Abstract:
A universal automation line is configured for the assembly of electronics and mechanical devices. The universal automation line includes universal cells or stations that can be programmed to perform a variety of automated assembly tasks such as glue dispensing, screw driving, pick and place, etc. The stations are interchangeable by different module design such as selective soldering, heat stacking, bottom lead trimming, bottom screwing and ultrasonic welding. Each station can also include an automated robot, which is also interchangeable, to perform different tasks and complete fully automated assemblies. The stations can be sequenced inline for a fully automated line or combined with some manual operation. The stations can communicate by standardized interfaces and local networks, and can be expanded to an intranet or the internet for remote control.

Description:
RELATED APPLICATIONS 
     This patent application claims priority under 35 U.S.C. 119 (e) of the U.S. Provisional Application, Ser. No. 61/925,587, filed Jan. 9, 2014, and entitled “Universal Assembly Line”. This application incorporates U.S. Provisional Application, Ser. No. 61/925,587 in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is generally directed to the field of automated assembly lines. More specifically, the present invention is directed to an automated assembly line made of a series of universal cells or stations that can be programmed to perform a variety of assembly tasks. 
     BACKGROUND OF THE INVENTION 
     Currently the assemblies done in most factories for consumer electronics and other small mechanical parts are done manually or with semi-automated stations. This has been the standard for a long time because labor costs were so cheap in other countries, but now as labor wages increase and available labor decreases an automation solution is necessary. The problem with most automation solutions is that they are designed for specific tasks and come with a big price tag that can take years to see a return on the investment. Because of this big initial investment, the systems can lose money if the product is changed, discontinued or if production is decreased. Unfortunately this is something that happens very often in the consumer electronics business. Therefore a solution is needed that provides automation that can be reused and is universal for many different products. 
     SUMMARY OF THE INVENTION 
     Embodiments of a universal automation line are configured for the assembly of consumer electronics and other mechanical devices, for example devices between the sizes of personal digital assistants (PDAs) and laptop computers. The universal automation line can also be reconfigured to a larger platform for the large form factor assembly of products such as servers, chassis assemblies, etc. The universal automation line includes universal cells or stations that are interchangeable modules and can be programmed to perform a variety of automated assembly tasks such as glue dispensing, screw driving, pick and place, etc. Each station can have different module design such as selective soldering, heat stacking, bottom lead trimming, bottom screwing and ultrasonic welding. Each station can also include an automated robot, which is also interchangeable, to perform different tasks and complete fully automated assemblies. Examples of different robot types that can be used include, but are not limited to, 6-axis, 4-axis, cartesian or XYZ, and SCARA (Selective Compliance Assembly Robot Arm). The stations can be sequenced inline for a fully automated line or combined with some manual operation. The stations can communicate by SMEMA (Surface Mount Equipment Manufacturers Association) interface standard or by other local networks and standards, and can be expanded to an intranet or the internet for remote control. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Several example embodiments are described with reference to the drawings, wherein like components are provided with like reference numerals. The example embodiments are intended to illustrate, but not to limit, the invention. The drawings include the following figures: 
         FIG. 1  illustrates a universal automation line according to an embodiment. 
         FIG. 2  illustrates the universal automation line of  FIG. 1  with the housing removed. 
         FIG. 3  illustrates a different view of the station  4  from  FIG. 2  with portions of the housing and the module removed according to an embodiment. 
         FIG. 4  illustrates another view of the station  4  from  FIG. 2  with portions of the housing removed according to an embodiment. 
         FIG. 5  illustrates a conceptual block diagram of a control structure of the universal automation line of  FIGS. 1 and 2  according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present application are directed to a universal automation line. Those of ordinary skill in the art will realize that the following detailed description of the universal automation line is illustrative only and is not intended to be in any way limiting. Other embodiments of the universal automation line will readily suggest themselves to such skilled persons having the benefit of this disclosure. 
     Reference will now be made in detail to implementations of the universal automation line as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts. In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer&#39;s specific goals, such as compliance with application and business related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure. 
     The universal automation line enables a system that can be used for different assembly applications with very little cost and time to change between products compared to that of a conventional assembly line. The ability to quickly and cost-effectively re-purpose an assembly line is particularly useful for products having shorter product life-cycles, such as electronic devices. For each new assembly process a sequence of stations is configured according to the specific steps of the assembly process. The sequence of stations specifies a number of stations and one or more modules within each station. Those stations from a previous assembly process which already have the needed module built in are equipped with the correct tools, fixtures and program corresponding to the new assembly process. Once the raw materials are supplied to the newly configured universal automation line having re-purposed stations, the universal automation line is ready for operation. 
