Related Applications

[0001] This Application claims priority to Israeli Patent Application No. 296,668, filed September 20, 2022, entitled "Automated Apparatus and Process for Stacking and Bonding Acoustic Stack Components of Ultrasonic Transducer," the contents of which are incorporated by reference as if fully set forth herein.

Field of the Invention

[0002] The present Application relates to the field of manufacture of ultrasonic transducers, and more specifically, but not exclusively, to an automated apparatus and process for stacking and bonding acoustic stack components of an ultrasonic transducer.

Background of the Invention

[0003] With the advent of home-use ultrasonic transducers that may be integrated with a handheld smartphone, the demand for manufacture of ultrasonic transducers is steadily increasing. Existing production processes are insufficient for meeting the present demand for ultrasonic transducers.

[0004] One source of expense and delay in the production of ultrasonic transducers results from the stack bonding process. The stack of acoustic components in an ultrasonic transducer includes, from top to bottom, a second matching layer, a first matching layer, a ground component of a flexible printed circuit board; a piezoelectric element, a signal component of a flexible printed circuit board, and a backing layer. Depending on the quality requirements of the transducer, the transducer might be composed of only one matching layer or up to four or more matching layers. During the production of an ultrasonic transducer, these components are bonded together in a process known as stack bonding. Typically, stack bonding is performed manually.

[0005] The typical stack bonding process involves manual mechanical bonding of the components by means of dedicated jigs. The process is typically comprised of the following steps: cleaning the components; mixing bonding adhesive and applying it on the components; placing the components into a jig; applying pressure, and cleaning excess adhesive. This process is done for each transducer array separately.

Summary of the Invention

[0006] The present application discloses an apparatus and a process for automated stack bonding of multiple ultrasound stack components simultaneously. The apparatus is configured to perform the following processes in an automated fashion: applying plasma to clean upper and lower surfaces of the stack components; optical analysis of the stack components; layering of the stack components within a lower jig; application of adhesive between the stack components; placement of an upper jig operating pneumatic pressure onto the layered stack components; and bending the flexible printed circuit boards. In addition, the machine may perform automatic loading of the acoustic components, and automatic placement of jig assemblies including the stack components in an oven for adhesive curing.

[0007] Using the apparatus and processes described herein, it is possible to complete the stacking of each of the stack components within the jigs in approximately three minutes, and to complete stacking of a series of ten stacks within jigs within approximately 30 minutes.

[0008] The automated stack bonding apparatus and process described herein reduces costs of production, minimizes errors, allows the usage of low-cost raw materials (which are more sensitive to variations in the process) and increases yield. During the automated assembly, each stack component is automatically cleaned, analyzed for defects, and checked for proper alignment. These processes prevent the introduction of defects which reduce the operating quality of the transducer. As another advantage, the disclosed automated stack bonding machine is compact. In addition, the automated stack bonding machine may be easily operated by a regular person without any special skills.

[0009] The stack bonding process described herein may be part of a streamlined automatic production process for ultrasonic transducers. This streamlined automatic production process may relate to the production of transducer components (e.g., acoustic lens, matching layers, backing block) through processes such as injection and molding technology, roller, print screen, and automatic grinding. The production process may further include automated processes for stacking, bonding, dicing, and assembling the backing block and acoustic lens. Furthermore, manual soldering may be replaced by an automatic wire bonding machine, or by automatic techniques such as direct bonding or hot bar. The automatic production machinery may be integrated into an industrial production line, using materials such as conveyors, rollers, combined automatic dispensers, robots, plasma cleaning ovens, automatic adhesive mixing machines, and grinding or print screen technology.

[0010] According to a first aspect, an apparatus for automated stacking and bonding of acoustic stack components is disclosed. The apparatus includes: a tray for storage of stack components, lower jigs, and upper jigs; a first station comprising a cleaning apparatus adapted to clean an upper surface of a stack component; a second station comprising an image sensor for optical analysis of the stack component; a third station comprising a cleaning apparatus adapted to clean a lower surface of the stack component; a fourth station comprising a platform, lower jig loader, and adhesive dispenser for transporting a lower jig onto the platform, layering the stack components onto the lower jig, and for applying an adhesive between stack components; and a fifth station comprising an upper jig loader and jig compressor for placement of an upper jig onto the layered stack components; and conveyors for transporting the stack components and jigs between each station.

[0011] In another implementation according to the first aspect, the stack components include a backing layer, a flexible PCB including signal and ground components, a PZT layer, and a plurality of matching layers.

