WO2002005319A2

WO2002005319A2 - Component source interchange gantry

Info

Publication number: WO2002005319A2
Application number: PCT/US2001/041221
Authority: WO
Inventors: Peter Davis; Dean Tarrant; Michael A. Summers
Original assignee: Hover-Davis, Inc.
Priority date: 2000-07-07
Filing date: 2001-07-02
Publication date: 2002-01-17
Also published as: AU2001279280A1; WO2002005319A3; US20020003994A1

Abstract

The present invention is a method and apparatus for automatically storing and replenishing expandable wafers (140) used in component feeders (130) used automated printed circuit board assembly systems, for example the Hover-Davis Direct Die Feeder (DDF). In the mass production of printed circuit boards automated pick-and-place equipment accepts die from 'chip feeders' and then mounts them at predetermined location on the circuit board. The present invention includes a wafer or tape reel storage bay (116) and a gripping assembly (150) that is moved by a gantry robot to retrieve a wafer or reel (140) from the storage bay (116) and automatically deposit in into a component feeder (130).

Description

COMPONENT SOURCE INTERCHANGE GANTRY

TECHNICAL FIELD

This invention relates generally to an apparatus for automatically replenishing a component source in an automated component feeder such as a surface mount die source, and more particularly to a gantry-type apparatus for storing and automatically delivering a plurality of components to a component feeder.

BACKGROUND OF THE INVENTION

The present invention is a component source interchange gantry designed to automatically store and replenish semiconductor components stored on both wafers used in a direct die feeder such as the Hover-Davis Direct Die Feeder (DDF), or in component tape reels employed with component tape feeders such as the SELF-THREADING COMPONENT TAPE FEEDER (60/293,397) noted above. In the mass production of printed circuit boards automated pick-and-place equipment generally accept die from a tape and reel feeder and/or waffle tray method and subsequently places them at a predetermined location on the circuit board or similar substrate. The direct die feeder or DDF is capable of performing this function of presenting die directly from a wafer without taking up significantly more space than a tape feeder. By reducing the handling of bare die on its journey from wafer to assembly, significant cost reduction is realized, and the limited handling mitigates the potential for damage to the individual die, thereby enhancing the reliability of the end product.

However, the supply of die to a DDF, via expanded wafers holding the die, currently requires human intervention, where a technician or machine operator is responsible for removing a depleted wafer frame, and replenishing the feeder with a new or full wafer. Such a process not only requires labor, but may also result in additional operation costs if the pick-and-place equipment must be shut down or idled during the replacement of a wafer. Accordingly, the present invention is directed to an apparatus that can preferably store and automatically replenish spent wafers so as to avoid the need for operator intervention and to reduce wafer interchange time and handling. It will be further appreciated that similar benefits may be achieved in conventional component tape feeders were a similar system adapted to automatically supply component tape reels to self-threading or autoloading component tape feeders.

DISCLOSURE OF INVENTION In accordance with the present invention, there is provided an apparatus for supplying component storage units to a component feeder, comprising: a frame for positioning the apparatus in juxtaposition with the component feeder; a storage bay located within the confines of said frame for storing a plurality of component storage units therein; a gripper assembly for gripping one of the plurality of component storage units stored in said storage bay; and gripper assembly movement means for automatically moving the gripper assembly from a position adjacent the storage bay to a position adjacent the component feeder.

In accordance with another aspect of the present invention, there is provided an apparatus for supplying wafers to a direct die feeder, comprising: a frame for positioning the apparatus in juxtaposition with a direct die feeder; a wafer bay located within the confines of said frame for storing a plurality of wafers therein; a gripper assembly for gripping one of the plurality of expandable wafers stored in the wafer bay; and gripper assembly movement means for moving the gripper assembly from a position adjacent the wafer bay to a position adjacent the direct die feeder.

In accordance with yet another aspect of the present invention, there is provided a method for automatically supplying components to a component feeder, comprising the steps of: positioning a collection of component storage units in a bay in juxtaposition with a component feeder; releasably gripping a component storage unit in the bay; and moving the component storage unit from a position within the bay to a position adjacent the component feeder to facilitate the automatic insertion of the component storage unit into the feeder for use.

