Abstract: The system comprises a conveyor for conveying a plurality of moulds along a production path on which is located a plurality of stations, each of which can execute at least one corresponding operation. Each mould carries an electronic identification device including memory devices from and to which information or data can be read and written without contact by means of an antenna. Each station is provided with an electronic unit including a processor, having memory devices and at least one antenna, and designed to read and/or write information or data from or to the memory devices of a mould passing through the station. An initial input station transfers or writes to the memory devices of each mould passing through it information identifying the products to be formed in the mould and relating to corresponding forming operations.

Abstract: The present invention relates to conveyor control system and methodology that may be operatively coupled with other such systems in order to implement a control strategy for a modular conveyor system. A module and/or series of modules are provided that clamp to a cable, the modules having associated logic and inter-module communications for control. This includes relatively inexpensive power distribution, interconnection and motion logic for industrial conveyor systems.

Abstract: Disclosed is a processing apparatus to restrain load of a common usage system shared by a plurality of liquid processing modules. A processing module group includes k sets of share groups comprising a plurality of processing modules to perform an identical processing for each substrate (where, k?2), each set of share groups includes n processing modules (where, n?2), and each processing module includes the common usage system shared by n processing modules in each set and having a maximum capacity capable of processing m processing modules (where m?n). A carrying mechanism repeatedly loads a substrate one by one to the processing module of each set in sequence.

Abstract: A processing furnace for performing prescribed heat treatment on plural substrates, a boat for carrying the plural substrates that are laid one over another in the boat into and out of the processing furnace, a substrate detecting sensor for detecting the plural substrates laid one over another in the boat by changing a relative position of the substrate detecting sensor with respect to each of the plural substrates, and a control section for registering reference positions of the plural substrates and an allowable range of positional deviations from the reference positions of the plural substrates are provided.

Abstract: A substrate treatment apparatus eliminates breakage of a wafer W due to having the wafer supported by a supporting member when heat treatment is performed on the wafer W a plurality of times by a heat treatment module. The substrate processing apparatus includes a recipe setting unit for setting process conditions for a process recipe for the semiconductor wafer W and a direction of the semiconductor wafer W, by associating the conditions and the direction with each other. Through the recipe setting unit, the direction of the semiconductor wafer W can be set, and the semiconductor wafer W can be arranged in a direction set by an alignment module. Thus, portions R to be supported by the supporting members 60a, 60b and 60c on the rear surface of the semiconductor wafer can be changed every time the heat treatment module performs heat treatment.

Abstract: A computer readable storage medium storing a program for performing an operation method of a substrate processing apparatus is provided. The operation method includes the steps of introducing a nonreactive gas into the vacuum preparation chamber before the gate valve is opened while the substrate is transferred between the vacuum preparation chamber of the vacuum processing unit and the transfer unit, stopping introducing the nonreactive gas when an inner pressure of the vacuum preparation chamber becomes same as an atmospheric pressure, starting an evacuation process of the corrosive gas in the vacuum preparation chamber and then opening to atmosphere performed by letting the vacuum preparation chamber communicate with an atmosphere, and opening the gate valve after the step of opening to atmosphere.

Abstract: A method for controlling handling of a plurality of substrates to be processed in an integrated mastering system and an integrated mastering system for performing the method of the invention is provided. The system comprises various treating stations to be passed through by the substrates in a predetermined order, a buffer for temporarily storing the substrates and a handler for moving the substrates between the buffer and the treating stations. According to the method each one of the plurality of substrates is moved to the buffer upon completion of processing in each one of said treating stations.

Abstract: Depending on the degree of microfabrication requested for each wafer lot, transfer of wafers is controlled. A substrate processing apparatus includes a plurality of PMs 400 and an LLM 500 and is controlled by an EC 200. The EC 200 includes a selection unit 255 and a transfer control unit 260. The unit 255 selects the PM to which the next wafer is to be transferred, and selects, for each lot, whether the wafers are transferred to the same PM in one-lot units or in one-substrate units depending on the degree of the microfabrication requested for each lot. When the wafer transfer in lot units is selected, the unit 260 sequentially transfers the wafers included in the lot to the selected PM. Otherwise the unit 260 sequentially OR transfers the wafers included in the lot from the selected PM to a different PM one by one.