[0012] Optionally, the apparatus further includes a sixth station comprising a compression block for bending the flexible PCB following placement of the upper jig onto the layered stack. [0013] Optionally, the stack components further include a protective layer configured to be inserted, without adhesive, between an uppermost matching layer and the upper jig.

[0014] In another implementation according to the first aspect, the second, third, fourth, and fifth stations are aligned linearly.

[0015] Optionally, the trays for the stack components, lower jigs, and upper jigs are oriented such that the conveyors for transporting the stack components to the first station, lower jig to the fourth station, and upper jig to the fifth station move in a perpendicular direction relative to a direction of movement of the stack components between the second, third, fourth, and fifth stations.

[0016] Optionally, the tray for storage of stack components, first station, and second station are aligned linearly, in a direction perpendicular to the linear alignment of the second, third, fourth, and fifth stations.

[0017] In another implementation according to the first aspect, the apparatus further includes an oven for drying the adhesive that was applied between the stack components.

[0018] In another implementation according to the first aspect, the third station further includes an image sensor for optical analysis of a lower surface of the stack component.

[0019] In another implementation according to the first aspect, the apparatus further includes a reject bin for disposal of stack components found to be defective or misaligned at the second station.

[0020] Optionally, the cleaning apparatus of the first station and the cleaning apparatus of the third station are plasma dispensers.

[0021] According to a second aspect, a method of automated stacking and bonding of an acoustic stack comprised of layered stack components is disclosed. The method includes: delivering each stack component from a storage tray to a first station, and, for each stack component whose upper surface is configured to contact another component in the acoustic stack, cleaning an upper surface of the stack component at the first station; delivering each stack component from the first station to the second station, and optically analyzing the stack component at the second station; delivering each stack component from the second station to a third station, and for each stack component whose lower surface is configured to contact another layer of the acoustic stack, cleaning a lower surface of the stack component at the third station; delivering a lower jig to a fourth station; delivering each stack component from the third station to the fourth station, stacking each stack component on the lower jig, and, for each stack component whose upper surface is configured to contact another component in the acoustic stack, applying an adhesive to the upper surface of the stack component at the fourth station; repeating each of the preceding steps until each layer of the acoustic stack is stacked on the lower jig at the fourth station; and delivering the lower jig and stack to a fifth station, delivering an upper jig to the fifth station, and placing the upper jig on the lower jig and layered stack components.

[0022] In another implementation according to the second aspect, the method further includes forming the acoustic stack from the following components: a backing layer, a flexible PCB including signal and ground components, a PZT layer; and a plurality of matching layers.

[0023] Optionally, the method further includes delivering the layered stack components within the lower jig and upper jig to a sixth station, and bending the flexible PCB layers at the sixth station.

[0024] Optionally, the method further includes inserting an additional protective layer, without adhesive, between an uppermost matching layer and the upper jig.

[0025] In another implementation according to the second aspect, the steps of delivering between the second, third, fourth, and fifth stations comprise transporting the acoustic stack components from station to station in a single straight line.

[0026] Optionally, the steps of delivering each stack component from the storage tray to the first station; delivering the lower jig to the fourth station; and delivering the upper jig to the fifth station include transporting the component, lower jig, and upper jig in a direction that is perpendicular to the direction of the single straight line.

[0027] Optionally, the step of delivering each stack component from the storage tray to the first station and from the first station to the second station comprises transporting the component in a direction that is perpendicular to the direction of the single straight line.

[0028] In another implementation according to the second aspect, the method further includes drying the adhesive in an oven.

[0029] In another implementation according to the second aspect, the method further includes optically analyzing a lower surface of the stack component at the second station.

[0030] In another implementation according to the second aspect, the method further includes determining, based on the optical scanning, whether the stack component is defective or misaligned, and discarding any defective or misaligned stack component in a reject bin.

[0031] In another implementation according to the second aspect, the steps of cleaning at the first station and at the third station comprise cleaning with plasma.

