Abstract:
A computer-implemented method for evaluating tool performance is described which includes maintaining tool history data in an electronic memory, updating the tool history data with tool servicing data, determining from the tool history and servicing data a predicted tool remaining useful life, and displaying the predicted useful life on a computer output device. Average tool data is compared to tool benchmark data to determine tool efficiency. Tool servicing, performance and efficiency data are maintained in a spreadsheet format. Data entered into one spreadsheet is used to update a plurality of spreadsheets. The spreadsheet format allows manufacturers to keep abreast of tool performance over time and in a plurality of locations and to anticipate tool rebuild and replacement requirements.

Description:
COPYRIGHT NOTICE 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     BACKGROUND OF THE INVENTION 
     This invention relates generally to tool maintenance and performance and, more particularly, to methods and apparatus for evaluating tool performance and useful life. 
     Manufacturers typically track tool and equipment condition and useful life, to maintain tools in good operating condition and to repair or replace the tools without disrupting production schedules. Service and repair records are a primary information source from which to track tool condition. Service and repair records, however, provide only a limited picture, in that they typically describe an individual tool or piece of equipment at a single instant, i.e. the time of servicing. For example, punch and die equipment service records typically state amounts ground from, and heights remaining on, serviced punches and dies. Unless such information is placed in perspective, it is difficult to draw meaningful conclusions as to tool performance. It also is particularly difficult to analyze performance of tools and equipment in use over extended time periods in a plurality of manufacturing locations. 
     It would therefore be desirable to provide a method for tracking and analyzing the condition and useful life of tools and equipment over time and in a plurality of locations. It also would be desirable to provide a method for forecasting and forewarning as to upcoming needs for tool re-building or replacement. 
     BRIEF SUMMARY OF THE INVENTION 
     In an exemplary embodiment, a computer-implemented method for evaluating tool performance includes maintaining tool history data in an electronic memory, updating the tool history data with tool servicing data, determining from the tool history and servicing data a predicted tool remaining useful life, and displaying the predicted useful life on a computer output device. Average tool data is compared to tool benchmark data to determine tool efficiency. Tool servicing, performance and efficiency data are maintained in a spreadsheet format. Data entered into one spreadsheet is used to update a plurality of spreadsheets. The spreadsheet format allows manufacturers to keep abreast of tool performance over time and in a plurality of locations and to anticipate tool rebuild and replacement requirements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a New Die Data Entry Sheet spreadsheet; 
     FIG. 2 is a Die Life Data Sheet spreadsheet; 
     FIG. 3 is a Die Service Record spreadsheet; 
     FIG. 4 is a Weeks Remaining Sheet spreadsheet; 
     FIG. 5 is a Die Performance Sheet spreadsheet calculated with long-term data; 
     FIG. 6 is a Die Performance Sheet spreadsheet calculated with short-term data; and 
     FIG. 7 is a Die Summary Sheet spreadsheet. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A method for evaluating tool performance is implemented by a die evaluation software program installed on a computer such as a Pentium II® running Windows 95® and having user interface (not shown), for example, a keyboard, a cathode ray tube (CRT) monitor and a mouse. Alternatively, the program could be adapted to run under LINUX or Mac OS® or other operating system. In one embodiment the die evaluation program runs under a spreadsheet program having a macro creation feature, for example, Microsoft Excel version 7 running under Microsoft Office 95. The spreadsheet program is loaded onto the computer and the die evaluation program is loaded under the spreadsheet program and saved as an Excel application program. A user enters identifying and historical information pertaining to a die and associated punches onto spreadsheets (see FIGS. 1 through 6) displayable on the CRT and which are maintained in a computer database (not shown) over time. After the user has entered initial identifying and historic data for a particular die and punches, the user enters subsequent servicing data into the database for the die and punches at times when servicing is performed. 