Abstract: A cross-semiconductor fabrication (fab) facility transportation system and method for cross-fab transportation is provided. An exemplary method for cross-fab transportation includes providing a unified control unit that facilitates transportation of one or more wafers across a plurality of wafer fabrication facilities (“fabs”). The unified control unit facilitates selecting a wafer at a first location in a first automated material handling system (“AMHS”) of a first fab for transfer to a second AMHS of a second fab; selecting a second location within the second AMHS of the second fab; selecting a route for transferring the wafer between the first location and the second location; and issuing instructions to the first and second fabs, such that the wafer is transferred from the first location to the second location.

Abstract: A system and method provides computer-assisted organization of workpieces to be processed in a production process, wherein the workpiece in question is subjected to at least one processing, preferably to a plurality of different processings. A workpiece position is assigned to each workpiece, and at least one, preferably several, workpiece positions are combined in a magazine. Each workpiece position includes a device for status determination of the respective workpiece position. A control unit is provided for controlling the individual workpiece positions, and a data-processing unit is provided, which communicates with the control unit and in which the information queried from the individual workpiece positions is processed and status data is generated.

Abstract: A fabricating method for a system that includes a plurality of processing apparatuses connected to each other by an inter-apparatus transporter and a computer storing managing information of processing and transporting of semiconductor wafers. The processing apparatuses have an interface for loading and unloading a plurality of the semiconductor wafers that are contained in a carrier. The semiconductor waters are processed in processing chambers of the processing apparatuses and the result of processing is monitored. In the processing, a first carrier containing the plurality of the semiconductor wafers having been processed in the first processing apparatus is transported toward the second processing apparatus by the inter-apparatus transporter prior to unloading of a second carrier containing semiconductor wafers processed in the second processing apparatus, according to the managing information.

Abstract: Disclosed herein is a modular system for manufacturing printed circuit boards. The system comprises a plurality of pieces of processing equipment including at least one assembly material applicator, and at least one electronic component placement machine, and a transport system configured to transport circuit boards from the at least one stencil printer to the at least one electronic component placement machine, the system including an upper track and a lower track disposed below the upper track.

Abstract: A generic device controller unit system (10) includes a generic “true real time” peripheral device controller and a data and protocol communications interface that uses a common set of instructions from a meta-message set. The system (10) is generic, in that the system (10) is capable of connecting a processor (40) to any number of various peripheral devices (50), instead of being designed to interconnect a processor (40) only to a specific peripheral device (50). The system (10) interfaces between a standard non-true real time operating system and peripheral devices (50) in such a manner as to employ true real time peripheral device control using the meta-message set. The device controller of the system (10) allows a standard non-true real time operating system to send instructions from the meta-message set to implement true real time control of peripheral devices (50).

Abstract: Systems, tools, and methods are provided in which a first signal is transmitted from a tool to a Fab indicating that all substrates to be processed have been removed from a specific carrier and that the specific carrier may be temporarily unloaded from a loadport of the tool. A second signal is transmitted from the tool to the Fab indicating that the specific carrier may be returned to the tool. While the carrier is unloaded from the tool, other carriers may be loaded on the vacated loadport. Numerous other features and aspects of the invention are disclosed.

Abstract: A simulation condition input apparatus inputs information required for simulation analysis on a system including plural element members. The apparatus includes a display unit, a specifying unit and an input unit. The display unit displays the plural element members on a screen with geometrical shapes corresponding to the element members. The specifying unit specifies a contact portion between at least one set of the element members, which is an information input target, on the screen of the display unit. The input unit displays a new window screen and inputs information about a contact state of the contact portion specified by the specifying unit.

Abstract: The transport apparatus is provided with a path that extends past a plurality of article transferring locations, a plurality of article transporting vehicles that run on the path, a travel driving means provided on each of the article transporting vehicles for controlling movement of the article transporting vehicle, and a ground-side controller for managing operation of the plurality of article transporting vehicles by managing the travel driving means, wherein the ground-side controller is capable of transmitting run command information and stop command information, relating to each of the article transporting vehicles, to their corresponding travel driving means, and wherein the travel driving means drives and stops the article transporting vehicles based on the run command information and the stop command information from the ground-side controller.

