Abstract:
A method, system, and storage medium for facilitating a transport scheme in an automated material handling system environment are provided. The method includes detecting an occurrence of a trigger event while monitoring production operations in an automated material handling system environment, identifying a materials candidate to purge from a production line in response to the trigger event, production data captured relating to the materials candidate, and user-defined criteria for purging materials from the production line. The method also includes selecting a disposition plan for handling the materials candidate, generating a transport process job for the materials candidate for instructing the automated material handling system on executing the disposition plan, and transmitting the transport process job to the automated material handling system for execution.

Description:
BACKGROUND OF INVENTION 
   The present invention relates generally to materials management, and more particularly, to a method, system, and storage medium for facilitating a transport scheme in an automated material handling system environment. 
   In a production environment, there are quantities of materials that sit idle in local storage (e.g., stockers) until a production machine is ready to receive them. When there is a large amount of materials in a given production line, the local stockers can become filled to capacity and the production area becomes backed up. In order to free up space in the production environment, many of these materials are transported to a centralized storage location until they are needed. Automated material handling systems (AMHSs) provide some assistance in managing the transport of these materials within a production area. AMH systems generally consist of material handling equipment and a material control system. The material handling equipment manages the flow of materials, while the control system manages the flow of information relating to these materials. Where an automated material handling system (AMHS) is employed, these idle materials are often automatically transferred to central storage when a stocker is full, regardless of whether the materials will be needed by the production line soon. 
   This process can result in unnecessary transport, both to the central storage location and back to production, of the materials in cases where the production equipment requires these materials in a short period of time. As central storage may be located a significant distance away from the production area, additional costs are incurred in transporting these materials. These costs include the actual cost of transport (e.g., capital cost, storage fees, overhead, wear and tear, floor space, and support) and the costs of additional cycle time and reduced equipment utilization, since a process tool may sit idle waiting for work to arrive. 
   What is needed, therefore, is a way to intelligently determine and execute the transport requirements for materials in a production environment. 
   SUMMARY OF INVENTION 
   Exemplary embodiments of the invention include a method, system, and storage medium for facilitating a transport scheme in an automated material handling system environment. The method includes detecting an occurrence of a trigger event while monitoring production operations in an automated material handling system environment, identifying a materials candidate for purging from a production line in response to the trigger event, production data captured relating to the materials candidate, and user-defined criteria for purging materials from the production line. The method also includes selecting a disposition plan for handling the materials candidate, generating a transport process job for the materials candidate for instructing the automated material handling system on executing the disposition plan, and transmitting the transport process job to the automated material handling system for execution. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     Referring now to the drawings, wherein like elements are numbered alike in the several FIGURES: 
       FIG. 1  is a block diagram of a system upon which the purge tool may be implemented in exemplary embodiments; 
       FIG. 2  is a flowchart illustrating a process for implementing the purge tool in exemplary embodiments; 
       FIG. 3  is a user interface as seen by a production system individual for establishing and/or modifying criteria used by the purge tool in exemplary embodiments; and 
       FIG. 4  is computer screen window illustrating a sample transport process job created by the purge tool in exemplary embodiments. 
   

   DETAILED DESCRIPTION 
   The purge tool of the invention enables a production control manager or similar individual to establish customized guidelines for handling production materials assigned to a production line in a manufacturing environment. These guidelines can be changed over time as the needs of the manufacturing plant or enterprise change. The purge tool of the invention uses custom criteria to search materials in a production line for potential candidates for transport to storage, or alternatively, for scrapping purposes. Once a candidate has been identified, the purge tool creates a transport process job for the candidate materials and transmits the transport process job to the automated material handling system of the production environment for execution. 
   Referring now to  FIG. 1 , a system upon which the purge tool may be implemented will now be described. System  100  includes a production area  102  in communication with a server  104  via a network  106 . Production area  102  equipment is preferably SEMI-compliant. Also included in system  100  is a centralized stock location  108 . 
   Production area  102  includes two production bays  110  and  112  that, in turn, include two process tools  114  and  116 , respectively. Production bay  110  further includes work-in-process (WIP) materials  118  engaged in a process or procedure performed by tool  114 . Materials that are used in manufacturing may include substances, component parts, assemblies, and other items typically found in a manufacturing environment. WIP materials refer to those materials that are currently undergoing a machine process or en route between machines or production bays. Materials that are awaiting processing are stored in local storage (e.g., local stockers  122 – 126 ). An interbay transport device  121  enables WIP materials such as WIP materials  120  to be conveyed between production bays. 