Brief Description of the Drawings

[0032] FIG. 1 schematically illustrates different stations in an apparatus for automated stacking and bonding of acoustic stack elements, according to embodiments of the present disclosure;

[0033] FIG. 2A schematically depicts components of an acoustic stack within a jig assembly, according to embodiments of the present disclosure;

[0034] FIG. 2B schematically depicts a second embodiment of an acoustic stack within a jig assembly, according to embodiments of the present disclosure;

[0035] FIG. 2C schematically depicts a jig assembly including internal elements thereof, according to embodiments of the present disclosure; [0036] FIGS. 3A and 3B depict upper and lower views of an acoustic stack element following completion of the stack bonding process, according to embodiments of the present disclosure;

[0037] FIG. 4 schematically illustrates an apparatus for automated stacking and bonding of acoustic stack components, according to embodiments of the present disclosure;

[0038] FIGS. 5A-5I schematically illustrate different fixtures of the apparatus of FIG. 4, according to embodiments of the present disclosure; and

[0039] FIGS. 6A-6L are photographs of an apparatus for automated stacking and bonding of acoustic stack components, according to embodiments of the present disclosure.

Detailed Description of the Invention

[0040] The present Application relates to the field of manufacture of ultrasonic transducers, and more specifically, but not exclusively, to an automated apparatus and process for stacking and bonding acoustic stack components of an ultrasonic transducer.

[0041] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

[0042] As used in the present disclosure, the term "acoustic stack component" refers to any one of the components described above that is combined into an acoustic stack, i.e., a backing layer, a flexible PCB signal layer, a PZT layer, a flexible PCB ground layer, and matching layers. An acoustic stack component may also be referred to as an acoustic stack element. As used in the present disclosure; the term "acoustic stack" refers to the stack resulting from the bonding of the acoustic stack components. As used in the present disclosure, the term "jig" refers to a frame for holding the acoustic stack components during the stacking and bonding processes. The term "jig assembly" refers to a combination of an upper and lower jig. As used in the present disclosure, the term "conveyor" refers generally to any device that may be used to transport an object within apparatus 10 from one location to another. The term "conveyor" includes components such as loaders, pickers, sliding platforms, and tracks.

[0043] Referring to FIG. 1, apparatus 10 includes various stations, or modules, at which operations are performed on acoustic stack components in order to form an acoustic stack. Specifically, apparatus 10 includes: storage trays 20 for acoustic stack components; a first station 30 for applying plasma to an upper surface of an acoustic stack component; a second station 40 for performing optical analysis of the upper surface of the acoustic stack component; a third station 50 for applying plasma to a lower surface of an acoustic stack component; a fourth station 60 for stacking acoustic stack components on lower jigs, and for applying adhesive between the acoustic stack components; a fifth station 70 for placement of the upper jig to the acoustic stack components and the lower jig; and a sixth station 80 for bending of the flexible printed circuit boards. The apparatus 10 further includes storage trays 62 for lower jigs; storage trays 72 for upper jigs; and storage trays 82 for completed stacks within jigs. Following completion of assembly of the upper jig over the lower jig, with the acoustic stack components inside, the acoustic stack components are delivered, within the jigs, to an oven 90. Within the oven 90, heat is applied to cure the adhesive. The oven may be integrated within apparatus 10 or may be a separate component.

[0044] FIG. 2A illustrates a schematic cross-section view of the acoustic stack components within a jig assembly 200 including lower jig 201 and upper jig 202, which would result from the manufacturing process described herein. The acoustic stack components include backing layer 101; signal flexible PCB layer 102; PZT layer 103; ground flexible PCB layer 104; first matching layer 105, and second matching layer 106. In addition, when loaded within the jig assembly 200, a protective layer 107 is overlaid on top of the acoustic stack components. The protective layer may be made of polytetrafluoroethylene (PTFE) or a polymeric material with similar qualities. Protective layer 107 cushions the acoustic stack components from damage arising from pressure exerted by the upper jig 202 on the components and lower jig 201. The protective layer 107 also prevents any adhesive from contacting the upper jig 202.

[0045] FIG. 2A schematically illustrates the edges of signal flexible PCB layer 102, the ground flexible PCB layer 104, and the protective layer 107 as protruding through the walls of the lower jig 201 and upper jig 202. This is obviously a schematic representation, and, actually, the edges of these components exit the jigs at opening 204 between the upper jig 202 and lower jig 201. In addition, the parts of these acoustic stack components that extend beyond the contours of the jig assembly are bent, rather than straight, as will be described further herein.

[0046] Upper jig 202 includes central portion 203. Central portion 203 includes the portion of upper jig 202 that is oriented over the stack components and exerts pressure on the attached stack, for example, with springs. Central portion 203 is initially raised relative to the rest of upper jig 202 and is lowered during the bending process.