     The universal automation line is configured as a fully automated or partially automated assembly line with multiple stations. Each station functions as a cell for performing one or more assembly steps associated with the entire assembly process. Each station can perform the one or more assembly steps using one or more tools per station. The amount of tools or assembly steps to be performed is based on production speed and line balancing. Each station includes one or more modules for performing assembly steps. The module can be a robot, an ultrasonic welding machine, a press machine, a laser engraving machine, a heat staking machine or any other device that may be used for an assembly line, all of which can be automated. Examples of different robot types that can be used include, but are not limited to, 6-axis, 4-axis, cartesian or XYZ, and SCARA. Each station can include tools for use by the module. For some modules, like the ultrasonic welding machine, there may not be any extra tools needed, but for other modules, like the 6-axis robot, the station may have multiple tools, such as a screw driver, and a pick and place tool, for use by the module. Each station can include one or more home docking locations for the extra tools so that the robot can be programmed to retrieve and change the tools itself. A station-to-station conveyance mechanism transports a partially assembled device between stations. Such a conveyance mechanism can include, but is not limited to, a conveyor belt standardized in position and size for alignment between stations. In some cases, the position of the conveyor belt is adjustable in one or more dimensions. In some cases, a width of the conveyor belt is adjustable. Intra-station and inter-station control is achieved through localized and/or remote control. 
     In some embodiments, each station is equipped with several universal features. For example, on a back side of each station is a universal material access port for loading of raw materials. The material access port can be aligned with trays, bowl feeders, a conveyor belt, a vibration feeder, a tape and reel feeder, etc. A universal material access port is useful because for almost every product the material handling is different. By having a universal connector that can load raw materials using different material handling options further enhances the systems ability for automation as well as improves design flexibility and minimizes line reconfiguration. There is a Human Machine Interface touch screen monitor on the front of each station to check progress, install new programs, and provide additional interface for station interaction by the user. The conveyance mechanism is also standardized for simple alignment from station to station. 
     In some embodiments, a station is equipped with the ability to perform operations from the top side, the bottom side or both. For some applications, it is more efficient and convenient for certain assembly steps to be performed bottom-up within the station as opposed to top-down. A station can be configured with only top-down functionality or only bottom-up functionality. A station can also be configured with both top-down and bottom-up functionality that can be performed serially or simultaneously. By having the ability to perform operations from the bottom-up, production speed can be increased because products do not need to be flipped and products can be kept in the same carrier. Examples of such bottom-up functions include, but are not limited to, screwing, soldering and heat staking. 
     The tools for each different assembly process will vary, as each product has its own unique design specifications and corresponding assembly requirements. Some of the tools may be specific for a single assembly step or for the assembly of a single product, such as a pick and place tool that is used for an odd shaped object. Other tools may be designed for multiple assembly steps within the assembly of a single product, and for use in the assembly of multiple different products. Examples of multiple use tools include, but are not limited to, glue dispensers, soldering tools, screw drivers, universal pick and place tools, vacuum nozzle, etc. Each different assembly step performed by the multiple use tool is controlled by a different control algorithm. For example, a screwing tool can be configured to tighten a screw at multiple different locations on the product, each location requiring the screwing tool to move to each specific screwing location. For each location where a universal automation line is installed there can be a “tool shed” that stores a variety of tools that can be used for each station/module pair in the universal automation line. Based on the application an operator can place the needed tools into the correct locations within each station. This process can also be automated. 
     In some embodiments, a station includes a smart camera to perform inspection, scanning, positioning, and other functions benefiting from the use of visual monitoring. In some embodiments, a station control is configured to run a self-calibration to properly calibrate the components within the station including, but not limited to, the conveyor mechanism, the module and corresponding tools, the universal material access port and corresponding feeding mechanism and the camera. The self-calibration process ensures the control program can be transferable to different station without any modification. 
