Patent Publication Number: US-2007112451-A1

Title: Glass demand scheduling system

Description:
CROSS REFERENCE TO RELATED APPLICATION  
      The present application is a Continuation-in-Part application of currently pending U.S. application Ser. No.: 10/751,382 having a filing date of Jan. 5, 2004 entitled “Glass Production Sequencing” claiming priority as a Continuation-in-Part of U.S. application Ser. No. 10/646,191, entitled “Glass Optimization” filed Aug. 22, 2003. The present application claims priority to, and incorporates in their entireties both of the above-identified applications for all purposes. 
    
    
     FIELD OF THE INVENTION  
      The present invention concerns a method and apparatus for controlling production run sequences of insulating glass units.  
     BACKGROUND ART  
      Window manufacturers typically receive orders that include a variety of different sizes and types of windows and/or patio doors. The different sizes and types of windows and/or patio doors require different sizes and types of insulating glass units (IGs) that are assembled into a frame or sash to form a completed window or patio door at one or more glazing lines. The window manufacturers separate and group the orders for the IGs into regular or planned production runs. The regular or planned production runs are scheduled to be manufactured in a certain sequence on a certain future date, usually within one to three business days ahead.  
      Variables in the manufacturing process rarely allow the regular production runs to be manufactured in the exact planned sequence. For example, rush orders for important customers and remake orders that occur when IGs break are often prioritized, changing the sequence of the production runs. The operational status of machines used to make the components of the IGs may also cause the sequence of the regular or planned production runs to be altered. Further, demand fluctuations, such as a shortage at one of the glazing lines may cause the sequence of the regular or planned production runs to be altered. As a result, a supervisor of an IG production line must constantly monitor each of the manufacturing variables and modify the sequence of the production runs accordingly.  
      Current methods employed by IG supervisors for monitoring IG manufacturing variables and modifying production run sequences are slow, inaccurate and confusing. The existing methods typically rely on informal communications, such as word of mouth, handwritten documents and manual data entry. Use of these non-automated forms of communication often confuse operators, tie up machines and delay standard manufacturing procedures. Use of these informal communication methods cause production efficiencies to drop even further while new employees are being trained or new machines are being commissioned.  
      The glass lites that are needed to construct the IGs are separated and grouped into scheduled production batches or runs. For each production batch, the glass lites are further grouped and arranged to be cut from large stock glass sheets to achieve the highest yield. The process of grouping and arranging glass lites to be cut from stock glass sheets to achieve the highest yield is called glass optimization.  
      Glass optimization is usually performed by a computer executing a computer program. The output from the glass optimization process is a control program that is sent to a computer-controlled cutting table. The glass optimization software outputs a computer program that optimizes one or more production batches containing patterns of lites arranged on stock glass sheets. The cutting table automatically scores the glass according to each pattern. Each production batch normally contains one or more glass layout patterns that provide a lower yield than desirable.  
      These Low Yield Patterns or Low Yield Sheets significantly reduce the yield of entire production batches resulting in higher manufacturing costs due to wasted glass. Waste is particularly expensive when manufacturing windows from increasingly popular specialty glasses such as Low-E or self-cleaning materials.  
      Today, there are several existing methodologies used to increase glass yields. Unfortunately, each method presents one or more problems to manufacturing operations. The methods and their resulting problems are described below. 
          a) Standard dimensioned lites called filler lites can be introduced to scheduled production batches to fill-in unused space on the stock glass sheets. The glass optimization software determines where filler lites can be inserted when creating the initial programmed patterns. Because fillers are inserted prior to the actual manufacturing process, the number and type of filler lites rarely meet actual production demand. Too few filler lites starve production lines while too many fillers create storage and quality problems.     b) Adding different sizes of large sheets can be stocked to increase yield.        

      This allows the glass optimization software to pick the size of stock sheets that produce the best yield. Although this method enhances yield, it also increases inventory space and costs while decreasing throughput (more glass sizes to shuttle in and out). 
          c) Certain cutting tables allow the sizes and types of lites from Low Yield Sheets to be manually entered at the cutting table controller with the sizes and types of other of selected lites, then re-optimized to increase yields.        

      Although these features provide flexibility and increase yield, they also cause the cutting table to remain idle during the manual entry process.  
      This greatly reduces production throughput and efficiency.  
     SUMMARY OF THE INVENTION  
      In accordance with one exemplary embodiment of the claimed invention is a method for optimizing material flow and equipment utilization in the fabrication of insulating glass units in a production operation. The method comprises compiling a plurality of orders and converting the plurality of orders into production schedules for operating a plurality of processes that fabricate the insulating glass units over a prescribed period of time. The method further includes releasing the production schedules to the plurality of processes used to fabricate insulating glass units. The production schedules are accessible to users through a computer network. The method also includes monitoring production operations data produced as a result of the releasing the production schedules to the plurality of processes used to fabricate the insulating glass units and providing reports used by the monitoring production operations having image readable indicia that are imaged for providing real-time data for tracking material flow to, from, and through the processes used in the fabrication of insulating glass units.  
      In accordance with another exemplary embodiment of the claimed invention includes computer-readable media having computer-executable instructions for performing a method optimizing material flow and equipment utilization in the fabrication of insulating glass units in a production operation, the instructions comprising the step of producing a plurality of production schedules for equipment and assembly operations used to fabricate windows and window components over a prescribed period of time. The instructions further comprise releasing the production schedules to the equipment and assembly operations used to fabricate window and window components. The production schedules are accessible to users through a computer network. The instructions also comprise calculating production operations data associated with the productions schedules. The calculating of the production operations includes using information from continuous real-time data collected from tracking material and components through the equipment and assembly operations used to fabricate window and window components.  