   Production bays  110  and  112  each refer to a specific location and equipment device(s) within production area  102  whereby a specified manufacturing process is performed on production materials. Each of process tools  114  and  116 , as indicated above, perform one or more processes on WIP materials in accordance with a manufacturing plan. Interbay transport device  121  may be a mechanized ground vehicle such as an automated guided vehicle (AGV) or personal guided vehicle (PGV), or may be an overhead transport (OHT) device supported by a monorail  123  that transfers WIP materials between production bays  110  and  112 . 
   As indicated above, local stockers  122 – 126  refer to temporary storage devices used to retain materials that are awaiting processing in production area  102 . In a typical manufacturing environment, a transport vehicle  119  would retrieve WIP materials from a local stocker and transport the materials to the production bay for which the materials have been assigned. These process materials are assigned to various production bays, some of which materials may be ready for processing within minutes and others that may be waiting for hours or days. For example, the materials  128  stored in local stocker  122  may be assigned to a current job (e.g., next in line in processing), the materials  130  in local stocker  124  may be assigned to a short-term pending job (e.g., ready for processing within minutes or hours), and local stocker  132  may carry materials  132  that are assigned to a long-term pending job (e.g., hours or days). If the scheduled production cycle is interrupted for any period of time, this can result in local stockers filling up to their capacity and also backed-up of process materials and stockers within the production area. 
   Centralized stock location  108  refers to a storage facility that is remotely located from production area  102 . One utility of centralized stock location  108  is to store materials that have been transported from production area  102  to free up space and resources at the manufacturing plant. These materials are awaiting processing in production area  102  and are referred to as lots  128 . Centralized stock location  108  may be a storage facility operated by a warehouse entity that charges storage fees for its use or may be a facility operated by the enterprise executing the production processes described herein. 
   Server  104  executes a variety of business applications utilized by an enterprise for facilitating the production processes occurring in production area  102 . Server  104  may be a computer with a high-powered processor for handling the volume of production activities occurring in production area  102 . Further, while only a single production area  102  is shown, it will be understood that multiple production areas (e.g., manufacturing facilities) may be managed by server  104  in terms of implementing the purge tool of the invention. 
   Server  104  executes an automated material handling system control application (AMHS control application)  130  that manages the transport of materials within a production area. Control application  130  may be a material control system (MCS) application such as Murata&#39;s Automated Control System by Murata Machinery, Ltd.™ AMHS control application  130  receives operations and scheduling information for processing of materials on equipment in production area  104  via server  104 . This information can be obtained from any suitable manufacturing execution system software utilized by the production system enterprise. 
   Server  104  also executes parser  132 , which formats production data used by AMHS control application  130  so that it can be read and understood by the purge tool. The functions of parser  132  are described further herein. 
   Purge tool  134  is executed on server  104  and includes a monitor component  136 , AMHS interface  138 , and rules engine  140 . Monitor component  136  serves as a watchdog for production operations in area  102  and looks for any activated triggers as will be described further herein. AMHS interface  138  enables purge tool  134  to communicate with AMHS control application  130  for monitoring production operations, searching production data, and transmitting information as described further herein. AMHS interface  138  further enables a user to customize and modify purge criteria and triggers. Rules engine  140  comprises logic for processing triggers, purge criteria, and disposition rules. 
   Data repository  142  is in communication with server  104  and stores a variety of data used by AMHS control application  130  and purge tool  134 . Data repository  144  is logically addressable to server  104  for receiving requests for data and communicating search results to server  104 . One type of data stored in data repository  142  is production data  144 . Production data  144  refers to the specific information used by AMHS control application  130  to perform production transport activities in accordance with scheduled production operations. For example, production data  144  may include tables identifying each local stocker, the stockers&#39; current load and capacity, the materials carried within the stocker, etc. Detailed performance metrics for stockers may also be stored as part of production data  144  such as relative throughputs, mean stocker cycle times for materials capacity, peak stocker cycle times for materials, stocker mean times between incidents, stocker availability, alarm conditions relating to carrier drops, weight loads, contamination control, charge build up on carrier, etc. These and other SEMI-derived performance metrics standards may be utilized. Production data  144  may also include process steps for manufacturing processes utilized within production area  102 , the status of production activities occurring within production bays  110  and  112 , etc. 