       FIG. 1  illustrates a universal automation line according to an embodiment. The exemplary universal automation line  2  includes three stations  4 ,  6  and  8 . It is understood that the configuration of the universal automation line  2  is for exemplary purposes only and that alternative configurations having more or less than three stations are also contemplated. Each station performs one or more assembly steps in the fabrication of a device. The end result of the universal automation line may be a completely assembled device or a sub-assembly that can be subsequently used as part of a completely assembled device. The stations  4 ,  6  and  8  are aligned in sequence, each having a conveyance mechanism for inputting the device into the station and for outputting the device from the station. The conveyance mechanism is universally aligned so that when multiple stations are aligned, the respective conveyance mechanisms are also aligned. Although reference is made to a “device” being input to and output from each station, it is understood that such reference may refer to any partially assembled state of the device. The conveyance mechanism is standardized from station to station enabling the stations to be used as “building blocks” for forming the universal automation line. Any number of stations, arranged in any order, can be used to meet the desired assembly steps. When a new product is to be assembled, stations can be added, removed and/or rearranged. 
     Each of the stations includes a human machine interface (HMI), such as a touchscreen monitor. Specifically, station  4  includes HMI  18 , station  6  includes HMI  20  and station  8  includes HMI  22 . 
     In some embodiments, the universal automation line also includes material handling devices selectively coupled to one or more stations for loading and unloading materials associated with the assembly of the device. In the exemplary universal automation line  2 , a front-end loading device  10  is coupled to the station  1 , a back-end unloading device  12  is coupled to the station  3 , a material supply cabinet  14  is coupled to the station  1 , and a material supply cabinet  16  is coupled to the station  6 . The loading device  10  is configured to supply a base unit to which additional assembly steps are performed. Examples of such base units include, but are not limited to, a portion of an outer housing of the device or other mounting element which can be used as a foundation for adding the remaining components of the device, a printed circuit board including station electronics, or a printed circuit board already secured to a portion of the outer housing or other mounting element. In some embodiments, the base unit is positioned on a tray or other type of carrier configured to couple with the conveyance mechanism of each station. 
     The unloading device  12  is configured to receive the assembled device from the station  8 . The material supply cabinet  14  is configured to supply components or sub-assemblies to the station  4  via an input opening (not shown) in the frame of the station  4 . The material supply cabinet  16  is configured to supply components or sub-assemblies to the station  6  via an input opening (not shown) in the frame of the station  6 . 
     In the exemplary universal automation line  2  shown in  FIG. 1 , each of the stations  4 ,  6  and  8 , as well as the loading device  10  and the unloading device  12  include a housing.  FIG. 2  illustrates the universal automation line  2  of  FIG. 1  with the housing removed. In the exemplary configuration of  FIG. 2 , the loading device  10  includes a movable tray holder  26  configured to hold multiple trays. In some embodiments, the movable tray holder  26  is a rack having multiple shelves, each shelve for holding a tray. Each tray includes one or more base units. The loading device  10  also includes a conveyor mechanism  28  coupled to receive trays, such as tray  36 , from the movable tray holder  26 . The movable tray holder  26  is configured to move up and down to align one shelf at a time with the conveyor mechanism  28 . When a shelf is aligned with the conveyor mechanism  28 , the tray in the aligned shelf is moved from the shelf to the conveyor mechanism. In some embodiments, the conveyor mechanism includes an alignment mechanism, such as side rails, for establishing and maintaining the tray in the proper position. The conveyor mechanism can be any conventional mechanism for transporting the tray including, but not limited to, a conveyor belt, rollers and a drive train that engages the tray such as a chain and interlocking mechanism that engages a corresponding interlocking element on the tray. The conveyor mechanism  28  is aligned with an output opening (not shown) in the frame of the loading device  10 . 
     The unloading device  12  includes a movable tray holder  24  configured to hold multiple trays. In some embodiments, the movable tray holder  24  is a rack having multiple shelves, each shelve for holding a tray. The unloading device  12  also includes a conveyor mechanism  35  coupled to supply trays to the movable tray holder  24 . The movable tray holder  24  is configured to move up and down to align one shelf at a time with the conveyor mechanism  35 . When a shelf is aligned with the conveyor mechanism  35 , the tray is moved from the conveyor mechanism to the aligned shelf. The conveyor mechanism  35  is aligned with an input opening (not shown) in the frame of the unloading device  12 . 