Abstract: In a first aspect, a method of managing work in progress within a small lot size semiconductor device manufacturing facility is provided. The first method includes providing a small lot size semiconductor device manufacturing facility having (1) a plurality of processing tools; and (2) a high speed transport system adapted to transport small lot size substrate carriers among the processing tools. The method further includes maintaining a predetermined work in progress level within the small lot size semiconductor device manufacturing facility by (1) increasing an average cycle time of low priority substrates within the small lot size semiconductor device manufacturing facility; and (2) decreasing an average cycle time of high priority substrates within the small lot size semiconductor device manufacturing facility so as to approximately maintain the predetermined work in progress level within the small lot size semiconductor device manufacturing facility. Numerous other aspects are provided.

Abstract: In a flexible manufacturing system, a control apparatus for a transfer device stores in a memory section thereof correlation information for correlating workpieces (ante-machining workpieces) to be attached to pallets with blank materials contained in blank material baskets. When a selected one of the pallets is to be transferred to a pallet loading station, the control apparatus determines blank materials corresponding to the workpieces to be attached to the selected one of the pallets based on the correlation information and then, controls the transfer device to transfer a blank material basket containing the determined blank materials from a basket rack to a basket loading station located adjacent to the pallet loading station in connection with transferring the selected one of the pallets to the pallet loading station. Thus, when the selected one of the pallets is transferred to the pallet loading station, it becomes possible to reduce the time taken for the worker to search for the blank material basket.

Abstract: The invention relates to a method for positioning a wafer (3) with a reference mark (6) in a vacuum processing unit with a transport chamber containing a transport device (2, 20, 21) for moving the wafers (3) in a plane to a process chamber arranged on said chamber and a single sensor (1), arranged within the transport chamber before the process chamber for recording the position of the wafer (3) by means of recording the edge thereof at a first detection point (4) and a second detection point (5), such that the actual position of the wafer (12) with a known wafer diameter can be determined with electronic analysis of both measured detection points (4, 5) and the transport device (2, 20, 21) guides the wafer (3) to a desired set position.

Abstract: An operation sequence creating apparatus creates an operation sequence of a workpiece processor using an industrial robot carrying a workpiece between a plurality of devices.

Abstract: In one aspect a factory automation system for a wafer fab is provided. The factory automation system is adapted to facilitate cross-AMHS transfers of wafer lots within a semiconductor foundry. The factory automation system may include a first MCS and an associated first AMHS; a second MCS and an associated second AMHS; and a third MCS and an associated third AMHS. The system may also include a first bridge connecting the first AMHS and the second AMHS to allow a FOUP to travel between the first AMHS and the second AMHS. The system may also include a second bridge connecting the second AMHS and the third AMHS to allow a FOUP to travel between the second AMHS and the third AMHS. The system also includes a unified control unit in communication with the first, second, and third MCSs, the unified control unit for coordinating transfers of FOUPs between the first, second, and third AMHSs.

Abstract: An efficient manufacturing automation system and method is described. The system and method include bays, with each bay having a group of tools. Temporary storage locations are provided. A transport system facilitates movement of materials from the tools. The system and method enable direct transfer of materials from a first tool to a second tool or transfer of materials from a first tool to a temporary storage location when a second tool is unavailable.

Abstract: A method for dispatching wafers for processing in a tool includes identifying a queue of wafers available to be processed in the tool. One of the wafers is randomly selected based at least in part on a length of time each wafer has been in the queue. The selected wafer is dispatched for processing in the tool.

Abstract: A new Task Queue Methodology (TQM) is provided for reducing traffic jams and for controlling transportation priority in an Automatic Material Handling System (AMHS). A Stocker Resource Q, under control of TQM, maintains records of stockers that are under control of the AMHS and the availability thereof. For available stockers, a Task-Q under control of a Queue Manager (TQM) is accessed, extracting therefrom records that match available stocker resources. For the available stocker resources, the tasks that are scheduled against these resources are sorted by priority and by longest wait time, resulting in one selected task. For the in this manner selected task, a Move command is issued by the TQM to the Automatic Material Handling System.

Abstract: A pre-plating station may include an automated pre-plating device configured to receive a cut truss member and at least partially fasten a connector plate to a portion of the truss member based on truss design data prior to communication of the truss member to a truss assembly location.