     FIG. 1 illustrates a New Die Data Entry Sheet  10  for entering initial identifying and historical information for a die and punches into the computer. Each new die is assigned a die identification number  12  when entered into the computer. The user enters die-related information into New Die Data Entry Sheet  10  by filling in, for example, a plant location cell  14 , rotor and stator number cells  16 , a die manufacturer cell  18 , a die dimension cell  20 , a service date cell  22  (i.e. date on which die was put into service), a tonnage cell  24 , a strip width and thickness cell  26 , a progression cell  28 , a total die weight cell  30 , an exit method cell  32 , a die serial number cell  34 , an amount punches enter die cell  36 , a number of rows in die cell  38 , and a die weekly line rate cell  40 . Automated information entry, such as automatic gauging, bar code scanning or OCR scanning of forms can replace some of this data entry for greater speed and accuracy, if desired. Station number cells  42  identify each punch and die station in the die to be tracked by the die evaluation program. New Die Data Entry Sheet  10  includes data for each punch in a punch and die station, for example, a punch description cell  44 , a punch height cell  46 , a cell  48  for stripper plate thickness minus any counter-bores, and a die height cell  50 . New Die Data Entry Sheet  10  also includes, for example, rotor/stator strike plate thickness cells  52 , a cell  54  to indicate whether 0.090-inch punch safety margins are desired, a cell  56  for laminations per stack, cells  58  and  60  for goal amounts respectively for punch and die grinds, a cell  62  for goal number of hits per grind, a cell  64  for goal number of hits per die set, and cells  66  for other historical information predating entry of the die into the die evaluation program. 
     When New Die Data Entry Sheet  10  has been completed, the user activates (for example, via mouse) a Create New Worksheets Macro Button  68 , to create additional spreadsheets (not shown in FIG. 1) for the newly entered die. One of the additional spreadsheets, a Die Summary Sheet (not shown in FIG.  1 ), can be displayed by activating a Return To Summary macro button  76 . The die evaluation program automatically transfers New Die Data Entry Sheet  10  information into corresponding cells in the additional spreadsheets. For example, FIG. 2 illustrates a Die Life Data Sheet  70  displaying some of the cell data originally entered by the user into New Die Data Entry Sheet  10 . Die Life Data Sheet  70  automatically includes die identification number  12 , plant location cell  14 , rotor and stator number cells  16 , die manufacturer cell  18 , die dimension cell  20 , service date cell  22  (i.e. date on which die was put into service), tonnage cell  24 , strip width and thickness cell  26 , progression cell  28 , total die weight cell  30 , exit method cell  32 , die serial number cell  34 , and amount punches enter die cell  36 . Die Life Data Sheet  70  displays data for each punch and die station in the newly entered die, for example, station number cells  42 , punch description or punch and die description cells  44 , punch height cells  46 , stripper plate thickness minus any counter-bores cells  48  and die height cells  50 . Die Life Data Sheet  70  also includes rotor/stator strike plate thickness cells  52  and cell  54  indicating whether 0.090-inch punch safety margins are desired. 
     The user inserts into Die Life Data Sheet  70  a standard height dimension for non-usable die life  72 . A cell  74 , to check for punch rebuild or repair, provides a warning message “NOW” (not shown) when 0.090-inch safety margin cell  54  has been activated and it is determined that a punch for a corresponding station has reached a value within 0.090 inches of bottoming out on a corresponding stripper plate. When 0.090-inch safety margin cell  54  has not been activated, check for punch rebuild or repair cell  74  provides a warning “LESS THAN 0.030!” (not shown) when it is determined that a punch for a corresponding station has reached a value within 0.030 inches of bottoming out on a corresponding stripper plate. If rotor/stator strike plate thickness cells  52  indicate that spring loaded interlock strike plate thickness for. a die has decreased to less than 0.125 inches, check for punch rebuild or repair cell  74  also provides a “NOW” warning (not shown). 
     Die Life Data Sheet  70  also is automatically updated with information entered by the user, for example, into a Die Service Record  80  as shown in FIG.  3 . Die Service Record  80  receives information cumulatively entered by the user to describe punch or die servicing or repair. When a die is serviced or repaired the user completes, for example, a cell  82  for current service date, a cell  84  for total number of hits on a just-completed press run, a cell  86  for amount ground from die during present servicing, a cell  88  for amount ground from punch during present servicing, a cell  90  for reason for servicing, a cell  92  for repair parts used, a cell  94  for person performing servicing, and a comments cell  96 . Die Service Record  80  displays other information automatically determined by the die evaluation program when servicing information is entered onto Die Service Record  80  for a particular die. For example, the program generates a histogram  98  of frequency for reason die was sent to repair. The program also determines, for example, hits since last grind  100 , whether die needs full grind  102 , total hits on die to date  104 , total amount ground from die to date  106 , remaining die height  108 , total amount ground from punch to date  110 , and remaining punch height  112 . Die Service Record  80  also displays short-term die accumulation data  114 , historical data from prior to Die Service Record  116 , and long-term die accumulation data  118  (a combination of short-term die accumulation data  114  with historical data from prior to Die Service Record  116 ). When, for example, Die Service Record  80  has been filled, the user can activate Reset Service Record macro button  124  to make room for entering additional servicing information and to update long-term die accumulation data cells  118 . 