     The station  4  includes a module  44 . In the exemplary universal automation line  2 , the module  44  is a 6-axis robot. The station  4  also includes a conveyor mechanism  30 . The conveyor mechanism  30  is configured similarly as and is aligned with the conveyor mechanism  28  of the loading device  10 . A first end of the conveyor mechanism  30  is aligned with an input opening (not shown) in the frame of the station  4  and a second end of the conveyor mechanism  30  is aligned with an output opening (not shown) in the frame of the station  4 . The input opening in the frame of the station  4  is aligned with the output opening in the frame of the loading device  10 . The conveyor mechanism  30  is configured to receive a tray, such as tray  38 , from the conveyor mechanism  28 . The conveyor mechanism  30  transports the tray  38  to a defined work position along the conveyor mechanism  30  where one or more assembly steps are performed on the base unit by the module  44 . 
     The station  6  includes a module  46 . In the exemplary universal automation line  2 , the module  46  is a 6-axis robot. The station  6  also includes a conveyor mechanism  32 . The conveyor mechanism  32  is configured similarly as and is aligned with the conveyor mechanism  30  of the station  4 . A first end of the conveyor mechanism  32  is aligned with an input opening (not shown) in the frame of the station  6  and a second end of the conveyor mechanism  32  is aligned with an output opening (not shown) in the frame of the station  6 . The input opening in the frame of the station  6  is aligned with the output opening in the frame of the station  4 . The conveyor mechanism  32  is configured to receive a tray, such as tray  40 , from the conveyor mechanism  30 . The conveyor mechanism  32  transports the tray  40  to a defined work position along the conveyor mechanism  32  where one or more assembly steps are performed on the device by the module  46 . 
     The station  8  includes a module  48 . In the exemplary universal automation line  2 , the module  48  is a press machine configured to apply downward pressure on a device under assembly. The station  8  also includes a module  50 . In this exemplary application, the module  50  is a cartesian robot. The module  48  is considered a top-side module and the module  50  is considered a bottom-side module. The module  44  in the station  4  and the module  46  in the station  6  are also considered top-side modules. In general, top-side modules are positioned above the device under assembly and can perform top-down assembly steps on an upward facing portion of the device under assembly. Bottom-side modules are positioned underneath the device under assembly and can perform down-up assembly steps on a downward facing portion, or underside, of the device under assembly. The bottom-side module eliminates the need for rotating the device under assembly to expose the underside to the top-side assembly. In order for the bottom-side module  50  to interface with the underside of the device under assembly, the tray  42  on which the device under assembly is positioned has an opening (not shown) under the device under assembly. 
     The station  8  also includes a conveyor mechanism  34 . The conveyor mechanism  34  is configured similarly as and is aligned with the conveyor mechanism  32  of the station  6 . A first end of the conveyor mechanism  34  is aligned with an input opening (not shown) in the frame of the station  8  and a second end of the conveyor mechanism  34  is aligned with an output opening (not shown) in the frame of the station  8 . The input opening in the frame of the station  8  is aligned with the output opening in the frame of the station  6 . The conveyor mechanism  34  is configured to receive a tray, such as tray  42 , from the conveyor mechanism  32 . The conveyor mechanism  34  transports the tray  42  to a defined work position along the conveyor mechanism  34  where one or more assembly steps are performed on the device by the module  48  and the module  50 . Once the assembly steps are completed by the module  48  and the module  50 , the conveyor mechanism  34  transports the tray  42  to the output opening in the frame of the station  8 , which is aligned with the input opening in the frame of the unloading device  12 . The conveyor mechanism  35  in the unloading device  12  is configured to receive a tray from the conveyor mechanism  34 . 
       FIG. 3  illustrates a different view of the station  4  from  FIG. 2  with portions of the housing and the module  44  removed according to an embodiment. The station  4  includes a main tooling plate  52  onto which a tool storage plate  54 , a module plate  56  and a material handling area/sub-assembly area  58  are configured. The module plate  56  provides a foundation for mounting the module  44 . In some embodiments, the module plate  56  is a separate element from the module  44 . In other embodiments, the module plate  56  and the module  44  are integrated together. 
     In some embodiments, the module  44  is configured to use multiple different tools. In such a configuration, the tools can be stored in the tool storage plate  54 , each tool having a defined storage location on the tool storage plate  54 . The tool storage plate  54  is accessible by the module  44  for returning a tool currently in use and for retrieving a different tool for subsequent use. 