Abstract: By adopting a workpiece transfer apparatus, which grips a workpiece by use of a predetermined grip device and transfers the workpiece between press apparatuses each of which drives a die, including a transfer control device for controlling a position of the grip device based on a resultant target value obtained by combining a die position of a press apparatus located on an upstream side of a workpiece transfer direction (an upstream side die position) and a die position of a press apparatus located on a downstream side of a workpiece transfer direction (a downstream side die position), in which the transfer control device sets a resultant target value so that the grip device moves smoothly, it becomes possible to suppress vibration in a workpiece transfer apparatus in a press line.

Abstract: A cassette control device by which high-speed processing can be expected even by using an arithmetical unit with current processing capability, even when the number of cassettes increases simultaneously with an increase in the number of nozzles which can suck electronic parts. There is provided storage unit (18) having storage regions in which programs for respective operation patterns of the cassettes (3-1 to 3-M) are set for each of the nozzles. An arithmetic unit (19) extracts a specific program required for driving in a specific operation pattern based on a command (17) inputted according to the content of packaging, from a specific region which is provided in the storage unit (18) to correspond to a specific nozzle to be used, and the arithmetic unit (19) operates the specific cassette using the specific program.

Abstract: A method for automatically checking a sequence of loading boats and batches for a semiconductor manufacturing process is provided. According to a developed logic, a loading sequence is automatically calculated by a system. By comparing the actual loading sequence with the calculated sequence when the boats are entering, it is ensured that no errors occur when loading the boats in the batches. When loading the boats in the batches, operators can truly load the boats in the batches according to the entering sequence together with the current confirmation mechanism, so as to ensure the boat positions for the loaded materials to be correct. The method for automatically checking the sequence of loading boats and batches is further capable of calculating the loading sequence through the developed logic by automatically determining runnable boat positions for the material after recording a parameter for detecting a previous boat by the system.

Abstract: An integrated miniature factory for fabrication of a device is provided. In one example, the factory includes an enclosure, multiple compartmentalized process modules, and a transportation mechanism. The compartmentalized process modules are configured to removably couple to the enclosure. Each compartmentalized process module is sized to receive a substrate on which the device is to be fabricated and is configured to aid in fabrication of the device. The transportation mechanism is configured to transfer the substrate between at least two of the compartmentalized process modules during a fabrication process.

Abstract: The present invention generally comprises a method for achieving fault tolerance in a PV FAB. A plurality of processing tools may be coupled together along a processing line, and a plurality of substantially identical processing lines may be arranged within the FAB. Whenever a processing tool within any processing line is shut-down, rather than shut-down the entire processing line containing the shut-down processing tool, work-pieces may be routed around the shut-down processing tool by transferring the work-pieces to an adjacent processing line within the FAB. At a location after the shut-down processing tool, the work-pieces may be transferred back to the processing line containing the shut-down processing tool. During the time period that the processing tool is shut-down, the other processing lines within the FAB may increase their throughput in order to maintain a substantially constant optimum throughput for the FAB over a given period of time.

Abstract: A method for increasing overall yield in semiconductor manufacturing including routing wafers or wafer lots from tool to tool in a manner which at least partially neutralizes or compensates for processing variations. A system for increasing overall yield in semiconductor manufacturing includes a module for recording processing data from plural first and second types of tools and a module for routing wafers or wafer lots from tools of the first type of tools to tools of the second type of tools so as to at least partially neutralizes or compensate for processing variation.

Abstract: A plurality of autonomous control processes, with each controlling one or more components of the material transport (or processing) system, is used to radically simplify the controller software. Each autonomous control process is responsible for the actions of only a subset of the cluster tool components. For example, in one embodiment, a separate autonomous control process is used to control each automated component in the material handling system. However, other embodiments in which a control process controls a plurality of components are also contemplated. The control processes can also be implemented as rules-based machines, determining the proper action based on a set of fixed or programmable rules. Alternatively, the control processes may also execute traditional software algorithms. The control processes are designed such that, together they achieve the process flow and throughput requirements previously achieved via a single control process.

Abstract: In a substrate processing system according to the present invention, module cycle periods at a plurality of process modules PM1 through PM4 connected around a transfer module TM having installed therein a vacuum pressure-side transfer robot RB1, each representing the sum of a wafer stay time including the wafer processing time and an attendant busy time during which the wafer is transferred before and after the wafer stay time, are all set to a uniform length. The vacuum pressure-side transfer robot RB1 takes out a processed wafer Wi and carries a next wafer Wi+1 to be processed next by executing a pick and place operation for each of the process modules PM1 through PM4 during a single access to the process module.