   Also stored in data repository  142  are purge triggers  146 , purge criteria  148 , and disposition operations  150  used by purge tool  134  (collectively referred to as set-up criteria). Purge triggers  146  refer to the events that may be defined as trigger points to initiate an action which results in one or more candidate lots (i.e., WIP materials) to be selected for removal and transport to centralized stock location  108 . Trigger points may include a time stamp, a stocker identified as being ‘full’, a WIP level achieved, a product type, a process time, throughput levels, etc. 
   Purge criteria  148  refers to the criteria used to determine whether a purge of WIP materials will be performed. Criteria  148  are flexible and may be modified based on the type of trigger event or other user-defined event. For example, a daily search (e.g., timestamp-based search) may utilize one type of purge criteria while a manually requested search may have different criteria. Examples of purge criteria include the age of the product being manufactured for which the materials are scheduled to be processed, the nature and/or class of the product for which the materials are scheduled to be processed, production priorities established for scheduled materials as set out in a production schedule (e.g., changes to priorities due to customer requirements), life span of materials in a production line (e.g., in an electronics manufacturing environment, monitor wafers have a fixed number of times for which they may be reused due to factors such as thermal cycles or coating thickness), lots which have not been processed for a given period of time (e.g., engineering lots, non-product lots, lots involved in a production stop, lost lots, etc.). 
   Disposition operations component  150  refers to specified actions that will be performed on selected WIPs to be purged, such as a time and manner for transporting the materials, a number and identification of the WIPs to be transported, an origination location and destination location assigned to the WIP materials, and may include any other instructions desired for handling the materials. The disposition may also include instructions for scrapping materials. 
   Data repository  142  also stores transport process jobs  152 . Transport process jobs  152  refer to work orders or directives generated by the purge tool that instruct the AMHS control application  130  to carry out specified operations on candidate materials selected for purging. 
   The above-described and other features of the purge tool will become readily apparently with reference to the description of  FIG. 2 . Referring now to  FIG. 2 , a process for implementing the purge tool is described. At step  200 , a user of the purge tool  134  enters desired set-up criteria that will define the handling and activities to be performed on materials. A sample user interface screen for implementing step  200  is shown in  FIG. 3 . Monitor  136  observes production activities occurring on server  104  via AMHS control application  130  and checks for any triggering events at step  202 . At step  204 , monitor  136  detects a trigger event that has occurred and initiates rules engine  140  at step  206 . Rules engine  140  of tool  134  searches production data  144  and captures information relating to the production elements affected by the trigger at step  208 . Rules engine  140  also searches purge criteria  148  at step  210  to determine what criteria will be used for the triggering event in light of the related production data captured. 
   Using the data found in steps  208  and  210 , as well as the triggering event of step  204 , the purge routine searches disposition rules at step  212  to identify a disposition plan that applies based upon the trigger event, purge criteria, and captured production data. The data acquired in steps  204  and  208 – 212  are processed by rules engine  140  of purge tool  134  at step  214 . At step  216 , it is determined if a purge candidate is found. A purge candidate refers to materials that meet the purge criteria identified in step  210  in light of the captured production data and triggering vent. 
   If no candidate is found at step  216 , the process returns to step  202  whereby production operations are again monitored. If, on the other hand, a candidate for purging is found at step  216 , rules engine  140  determines whether to issue a transport directive as a result of step  214  at step  218 . For example, it may be determined that a transport directive will not be issued where a lot is already in a designated long-term storage area, or where a lot is in a designated area pending disposition. If rules engine  140  determines that no transport directive should be issued step  218 , the process returns to step  202  where monitor  136  continues to observe production operations. Otherwise, parser  132  formats the search results into a format that is compatible with AMHS control application  130  at step  220 . 
   At step  222  a transport process job  152  is created by purge tool  134  for directing the AMHS control application  130  on how the candidate materials are to be handed. A sample transport process job is shown in  FIG. 4 . 
   the transport process job is transmitted via AMHS interface  138  to AMHS control application  130  at step  224  and the production data  144  is updated in data repository  142  to reflect this transport activity. 
   As described above, the purge tool of the invention enables a production control manager or similar individual to establish customized guidelines for handling production materials assigned to a production line in a manufacturing environment. These guidelines can be changed over time as the needs of the manufacturing plant or enterprise change. The purge tool of the invention uses custom criteria to search materials in a production line for potential candidates for transport to storage, or alternatively, for scrapping purposes. Once a candidate has been identified, the purge tool creates a transport process job for the candidate materials and transmits the transport process job to the automated material handling system of the production environment for execution. 
   As described above, the present invention can be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into an executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. 
   While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.