     The material handling/sub-assembly area  58  is configured to either store assembly materials to be used for subsequent assembly onto the device under assembly  60  or as an area where both assembly materials are stored and where a sub-assembly unit can be assembled, the sub-assembly unit then assembled to the device under assembly  60 . In the former case, assembly materials such as individual components and/or pre-assembled sub-assembly units are received from the material supply cabinet  14  and stored in the material handling/sub-assembly area  58 . In some embodiments, the material handling/sub-assembly area  58  includes a conveyor mechanism (not shown) configured to receive assembly materials from the material supply cabinet  14 , for example through a universal material access opening  68  in the rear of a housing  66  as shown in  FIG. 4 . In some embodiments, the assembly materials are placed on a tray and the tray is transported from the material supply cabinet  14  to the material handling/sub-assembly area  58 . The assembly materials are positioned in a defined area for subsequent retrieval by the module  44 . In some embodiments, the material supply cabinet  14  is configured with a movable tray holder similar to the movable tray holder  26  in the loading device  10 , and the conveyor mechanism in the material handling/sub-assembly area  58  and the movable tray holder in the material supply cabinet  14  function similarly as the conveyor mechanism  28  and the movable tray holder  26  of the loading device  10 . It is understood that alternative mechanisms for transporting assembly materials from the material supply cabinet  14  to the material handling/sub-assembly area  58  can be used. 
     In the later case where the material handling/sub-assembly area  58  includes the sub-assembly area, a sub-assembly unit is assembled in the material handling/sub-assembly area  58 . Similar to the case where the material handling/sub-assembly area  58  is configured as an assembly materials receiving and holding area, assembly materials are received from the material supply cabinet  14  and stored in the material handling/sub-assembly area  58 . Additionally, one or more assembly steps are performed in the material handling/sub-assembly area  58  to complete the sub-assembly unit. The sub-assembly unit is then transported by the module  44  and assembled to the device under assembly  60 . 
     In some embodiments, the module  44  may not be required to use multiple different tools and as such the tool storage plate  54  may not be necessary. In this case, the tool storage plate  54  can still be present and used for tool storage, or the tool storage plate  54  can be replaced by an additional material handling/sub-assembly area. In some embodiments, the station  4  may not be configured to add any new parts or sub-assemblies to the device under assembly. In this case, the material handling/sub-assembly area  58  can still be present, or the material handling/sub-assembly area  58  can be replaced by an additional tool storage plate. 
     It is understood that the relative position of the module plate  56 , the tool storage plate  54  and the material handling/sub-assembly area  58  shown in  FIG. 3  is for exemplary purposes and that alternative positions and configurations are also contemplated. 
     As described above, the conveyor mechanism  30  is configured to transport the tray  38  to a defined work position. In some embodiments, tray securing mechanisms  62  are used to properly align and secure the tray  38  in the defined work position so as to ensure that a device under assembly  60  is properly positioned for subsequent assembly steps. 
     The station  4  also includes station electronics  64 . The station electronics  64  are coupled to the module  44 , the conveyor mechanism  30  and the tray securing mechanisms  62  to provide electronic control. In some embodiments, the station electronics  64  are also coupled to a conveyor mechanism for transporting materials or sub-assemblies, such as from the material supply cabinet  14 , to the material handling/sub-assembly area  58 . The station  4  can include various sensors (not shown) for monitoring operations and providing control feedback. 
     The station electronics for each station and material handling device can be locally controlled and/or remotely controlled. Each of the stations and material handling devices can include a user interface, such as the HMI  18  included with the station  4 , the HMI  20  included with the station  6 , the HMI  22  included with the station  8  and the HMI  23  included with the loading device  10  shown in  FIG. 1 . Also not shown in  FIG. 1 , the unloading device  12 , the material handling cabinet  14  and the material handling cabinet  16  can also each have a user interface. The user interface enables a user to check progress, install new programs, and provide additional interface for interaction by the user at a localized level. One or more of the local user interfaces can be configured for system wide interface and control of each of the stations and material handling devices in the universal automation line. A remotely located controller can also be networked to the universal automation line for remote control.  FIG. 5  illustrates a conceptual block diagram of a control structure of the universal automation line  2  of  FIGS. 1 and 2  according to an embodiment. A loading device controller  70  is included as part of the station electronics and/or the HMI  23  of the loading device  10 . A station controller  72  is included as part of the station electronics and/or the HMI  18  of the station  4 . A station controller  74  is included as part of the station electronics and/or the HMI  20  of the station  6 . A station controller  76  is included as part of the station electronics and/or the HMI  22  of the station  8 . An unloading device controller  78  is included as part of the station electronics and/or the HMI of the unloading device  12 . A main controller  80  is networked to each of the controller  70 ,  72 ,  74 ,  76  and  78  for overall control of the universal automation line  2 . The main controller  80  is shown conceptually in  FIG. 5  as a separate controller but can implemented as part of one of the station or material handling controllers  70 ,  72 ,  74 ,  76  or  78 . Each of the station and material handling device controllers are networked together to provide inter-controller signaling, such as signaling to indicate that a station has completed the programmed assembly steps and is ready to transport the tray to a next station, or that a station is ready to receive a tray. 