[0047] FIG. 2B illustrates a second embodiment of the acoustic stack components within a jig assembly. The acoustic stack of FIG. 2B differs from that of FIG. 2A in that the flexible printed circuit board includes two portions 112, 114 that wrap around the PZT layer 103. PZT layer 103 includes a kerf 111 on an underside of the PZT layer 103, a larger portion 113 that is in contact with the signal flexible printed circuit board portion 112, and a smaller portion 115 that is in contact with the ground flexible printed circuit board portion 114.

[0048] FIG. 2C illustrates certain internal elements of the jig assembly 200. In particular, lower jig 201 includes nubs 204 which are flexibly held in place by spring- loaded assembly 206. Upper jig 201 contains protrusions 205 which are configured to match the recesses in nubs 204. When sufficient downward pressure is exerted by upper jig 202 on lower jig 201, protrusions 205 push nubs 204 against the counterpressure of assembly 206, thereby allowing the upper jig 202 to be locked into place. Coil springs 207 collectively exert a pressure of approximately 10-40 kg / cm ² . The dimensions of jig assembly 200 may be, approximately, 186 mm length, 40 mm width, and 82 mm height.

[0049] FIG. 3A illustrates an upper view of acoustic stack 100, and FIG. 3B illustrates a lower view of acoustic stack 100. Second matching layer 106 is visible at the top of stack 100, and backing layer 101 is visible at the bottom of stack 100. The exterior portion of the flexible printed circuit board is curved relative to the plane of the acoustic stack components. Interconnect region 110 of the signal flexible printed circuit board includes connectors 111. The interconnect region 110 is used to connect the flexible printed circuit board 100 with an external processing ultrasound device.

[0050] FIG. 4 schematically illustrates different components of apparatus 10. FIGS. 5A-5I illustrate schematic embodiments of particular sub-systems within apparatus 10, and FIGS. 6A-6L illustrate photographs of different sub-systems of apparatus 10 during stacking and bonding of an acoustic stack. It should be noted that certain components appear in a slightly different relative orientation in FIG. 4 compared to FIGS. 6A-6L, or appear only in the schematic illustrations but not in the photographs, or vice versa. Any such differences are due to design choices that do not affect the primary functioning of the apparatus 10, and accordingly the description below relates to these Figures as depicting a single embodiment.

[0051] Stack component tray is illustrated in FIGS. 5B, 6A, 6C, and 6D. Stack component tray 20 has eight slots for placement of stack components. FIG. 5B depicts one exemplary orientation for the different stack components 101-107 on tray 20. Stack component tray 20 further includes an additional slot 109. The slot 108 may be used to hold spacers which may be used to separate between flexible printed circuit boards 102, and to prevent bending and damaging of these boards, when the flexible printed circuit boards 102 are initially placed on tray 20. Tray 20 may include additional slots for additional components, such as additional matching layers, if included in the stack. [0052] Optionally, apparatus 10 includes a station (not shown) for cleaning each stack component with solvent, prior to placement of the stack component onto the stack component tray 20. Alternatively, the stack components may be cleaned with solvent prior to their introduction into apparatus 10.

[0053] Loader 22, seen in FIGS. 5A, 6C, and 6D, is configured to transport each stack component from tray 20 to the first station 30. Loader 22 is equipped with a picker 24 and with servo motors and tracks that allow free movement of the picker 24 in the X, Y, and Z directions. The resolution of the location of loader 22 in each of the X, Y, and Z directions (and of other loaders described in the present disclosure) may be 2 pm or less. Application of vacuum causes a stack component to adhere to the picker 24, and release of the vacuum enables the picker 24 to place the component.

[0054] In operation, the picker 24 picks a component from the tray 20 and delivers the component from tray 20 to platform 34. This is seen particularly in FIG. 6D, in which the picker 24 is transporting signal flexible printed circuit board 102. Optionally, when there are spacers in between flexible printed circuit boards 102 on the tray, the picker 24 first takes a spacer and deposits it on slot 109, before transporting the flexible printed circuit board 102.

[0055] The first station 30 includes a cleaning apparatus. In the illustrated embodiments, the cleaning apparatus is a plasma dispenser 32. Other cleaning apparatuses and methods may be used, such as cleaning apparatus utilizing corona, laser, UV, or excimer. Plasma dispenser 32 is mounted on arm 38, which is movable in a linear direction. When a stack component is on platform 34, the plasma dispenser 32 dispenses plasma 31 onto the upper surface of the stack component. During the dispensing, arm 38 moves the stack component horizontally along the length of the stack component, so that the plasma covers the relevant upper surface of the component. This process is illustrated in FIG. 6E.

