Adjustment of supply quantity based on the gap width of the localized feature area

Abstract

A method for depositing material onto an electronic substrate using a supply system includes: acquiring images of a first feature portion of a first component and a second feature portion of an adjacent second component; executing a measurement command to measure the actual distance of the gap between the first feature portion of the first component and the second feature portion of the second component; dividing the length of the gap into segments and determining the gap width for each segment; determining the number of dots to be supplied by the supply unit for each segment based on the gap width; and performing a supply operation for each segment.

Description

Technical Field

[0003]

[0001] The present disclosure relates generally to an apparatus and method for supplying a viscous material onto an electronic substrate such as a printed circuit board, and more particularly to an apparatus and method for supplying a material onto an electronic substrate using a supply unit configured to adjust the amount of the supplied material based on a position - specified feature.

Background Art

[0002] There are several types of supply systems used to supply precise amounts of liquid or paste for various applications. One such application is the assembly of integrated circuit chips and other electronic components onto a circuit board substrate. In this application, an automated supply system is used to supply dots of liquid epoxy or solder paste, or some other relevant material onto a printed circuit board. The automated supply system is also used to supply lines of underfill material and encapsulant, which can be used to mechanically secure components to the printed circuit board. Exemplary supply systems described above include supply systems manufactured and commercially available from Illinois Tool Works Electronic Assembly Equipment (ITW EAE), which has offices in Hopkinton, Massachusetts.

[0003] In a typical feeding system, the feeding unit is mounted on a moving assembly or gantry to move along three mutually orthogonal axes (x, y, and z axes) using servo motors controlled by a computer system or controller. To feed liquid dots to a desired location on a printed circuit board or other substrate, the feeding unit is moved along the coplanar horizontal x and y axes until it is positioned above the desired location. The feeding unit is then lowered along the vertically oriented vertical z axis until the nozzle / needle of the feeding unit and feeding system is at the appropriate feeding height above the electronic substrate. The feeding unit feeds a liquid dot, then rises along the z axis, moves along the x and y axes to a new position, and lowers along the z axis to feed the next liquid dot. In applications such as underfill sealing or feeding as described above, the feeding unit is typically controlled to feed the material line as it moves along the desired path of the material line along the x and y axes. In the case of some types of supply units, such as injection pumps, z-axis movement before and after the supply operation may not be necessary.

[0004] Vision systems are used to locate objects on electronic circuit boards. Determining the amount of material to supply can be difficult. For gaps with varying widths and small gaps, controlling the amount of material and supplying it under components on the circuit board is challenging. [Overview of the project]

[0005] One aspect of the present disclosure relates to a method for depositing material onto an electronic substrate using a feeding system of the type comprising a frame, a feeding unit gantry movably coupled to the frame, a feeding unit coupled to the feeding unit gantry, a feeding unit configured to deposit material onto an electronic substrate during a feeding operation, a vision system gantry coupled to the frame, and a vision system coupled to the vision system gantry. The vision system is configured to acquire one or more images of an electronic substrate having two adjacent feature portions before performing a feeding operation. In one embodiment, the method includes acquiring images of a first feature portion of a first component and a second feature portion of an adjacent second component, executing a measurement command to measure the actual distance of the gap between the first feature portion of the first component and the second feature portion of the second component, dividing the length of the gap into segments and determining the gap width for each segment, determining the number of dots to be supplied by the feeding unit for each segment based on the gap width, and performing a feeding operation for each segment.

[0006] Embodiments of this method may further include determining the number of dots by a table having dots to be supplied based on the gap width. Performing the supply operation may include controlling the speed of the gantry to supply a desired number of dots within each segment. Performing the supply operation may further include controlling the speed of the dots supplied by the supply unit to be substantially consistent (constant) along the length of the gap. Performing the supply operation may include controlling the speed of the dots supplied by the supply unit to supply a desired number of dots within each segment. Performing the supply operation may further include controlling the speed of the gantry to be substantially consistent along the length of the gap. Each image may consist of pixels, each pixel being the smallest pixel that the vision system can uniquely identify and is interpreted as black or white with shades of gray. The method may further include determining whether the actual gap is less than a predetermined minimum limit and, if it is less than the predetermined minimum limit, not performing the operation.