     The die evaluation program uses information from Die Service Record  80  to update Die Life Data Sheet  70  (shown in FIG.  2 ). For example, Die Life. Data Sheet  70  cells for total amount ground from punch to date  110  and total amount ground from die to date  106  are automatically updated each time Die Service Record  80  is updated. Cells for remaining usable punch life  120  and remaining usable die life  122  also are determined from Die Service Record  80  data. Cell  120  for remaining usable punch life is linked to 0.090 safety margin cell  54  and will display values including safety margins if the user has activated cell  54 . Cell  122  for remaining usable die life is linked to cell  72  for standard height dimension for non-usable die life and will display values determined by the die evaluation program using cell  72  value. 
     The die evaluation program uses information in Die Service Record  80 , Die Life Data Sheet  70  and New Die Data Entry Sheet  10  (shown in FIG. 1) to determine a die useful life in terms of weeks remaining. For example, FIG. 4 illustrates a Weeks Remaining Sheet  128  including data determined from Die Service Record  80  and data transferred from New Die Data Entry Sheet  10  and Die Life Data Sheet  70 . Weeks Remaining Sheet  128  includes data for each punch and die station in the die identified by identification number  12 , for example, punch and die description  44 , punch life remaining  120 , and die life remaining  122 . The die evaluation program determines cells  132  for punch grinds remaining, cells  134  for die grinds remaining, cells  136  for cores or laminations remaining before re-punch, cells  138  for cores or laminations remaining before die life is exhausted, cells  140  for weeks remaining before re-punch, and cells  142  for weeks remaining before die life is exhausted. The die evaluation program makes the foregoing determinations based on values in cells  144  for average amount of punch grind, cells  146  for average amount of die grind, cells  148  for average number of hits per grind, and cells  150  for number of laminations. Weeks Remaining Sheet  128  displays a safety margin indicator  130  indicating whether safety margin cell  54  has been activated from Die Life Data Sheet  70  (shown in FIG.  2 ). Values in cells  144 ,  146 ,  148  and  150  are entered by the user. The program also determines values for cell  152  for average number of weeks remaining before re-punch, cell  154  for average number of weeks remaining before die life is exhausted, cell  156  for minimum number of weeks remaining before re-punch and cell  158  for minimum number of weeks remaining before die life is exhausted. Weeks Remaining Sheet  128  also displays New Die Data Entry Sheet  10  cells  38  for die number of rows and  40  for current weekly line rate. 
     FIG. 5 illustrates a Die Performance Sheet  170  including sections  212 ,  174 ,  176 ,  178  and  196  for die demographics, die measurements, benchmark data, performance results, and efficiency ratings. The user activates cell  210  to select whether information on Die Performance Sheet  170  is to be determined with short-term or long-term data maintained in Die Service Record  80 . FIG. 5 depicts Die Performance Sheet  170  with long-term data selected, and FIG. 6 depicts Die Performance Sheet  170  with short-term data selected. Section  212  includes cells for plant location  14 , date of most recent service  82  (from Die Service Record  80 ), and time period to date  172 . If the user selects short-term data via cell  210 , time period to date  172  is determined as a time period between earliest service date  82  shown on Die Service Record  80  and most recent service date  82 . If long-term data is selected, time period to date  172  is determined as a time period between date die was put into service  22  and most recent service date  82 . Die and punch measurements  174  over time period to date  172  are automatically entered into Die Performance Sheet  170  from Die Service Record  80  and include, for example, a total number of hits to date cell  214 . Benchmark data  176  include a cell  160  for goal hits per grind, a cell  162  for goal amount of die grind, a cell  164  for goal amount of punch grind, and a cell  166  for goal hits per die set. Benchmark data  176  values are included automatically from New Die Data Entry Sheet  10 , but the user can enter different benchmark values  176  onto Die Performance Sheet  170 . Performance results  178  are determined from, for example, Die Service Record  80  information. Performance results  178  include, for example, cells for total amount removed from die  180 , total amount ground from punch  182 , average number of hits per 0.001 die grind  184 , average number of hits per 0.001 punch grind  186 , average number of hits per die set  188 , average number of hits per grind  190 , average amount of die grind  192 , and average amount of punch grind  194 . 