In accordance with a further aspect of the present invention, there is provided a method for automatically supplying wafers to a direct die feeder, comprising the steps of: positioning a collection of wafers in a wafer bay in juxtaposition with a direct die feeder; releasably gripping a wafer stored in the wafer bay; and moving the wafer from a position adjacent the wafer bay to a position adjacent the direct die feeder to facilitate the automatic insertion of the die into the feeder for use.

One aspect of the invention is based on the discovery of techniques for automatically gripping and transporting wafers and component tape reels from a storage bay to a component feeder such as a direct die feeder. For example, a gantry-type system for providing wafers to a direct die feeder in a surface mount assembly system. The techniques implement a robotic or automated feeding operation in order to handle the wafers in a careful and controlled manners so as to retrieve empty wafer frames and replenish the direct die feeder thereby limiting operator intervention. Moreover, the storage bay of the system may include positioning systems for interchangeable wafer or reel magazines, as well as pre- or post-processing functions.

The technique described above is advantageous because it is efficient compared to manual, labor-intensive approaches. The techniques of the invention are advantageous because they provide a range of alternatives for the fetch and retrieval of components (on wafers or reels) to re-supply the component feeder, each of which is useful in appropriate situations. As a result of the invention, longer term, automated operation of component feeders will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 and 2 are perspective views of an embodiment of the component interchange gantry system in a closed and an open position, respectively, in accordance with an aspect of the present invention;

Figure 3 is a perspective view of a portion of an alternative embodiment of the component interchange gantry system for use with tape reel component feeders;

Figure 4 is a detailed view of components of the system of Figure 1 ; Figure 5 is a detailed view of a gripper assembly of the system of Figure 1 with a wafer held therein;

Figure 6 is a schematic block diagram illustrating various components of a component interchange gantry system in accordance with the present invention; and Figure 7 is a flow chart depicting the various steps in the automated process executed in accordance with an embodiment of the present invention.

MODES FOR CARRYING OUT THE INVENTION

For a general understanding of the present invention, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate identical elements.

Figure 1 depicts a perspective view of an embodiment of the component source interchange gantry 100 in an operating position as it may be configured for use as a supply of wafers for a direct die feeder. Figure 2 depicts the same component source interchange gantry in an "open" position where it would allow access to an associated component feeder 130. Referring to Figures 1 and 2, frame support members 102 and 104 are intended to be integrally affixed to the frame or structure of a component pick-and-place assembly system (not shown). Frame member 102 preferably includes pivot axis 110 and 112 about which the storage bay and gantry frame 114 is hingedly affixed to the member 102. In one embodiment, the pivots provide a means for moving said gripper and gantry assembly away from the component feeder. On the opposite support member 104, the frame 114 is supported, when in a "closed" position, by support member 106 that rotateably interferes with and supports the bottom of frame 114 when it is moved to a position adjacent frame member 104. Although not shown, it is also possible that gantry frame 114 may employ casters or other support mechanisms to support the frame when it is an opened position.

As an alternative means for moving the gripper assembly and gantry frame 114 away from the component feeder, it is further contemplated that the assemblies may be accurately positioned and moved via a linear mechanism such as a slide or rail-type device (manual or automated), so as to provide access to the component feeders there below. More specifically, the mechanism may slide in either an outward or an upward direction so as to provide access to the feeders. It will be further appreciated that a slide or rail system, to provide such access, may require hardware not currently reflected in Figure 2.

The component source interchange gantry includes a component source storage bay 116 for storing a plurality of component storage units that have a plurality of components associated therewith (e.g., wafers or component tape reels) therein. Within the gantry frame 114, and particularly within component source storage bay 116, a plurality of expandable (or unexpanded) wafers, such as those disclosed and taught in U.S. Patent 5,976,306, are stored. In particular, a component storage unit such as a wafer ring 140 is preferably held in a wafer frame 142, the wafer frame being suitable for storing the wafer (or more appropriately the die divided therefrom) in a rack or magazine 118 within the wafer bay. Preferably the magazine is comprised of parallel grooves or slots positioned along the top and bottom thereof, and is slidably mounted within component source bay 116 so the wafer ring(s) and frame(s) are preferably held in a vertical or upright position, such as a Wafer Frame Magazine made by Perfection Products, Inc. (Model # FFM-4263-01 ) and preferably able to hold approximately twelve expanded wafer frames therein.