Abstract: System comprising mold-moving assembly cooperative with molding station and insert-integration station.

Abstract: Systems and methods of identifying and manipulating objects are disclosed. One system disclosed comprises a light source adapted to emit a collimated light beam onto a contoured surface, a sensor adapted to view a profile of the contoured surface illuminated by the collimated light beam, a processor in communication with the sensor, and a controller in communication with the processor. The controller may be adapted to generate a signal based on an attribute of a predefined profile.

Abstract: An object of the present invention is to provide a semiconductor manufacturing system used for manufacturing a semiconductor in a semiconductor manufacturing facility according to a flow shop scheme. The semiconductor manufacturing system is provided with a plurality of bays having a plurality of pieces of semiconductor manufacturing equipment and intra-bay conveyance devices; an inter-bay conveyance device for conveying a carrier between the bays; and a flow shop controller, wherein each piece of semiconductor manufacturing equipment has one or more modules comprising a subsystem provided with at least one or more I/O devices; the bays, the semiconductor manufacturing equipment, the modules, the subsystems, and the I/O devices are each provided with a controller; each of the controllers is provided with a controller framework for implementing each function in accordance with a shared control scheme.

Abstract: A system for manufacturing tobacco products whereby, a number (Pn) that represents a nominal production target for products of a given brand, and a number (Cmax) representing the maximum output capacity of the system, or in practice the maximum quantity of products in process that the system is able to handle, are programmed into master control unit (33). A tally (P) of products is kept, and, at a given moment (t1) following the completion of a number (Pr) of products that matches the target (Pn=Pr+Cmax), a first flash check is run on the quantity (C1) of the product actually turned out by the system; should it emerge from this first flash check that the actual quantity (C1) is equal to the maximum output capacity (Cmax), then a brand changeover procedure will be initiated by the master control unit (33).

Abstract: A material handling system and method of automatic address assignment of components of the material handling system, includes a conveying surface divided into a plurality of zones, a plurality of motors propelling each zone, a plurality of lower level controllers and a plurality of sensors adapted to communicate the presence of an article on the conveying surface to the associated lower level controller. An upper-level controller in communication with the lower level controllers assigns a unique communications address to a specific lower level controller identified by a reference article being detected by the sensor with that lower level controller.

Abstract: In at least one aspect, the invention provides an electronic device fabrication facility (Fab) that uses small lot carriers that may be transparently integrated into an existing Fab that uses large lot carriers. A manufacturing execution system (MES) may interact with the inventive small lot Fab as if the small lot Fab is any other Fab component in an existing large lot Fab without requiring knowledge of how to control small lot Fab components (e.g., beyond specifying a processing recipe). A small lot Fab according to the present invention may encapsulate the small lot Fab's internal use of small lot components and present itself to a large lot Fab's MES as if the small lot Fab is a component that uses large lot carriers.

Abstract: A fabricating method for a system that includes a plurality of processing apparatuses connected to each other by an inter-apparatus transporter and a computer storing managing information of processing and transporting of semiconductor wafers. The processing apparatuses have an interface for loading and unloading a plurality of the semiconductor wafers that are contained in a carrier. The semiconductor waters are processed in processing chambers of the processing apparatuses and the result of processing is monitored. In the processing, a first carrier containing the plurality of the semiconductor wafers having been processed in the first processing apparatus is transported toward the second processing apparatus by the inter-apparatus transporter prior to unloading of a second carrier containing semiconductor wafers processed in the second processing apparatus, according to the managing information.

Abstract: Methods and apparatus are provided for managing movement of small lots between processing tools within an electronic device manufacturing facility. In some embodiments, a number of priority lots to be processed is determined and an equivalent number of carrier storage locations are reserved at a substrate loading station of a processing tool. The number of reserved carrier storage locations are made available either by processing and advancing occupying non-priority lots and/or moving unprocessed occupying non-priority lots from the substrate loading station. Priority lots are then transferred to the reserved carrier storage locations. Other embodiments are provided.

Abstract: A modular manufacturing station is provided. The modular manufacturing station has plurality of beams forming a skeleton and an article transportation system. The article transportation system is configured to transport one or more articles through the manufacturing station at a speed selected from a plurality of speeds and at a height selected from a plurality of heights. The modular manufacturing station also has at least one utility connection for receiving external utilities and at least one piece of manufacturing equipment. The modular manufacturing station further has a controller configured to regulate the speed and height at which articles are transported through the modular manufacturing station and regulate the operation of the manufacturing equipment.