      In accordance with yet another exemplary embodiment of the claimed invention is a method for controlling production schedules of insulating glass units, components, and materials in equipment and assembly operations comprising the steps of compiling a plurality of new, remake, and rush orders used to fabricate insulating glass units and converting the plurality of orders into production schedules for operating a plurality of equipment and assembly operations that fabricate the insulating glass units over a prescribed period of time. The method further includes releasing the production schedules to the plurality of equipment and assembly operations that fabricate insulating glass units, the production schedules being accessible to operators and management through a computer network and monitoring production operations data produced as a result of the releasing the production schedules to the plurality of equipment and assembly operations and real-time feedback information. The monitoring production operations data includes: monitoring individual machine production rates used to fabricate the insulating glass units; monitoring individual machine completion rates used to fabricate the insulating glass units; monitoring individual kanban arrival times having a known amount of material used to fabricate the insulating glass units; monitoring individual kanban consumption rates of the known amount of material used to fabricate the insulating glass units; and monitoring individual machine start times used to fabricate the insulating glass units. The method further includes the steps of alerting operators and/or management should the materials supplied to one or more of the plurality of equipment or assembly operations fall below a prescribed material queue threshold, creating a material notice condition based on the monitoring production operations data and altering one or more of the production schedules based on the material notice condition.  
      These and other objects and advantages of the system constructed in accordance with an exemplary embodiment of the invention is more completely described in conjunction with the accompanying drawings.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic representation of a window and/or door manufacturing facility;  
       FIG. 2  is a schematic representation of a window and/or door manufacturing facility equipped with a system for controlling production run sequences of insulating glass units;  
       FIG. 3  is a schematic representation of a user interface by means of which an operator controls production run sequences;  
       FIG. 4  is a schematic representation of a user interface by means of which an operator controls production run sequences;  
       FIG. 5  is a schematic representation of a user interface by means of which an operator controls production run sequences;  
       FIG. 6  is a flow chart that illustrates one method of controlling production run sequences;  
       FIG. 7  is a schematic representation of a cutting station located within a window or door manufacturing facility;  
       FIG. 8  is a schematic of a user interface by means of which an operator sets up cutting operations at the  FIG. 1  cutting station;  
       FIGS. 9-15  are schematic depictions of glass sheets illustrating layouts of lites to be cut from the sheets at the cutting station;  
       FIGS. 16A and 16B  are flowcharts for optimizing lite layouts on glass sheets of a production run;  
       FIGS. 17A and 17B  are flowcharts illustrating a process for managing and optimizing material flow and equipment utilization through the production process of  FIG. 2  in accordance with the present invention; and  
       FIG. 18  illustrates a printing operation for a plurality of reports for providing information to the production process of  FIG. 2  in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION  
      The disclosed invention provides an integrated software and apparatus solution used in the manufacture of windows and/or doors for dynamically monitoring manufacturing variables and controlling production sequences using central production control workstation  10  ( FIG. 2 ).  
       FIG. 1  schematically illustrates a window and/or door manufacturing facility  12 . The facility  12  includes a front end system or terminal  14  where orders for windows and/or doors are entered and window assembly is scheduled. The front end system  14  provides orders  16  to an insulating glass unit (IG) production control terminal  18 . The orders  16  may include regular production orders  20 , rush orders  22 , and remake orders  24 . The rush orders  22  are orders that are prioritized, usually due to a customer demand. The remake orders  24  are entered when an IG  25 , a component of an IG, or a finished window or door  58  is damaged. In the exemplary embodiment, remake orders are provided directly to the central control workstation  18  by an electronic communication  19  from a glazing line or a window component processing station ( FIG. 2 ). The regular production orders  20  are orders that have not been tagged as a rush order or a re-make order.  
      The production control terminal  18  receives the orders  16  as input and creates a sequence of runs of insulating glass units to be produced at an insulating glass unit (IG) department  26 . In the illustrated embodiment, the IG department includes several insulating glass component processing machines or stations that construct IG components and assemble the IG components to create IGs. In the illustrated embodiment, the IG component processing stations include a glass cutting station  28 , a spacer frame production station  30 , a muntin bar production station  32 , a muntin bar assembly station  34 , a glass washing station  36 , an IG assembly station  38 , an oven  40 , a gas fill station  42 , and a patching station  44 . Glass lites  46 , spacer frames  48 , and muntin bars  50  are constructed at the glass cutting station  28 , the spacer frame production station  30 , and the muntin bar production station respectively. The glass lites, spacer frames, and muntin bar grids  50  are assembled to form IGs at the IG assembly station  38 . The IGs are fed through the oven/press  40 , which presses the IG to a predetermined thickness and heats the adhesive/sealant that secures the lites to the spacer frame. The IGs are then filled with an inert gas at the gas fill station  42  and patched at the patching station  44 . An IG department supervisor  45  is responsible for managing each of the IG component processing stations to ensure that demands for IGs by a glazing department  60  are met.  
      To simplify the disclosure of this inventive method and apparatus, the term glazing is to be interpreted as installing a glass lite or IG in any window or door component and the term sash is to be interpreted as any window or door component that surrounds a glass lite.  
      Once patched, the finished IGs are placed on carts  54  in a staging area  56 . The carts  54  in the staging area  56  form a visual kanban system  55 , providing production personnel with a visual signaling system by monitoring the number of carts in the staging area assigned to an assembly line in a glazing department  60 . More specifically, the IGs are taken from the carts  54  and are assembled with window sash and frames or doors in the glazing department  60  to construct completed windows and/or doors  58 . Assembly of an IG to a window or door sash and/or a frame is broadly referred to herein as glazing. The glazing department  60  includes several discrete glazing lines  62 .  