[0056] In certain implementations, cleaning the upper surface with plasma is performed only for stack components whose upper surfaces will be adhered to other stack components. Thus, it is not necessary to perform this process for the second matching layer 106. However, optionally, all stack components may be cleaned on their upper surfaces. Cleaning with plasma is also not necessary for the protective layer 107.

[0057] In the next stage of the manufacturing process, platform 34 is moved laterally along track 35 (shown in FIG. 5A) to bring the stack component to the second station 40. At the second station 40, optical sensor 42 optically scans the upper surface of the stack component. For example, the scanning may be performed by projecting light 44 in the visible or infrared ranges (seen in FIG. 6F), and by capturing the reflection of the light from the surface of the component. The optical sensor serves to verify that the stack component is the correct stack component, that it is not damaged in any way, and that it is properly aligned on the platform 34. If the results of the optical sensing indicate a defect, the stack component is discarded into the reject bin 43 (illustrated in FIG. 4 and in FIG. 5C).

[0058] Following the optical sensing, the stack component is picked up by loader 47, illustrated in FIG. 5C. Loader 47 includes a vacuum-operated picker 49, illustrated in FIG. 5D and in FIG. 6F.

[0059] When the stack component is carried by loader 47, the underside of the stack component passes third station 50. At third station 50, plasma dispenser 52 dispenses plasma 51 to the underside of the stack component. This process is illustrated at the left side of FIG. 6G. The plasma may be dispensed only on the underside of stack components whose undersides contact another stack component (i.e., all but backing layer 101). Alternatively, the plasma may be dispensed on the underside of all stack components. In addition, the third station may include optical sensor 45, whose location is schematically indicated in FIG. 4, adjacent to plasma dispenser 52. Optical sensor 45 may optically scan the underside of the stack component, in the same manner as optical sensor 42.

[0060] Following completion of application of plasma 51 to the underside of the stack component, and, optionally, optical scanning of the underside of the stack component, loader 47 brings the stack component to the fourth station 60. [0061] FIGS. 5E, 5F, 6G, and 6H illustrate the actions performed at the fourth station 60. First, a lower jig 201 is delivered to fourth station 60, so that the lower jig 201 is waiting at the fourth station for placement of the stack components. When the stack component is the backing layer 101, the lower jig 201 is delivered to fourth station 60 during performance of the previous steps, so that the lower jig 201 is waiting for delivery of the backing layer 101. The lower jig 201 is then retained in place at fourth station 60 until all components are stacked thereupon.

[0062] Prior to delivery of the lower jig 201 to fourth station 60, the lower jigs 201 are arranged on tray 62. Jig loader 63 delivers lower jigs 201 to a platform (not visible) at the fourth station 60. Jig loader 63 is illustrated schematically in FIG. 5F. Jig loader 63 may operate in a similar fashion to the loaders previously described in the present disclosure. Following delivery of a lower jig 201 to the fourth station 60, a timing belt 65 delivers the next lower jig 201 to a position in which it may be transported by the jig loader 63.

[0063] After layering of the stack component onto the lower jig 201, for all stack components except for the uppermost one, adhesive dispenser 64 deposits adhesive onto the stack component. The adhesive may be any suitable adhesive, such as a heat-cured epoxy.

[0064] Adhesive dispenser 64 is mounted on a loader that is configured to move in three dimensions. Adhesive dispenser 64 further includes nozzle 66, which has a narrow dispensing tip, and adhesive reservoir 69, which is above the nozzle 66. Prior to dispensing of the adhesive, the adhesive dispenser 64 optionally moves the nozzle 66 to cleaning sponge 68 and rubs the nozzle 66 against sponge 68. The cleaning sponge 68 removes residual epoxy, if present, from the tip of the nozzle 66. The dispenser 64 is moved by the loader to a position above the edge of the stack component. The dispenser 64 deposits a line 67 of adhesive onto the stack component while moving linearly over the stack component. It is sufficient to deposit a narrow line of adhesive onto the stack component, because, when the stack components are compressed by the upper jig, the pressure causes the adhesive to spread to the entire surface between the stack components. [0065] Each new component is stacked onto the stack, and the adhesive dispenser 64 applies adhesive, until each of the elements of the acoustic stack are stacked on top of the lower jig 201. Subsequently, protective layer 107 is layered onto the uppermost matching layer 106, without adhesive.