[0007] The computer-readable medium includes instructions that, when executed by a computer, cause the computer to perform a method comprising: acquiring images of a first feature portion of a first component and a second feature portion of an adjacent second component; executing a measurement command to measure the actual distance of the gap between the first feature portion of the first component and the second feature portion of the second component; dividing the length of the gap into segments and determining the gap width for each segment; determining the number of dots to be supplied by a supply unit for each segment based on the gap width; and performing a supply operation for each segment.

[0008] Embodiments of a computer-readable medium may further include determining the number of dots by a table having dots to be supplied based on the gap width. Performing a supply operation may include controlling the speed of a gantry to supply a desired number of dots within each segment. Performing a supply operation may further include controlling the speed of the dots supplied by the supply unit to be substantially consistent along the length of the gap. Performing a supply operation may include controlling the speed of the dots supplied by the supply unit to supply a desired number of dots within each segment. Performing a supply operation may further include controlling the speed of the gantry to be substantially consistent along the length of the gap. Each image may consist of pixels, each pixel being the smallest pixel that a vision system can uniquely identify and being interpreted as black or white with shades of gray. The computer-readable medium may further include determining whether the actual gap width is less than a predetermined minimum limit and, if it is less than the predetermined minimum limit, not performing an operation.

[0009] Various aspects of at least one embodiment are discussed below with reference to the accompanying drawings. These drawings are not intended to be drawn to a uniform scale. The drawings are included to illustrate and further understand the various aspects and embodiments and are incorporated into this specification, forming part of this specification, but are not intended to define any limitation to any particular embodiment. The drawings, together with the rest of this specification, serve to illustrate the principles and operation of the described and claimed aspects and embodiments. In the drawings, each identical or substantially identical component shown in different drawings is represented by the same reference numeral. For clarity, not all components are labeled in every drawing. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of the supply system. [Figure 2]This is a plan view of a component on an electronic circuit board. [Figure 3] This is an enlarged plan view of a portion of the component, showing gaps divided by numerous segment lines. [Figure 4] This is an enlarged plan view of a portion of the component, showing four segments. [Modes for carrying out the invention]

[0011] Various embodiments of this disclosure relate to viscous material supply systems and devices including supply systems. Embodiments disclosed herein relate to techniques for supplying materials onto electronic substrates by supply systems. Such supply systems are configured to supply assembly materials (e.g., solder paste, conductive ink, adhesive, or encapsulating material) onto electronic substrates (e.g., printed circuit boards referred to herein as “electronic substrates,” “circuit boards,” “boards,” “PCBs,” “PCB substrates,” “substrates,” or “PCB boards”) or to perform other operations. Specifically, embodiments of this disclosure relate below to supply systems used for manufacturing printed circuit boards. A supply system may also be referred to as a “dispenser.”

[0012] The present disclosure is described in detail here with reference to the accompanying drawings, for illustrative purposes only and not to limit its universality. The present disclosure is not limited to the details of configurations and arrangements of components described in the following description or shown in the drawings, with respect to its applications. The principles described in the present disclosure are also applicable to other embodiments and can be practiced or implemented in various ways. Furthermore, the expressions and terminology used in this application are for illustrative purposes only and should not be considered limiting. Any reference in this application to an example, embodiment, component, element or operation of a system or method referred to singularly may also encompass embodiments containing multiple components, and any reference in this application to any embodiment, component, element or operation as plural may also encompass embodiments containing only one component. References in singular or plural form are not intended to limit the systems or methods, their components, operations or elements disclosed herein. The use of the terms “including,” “equipped with,” “having,” “containing,” “accompanied by,” and variations thereof in this application means that the article described therein, its equivalents and additional articles, are included. A reference to “or / or” can be interpreted as comprehensive, such that any term used with “or / or” can refer to any single, one or more, or all of the terms described. In addition, if there is inconsistency in the use of terminology between this document and any document that, by reference, forms part of this application, the use of terminology in the document forming part of this document is supplementary to the use in this document, and the use of terminology in this document shall prevail if the inconsistency results in a contradiction.