       FIG. 2  illustrates a window and/or door manufacturing facility  12  equipped with a system  64  for controlling production run sequences of insulating glass units. In the embodiment illustrated by  FIG. 2 , the production control terminal  18  receives orders electronically as indicated by arrow  66  from the front end system  14 . The control terminal  18  electronically sends and receives information to and from the glass component processing machines as indicated by arrow  68 . The front end system  14  and the control terminal  18  receive demand information electronically from the glazing lines as indicated by arrows  70 ,  72  respectively. This information includes a number of runs  74  in a queue  76  for each glazing line. The control terminal  18  also receives remake requirement information from the glazing lines as indicated by arrow  78 . Additional remake information may be provided from one or more of the stations in the IG department.  
      In the exemplary embodiment, the production control terminal  18  is a controller or ancillary computer including a programmable device in communication with a programmable device  80  located at each window component processing station and a programmable device  82  located at the plurality of glazing lines. In the exemplary embodiment, programmable devices  80  are electrically coupled to controllers of window component processing stations that include compatible machine controllers. This allows the sequence of these window processing stations to be altered automatically. Compatible machines automatically run the next production run in the sequence, if configured for Auto Sequencing. Such window component processing stations include the glass cutting station  28 , the spacer frame production station  30 , the muntin bar production station  32 , and the oven  40 , in the exemplary embodiment. Non-compatible machines utilize the satellite programmable devices  80  to alert the operator of the new production run sequence. Such stations may include a muntin bar assembly station  34 , the glass washing station  36 , an IG assembly station  38 , a gas fill station  42 , and a patching station  44 .  
      Referring to  FIGS. 3-5 , the status of the runs of IGs, the status of the insulating glass component processing machines, and the queue of insulating glass units to be assembled at each glazing line can be viewed at the production control terminal  18  or workstation. The screen illustrated by  FIG. 3  provides the IG supervisor with the status of complete IG production runs, the status of runs of IG components, and the status of completed IG runs in queue at the glazing lines. Column  400  provides the IG supervisor with the overall status of IG production runs. Column  402  provides the IG supervisor with the status of runs of muntin bars that correspond to each overall IG production run. Column  404  provides the IG supervisor with the status of runs of glass lites that correspond to each overall IG production run. Column  406  provides the IG supervisor with the status of runs of spacer frames that correspond to each overall IG production run. Column  408  provides the IG supervisor with the status of the IG runs of at the gas fill and patching station. Column  410  provides the IG supervisor with the glazing line number or description and the status of each completed IG production run at the identified glazing line.  
      The screen of  FIG. 4  provides the IG supervisor with the status of the completed IG runs in the glazing queue of each glazing line. On the screen illustrated by  FIG. 4 , columns  412 ,  414 ,  416 ,  418  provide the status of each run  420  of assembled IGs in the queues  422  of glazing lines  1 ,  2 ,  3 , and  4  respectively. The stiphing and cross-hatching of  FIG. 4  corresponds to the legend shown in  FIG. 3 .  
      The screen illustrated by  FIG. 5  provides the IG supervisor with the status of each production run  424  in the production run queue for each window component processing station. Column  428  provides the status of the muntin runs. Column  430  provides the status of the glass cutting runs. Column  432  provides the status of the spacer frame runs. Column  434  provides the status of the IGs at the gas fill and patch station.  
      The IG supervisor alters the sequence of runs based on one of the status of the runs, the status of one or more of the glass processing machines, and the queue of insulating glass units at the glazing line at the production control terminal. In the exemplary embodiment, the following manufacturing variables can all be monitored at the production control terminal  18 : 
          a) The status of sequenced regular, rush or remake production runs.     b) The status of sequenced muntin production runs and machine status at the muntin bar production Station  32 .     c) The status of sequenced glass production runs and machine status.     d) The status of sequenced spacer production runs and machine status.     e) The status of sequenced IG patch production runs.     f) The status of production runs in each glazing line queue.     g) Electronic requests to prioritize specific regular, rush or remake production runs.        

      Referring to the flow chart of  FIG. 6 , in the exemplary embodiment production run sequences are downloaded  86  from the terminal  14  to the control terminal  18 . Software running on the control terminal  18  determines  88  whether the runs received from the customer terminal  14  are larger than a user defined Run Size Parameter. If the number of IG units per production run surpass the number of IG units specified in the Production Run Size Parameter, the method automatically divides or segments  90  the runs into segments based on the size parameter setting. In the exemplary embodiment, the Production Run Size Parameter is entered by a user via a setup menu. Some customers create one or more very large daily production runs. For those customers, the system automatically segments large runs from the terminal  14  into a number of smaller runs, identifying each as some subset of the whole. Small production runs, typically matching the IG cart size, provide the flexibility required to properly level-load the glazing lines.  
