Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-05-08
2001-07-03
Beausoliel, Jr., Robert W. (Department: 2184)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S117000
Reexamination Certificate
active
06256548
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for controlling lots dispatch of tool groups, and more particularly, to a method for balancing tool loading whenever the productions increase or decrease.
2. Description of the Prior Art
Nowadays, single production line never satisfies the desire of the modern factories. Especially for those large scaled factories, tool groups consisted of tools with the same functions are often used for mass production. However, the lots must be moved to a proper place for continuously performing the next processes, and furthermore, those tools of tool groups may be allocated everywhere inside the factories. An inferior control method usually moves the lots to an improper place for further processing, and thus seriously influence the process progresses. Therefore, it is important to maintain the tools being operating smoothly.
FIG. 1
represents a factory including six tool groups for performing six specific processes. The first tool group consists of tools
102
A,
102
B, and
102
C for performing the first process. The second process is performed by the second tool group composed of tools
104
A,
104
B, and
104
C. The third process is performed by only a single tool
106
A. The fourth tool group consisting of tools
108
A and
108
B are used to perform the fourth process, and the fifth process is performed by the fifth tool group composed of tools
110
A and
110
B. The sixth tool group consists of tools
112
A,
112
B,
112
C to perform the sixth process.
Each the above-mentioned tool relates to a specific storage place. For example, the tools
102
A and
104
C, the tools
102
B and
104
C, the tools
102
C and
104
A respectively relate to the storage places
101
A,
101
B, and
101
C. The storage place
103
A stores the lots for the tool
106
A. The tools
108
A and
110
B, the tools
108
B and
110
A respectively utilize the storage places
105
A and
105
B, and the tools
112
A,
112
B and
112
C also respectively store lots in the storage places
107
A,
107
B, and
107
C.
Please note that any process can export processed lots to any tool of the tool group of the next process. For example, lots exported by the tool
102
A can be routed to one of the tools
104
A,
104
B,
104
C. Similarly, those lots processed by the tools
102
B and
102
C also can be exported to one of the tools
104
A,
104
B, and
104
C. Although the sockets
101
A,
101
B and
101
C are shared sockets, however, one or more transference steps for the lots are required sometime, especially when the selected socket is selected but overloading. For instance, when the socket
101
A is overloading, it is better to move the lots to elsewhere. A redundant transference step is thus required to move the lots that will be transferred to the socket
101
A. Obviously, the operators have to waste their time to move the lots, and also increase their work burdens.
A simple method for dispatching the lots is to randomly select a tool among a tool group, and to move the lots to the selected socket. Although all the tools of the tool group may work with average loading, the method can not take charge of the entire tool loading. It is clearly not an appropriate control method to be applied in the modern factories. Another control method assigns priorities to tools in each tool group. Every lot is transferred to a storage place of a tool that has highest priority until the storage place achieves full loading, and furthermore, each lot must be sent to the tool with next priority when a tool achieved its full loading.
Suppose that each the first tool of the tool groups in the
FIG. 1
has the highest priority, and the loading distributions will be similar to the diagram of the FIG.
2
. Obviously, a tool having higher priority will have higher loading at the same time, and those tools having lower priorities are usually idle. Unfortunately, when the factory's productions increase will also increase the differences among the tool loading, which seriously influences the factory's production. A need has been arisen to disclose a method that completely controls the lots dispatch and balances the tool loading for the modem factories.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a factory to dispatch lots with minimum moving steps.
It is a further object of the invention to provide the factory a capability to balance the tool loading whether the production increase or decrease.
Accordingly, the present invention discloses a method for controlling lots' dispatches of tool groups by transferring the lots to a correct storage place at each move. At each moving step, the lots are transferred to the storage places of the tool when there is only a tool for the next process. A decision step is performed for deciding whether the storage places of the next tool group and the next-next tool group are overlapped when the next process contains a tool group. If there are overlapped storage places, then the lots will be transferred to the overlapped storage place having minimum loading. When there is no overlapped storage place, the lots will be moved to the storage place having minimum loading among the next tool group. All the lots can be processed with least moving times, and all the tools perform their processes under balance loading whenever the productions increase or decrease.
REFERENCES:
patent: 5375061 (1994-12-01), Hara et al.
patent: 5757648 (1998-05-01), Nakamura
patent: 5818716 (1998-10-01), Chin et al.
patent: 5841677 (1998-11-01), Yang et al.
patent: 5880960 (1999-03-01), Lin et al.
patent: 5963911 (1999-10-01), Walker et al.
Beausoliel, Jr. Robert W.
Nath & Associates
Novick Harold L.
Taiwan Semiconductor Manufacturing Co. Ltd.
Ziemer Rita
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