     In some embodiments, station control is configured to also provide control of any auxiliary material handling device coupled to the station. For example, the station controller  72  can be configured to control both the station  4  and the material handling cabinet  14 . In other embodiments, the auxiliary material handling device includes separate control from the station. For example, the station controller  72  can be configured to control the station  4  and a separate controller can be configured to control the material handling cabinet  14 . In this case, the separate controller of the material handling cabinet  14  is networked to the station controller  72 , the main controller  80  and/or at least one of the other controllers in the universal automation line network. 
     An exemplary application of the universal automation line  2  is for the assembly of a computer mouse. In this case, the loading device  10  is loading with trays, each tray having a bottom mouse sub-assembly, referred to as the mouse base. The loading device  10  transports a tray to the station  4 . Station  4  is configured to perform three assembly steps. Before the assembly steps are performed, one or more scroll wheels are loaded into the material handling/sub-assembly area  58  of the station  4  from the material supply cabinet  14 . A first assembly step is to load one of the scroll wheels from the material handling/sub-assembly area  58  onto the mouse base. To perform this step, the 6-axis robot retrieves a gripper tool from the tool storage plate  54 , uses the gripper tool to pick the scroll wheel from the material handling and sub-assembly area  58  and place the scroll wheel in the proper position on the mouse base. A second assembly step is to add and tighten three screws. To perform this step, the 6-axis robot returns the gripper tool to the tool storage plate  54 , retrieves a screw driver tool from the tool storage plate  54 , loads the screw driver tool with a screw, places the screw in the proper position on the mouse base, and tightens the screw. In some embodiments, the station includes a screw loading device that supplies the screw to the screw driver tool. In other embodiments, the screw driver tool is pre-loaded with screws that can be sequentially loaded to the tip of the screw driver tool, such as from a cartridge. In still other embodiments, the screws are loaded into and stored in the material handling/sub-assembly area  58  concurrently or separately from the mouse base. The 6-axis robot then loads the screw driver tool with a second screw, places the screw in the proper position on the mouse base, and tightens the screw. The same procedure is repeated to place and tighten a third screw onto the mouse base. A third assembly step is to dispense adhesive on an edge of the mouse base. To perform this step, the 6-axis robot returns the screw driver tool to the tool storage plate  54 , retrieves a dispenser tool from the tool storage plate  54 , and applies adhesive from the dispenser tool to the edge of the mouse base. In some embodiments, the dispenser tool is pre-loaded with adhesive. The 6-axis robot then returns the dispenser tool to the tool storage plate  54 . After the third assembly step is performed, the tray is then transported to station  6  after proper signaling control is established between the two stations. 