      The IG supervisor may view  92  the IG Department Queue at the Central Workstation  18  (see  FIG. 3 ). This view provides the supervisor with an accurate snapshot of the status of all scheduled IG production runs via color codes (These codes are designated by cross-hatching and stiphing different patterns in the Figures). The supervisor can view the production run status  94  of each of the machines, the overall production run status and requests to prioritize a particular run  96  from satellite devices  80 ,  82 , and low queue conditions  98  from the glazing lines. A low queue condition at a glazing line may be automatically detected or entered through a satellite device by a glazing line worker. In the exemplary embodiment, the supervisor uses the information on the display to determine  100  whether the current production sequence maintains an efficient, uninterrupted production flow through the IG Department. If the current production sequence would not result in an efficient, uninterrupted production flow through the IG Department, the IG supervisor changes  102  the production control sequence at the control workstation  18 . In an alternate embodiment, the determination  100  of whether action needs to be taken and the run sequence changed  102  is performed by the software in the control terminal  18 . Each status or sequence changed at the central control terminal  18  is updated  104  automatically and provided  106  to all of IG component processing stations and the glazing lines by compatible machine software and/or the satellite programmable devices  80 ,  82 .  
      In the exemplary embodiment, a change of the production run sequence at the central workstation, immediately changes the corresponding sequences in a database maintained at the workstation  18  and display of compatible machine controllers and satellite programmable devices. Compatible machines automatically run  110  the next production run in the sequence, if configured for auto sequencing. Non-compatible machines utilize satellite programmable devices to alert the operator of the new production run sequence.  
      In the exemplary embodiment, required labels and reports are automatically printed  112  for each production run using a compatible printer. A parameter in the setup menu determines how far in advance to print labels and reports for each production run. The IG supervisor may manually print selected reports via a user-friendly menu. The labels and reports will accompany the IG through the manufacturing process. In the exemplary embodiment, an operator may use the graphical display to print and/or display  114  labels, reports, and/or low queue condition statistics.  
      A number of factors dictate whether the IG supervisor (or the computer program loaded on the control terminal  18 ) needs to change the production run sequence. Examples include ease of production, delivery priority, component availability and glazing line requirements. Based on these factors, the IG supervisor uses a graphical “drag and drop” function on the screen of the control terminal  18  to change the production run sequence. In the exemplary embodiment, the system will not allow the IG supervisor to change the sequence of any completed or partially completed production runs. A partially completed production run has either been started at the machine or is reserved using a Production Run Look-Ahead Parameter. This parameter reserves a specific number of the next available production runs for glass optimization purposes or to give the IG supervisor sufficient time to print and deliver labels and reports to the production floor. The Production Run Look-Ahead Parameter is entered via a setup menu.  
      In the exemplary embodiment, the system may allow the IG supervisor to display the glazing line queue (see  FIG. 4 ). The supervisor uses this display to monitor the level-loading of each glazing line and changes the run sequence as needed to prevent low queue conditions at a given glazing line. In one embodiment, the system includes a glazing line monitoring system. In this embodiment, the system automatically monitors each glazing line queue  422  for a “low queue condition.” This condition is met when the production runs  104  waiting to be glazed fall below a parameter set for each glazing line  62  in the setup menu. In the exemplary embodiment, the low queue condition is automatically detected by identifying runs of assembled insulating glass units that are delivered to each glazing line and identifying runs of assembled insulating glass units that are assembled to windows, or otherwise processed at each glazing line. In the exemplary embodiment, this identifying of runs of IGs that enter and exit the glazing lines is performed by scanning an identification label.  
      If the “low queue condition” is met, the system automatically highlights the next available production run for that glazing line in red at the central workstation  18 . This highlighting alerts the IG supervisor that he should change the sequence to prevent shutting down the glazing line.  
      In one embodiment, glazing line personnel may also use satellite programmable devices  82  located at each glazing line to force a “low queue condition”. This feature allows the glazing line personnel to request the next available production run for that glazing line from the IG Department at the terminal  18 . Glazing line personnel may also use satellite programmable devices to prioritize specific regular, rush or remake production runs. The request alerts the IG supervisor by highlighting the corresponding production run on the display of the central workstation  18 .  
      In the exemplary embodiment, the invention allows the IG supervisor to react to manufacturing variables by modifying the sequence of the production runs using a graphical drag and drop function. The software uses the input from the drag and drop function to create a new or altered production run sequence. Once the software has completed creating the new production run sequence, the system automatically performs the following tasks:  
      a) Changes the sequence of the production runs in the central workstation  18  database and updates the display (see  FIGS. 3 and 4 ).  
      b) Changes the sequence of the production runs in each manufacturing machine with a compatible database and updates the display (see  FIG. 5 ).  
      c) Changes the sequence of the production runs in the database of each satellite programmable device adjacent to non-compatible machines or manual production areas and updates the display (see  FIG. 5 ).  
      d) Changes the sequence of the production runs in the database of each satellite programmable device at the glazing lines (see  FIG. 4 ).  
      e) Prints the appropriate production paperwork and labels to accompany the corresponding IG.  
      The system includes three software tools that help manage each glazing line queue. The first tool provides a parameter in the setup menu to dictate the minimum number of production runs staged for each glazing line. The system uses this parameter to automatically alert the IG supervisor of a “low queue condition” by highlighting the next available production run for that glazing line in red when the number of production runs in queue falls below the set minimum number. The IG supervisor will then make the decision to change the priority of that production run.  
      The second tool provides statistics describing the number of “low queue conditions” for each glazing line over time. This provides the IG supervisor with information to increase or reduce the size of the queue limit for each glazing line These tools help the IG supervisor optimize the size of the glazing line queues to achieve the highest throughput.  
      The third tool allows glazing line personnel to use a satellite programmable device  82  to force a “low queue condition” or to prioritize a specific regular, rush or remake production run for a particular glazing line. The request alerts the IG supervisor by highlighting the corresponding production run on the display of the central workstation.  
      The disclosed system provides the IG supervisor with real-time, accurate and simple tools to monitor manufacturing variables and control production run sequences. The supervisor will easily accomplish existing tasks in a fraction of the time, using accurate real-time data. Production run sequences will be set in plenty of time to continue standard manufacturing procedures without any loss of production efficiency.  