     Cells  196  for efficiency ratings are determined by comparing performance results  178  to benchmark data  176 . Efficiency ratings include, for example, a ratio  198  of actual average hits per grind to goal hits per grind  160 , a ratio  200  of actual average number of hits per 0.001 die grind to benchmark data  176 , a ratio  202  of actual average number of hits per 0.001 punch grind to benchmark data  176 , a ratio  204  of actual average number of hits per die set to goal hits per die set  166 , a ratio  206  of actual average amount removed from die during routine service to benchmark data  176  (i.e. stock removal rate from die), and a ratio  208  of actual average amount removed from punch during routine service to benchmark data  176  (i.e. stock removal rate from punch). 
     Die Performance Sheet  170  summarizes and analyzes a plurality of data from, for example, New Die Data Entry Sheet  10  and Die Service Record  80  and thus provides insights into die performance relative to general industry-accepted benchmarks. For example, ratio  198  of average hits per grind to goal hits per grind  160  provides insight into whether a die is being ground prematurely based on industry norms, whether a die is being serviced correctly and at appropriate intervals, and whether punch or die washout is occurring. Ratio  200  of hits per 0.001 die grind to benchmark data  176  provides insight into die lower half consumption rate and whether die washout is occurring. Ratio  202  of hits per 0.001 punch grind to benchmark data  176  provides insight into die upper half (i.e. punch) consumption rate and whether punch washout is occurring. Ratio  204  of hits per die set to goal hits per die set  166  provides insight into how well a die is designed, built, maintained and suited to press capacity. Hits per die set ratio  204  is affected by, for example, poor die maintenance, punch press overload, improper grinding procedures and off-center punch press loading. Stock removal rate from die ratio  206  and stock removal rate from punch ratio  208  are factors providing insight into punch and die consumption rates and whether sharpening is inadequate or excessive. Stock removal rate from die ratio  206  is a ratio of (total number of hits to date  214  divided by total amount removed from die  180 ) to (goal hits per grind  160  divided by goal amount of die grind  162 ). Stock removal rate from punch ratio  208  is a ratio of (total number of hits to date  214  divided by total amount removed from punch  182 ) to (goal hits per grind  160  divided by goal amount of punch grind  164 ). 
     FIG. 7 illustrates a Die Summary Sheet  220 , which supplies, in summary form, cells for punch life  222  and die life  224  in terms of weeks remaining. Die Summary Sheet  220  includes, for example, a list  226  of dies at plant location  14  and is automatically updated when a Die Service Record  80  is updated. Die Summary Sheet  220  also includes cells  228 ,  230 ,  232  and  234  for checks for partial and full punch and die rebuild requirements. Cells  228 ,  230 ,  232  and  234  automatically determine need for and display a warning  236  for such rebuild requirement. The user can activate macro button  238  for a die identification number  12  in list  226  to view Die Service Record  80  corresponding to die identification number  12 . 
     The above-described method provides a range of useful information, from aspects of a particular servicing occasion to long-term tool performance and efficiency in a plurality of locations. The user thereby gains a broadened perspective on tool consumption and servicing that can serve to inform the user&#39;s selection of tools and suppliers. User access to tool information is enhanced by installing the die evaluation program for use over a computer network, for example, an intranet or internet. The tool data in spreadsheet format also is amenable to further analysis with available spreadsheet methods, for example, to uncover hidden costs associated with poor tool maintenance or operating procedures. 
     The above-described computer-implemented method is modifiable in a plurality of aspects and is applicable for tracking many items in addition to punch/die tooling. While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.