[0013] Figure 1 schematically shows a supply system, shown collectively as 10, according to one embodiment of the present disclosure. The supply system 10 is used to supply viscous materials (e.g., adhesives, encapsulants, epoxy, solder paste, underfill materials, etc.) or semi-viscous materials (e.g., solder flux, etc.) onto an electronic substrate 12 such as a printed circuit board or semiconductor wafer. The supply system 10 can also be used in other applications, such as for coating automotive gasket materials, or for application in certain medical fields, or for coating conductive inks. It should be understood that, as used in this application, references to viscous materials or semi-viscous materials are illustrative and not intended to be limiting. In one embodiment, the supply system 10 comprises a first supply unit and a second supply unit, shown collectively as 14 and 16, respectively, and a controller 18 for controlling the operation of the supply system. It should be understood that the supply units may also be referred to in this application as a supply pump and / or supply head. Although two supply units are shown, it should be understood that a single supply unit or multiple supply units may be used.

[0014] The supply system 10 may also include a frame 20 having a base or support 22 for supporting the electronic substrate 12, a supply unit gantry 24 movably coupled to the frame 20 for supporting and moving the supply units 14, 16, and a weighing device or weighing instrument 26 for weighing the amount of viscous material supplied and providing weight data to the controller 18, for example, as part of a calibration procedure. To control the mounting and detachment of the electronic substrate to the supply system, the supply system 10 may use other transfer mechanisms such as a conveyor system (not shown) or a moving beam. The gantry 24 can be moved using motors under the control of the controller 18 to position the supply units 14, 16 in predetermined positions above the electronic substrate. The supply system 10 may also include a display unit 28 connected to the controller 18 for displaying various information to the operator. An optional second controller for controlling the supply units may be provided. Each supply unit 14, 16 may also be configured to use a z-axis sensor (e.g., a laser) to detect the height at which the supply unit is positioned above the electronic substrate 12 or above a mechanism mounted on the electronic substrate. The z-axis sensor is coupled to the controller 18 and relays the information acquired by the sensor to the controller.

[0015] Before performing the supply operation described above, the electronic circuit board, for example, a printed circuit board, must be aligned with or otherwise positioned relative to the supply unit of the supply system. The supply system further comprises a vision system 30, which in one embodiment is coupled to a vision system gantry 32, and the vision system gantry 32 is movably coupled to a frame 20 to support and move the vision system. In another embodiment, the vision system 30 may be located on a gantry 24. As described above, the vision system 30 is used to match the position of a landmark, target, or reference point on the electronic circuit board, known as a reference. Once located, the controller can be programmed to operate the movement of one or more of the supply units 14, 16 to supply material onto the electronic circuit board.

[0016] The systems and methods of this disclosure relate to supplying material onto an electronic substrate, such as a printed circuit board. The description of the systems and methods provided herein refers to an exemplary electronic substrate 12 (e.g., a printed circuit board) supported on a support 22 of a supply system 10. In one embodiment, the supply operation is controlled by a controller 18, which may include a computer system configured to control a material supply unit. In another embodiment, the controller 18 may be operated by an operator. The controller 18 is configured to operate the movement of a vision system gantry 32 to move a vision system to acquire one or more images of the electronic substrate 12. The controller 18 is further configured to operate the movement of a gantry 24 to move supply units 14, 16 to perform a supply operation.

[0017] The methods disclosed herein, but are not limited to, further support the use of augers, pistons, time and pressure controls, and various types of supply units, including injection pumps.

[0018] In one embodiment, the exemplary dispensing system described herein can embody a Camalot® dispensing system, such as a PRODIGY® dispenser, sold by ITW EAE, Inc., Hopkinton, Massachusetts.

