System and method for designing a mixed-model manufacturing process

• US 6,198,980 B1
• Filed: 11/06/1998
• Issued: 03/06/2001
• Est. Priority Date: 11/06/1998
• Status: Expired due to Term

• Current Assignee: JCIT International, Inc. (DemandPoint, Inc.)
• Original Assignee: John Costanza Institute of Technology, Inc.
• Inventors: Costanza, John R.
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US09/186,919
• Time in Patent Office: 851 Days
• Field of Search: 700/95-97, 700/99-108, 700/111, 705/8, 703/1
• US Class Current: 700/99
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/32086 Integrate process planning and job shop scheduling
• CPC Class Codes: G05B 2219/32107 Operative process planning
• CPC Class Codes: G05B 2219/32116 Production ratio, proportion in which selected part types will be produced
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A demand-driven, mixed-model manufacturing line design system utilizes Demand Flow Technology to design an efficient mixed-model manufacturing line. Concurrent manufacture of several products in a continuous flow, mixed-model product line designed utilizing the design system exhibits essentially none of the inefficiencies associated with mixed-model, batch-oriented manufacturing lines. The method according to the present invention includes a product synchronization step for synchronizing product flow between unit processes, a resource balancing step to ensure sufficient resources are provided at each process, thereby reducing the product cycle time at each process to be approximately equal to an operational cycle time calculated for each process, a cell definition step for consolidating constant volume processes, an operational definition step for grouping tasks associated with the consolidated processes within each cell, and an operation balancing step for defining additional cells based on actual product cycle time diversity. A design system according to this invention includes a computer system wherein machine readable code accessible to the computer system enables execution of the above described method.

Claims

1. A method for computerized design of a demand-flow mixed-model manufacturing line, comprising:

defining a plurality of products in terms of a set of processes that results in manufacture of the plurality of products, the set of processes being a subset of the set of all processes included in the demand-flow mixed-model manufacturing line;

balancing process resources for each process of the set of all processes so that, for each process, an actual process time is approximately an operational cycle time, the operational cycle time being the maximum amount of time that a process can use to produce a unit of the plurality of products; and

outputting the computerized design reflecting the balanced resources.

2. The method of claim 1, further including defining each process in the set of process in terms of process parameters.

3. The method of claim 2, further including synchronizing the plurality of products.

4. A method for computerized design of a demand-flow mixed-model manufacturing line, comprising:

defining at least one product in terms of a set of processes that results in manufacture of the at least one product, the set of processes being a subset of the set of all processes included in the demand-flow mixed-model manufacturing line;

balancing process resources for each process of the set of all processes so that, for each process, an actual process time is approximately an operational cycle time;

defining each process in the set of process in terms of process parameters, wherein the process parameters include a sequence of events, a work content for each task in the sequence of events, and a yield and synchronizing the at least one product includes;

identifying a family of products for each process in the set of all processes, the family of products including each of the at least one product that includes the process in the set of processes for the at least one product;

defining a product demand-at-capacity for each of the at least one product, the product demand-at-capacity being the overall demand for the product;

defining the amount of time available for each process in the set of all processes;

calculating the process demand-at-capacity for each process in the set of all processes based on the product demand-at-capacity and the yield for that process;

calculating the actual process time from the work content for each task in the sequence of events and the process demand-at-capacity;

calculating an operational cycle time for each process in the set of all processes from the amount of time available; and

outputting the computerized design reflecting the balanced resources.

5. The method of claim 4, wherein balancing process resources comprises:

calculating a resource multiplier for each process in the set of all processes, the resource multiplier being the actual process time for that process divided by the operational cycle time for that process;

determining a total number of resources required to reach the product demand-at-capacity for all of the at least one product by multiplying the a currently available number of resources upon which the process parameters are based by the resource multiplier.

6. The method of claim 4, further comprising:

identifying at least one cell, each of the at least one cell comprising at least one process of the set of all processes;

identifying operations within each of the at least one cell;

balancing operations within each of the at least one cell so that, for each operation, an actual process time is approximately an operational cycle time.

7. The method of claim 6, wherein the at least one cell is defined manually by an operator.

8. The method of claim 6, wherein the at least one cell is defined by defining each of the at least one cell to be a process of the set of all processes.

9. The method of claim 6, wherein the at least one cell is defined under a cell definition criteria.

10. The Method of claim 9, wherein the cell definition criteria comprises balancing products so that, at each process in the set of all processes, each of the at least one product in the family of products utilize approximately the same time.

11. The method of claim 10, wherein, for each process in the set of all processes, balancing products comprises:

calculating a time index for each product;

removing the product from the family of products and placing it in an alternate family of products if the time index falls outside of an acceptable range;

defining additional option paths based on the alternate family of products.

12. The method of claim 6, wherein an operator chooses a method of cell definition for defining the at least one cell from choices including a manual definition, a definition using a constant volume criteria, or a definition equating each of the at least one cell with a process of the set of all processes.

13. The method of claim 6, wherein identifying operations within each of the at least one cell comprises:

defining an operation cycle time;

assigning tasks from the sequence of events for the processes in the at least one cell until a summed work content time exceeds the operation cycle time, the summed work content time is the sum of the work content time for each task added to the operation of the at least one cell.

14. The method of claim 13, wherein balancing operations for each of the at least one cell comprises

defining an upper cycle index limit;

calculating an operational time index for each operation in the at least one cell, the operation time index being the summed work content over the operation cycle time;

adjusting tasks of the operation until the operation time index is less than the upper cycle index limit.

15. A system for designing a demand-flow mixed-model manufacturing line, comprising:

a storage memory for holding computer programs and data;

a main memory for temporary storage of computer programs and data;

at least one data input device;

at least one display device;

a processor interacting with the storage memory, the main memory, the at least one data input device, and the at least one display device, the processor executing computer programs;

a computer program executable by the processor, the computer program including

computer code directing definition of a plurality of products in terms of a set of processes that result in manufacture of the plurality of products, the set of processes being a subset of the set of all processes included in the demand-flow mixed-model manufacturing line, each process in the set of processes being defined in terns of process parameters, and

computer code balancing process resources for each process of the set of all processes so that, for each process. an actual process time is approximately an operational cycle time, the operational cycle time being the maximum amount of time that a process can use to produce a unit of the plurality of products.

16. The system of claim 15, wherein the computer program further includes computer code for synchronizing the plurality of products.

17. A system for designing a demand-flow mixed-model manufacturing line, comprising:

a storage memory for holding computer programs and data;

a main memory for temporary storage of computer programs and data;

at least one data input device;

at least one display device;

a processor interacting with the storage memory, the main memory, the at least one data input device, and the at least one display device, the processor executing computer programs;

a computer program executable by the processor, the computer program including

computer code directing definition of at least one product in terms of a set of processes that result in manufacture of the at least one product, the set of processes being a subset of the set of all processes included in the demand-flow mixed-model manufacturing line, each process in the set of processes being defined in terms of process parameters,

computer code balancing process resources for each process of the set of all processes, and

computer code synchronizing the at least one product

computer code for identifying at least one cell, each of the at least one cell comprising at least one process of the set of all processes,

computer code for identifying operations within each of the at least one cell, and

computer code for balancing operations within each of the at least one cell so that, for each operation, an actual process time is approximately an operational cycle time.

18. The system of claim 17, wherein the computer program further includes computer code for balancing products.