[0066] In embodiments in which the stack that is assembled is that of FIG. 2B, the fourth station further includes an apparatus for bending the flexible printed circuit board around the PZT layer 103. The apparatus may include, for example, a vacuum-operated picker configured to raise the ground FPCB portion 114, a lever configured to depress the ground FPCB portion 114 onto the PZT layer 103, and an image sensor for checking the alignment of the ground FPCB portion 114 relative to PZT layer 103.

[0067] The lower jig 201 is then transported on the platform to fifth station 70, which is illustrated particularly at FIGS. 5G, 6B, and 61. At fifth station 70, loader 71 transports upper jig 202 and lowers the upper jig 202 onto the lower jig 201. Loader 71 may be identical in all relevant respects to loader 63, illustrated in FIG. 5F. Jig compressor 74 then presses onto the upper jig 202, at peripheral portions thereof. Specifically, air compressor 75 may apply downward pressure onto the jig compressor 74. As a result of this pressure, a locking mechanism engages between the upper jig 202 and lower jig 201, to thereby form jig assembly 200. Following the implementation of the locking mechanism, jig assembly 200 exerts a pressure of 10- 40 kg / cm ² onto the stack. Central section 203 of the upper jig continues to be in a raised position. This raised central section 203 is circled in FIG. 6J.

[0068] Jig assembly 200 is then transported on the platform to sixth station 80, which is illustrated in FIGS. 5H, 51, 6B, 6J, 6K, and 6L. At sixth station 80, compression block 84 (illustrated schematically in FIG. 5H) is lowered onto raised central portion 203 of upper jig 202. The compression block 84 may be lowered with pressure using an air cylinder, similar to air cylinder 75. The central portion 203 exerts pressure on the portions of flexible printed circuit board layers 102, 104 that are jutting out of the jig structure 200 (as described in connection with FIG. 2), and causes those layers to bend, up to 90 degrees. When present, protective layer 107 is also bent. This process is depicted in FIG. 6J, which shows compression block 84 just above central portion 203; and FIG. 6K, which shows compression block 84 following depression of central portion 203 and compression of the protective layer 107. The flexible PCB layers 102, 104 are not visible because they are on the opposite side of the jig assembly 200.

[0069] Following the bending at the sixth station, loader 86 carries jig assembly 200 to tray 82, as illustrated in FIGS. 51 and 6L. Following completion of a predetermined number of jig assemblies 200, e.g., ten, the jigs are transported to an oven 90 for curing of the adhesive. The oven 90 may be a separate structure from the apparatus 10. The above operations may be done to ten or tens of acoustic stacks simultaneously.

[0070] Apparatus 10 may be enclosed in a generally cuboid frame. The frame may be comprised of a combination of a welded steel pipe structure and an aluminum profile assembled structure. In exemplary embodiments, the frame has the following approximate dimensions: 1.85 meters length; 1.20 meters width; 1.70 meters height. In addition to the components described herein, the frame may include, in a bottom portion thereof, computing components and pneumatic parts. The computing components include a memory and processing circuitry including programming instructions for execution of each of the assembly steps described herein. The frame may also include a user input terminal, for inputting instructions to apparatus 10, and a display, for displaying status updates and information to a user. The computing components may operate automatic processes such as an initial self-test for each operation in the process and an automatic alert if there is a problem during the process.

[0071] In view of the foregoing, it is apparent that the automated stack bonding apparatus 10 described herein, and the methods of assembly described herein using apparatus 10, incorporate various advantageous features. First, apparatus 10 is organized in a compact fashion, with maximal utilization of space. For example, the third, fourth, fifth, and sixth stations are all in a single line, thus enabling the assembly process to proceed stepwise with a minimum of movement of the stack components and jigs from one station to the next. Furthermore, the storage trays for the lower jig 201, upper jig 202, and completed jig assemblies 200 are all perpendicular to the axis of movement between the third and sixth stations. This setup enables efficient delivery of the relevant components to and from the stations. Similarly, the first and second stations are in a straight line with each other and with the stack component tray 20, thereby enabling efficient cleaning and checking of each of the stack components.

[0072] Further advantageously, the automated cleaning and optical scanning described herein ensure that each stack component that is inserted into a stack is clean, oriented correctly, and defect-free. Finally, the automated functioning of apparatus 10 ensures that the manufacture proceeds efficiently, at a high rate, and without room for introduction of human error.