[0019] One particular challenge is supplying an appropriate amount of material to the gap between two feature parts. Embodiments of the method disclosed herein relate to adjusting the supply amount based on the location of the located feature parts. The width of the gap between the two feature parts may vary along the length of the gap. In one embodiment, a vision system, such as a vision system 30, can be used by a vision system gantry 32 to locate the edges of the components. The method then includes providing a measurement command for measuring the actual gap between the outer edge of the first feature part and the inner edge of the second feature part. A minimum limit value for the gap between the inner and outer edges is determined. If the gap is less than the minimum limit value, no supply operation is performed. If the gap is greater than or equal to the minimum limit value, the length of the gap is divided into segments, and a gap width is determined for each segment. Based on the viscosity of the material and other external factors, a table is provided for each line to define the line width based on the gap measurement. The line width controls the speed of a gantry, such as a gantry 24, which in turn controls the amount of material supplied within a particular segment. The line width may be defined as the number of dots supplied per given length, for example, millimeters (mm). The larger the line width, the slower the gantry speed. The rate at which dots are supplied can be defined as the number of dots supplied per second (Hz). A single line command can be provided for all segments, or separate line commands can be provided for each segment.

[0020] In one example, referring to Figure 2, an image of a component 40, for example, any type of component mounted on an electronic circuit board, is captured by a vision system such as a vision system 30. Specifically, in one example using the supply system 10 of Figure 1, the vision system gantry 32, under the control of a controller 18, moves the vision system 30 over the component 40 to acquire an image of the component. Figure 2 shows an image of the entire or complete component 40. However, an image of only a part of the component 40 may also be provided. As shown, the component 40 is supported within a chassis 42. A gap 44 is provided between the outer edge of the component 40 and the inner edge of the chassis 42. The gap 44 varies along the four sides of the component 40 and the chassis 42. Furthermore, the gap 44 varies along the length of each side, meaning that the gap 44 becomes wider or narrower along the length of each side.

[0021] Based on an image of the component, a controller such as controller 18 can be configured to program measurement commands for each side to measure the actual distance between the outer edge of component 40 and the inner edge of chassis 42. The edges on component 40 and chassis 42 may be chamfered, radial, or sharp, depending on the product design and how the edges are displayed by the vision system and vision system software. The controller can be configured to set a minimum limit value for the gap between the outer edge of component 40 and the inner edge of chassis 42. In one embodiment, the gap 44 can be set by the user to a predetermined minimum limit value, and if the gap is less than the minimum limit value, the controller can be configured to skip performing a feeding operation for the entire part if it is found that any edge portion is lower than the minimum limit value. For small gaps, e.g., less than 0.45 mm, if it is found that the gap distance of any edge portion is lower than the defined minimum limit value, the feeding operation may be omitted entirely or partially. However, the controller can be configured to perform a supply operation if a programmed measurement command determines that the measured gap 44 is greater than or equal to a minimum limit, for example, 0.45 mm or more.

[0022] Referring to Figure 3, in order to execute a measurement command, the controller is configured to divide each side of the gap 44 between the component 40 and the chassis 42 into a number of segments, each indicated by 46. In some embodiments, the number of segments 46 can be 3 to 20. The measurement command includes determining the gap width for each segment 46. Based on the determined gap width, the line width is derived from a pre-programmed template, as shown below.

[0023] In one embodiment, a table can be provided for each line to define the line width based on the gap measurement values obtained for each segment 46. Table 1 below can be referred to. When the line width is determined, the speed of the gantry is controlled and the amount of material supplied by a supply unit such as supply units 14 or 16 is controlled. The line width is defined as the number of supply dots per unit length, for example dots / mm. For example, if the line is 10 mm in length and the line width is 3 dots / mm, a total of 30 dots are supplied at the calculated intervals between individual dots determined by the speed of the gantry carrying the supply unit.