It will be appreciated that other regions within bay 116 may also be used for the staging of wafers awaiting loading as well as used or depleted wafer frames. Moreover, the other regions within bay 116, for example regions 117 and 119 may also be used for pre- or post-processing of wafers in conjunction with an aspect of the present invention. For pre-processing, it is contemplated that a region within the bay may be employed to provide a wafer-expansion capability within the bay and prior to positioning the wafer in the feeder. Similarly, one of the regions within bay 116 may include an ultraviolet (UV) light exposure station, where a wafer is inserted into the station prior to being loaded into one of the die feeders 130. Another possible pre-processing station would be a mapping station where the wafer may be scanned for missing or damaged die, or to confirm the presence of indicators (ink dots) on known bad die (KBD). Examples of post-processing operations, in addition to storage, may be a station to remove the expanding rings from the spent wafer frame for subsequent reuse on the next wafer within the wafer expansion queue. And lastly yet another functional application within the storage bay region would be the ability to read specific encoded data, which references the actual component via a part number and unique batch ID. The decoding means most generally employs the optical imaging of bar codes however OCR and magnetics (e.g., magnetic ink character recognition) are acceptable alternatives. The decoding and subsequent verification process can be exercised upon the loading of new components into the bay as well as just prior to transporting the components into the feeder.

As previously noted, and as depicted in Figure 3, it is further contemplated that in the place of a plurality of wafers stored in bay 1 16, a plurality of component storage units such as tape reels 122 may be stored. In particular such a system may be used for the automated reloading of a component tape feeder, preferably a self-threading component tape type feeder. A self-threading tape feeder (not shown), as contemplated for use in accordance with the present invention, does not require carrier tape splicing for reliably conveying parts to a pickup station for retrieval by a pick and place assembly machine. The self-threading tape feeder includes an open cover transport region, disposed between a cover tape peeling station and a pick location, where the carrier tape is advanced by a drive means such as a belt in contact with an upper surface thereof, where the drive means moves the carrier tape and also retains the components within the pockets. Furthermore, a clamshell cover tape reservoir and cover tape drive mechanism is employed to assure the reliable storage of cover tape peeled from the component carrier tape.

Also depicted in Figures 1 and 2 is a gripper assembly 150 for gripping one of the plurality of wafer frames 142 or component tape reels 122 stored in bay 116. The gripper assembly is moved from a position adjacent the storage bay to a position adjacent the component feeder 130 via gripper assembly movement means 124 that includes a plurality of translatable slides, and drive mechanisms associated therewith, positioned along at least two and preferably three axes (X, Y and Z as shown in the figures). Figure 1 further depicts a user-interface display 132 associated with the system 100. Preferably, the display 132 is a touch-screen type display (displays an image and is responsive to a user's touching of the display screen) that may be used in conjunction with the interchange system, and its control logic and circuitry (Figure 6) to support one or more of the following features/functions: (a) Teaching and calibration of the interchange system as well as the feeding apparatus can be controlled via icons on the screen; (b) Communicate status or errors to a user via the display screen; (c) Video output from the component feeder may be directed to the touch screen in lieu of an on-board viewer;

(d) Provide on-line documentation such as a service and/or an Operator's Manual; (e) Provide a diagnostics interface for troubleshooting the system;

(f) Provide an operator interface during operation of the system. It is further contemplated that the component source interchange system may be interconnected or networked with the component feeders and/or the printed circuit board assembly systems they support, where the display 132 may be adapted to display data or other information associated with other systems and components in communication with the component source interchange system 100.

Referring next to Figures 1 and 4, the process for moving the gripper assembly 150 relative to bay 116 and component feeder 130 involves the activation of the drive mechanism for at least one axis and possibly multiple axes concurrently. Motion along the X-axis is regulated by a pair of slides or rails 160, wherein a carriage 162, to which gripper assembly 150 is attached, is moved under the control of a linear actuator such as a screw-type drive 162, driven by a drive motor 166 operatively associated with the screw drive via a belt 168 and pulley assembly 170. Rotation of the drive motor 166 results in the rotation of the screw drive and the displacement of carriage 162 along the slides 160. As will be described below, operation of the drive is controlled as a function of the position of the carriage, such position being monitored in accordance with the engagement of the drive motor. If a stepper motor is employed as the drive motor, it may be possible to accurately control the X-axis motion without the need for real time position sensing feedback.