      One component of the disclosed system is a glass optimization module for increasing the yield of glass cutting runs during window or door manufacture, or other manufacture requiring glass lites. An exemplary glass optimization module or program automatically recognizes and optimizes Low Yield Sheets by adding glass lites from other production batches as well as lites entered or selected at the cutting station  28 . The exemplary glass optimization module also automatically creates, tracks, selects and re-cuts remnant sheets of glass if the process is unable to add sufficient lites to eliminate Low Yield Sheets from a production batch.  
      The  FIG. 7  cutting station  28  includes a controller  212  that provides the cutting station operator an option of easily selecting filler lite sizes that can be automatically inserted into each production batch. The controller is coupled to a display or breakout monitor  214  that graphically alerts the cutting table operator(s) which cart and slot to place each lite as it is cut. The controller  212  and breakout monitor  214  also graphically alert the cutting table operator(s) where to place or remove remnant sheets for subsequent processing. The controller and breakout monitor also graphically alert the cutting table operator(s) which temporary cart slot to place or remove lites for subsequent processing.  
      In addition, the system tracks and reports yield, throughput and filler lite information in real-time to the cutting table display or monitor  214  as well as other computers by means of a network  216  which allows the controller  212  to communicate with other computers in the manufacturing facility, including the central control terminal  18 . These other computers include computer-controlled manufacturing devices at other workstations and computer software for controlling the entire manufacturing process.  
       FIG. 7  depicts representative apparatus for optimizing the fabrication of products that include lites cut from the glass sheets. The cutting station  28  including a moveable cutting head  220  supported for movement with respect to a glass sheet  222  ( FIG. 9 ) positioned on a cutting table  224  with respect to the cutting head  220  from which glass lites are cut. The same controller  212  that updates the display or monitor  214  is also responsible for controlling the movement with respect to the cutting table of the cutting head  220 .  
       FIG. 9  shows a representative sheet  222  having a number of lites  230 - 233  scheduled to be cut from specified locations on the sheet  222 . Typical dimensions (prior to cutting) for a sheet such as the sheet  222  shown in  FIG. 9  are 72 inches by 84 inches. Other standard sizes are 96″ by 130″ and 48″ by 60″.  
      The sheet  222  is removed by an operator from one of two racks  240 ,  241  ( FIG. 7 ) positioned in relation to the cutting table  224 . The sheet is placed on its edge at the side or at the end of a free fall table  242 . The table  242  has a relatively smooth and soft top surface onto which the glass sheet falls. From its position on the table the sheet is automatically transferred to the cutting table  224 . While on the cutting table  224  the sheet  222  is cut by the cutting head and then moved to a break out table  244 . At the break out table  244  an operator breaks out the lites from the glass sheet  222 .  
      As seen in  FIG. 7 , a number of carts  250 - 253  are positioned with respect to the cutting station  28  for storing lites as they are cut from a glass sheet  222  by the cutting head  220 . The controller  212  or another ancillary computer includes software running on a processor, which performs a number of tasks used by the system for making the glass cutting process more efficient. The controller lists a number of batches wherein each batch requires a specified number and type of glass lites for use in fabricating products in an associated job. The controller  212  (or ancillary computer) and breakout monitor  214  displays a pattern of lites to be cut from a first set of glass sheets to fulfill the lite requirements for one batch and during cutting prompts the operator to place the lites for that job into a single one of the four carts  250 - 253 .  
      The controller  212  or ancillary computer is capable of recognizing and adjusting to under utilized glass sheets. In accordance with one exemplary embodiment of the invention, under utilized glass sheet is any sheet where less than 70% of the sheet has lites allocated for a given job. The sheet  222  depicted in  FIG. 9  is an underutilized glass sheet having free space  260  with no lites designated to be cut for the batch that the sheet  222  is associated with. The four lites  230  that have been designated for a particular batch have been labeled with the designation “P” to indicate that they are associated with a particular production batch. These four lites  230 - 233  take up much less than the 70% cutoff.  
      As explained more fully below, the controller  212  or ancillary computer responds to recognition of such an underutilized sheet by laying out a pattern of lites to be cut to fulfill other lite requirements, possibly the other requirements one or more additional batches in a queue of such batches. The controller utilizes at least some of the free space  260  on the underutilized glass sheets of a first batch by designating usage of the free space  260  for other batches. The controller  212  or ancillary computer then completes the designated lites for those other or subsequent batches by laying out other glass sheets from which to cut other lites in that subsequent batch(es). This process, of course, takes into account the lites that have already been designated from the underutilized sheet or sheets of the previous batch or batches.  
      Operation of the Cutting Station  28   
      The software running on the controller or ancillary computer of the cutting station begins heuristically optimizing a next production batch in a queue of such batches by identifying a Low Yield Sheet if it exists. The controller or ancillary computer automatically calculates how to fill the sheet according to a list of priorities exemplified by the flowchart  310  in  FIGS. 16A and 16B . To help illustrate the process of  FIGS. 16A and 16B , in  FIGS. 9-15  the glass lites are labeled with designators depending on where in the list of priorities these lites are identified for inclusion onto a Low Yield Sheet.  
      The highest priority is a regular production batch lite P. A next highest priority is a local remake or MDI lite L. Three such lites  31  are depicted in  FIG. 4 . An MDI lite is typically made in response to a request due to breakage or a prior knowledge of a need by the cutting station operator. MDI lite information is entered by the operator at controller  212  using a keypad. A local remake is typically required because a lite is broken at the cutting table. Local remake information is entered by the operator using pushbuttons to highlight the lite that needs to be replaced on the breakout monitor or on the controller display.  