[0024] [Table 1]

[0025] Referring to FIG. 4, in one example, an elongated gap or line 48 having a predetermined length is divided into a number of segments according to the length of the line. In the illustrated example, line 48 is divided into four segments. As shown in Table 2 below, the first segment (segment number 1) has a measured gap of 0.46 mm, which is greater than the minimum gap width of 0.45 mm and has a line width of 2 dots. The second segment (segment number 2) has a measured gap of 0.54 mm and a line width of 3 dots. The third segment (segment number 3) has a measured gap of 0.59 mm and a line width of 4 dots. And finally, the fourth line segment (segment number 4) has a measured gap of 0.65 mm and a line width of 5 dots.

[0026] [Table 2]

[0027] As shown in the example above, the width of line 48 gradually widens from left to right in Figure 4. However, embodiments of the method disclosed herein can be configured to accommodate line lengths having a measuring gap width that varies along the length of the line across each defined segment. A controller such as controller 18 can be configured to control supply units such as supply units 14, 16 and a supply unit gantry such as gantry 24 to supply a line of material through each segment of line 48, for example, segments 1 to 4.

[0028] In the illustrated embodiment, during the feeding operation, as the width of line 48 increases, the gantry, such as gantry 24, is configured by the controller to move at a slower speed, while the feeding unit, such as feeding unit 14 or 16, feeds at a continuous speed. The larger the line width, the slower the gantry speed; conversely, the smaller the line width, the faster the gantry speed. The gantry's movement speed depends on the amount of material being fed. Other factors may also be considered. As used in this application, revolutions per minute (RPM) or Hz may be used to define the number of dots fed per second. As shown in the table above, a single command can be provided to perform a feeding operation for all four segments, or individual commands can be provided for each segment. In the latter case, each segment will have a different RPM and therefore a different movement speed.

[0029] Therefore, in the example shown in Figure 4 and Table 2, the gantry is configured to move the supply unit relatively quickly to supply two dots in the first segment (segment number 1), relatively slowly to supply three dots in the second segment (segment number 2), even more relatively slowly to supply four dots in the third segment (segment number 3), and even more relatively slowly to supply five dots in the fourth segment (segment number 4). Since the rate at which the supply unit supplies dots of material is 100 Hz, the gantry's movement speed is adjusted accordingly.

[0030] In other embodiments, the rate at which dots are supplied by the supply unit can be varied to accommodate segments having varying gap widths. As referenced above, in one embodiment, the amount of material supplied is controlled by varying the speed of a gantry having a supply unit such as supply unit 14 or 16. However, in another embodiment, the rate at which the supply unit supplies dots can be varied according to a measured gap in a segment to vary the number of dots supplied in that segment. This is achieved while maintaining a constant speed of the supply unit on the gantry. Thus, in this embodiment, the rate at which material is supplied by the supply unit is relatively slow to supply two dots in a first segment, relatively fast to supply three dots in a second segment, even more relatively fast to supply four dots in a third segment, and even more relatively fast to supply five dots in a fourth segment.

[0031] In some embodiments, the line to be supplied is divided into four or five segments, each segment being 4mm to 5mm in length. The gap width is measured for each segment. Based on the measured gap width, the number of dots to be supplied for each gap is selected.

[0032] In some embodiments, each image is composed of pixels, each pixel being the smallest pixel that a vision system can uniquely identify, and is interpreted as black or white with a grayscale range.

[0033] Various controllers, such as controller 18, can perform the various operations described above. Using data stored in associated memory and / or storage devices, controller 18 can also execute one or more instructions stored in one or more non-temporary computer-readable media, which controller 18 may include and / or combine, thereby producing manipulated data. In some examples, controller 18 may include one or more processors or other types of controllers. In one example, controller 18 is at least one processor or includes at least one processor. In other examples, controller 18 performs at least some of the operations described above using application-specific integrated circuits tuned to perform specific operations in addition to, or in place of, a general-purpose processor. As illustrated by these examples, examples relating to the present disclosure can perform the operations described herein 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 computer program products configured to perform the methods, processes, and / or operations described above. A computer program product is or may include one or more controllers and / or processors configured to execute instructions for performing the methods, processes, and / or actions described above.