Similarly, the motion of the gripper assembly relative to the Y-axis is controlled by a linear slide 176. However, for this direction the position of a carriage 178 along the slide is controlled by the movement of a drive belt 180 operatively affixed to the carriage. Drive belt 180 is, in turn, driven in response to the rotation of pulley assembly 182 operatively coupled to drive motor 184.

Lastly, the Z-axis motion of the gripper assembly 150 is controlled by a linear slide 190 oriented in a direction parallel to the Z-axis. A carriage 192 is slidably coupled to the Z-axis linear slide as well as a drive belt 194. As with the Y-axis drive mechanism, a drive motor 196, and pulley assembly 198 operatively coupled thereto, are employed to control the movement of drive belt 194. Here again, stepper, servo, linear or similarly controlled motors may be employed to accurately position each of the slides along the associated slides or rails, thereby controlling the ultimate position of gripper assembly 150 in three directions.

Control and logic circuitry, including a stepper motor controller 280 (Figure 6) are contained within housing 200, which is operatively connected to frame 114. Control of system 100 is preferably accomplished using a general purpose programmable controller 260 (Figure 6) equipped with multiple i/o ports for sending and receiving from the various sensors and motion control devices As a result of the control circuitry a gripper assembly 150, with a wafer frame 142 grasped therein, may be moved in a generally continuous fashion from a position adjacent the storage bay 1 16, where a wafer frame is extracted from the storage magazine, to a position in proximity to the component feeder (load location) where the wafer frame may be automatically inserted into the feeder 130 for use.

Those skilled in the art of robotic equipment design will appreciate that there are numerous alternative configurations for the gripper assembly movement means, including single-arm robots and other mechanisms to reliably and accurately position the wafer gripper assembly relative to the storage bay 116 and the feeder(s) 130. It will be further appreciated that various shields and covers may be placed on the gantry apparatus during operation so as to shield the wafers and die from dust, and to prevent the apparatus from being tampered or interfered with during operation. Such covers may further provide safety protection by preventing operators from contact with the moving gripper assembly and other components of the component source interchange gantry 100. It is further contemplated that the covers and shield may be an integral part of the gantry frame 1 14, and that one or more of such covers and shield may employ casters or wheels so as to provide support to the gantry frame during use or when the gantry frame is in an opened state. Turning now to Figure 5, there is depicted an illustration of the various components of the gripper assembly 150. The gripper assembly includes a mount 206 for attaching the gripper assembly to the gripper assembly movement means, preferably a carriage that travels along a linear slide as described above. Mount 206, as depicted in the figure, includes a magnetic coupling surface 208 that, during operation of the system, is coupled to an opposing surface on the bottom of the Y-axis carriage 178 (Figure 4). One or more alignment pins 210 achieve alignment of the mount 206 with the carriage 178, and corresponding receptacles on the opposing surface (not shown). The magnetic coupling is preferably a permanent magnet, and provides a breakaway mount should the gripper assembly come into contact or interference with another piece of equipment. Furthermore, tether 174 in Figure 4 is included to prevent the mount and gripper assembly from falling to the floor beneath the system in the event they mount is decoupled. Assembly 150 further includes opposing clamping members 214 and 218 that are pivotably attached to one another by hinge 222. The clamping members are biased against one another by a plurality of springs 224 along the rear edge of members 218. Under the control of pneumatically operated actuators 230 and 234, the separation of the members 214 and 218 is controlled. It will be appreciated that in order to control the position of the clamping members relative to one another, it is preferable that actuators 230 and 234 are positioned on the opposite side of the hinge from the springs 224. Furthermore one or more sensors 238 (optical or manual switch type) may be employed in conjunction with the clamping members 214 and 218 to determine or verify the presence and position of a wafer frame or component tape reel when one is to be retrieved by "closing" members 214 and 218 of the gripping assembly 150.