Abstract: An objective of the present invention is to provide an assembly system capable of reducing the equipment space while various kinds of automotive parts are assembled on one production line. The assembly system assembles plural kinds of automotive parts consisting of a main body and a part to be installed to the main body. This assembly system comprises an operator area at which an operator is assigned, a plurality of travel carts on which a main body of each of automotive parts is placed, traveling along the operator area, a part pallet on which a part to be installed to each of the automotive parts is placed, a belt conveyer conveying this part pallet along the operator area, and a control device controlling thereof. The control device drives the travel carts and the belt conveyer so as to convey the travel carts and the part pallet synchronously.

Abstract: A coating/developing apparatus has a carrier block including a first transfer device, a process block including processing modules, an examination block including examination modules and a second transfer device, and first to forth stages. A controller executes a first operation mode preset to transfer substrates from the process block and carrier block into the examination block in parallel. The first operation mode includes transferring substrates processed by the process block to the third or fourth stage through or not through an examination module by the second transfer device, transferring substrates to be only examined from a carrier in the carrier block to the second stage by the first transfer device, and transferring these substrates from the second stage to an examination modules by the second transfer device, and transferring substrates thus examined from the examination block to the third or fourth stage by the second transfer device.

Abstract: A band to band transfer module according to the present invention may be used with a substrate carrier transport system, or other systems, to transfer substrate carriers (e.g., small lot substrate carriers) from one conveyor to another conveyor or between two points on the same conveyor. The transfers (e.g., pick and place) of the substrate carriers may be made between conveyors traveling at different speeds. Numerous other aspects and features are disclosed.

Abstract: It is an object to provide an AGV that enables preventing a substrate and a manufacturing system from being contaminated due to another substrate with an adhering contaminant generated in a manufacturing process, and also a production system for a semiconductor device and a production management method for a semiconductor device, which use the AGV. In the present invention, air filtered through a filter is introduced into a containing portion of an AGV, and air in the containing portion containing a carrier is exhausted after filtering the air in the containing portion through another filter. As the filter used before discharging the air, a filter that enables filtering an impurity on the order of a submicron level is used. In addition, a carrier used before doping is changed to another carrier after doping, and CIM system is used to control driving of the AGV and selection of the carrier.

Abstract: A control system is provided for each pair of a work fixing part and a work machining part. In each control system, a work receiving program block, a work machining program block and a work discharge program block are provided, and the work machining program block starts on the condition that the work receiving program block ends and the work discharge block program starts on the condition that the work machining program block ends. The work receiving program block is associated with the work supply program of the work supply apparatus, or the work discharge program block is associated with a work transfer program of a work transfer apparatus so that a command is issued to the work receiving program block or the work discharge program block, and a command to perform a cue of the head of the program of each control system is provided at the last part of the control system.

Abstract: By dynamically adapting the transport sequencing rules of a cluster tool, the overall performance of the tool may be increased. In some illustrative embodiments, the transport sequencing rule for a robot handler may be dynamically changed when a lot of small size is present in one of the load ports in order to increase the window of opportunity for carrier exchange of a standard lot size currently processed. Consequently, by reducing the overall process time for the currently processed lot while delaying the completion of the small lot, the currently processed carrier may be exchanged earlier, thereby reducing the overall cycle time of the currently processed lot and/or providing a next lot earlier to the tool.

Abstract: An apparatus and associated method directed to encoding data from an object in order to simultaneously identify a serialization value of the object from the data while incrementally tracking the object's position from the data.

Abstract: Embodiments of the present invention provide a workpiece transportation control method and system that automatically processes a plurality of steps in a successive manner, thereby enhancing production efficiency. According to one embodiment, a transportation control method includes the steps of: monitoring the state of an automated manufacturing system to see if there is a request for transporting a workpiece; extracting the subsequent step path for the workpiece when a transportation request is issued; calculating a standard necessary period along the extracted step path; converting the subsequent standard necessary period into an evaluation value, issuing a transportation request, stacking tasks in response to other transportation requests; and selecting a workpiece with the shortest subsequent standard necessary period from the stacked transportation requests.