      A next highest priority lite inserted into the Low Yield Sheet is a production run look ahead lite LA. Two such lites  232  are depicted in  FIG. 11 . A typical manufacturing sequence of batches will have need for lites from the same type of glass in multiple batches. The system recognizes this need by inserting lites for subsequent batches on a Low Yield Sheet. These are called look ahead lites LA because the system “looks ahead” to subsequent jobs for lites to add to a Low Yield Sheet. As the operator breaks out the lites from a sheet the viewing monitor  214  tells the operator where he or she should put that look ahead lite. This is typically in the form of a cart slot number at the cutting station.  
      The next priority lite added to a Low Yield Sheet is a filler lite F. Filler lites are certain sizes and glass types that are commonly used in production. The system adds filler lites to Low Yield Sheets to increase yield. They are stored in close proximity to the cutting table. The number of filler lites needed is noted on the display. (See  FIG. 16 ) As the number of filler lites that have been cut increases, the corresponding number of filler lites that are needed decreases and the video display will be updated until the desired number of filler lites has been cut. When a production batch calls for a lite with the size and glass type of a filler lite, an appropriate filler lite can be quickly retrieved from the storage area. Although the depictions of  FIGS. 9-15  suggest that the controller places lites of a similar nature together on the glass sheet, the controller may rearrange the lites on a pattern to increase yield and may for example intersperse lites of different types next each other on the glass sheet.  
      The next priority added to a Low Yield Sheet is a temporary lite T. A temporary lite is designated as a lite to be stored in a temporary cart until a cart for it&#39;s production batch has been placed at the cutting table in the positions illustrated in  FIG. 7  by carts  250 ,  251 ,  252 , or  253 .  
      The next priority added to a Low Yield Sheet is a remnant R. A remnant is designated as the remaining area of the large stock glass sheet that can be stored and used later in the optimization process. The invention will instruct the cutting table if and how to cut the remnant for easier storage and store the position and size information of the remnant for subsequent optimization.  
      During the glass optimization process  310  (which takes place prior to cutting) depicted in the flow chart of  FIGS. 16A and 16B , the controller optimizes glass usage to reduce waste during glass cutting utilizing the sequence of priorities. The invention may also heuristically change the sequence of priorities based on input gathered via a computer network from other machines or programmable devices.  
      The cutting table operator presses  312  a function key on the controller. The controller responds by displaying  314  a graphical display  270  similar to  FIG. 8 . Listed on the display  270  is a Production Run Look-Ahead Parameter  272 . This parameter corresponds to how many production batches the controller will look-ahead for lites to increase the yield on Low Yield Sheets. The yield (as a percentage) that the controller uses to determine a Low Yield Sheet is entered during the initial setup of the invention. Each production run typically corresponds to one cart. Therefore, if the Production Run Look-Ahead parameter displays the number ‘ 3 ’, the operator knows to place  316  three carts  250 ,  251 ,  252  around the cutting table.  
      The display  270  ( FIG. 8 ) also includes a Temporary Cart Look-Ahead Parameter  274 . If a number other than  0  is displayed, the operator places  318  a temporary cart or carts (cart  253  for example) at the cutting table. The displayed parameter indicates the number of additional production runs (in addition to the production run look ahead) to be checked with the look-ahead function. Assuming the temporary cart look ahead is other than zero, the Breakout Monitor will display which slot in the temporary cart the operator should place the lites identified from those production batches. In a typical application there is only one temporary cart for storing lites from multiple additional batches. When those additional batches are cut, the operator is prompted to move an already cut lite from its slot in the temporary cart and moved to its appropriate (and now in place) production run cart location or slot.  
      The operator views the Filler Lites Needed table  276  and enters the desired number of filler lites. Whenever possible, the invention adds the sizes of filler requested to Low Yield Sheet until the requested amount of filler lites is satisfied.  
      The operator views the Auto Sequencing Parameter. If “off”, the operator cannot change the order of the production batches in the queue. The order of the production batches will be determined by external software. If “on”, the operator may rearrange  322  the order of any production batches not started. Color coding of the display of  FIG. 2  indicates which production batches in a list  280  are not started.  
      The operator then presses  324  the cycle start button. The cutting table will begin the next production run in the queue. The invention automatically identifies Low Yield Sheets and will calculate how to get the best yield. The sequence of steps  330  depicted in  FIG. 16B  inform the operator which type of sheet to drop on the cutting table. The invention will follow a user-defined sequence of priorities to determine how to increase the yield by adding lites to the Low Yield Sheet from different sources. The invention adds lites from MDI (manual data input), local remake entry, future production runs and standard sizes (filler lites). The invention may also heuristically change the sequence of priorities based on input gathered via a computer network from other machines or programmable devices. If any Low Yield Sheets remain and the Remnant Management Parameter is “on”, the invention will determine if the lites on the low yield sheet can more efficiently fit on a stored remnant sheet in a manner that eliminates the low yield condition. If so, the controller and breakout monitor alert the operator to load the corresponding stored remnant sheet from a remnant storage and retrieval system  45  having a cart for storing remnant sheets. The size and configuration of the Remnant Sheet Queue will be entered during the initial setup of the invention.  