Referring briefly, to Figure 6, there is illustrated a general schematic diagram showing the control circuitry for system 100. In particular, a system controller 260 receives input from a plurality of sensors such as door sensors 264, from the touch screen user interface display 132, and from the host machine (input line 268 - e.g., Ethernet or a similar network protocol). In response to a set or preprogrammed instructions and the various inputs or programmatic variables, system controller 260 operates the component source interchange gantry system. Operation of the system includes not only the control and monitoring of the gantry drives (drive controller 280 and drives 166, 184 and 196), but also of the system pneumatics such as the pneumatic wafer gripper (block 150, having actuators 230 and 234 as depicted in Figure 5) and optional pre- or post-processing equipment 272 in bay 116 (not shown). Accordingly, system 100 is provided as a turnkey system that may be fully integrated with new or existing assembly systems and associated component feeders.

Referring again to Figure 2, the details of latch mechanism 120 will be discussed. Latch 120, as shown, may be an electromagnetic latch, wherein the application of power to the electromagnets within the latch cause the latch to remain coupled to a magnetic surface such as surface 121 positioned on frame 102 directly opposite the magnetic latch. Alternative latching mechanisms such as a catch or clasping mechanism may be employed, so long as the mechanism serves to assure that both of the pivot points (1 10 and 112) are completely closed in order for the latch to engage. The required functionality of latch 120 may be provided by a pneumatically actuated latch, whereby the latching mechanism is pneumatically operated via an actuator and an associated valve assembly (not shown). Furthermore, latch 120 may include an associated switch or sensor, wherein a failure to latch, unlocking or opening of the latch, will disable the system from automated operation. Such a feature is believed to be a safety feature that will not only prevent possible injury to a user, but will also prevent the unintended damage of system components were the system to be operated when the gantry and bay assemblies are open.

Referring lastly to Figure 7, there is depicted a basic flow diagram illustrating the various general steps accomplished by the present invention in an embodiment where it is configured to operate with one or more direct die feeders (DDF). Beginning with Step 300, the system receives a signal from the DDF that the current wafer has been exhausted of die. After receiving the signal, the gripper assembly is moved to a position adjacent the DDF load position, step 304, where the gripper is able to retrieve the exhausted wafer, step 308. Once the gripper has gripped and retrieved the exhausted wafer at step 308, as verified by a wafer frame sensor on the gripper (not shown), the gripper assembly is moved using the X-Y-Z axes (step 312) to a position where the wafer frame can be deposited in an open slot in the wafer bay, step 316. Having retrieved and deposited the exhausted wafer frame, the gripper assembly next moves to a full wafer slot in the bay, step 320, and grips the wafer frame so as to extract the full wafer frame from the bay, step 324. Subsequently, the gripper assembly is moved, again via the X-Y-Z axes to a position adjacent the DDF load position, step 328. The full wafer frame is deposited into the DDF, step 332, and the component source interchange gantry system automatically sends a signal to the DDF (and/or the host machine) indicating that a new wafer is available and then waits for a signal that another fetch and retrieve cycle is necessary, step 336.

In recapitulation, the present invention is a method and apparatus for automatically storing and replenishing a source of components (e.g., expandable wafers used in a direct die feeder such as the Hover-Davis Direct Die Feeder and component tape reels). In the mass production of printed circuit boards automated pick-and-place equipment accepts die from "chip" or component feeders and then mounts them at a predetermined location on the circuit board. The present invention includes a storage bay and a gripping assembly that is moved by a gantry robot to retrieve a wafer or reel from the storage bay and automatically deposit the wafer into a component feeder. It is, therefore, apparent that there has been provided, in accordance with the present invention, a method and apparatus for storing and automatically replenishing a component source in association with a component feeding system. While this invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Claims

1. An apparatus for supplying component storage units to a component feeder, comprising: a frame for positioning the apparatus in juxtaposition with the component feeder; a storage bay located within the confines of said frame for storing a plurality of component storage units therein; a gripper assembly for gripping one of the plurality of component storage units stored in said storage bay; and gripper assembly movement means for automatically moving the gripper assembly from a position adjacent the storage bay to a position adjacent the component feeder.