[0034] Having described several aspects of at least one embodiment of this disclosure, it should be understood that various modifications, changes, and improvements will readily come to mind for those skilled in the art. Such modifications, changes, and improvements are intended to be part of this disclosure and to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are merely examples.

Claims

1. A method for attaching material to an electronic substrate using a feeding system of the type comprising: a frame; a feeding unit gantry movably coupled to the frame; a feeding unit coupled to the feeding unit gantry, configured to attach material to an electronic substrate during a feeding operation; a vision system gantry coupled to the frame; and a vision system coupled to the vision system gantry, configured to acquire one or more images of the electronic substrate having two adjacent feature portions before performing the feeding operation; The process involves obtaining images of the first feature portion of the first component and the adjacent second feature portion of the second component, Executing a measurement command to measure the actual distance of the gap between the first feature portion of the first component and the second feature portion of the second component, The length of the aforementioned gap is divided into multiple segments, and the gap width is determined for each segment. Based on the gap width, the number of dots to be supplied by the supply unit for each segment is determined, The supply operation described above is performed for each segment, Methods that include...

2. The method according to claim 1, wherein determining the number of dots is defined by a table having dots to be supplied based on the gap width.

3. The method according to claim 1, wherein performing the supply operation includes controlling the speed of the gantry to supply a desired number of dots within each segment.

4. The method according to claim 3, wherein performing the supply operation further includes controlling the speed of the dots supplied by the supply unit to be substantially consistent along the length of the gap.

5. The method according to claim 1, wherein performing the supply operation includes controlling the rate at which the dots supplied by the supply unit are supplied so as to supply a desired number of dots within each segment.

6. The method according to claim 5, further comprising controlling the speed of the gantry to be substantially consistent along the length of the gap, in performing the feeding operation.

7. The method according to claim 1, wherein each image consists of multiple pixels, each pixel being the smallest pixel uniquely identifiable by the vision system and being interpreted as black or white having a grayscale range.

8. The method according to claim 1, further comprising determining whether the actual gap is less than a predetermined minimum limit value, and not performing an operation if it is less than the predetermined minimum limit value.

9. A computer-readable medium containing instructions, wherein the instructions, when executed by a computer, The process involves obtaining images of the first feature portion of the first component and the adjacent second feature portion of the second component, Executing a measurement command to measure the actual distance of the gap between the first feature portion of the first component and the second feature portion of the second component, The length of the aforementioned gap is divided into multiple segments, and the gap width is determined for each segment. Based on the gap width, the number of dots to be supplied by the supply unit for each segment is determined, The supply operation described above is performed for each segment, A computer-readable medium that causes the computer to execute the method described above.

10. The computer-readable medium according to claim 9, wherein determining the number of dots is defined by a table having dots to be supplied based on the gap width.

11. The computer-readable medium according to claim 9, wherein performing the supply operation includes controlling the speed of the gantry to supply a desired number of dots within each segment.

12. The computer-readable medium according to claim 11, wherein performing the supply operation further includes controlling the speed of the dots supplied by the supply unit to be substantially consistent along the length of the gap.

13. The computer-readable medium according to claim 9, wherein performing the supply operation includes controlling the rate at which the dots supplied by the supply unit are supplied so as to supply a desired number of dots within each segment.

14. The computer-readable medium according to claim 13, wherein performing the supply operation further includes controlling the speed of the gantry to be substantially consistent along the length of the gap.

15. The computer-readable medium according to claim 9, wherein each image consists of multiple pixels, each pixel being the smallest pixel uniquely identifiable by the vision system and being interpreted as black or white having a grayscale range.

16. The computer-readable medium according to claim 9, further comprising determining whether the actual gap width is less than a predetermined minimum limit value, and not performing an operation if it is less than the predetermined minimum limit value.

Images