      After the cutting table scores the sheet and it remains a Low Yield Sheets and the Remnant Management Parameter is “on” and there is room to store another remnant sheet on the remnant sheet cart, the system scores the largest rectangle possible in the unused area of the Low Yield Pattern. Via the breakout monitor, the system alerts the operator to transfer the remnant sheet to a manual, semi-automatic or automatic remnant storage and retrieval system  245 . The breakout monitor also indicates which cart and slot (standard or temporary cart) to place each lite via text and color coding.  
      The operator presses another function key at the cutting table controller to return to the previous screen.  
      The invention also tracks and reports yield, throughput and filler lite information in real-time to the cutting table display as well as other computers, computer-controlled devices and computer software.  
      Glass Demand System  
       FIGS. 17A and 17B  are flowcharts illustrating a process for managing and optimizing material flow and equipment utilization through a production process in accordance with the present invention. In particular,  FIGS. 17A and 17B  illustrate a glass demand system  500  that includes software  510  or other forms of computer readable media used to efficiently manage the material flow through the production process as illustrated in  FIG. 2 . In one example embodiment, the software  510  is loaded onto the computer network  216 , which would include all computer terminals related to the production operation, such as the central workstation  18 , satellite devices  80 , and programmable devices  82 .  
      In the first operation of the demand system  500  the software  510  is executed in the network  216  at  512 . The software  510  supports user created merge files  514  comprising regular production orders  20 , rush orders  22  and remake orders  24 . The merge files  514  are structured to conveniently allow for frequent changes and/or creation of new merge files for each day or shift of production as depicted at  516 . For each shift of production or during a production run, the software  510  converts the merge files into machine readable programs or machine schedules  524  at  520 . The machine schedules  524  are then placed into a demand pre-release folder  518  at  522 .  
      The demand pre-release folder  518  containing the machine schedules  524  are now readily accessible by a supervisor and/or operator via the software  510  at  526  linked to the computer network  216 . At this point  528 , the supervisor and/or operator can evaluate whether the machine schedules  524  are satisfactory or require modification. In one embodiment, the machine schedules  524  would be modified before the start of a shift, however, it would not depart from the spirit and scope of the claimed invention to enable the supervisor and/or operator to modify the machine schedules after a shift has started or during production run.  
      If the machine schedules  524  are not satisfactory the supervisor and/or operator will resequence or reassign (to alternate machines or kanbans) the machine schedules  524  to modified schedules  530  at  532 . Several factors in the production operation could render the machine schedules  524  unsatisfactory requiring resequencing or reassignment  532 . For example, changes in production orders  16 , including regular production orders  20  and/or rush orders  22  and/or remake orders  24  could influence such required changes, low queue  76  signals or indications in the IG runs  74  for particular glazing lines  62  could provoke a change, or machine breakdown in the IG department  26  or glazing department  60 . The resequencing or reassignment  532  by the supervisor or operator can be achieved at any network  216  terminal by a similar “drag and drop” application in the software  510 , as previously discussed. The resequencing or reassignment  532  may change the order or amount of materials being processed at any individual line or machine within the IG department  26 . This could include for example, changes to the assembly operation  38 , cutting station  28 , or oven  40  in the IG department  26 . Similarly, changes may occur at the glazing lines  62  as a result of the resequencing or reassignment process  532 .  
      The modified schedules  530  or satisfactory machine schedules  524  mature into final schedules  534  and are released to the machines, equipment, IG lines located within the IG department  26  or computer workstations on computer network  216  at  536 . The software  510  then calculates operations data  538  based on the final schedules  534  and the sequences are released to the equipment and assembly lines. The software  510  further uses the calculated operations data  538  to perform several different computations relating to the production operations shown in  FIG. 2 , including: 
          a) the machine production rate (MPR) for various equipment, for example: the glass cutting station(s)  28  (lites per unit of time); spacer frame production station  30 ; muntin machine(s)  32  (grids per unit time); and assembly  38  (IG units per unit of time);     b) the machine completion time (MCT) for each schedule (hours and minutes from the current time) for cutting stations  28 , spacer frame production station  30 , muntin machines  32 , and assembly operations  28 ;     c) the machine start time (MST) for each schedule (hours and minutes from the current time) for cutting stations  28 , spacer frame production station  30 , muntin machines  32 , and assembly operations  28  (the machine start time (MST) for each spacer frame production station  30  schedule (hours and minutes from the current time) is based on estimates of when the glass and muntin will be available for the spacer frame production station  30 );     d) the kanban arrival time (KAT) for each schedule in a kanban  55  (hours and minutes from the current time); and     e) the kanban consumption rate (KCR) the number of IG units removed from the carts  54  in the kanban  55  staging area  56  (IG units used per unit of time).        

      The calculated operations data  538  relating to the various operations described above, are monitored at  542  to help prevent future Out-of-Glass conditions  544  that could arise. For example, if the kanban  55  staging area  56  has only one hour of glass left in a particular glazing line  62  based on the KCR and the next cart  54  with IG units is scheduled to arrived at the kanban  55  in two hours an Out-of-Glass condition  544  is detected and the software  510  will issue an Out-of-Glass Alert  550 , indicating and notifying production personnel when the kanban staging area  56  will run out of glass. In one embodiment, the software  510  will calculate which schedule or schedules  524  will be advanced  552  in the production sequence upon issuing the alert  550 . In another embodiment, as shown at  554 , the software  510  in anticipation of the alert  550  will calculate which schedule or schedules  524  will be advanced in the production sequence and may be automatically advanced at  556  by the software  510 . In yet another embodiment, the operator or supervisor manually elects at  558  which schedule or schedules  524  will be advanced in the production sequence as a result of the calculation  552  provided by the software  510  or based on the supervisor/operator&#39;s own independent decision or instruction by another person or source.  