2. The apparatus of claim 1 , wherein said gripper assembly includes: a mount for attaching the gripper assembly to the gripper assembly movement means; and a pair of opposed clamping members for releasably clamping the expandable wafer.

3. The apparatus of claim 2, wherein said mount is a breakaway mount to prevent damage to the gripper assembly or the gripper assembly movement means in the event of interference.

4. The apparatus of claim 3, wherein said breakaway mount includes a pair of magnetized surfaces oriented in opposition to one another, and an alignment mechanism to assure proper alignment of the gripper assembly and the gripper assembly movement means when they are assembled.

5. The apparatus of claim 2, wherein said gripper assembly further includes: a spring for biasing the opposed clamping members toward one another; an actuator operatively opposed to said spring, wherein the actuator operates to separate the opposed clamping members when actuated; and a sensor operatively associated with at least one of said clamping members to indicate the presence of an expandable wafer being gripped by the opposed clamping members.

6. The apparatus of claim 1 , further including means for moving at least said gripper assembly away from the component feeder so as to allow access to the component feeder.

7. The apparatus of claim 6, wherein said means for moving at least said gripper assembly away from the component feeder includes: at least one pivot point along a first side of said frame so that the apparatus may be swung away from, and thereby allow access to, the component feeder.

8. The apparatus of claim 6, further including: a latch for releasably retaining said frame in an operating position juxtaposed to the component feeder.

9. The apparatus of claim 8, wherein said frame further includes: a frame support for releasably supporting said frame in an operating position juxtaposed to the component feeder.

10. The apparatus of claim 1 , further including a user-interface display for depicting at least one indicator as to the status of operation of the system.

11. The apparatus of claim 1 , further including a processing station, located within said storage bay, whereby a component storage unit may be automatically placed within said processing station by said gripper assembly.

12. An apparatus for supplying wafers to a direct die feeder, comprising: a frame for positioning the apparatus in juxtaposition with a direct die feeder; a wafer bay located within the confines of said frame for storing a plurality of wafers therein; a gripper assembly for gripping one of the plurality of expandable wafers stored in the wafer bay; and gripper assembly movement means for moving the gripper assembly from a position adjacent the wafer bay to a position adjacent the direct die feeder.

13. The apparatus of claim 12, wherein said gripper assembly includes: a mount for attaching the gripper assembly to the gripper assembly movement means; and a pair of opposed clamping members for releasably clamping the expandable wafer.

14. The apparatus of claim 13, wherein said gripper assembly further includes: a spring for biasing the opposed clamping members toward one another; an actuator (air operated) operatively opposed to said spring, wherein the actuator operates to separate the opposed clamping members when actuated; and a sensor operatively associated with at least one of said clamping members to indicate the presence of an expandable wafer being gripped by the opposed clamping members.

15. The apparatus of claim 12, further including: means for moving at least said gripper assembly away from the direct die feeder so as to allow access to the direct die feeder and a host to which the direct die feeder is operatively attached; and a latch associated with said frame for releasably retaining said frame in an operating position juxtaposed to the direct die feeder.

16. A method for automatically supplying components to a component feeder, comprising the steps of: positioning a collection of component storage units in a bay in juxtaposition with a component feeder; releasably gripping a component storage unit in the bay; and moving the component storage unit from a position within the bay to a position adjacent the component feeder to facilitate the automatic insertion of the component storage unit into the feeder for use.

17. The method of claim 16, further comprising the steps of: releasably gripping a component storage unit in the component feeder; removing the component storage unit from the component feeder; moving the component storage unit to an open position within the bay; and inserting the component storage unit into the open position within the bay.

18. A method for automatically supplying wafers to a direct die feeder, comprising the steps of: positioning a collection of wafers in a wafer bay in juxtaposition with a direct die feeder; releasably gripping a wafer stored in the wafer bay; and moving the wafer from a position adjacent the wafer bay to a position adjacent the direct die feeder to facilitate the automatic insertion of the die into the feeder for use.

19. The method of claim 18, further comprising the step of: verifying, subsequent to the step of releasably gripping a wafer stored in the wafer bay, that a wafer has been gripped.

20. The method of claim 18, further comprising the step of: sending a signal to the direct die feeder to indicate that a new wafer is available.