     Station  6  is configured to perform six assembly steps. Before the assembly steps are performed, a mouse cover, a click-scroll wheel cover, a battery cover and a light tube are loaded into the material handling/sub-assembly area of the station  6  from the material supply cabinet  16 . In this exemplary configuration, the material handling/sub-assembly area is divided into a material handling area and a sub-assembly area. A first assembly step is to load the mouse cover from the material handling area to the sub-assembly area. To perform this step, the 6-axis robot retrieves a first gripper tool from the tool storage plate, uses the first gripper tool to pick the mouse cover from the material handling area and place the mouse cover in the sub-assembly area. A second assembly step is to add the click-scroll wheel cover to the mouse cover. To perform this step, the 6-axis robot returns the first gripper tool to the tool storage plate, retrieves a first vacuum nozzle tool from the tool storage plate, picks the click-scroll wheel cover from the material handling area and places the click-scroll wheel cover on the proper position on the mouse cover. A third assembly step is to add and tighten a screw. To perform this step, the 6-axis robot returns the first vacuum nozzle tool to the tool storage plate, retrieves a screw driver tool from the tool storage plate, loads the screw driver tool with a screw, places the screw in the proper position on the mouse cover, and tightens the screw. In some embodiments, the station includes a screw loading device that supplies the screw to the screw driver tool. In other embodiments, the screw driver tool is pre-loaded with screws that can be sequentially loaded to the tip of the screw driver tool, such as from a cartridge. In still other embodiments, the screws are loaded into and stored in the material handling/sub-assembly area concurrently or separately from the mouse cover, the click-scroll wheel cover, the battery cover and the light tube. A fourth assembly step is to add the battery cover to the mouse cover. To perform this step, the 6-axis robot returns the screw driver tool to the tool storage plate, retrieves a second vacuum nozzle tool from the tool storage plate, picks the battery cover from the material handling area and places the battery cover on the proper position on the mouse cover. A fifth assembly step is to add the light tube to an underside of the mouse cover. To perform this step, the mouse cover is turned upside down while in the sub-assembly area. In some embodiments, the sub-assembly area includes a carrier configured to receive the mouse cover and to secure the mouse cover in place. The carrier can be coupled to a cam or other rotational mechanism for rotating the carrier from an upright to an upside down position, thereby turning the mouse cover upside down. The 6-axis robot returns the second vacuum nozzle tool to the tool storage plate, retrieves a second gripper tool from the tool storage plate, picks the light tube from the material handling area and places the light tube on the proper position on the underside of the upside down mouse cover. The carrier is then turned right side up. A sixth assembly step is to add the mouse cover to the mouse base. To perform this step, the 6-axis robot returns the second gripper tool to the tool storage plate, retrieves the first gripper tool from the tool storage plate, picks the mouse cover from the sub-assembly area and places the mouse cover on the mouse base positioned on the tray received from station  4 . After the sixth assembly step is performed, the tray is then transported to station  8  after proper signaling control is established between the two stations. 
     Station  8  is configured to perform one assembly step. This step is to add and tighten four screws. To perform this step, the press machine applies downward pressure on the mouse cover. The underside of the mouse base is exposed to the bottom-side cartesian robot. The cartesian robot is fitted with a screw driver tool. The cartisian robot sequentially places and tightens each of four screws into proper positions on the underside of the mouse base. In some embodiments, the station includes a screw loading device that supplies the screw to the screw driver tool used by the cartesian robot. In other embodiments, the screw driver tool is pre-loaded with screws that can be sequentially loaded to the tip of the screw driver tool, such as from a cartridge. After the four screws are added and tightened, the tray is transported to the unloading device  12  after proper signaling control is established between the station  8  and the unloading device  12 . The unloading device  12  receives the tray with assembled mouse from the station  8  and stores the tray in a rack of the movable tray holder. 
     In the case described above for assembling a computer mouse, each of the stations is configured to perform multiple assembly steps. Such a configuration increases utility of each station, however decreases the overall assembly speed of the entire line because having a module change tools is time consuming. Increased utility is often beneficial for prototyping. For high volume production, each station can be configured such that no tool swapping is performed. In some applications, each station performs a single assembly step. Also, the exemplary configurations described above show assembly of a single device per tray. For increased through-put each tray can transport multiple devices. 
     In some embodiments, a manual station is connected with the universal automation line. For certain production lines and products there are assembly steps that are too difficult or too expensive to be done automatically so these can be done manually. Interconnecting a manual station with a conveyor mechanism of the universal automation line enables the line to still run seamlessly and be almost completely automated. 
     Each of the controllers in the universal automation line is re-programmable for each new product to be assembled. In some embodiments, an external applications repository is maintained The repository includes a library of stations, modules and tools that are designed for different assemblies and different products. This library is accessible by line engineers as a template for designing a new line or product. This reduces non-recurring engineering and other costs involved in setting up the universal automation line. It also decreases the time to production because the tools have already been tested and proven to work for other products. 
     Most components of each station are reusable by simply reprogramming the controller and reusing the existing module within the station. In some applications, products may require customized module elements, such as a customized gripper tool used by a robot to pick and place a non-standard sized component. However, in this case only the tool is customized, not the robot or remainder of the station. The cost to manufacture a customized tool is much less expensive, and less timely to manufacture than manufacturing an entire robot with customized gripper. 
     The present application has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the universal automation line. Many of the components shown and described in the various figures can be interchanged to achieve the results necessary, and this description should be read to encompass such interchange as well. As such, references herein to specific embodiments and details thereof are not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications can be made to the embodiments chosen for illustration without departing from the spirit and scope of the application.