      The software  510  additionally supports a printing operation  600  that provides a number of reports that are used by both production personnel and management. The reports assist in providing real-time information  539  to the production operations data  538  via manual and automatic scanning of material throughput (discussed further below) during the manufacturing process.  
      The print operation  600  produces an IG Cart Report  610  for schedules  524  having at least one cut glass lite. The IG Cart Report is printed typically near the cutting glass station  28  when the schedule starts to assist production personnel in tracking the schedules  528  through the production operation. The print operation  600  also produces an IG Cart Office Report  620  for schedules  528  with all purchased glass. The IG Cart Office Report  620  is typically printed in a manager&#39;s office  625  when the schedule is released to the cutting glass station  28  for assisting management personnel in tracking the schedules  528  through the production operation. The print operation  600  also produces a Purchased Glass Report  630  for schedules  528  with at least one purchased glass lite. The Purchased Glass Report  630  is typically printed near the cutting glass station  28  when the schedule  528  starts. The Purchased Glass Report  630  assists production personnel in tracking the glass used by the various schedules  528 . The print operation  600  also provides a Purchased Glass Office Report  640  for schedules  528  with all purchased glass. The Purchased Glass Office Report  640  is typically printed in the manager&#39;s office  625  when the schedule is released to the cutting glass station  28  for assisting management personnel in tracking the schedules  528  through the production operation. The print operation  600  also provides a Production Muntin Report  650 . The Production Muntin Report  650  typically prints near the muntin bar station  32 . The Production Muntin Report  650  assists production and management personnel in tracking the raw materials used in forming the muntin bars. The print operation  600  also provides a Production IG Report  660 . The Production IG Report  660  typically prints near the spacer frame production station  30 . The Production IG Report  660  assists production and management personnel in tracking the raw materials being used to make the IG assemblies in the spacer frame production stations  30 . The print operation  600  also provides a Glass Label Report  670  consisting of one or more individual glass labels. The Glass Label Report  670  typically prints near the spacer frame production station  30 . The Glass Label Report  670  assists production and management personnel in tracking the IG assemblies as they are routed through the production operation.  
      The above reports can also be used to assist in the accuracy of the calculated operations data  538  by providing real-time data. For example, a patch operator assigned to the patch station  44  will scan data (using either a stationary or portable scanner device) such as a bar code relating to the IG assemblies on the Production IG Report  660  or glass label  670  as it leaves the patching station  44 . The content associated with the bar code on the Production IG Report  660  or glass label  670  is then automatically imported from the scanner to a computer on the network  216 , and used by the software  510  to update the calculated operation data  538 . The scanned Production IG Report and associated cart  54  is then tracked and rescanned as it enters the kanban  55  staging area  56  in the assigned glazing line  62 , thereagain updating the calculated operation data  538 . The software  510  and calculated operation data  538  accounts for all of the IG units listed in the cart  54  report and the operator provides further reassurance during the report or label scanning operation. A glazing line  62  operator will then scan the Production IG Report  660  or glass label  670  as it leaves the kanban  55  staging area  56 , automatically initiating an update to the calculated operations data  538 .  
      The MCT will be visually displayed on any terminal associated with the computer network  216  and displays the estimated machine completion time for each machine schedule  528  in the IG department  25  and glazing department  60 . For example, the operator at a particular machine may select, for example a fourth schedule in the cutting glass station  28  in the list of schedules  528  for the cutting machine. The terminal would display the MCT in the fourth schedule in the example, showing 1 hour 20 minutes, indicating that the glass cutting for the forth schedule is calculated to be completed in 1 hour and 20 minutes. The calculated MCT can be altered to include or exclude scheduled production breaks, such as lunch, time between shifts, or breaks. The calculated MCT time excludes unscheduled machine downtime. The amount of time scheduled for production breaks could be altered in the software  510 .  
      The MST for the spacer frame production station  30  represents the earliest possible time it could be started based on components being supplied from the glass cutting station  28  and muntin bar station  32 . For example, if the MST for the spacer frame production station  30  indicates a time of 2 hours and 10 minutes at a network terminal  216 , this corresponds to glass and muntin components that are required will be completed in 2 hours and 10 minutes for that particular schedule.  
      The MPR monitors actual machine output, excluding delays that exceed an Anomaly Threshold (AT). For example, an AT is set at 10 minutes, and the cutting glass station  28  has been producing schedules  528  at an average rate of 400 lites per hour for the previous three hours. If a 30 minute lunch break were to subsequently occur, which exceeds the AT, the software  510  would average the lites produced per hour until lunch started and store the average as the MPR value. Monitoring would not commence again until after the lunch break and cutting resumed. A new MPR would not be stored until units ran for a prescribed period of time, for example, one hour without a breach of the AT.  
      The AT is a prescribed period that can be varied for each machine, staging area  56  such as the kanban area  55 , or line based particular needs. Any time below the AT is considered normal production delays and is averaged in the MPR. Any time above the AT is considered an irregularity and will be excluded from the MPR. The AT prevents lunches, breaks, and time between shifts from influencing the MPR time.  
      The MPR can further be calculated over a number of machines and assembly lines. For example, the MPR can be measured from the time a schedule  528  starts at the cutting glass station  28  until the cart  54  is scanned into the kanban  55  staging area  56 . In this example, the MPR captures glass cutting, spacer fabrication, glass washing, IG assembly, IG carting, IG patch, and IG fill.  
      Although an exemplary embodiment of the invention has been described with a degree of particularity, it is the intent that the invention includes all modifications and alterations from the disclosed design falling within the spirit or scope of the appended claims.