume of air in the material cartridge; method.

26. 26. The method of claim 25, wherein measuring the volume of air is accomplished by a mass flow meter positioned between the material cartridge and a pressure regulator.

27. The cartridge comprises: a cylindrical body having an open upper end and a tapered lower end, the lower end having a relatively small opening for dispensing assembly material from the cartridge; a piston disposed within the cylindrical body, the piston exerting pressure on an assembly material disposed within a chamber below the piston; a cap disposed within the open end of the body so as to enclose the open end of the cartridge; 27. The method of claim 26, comprising:

28. 28. The method of claim 27, further comprising providing pressurized air into a chamber above the piston to force assembly material out of the cartridge.

29. 28. The method of claim 27, further comprising positioning the mass flow meter between the pressure regulator and the cartridge.

30. 28. The method of claim 27, further comprising positioning the mass flow meter downstream of the pressure regulator to measure the flow rate of air through the tube over a calculated time interval to determine a volume of free space in the chamber above the piston in the body of the cartridge, thereby determining a volume of assembly material in the chamber below the piston in the body of the cartridge.

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