Rough-cut capacity planning with production constraints and dynamic bottleneck considerations

• US 20050114202A1
• Filed: 10/29/2004
• Published: 05/26/2005
• Est. Priority Date: 10/30/2003
• Status: Active Grant

• Current Assignee: Agency For Science Technology and Research (Government of Singapore)
• Original Assignee: Agency For Science Technology and Research (Government of Singapore)
• Inventors: Chua, Tay Jin, Wang, Feng Yu, Yan, Wen Jing, Cai, Tian Xiang
• Granted Patent: US 7,925,365 B2
• Time in Patent Office: Days
• US Class Current: 705/10
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

To assess the sufficiency of a plurality of machines for processing a number of items, machine availability information indicative of availability of the machines for processing the items, machine capacity information indicative of a capacity of each of the machines for processing the items, and machine preference information indicative of a preference of each of the machines for processing the items are obtained. A capacity constraint, such as an upper limit of items to be processed during a time interval, is determined based on the machine availability information, machine capacity information and machine preference information. At least some of the machines are allocated to process at least some of the items based on the machine availability information, machine capacity information and machine preference information, subject to the capacity constraint. The resulting rough-cut capacity plan may be used to balance available capacity against required capacity.

Claims

1. A method of assessing the sufficiency of a plurality of machines for processing a number of items, the method comprising:

obtaining machine availability information indicative of availability of said machines for processing said items;

obtaining machine capacity information indicative of a capacity of each of said machines for processing said items;

obtaining machine preference information indicative of a preference of each of said machines for processing said items;

determining a capacity constraint based on said machine availability information, said machine capacity information and said machine preference information; and

allocating at least some of said machines to process at least some of said items based on said machine availability information, machine capacity information and machine preference information, subject to said capacity constraint.

2. The method of claim 1 wherein said machine availability information comprises, for each of said machines, a timeline indicative of the availability of said machine.

3. The method of claim 1 wherein said availability of said machine is based on one or more of a preventative maintenance schedule for said machine, a scheduled break for an operator of said machine, or a down time of said machine due to day of week or day of year.

4. The method of claim 1 wherein said machine capacity information comprises, for each of said machines, an indication of a processing rate of said machine for processing said items.

5. The method of claim 4 wherein said processing rate is based on a type of said items.

6. The method of claim 1 wherein said machine preference information comprises, for each of said machines, an indication of a preference of said machine for processing said items.

7. The method of claim 6 wherein said indication of a preference is based on a type of said items.

8. The method of claim 6 wherein said indication of a preference is a preference level selected from a range of preference levels.

9. The method of claim 8 wherein said allocating is performed for machines having a high preference level before it is performed for machines having a low preference level.

10. The method of claim 1 wherein said capacity constraint is an upper limit to the number of items capable of being processed.

11. The method of claim 10 wherein said upper limit is based on limited availability of one of said plurality of machines for processing a type of said items.

12. The method of claim 11 wherein said one of said plurality of machines is in a first work center having one or more machines for performing a first processing operation, wherein at least one other of said plurality of machines is in a second work center having one or more machines for performing a second processing operation, and wherein said allocating is limited to allocating capacity of said machines of said second work center sufficient for processing no more than said upper limit of said type of said items at said second work center despite availability of machines at said second work center for processing more than said upper limit of said type of said items at said second work center.

13. The method of claim 1 further comprising obtaining job priority information associated with each of said items, and wherein said allocating is performed based on said job priority information.

14. The method of claim 13 wherein said job priority information includes a job priority for each of said items, said job priority being based on one or more of an importance of the item to be processed, an importance of a customer for the item, or a deadline for completion of processing.

15. The method of claim 1 wherein said items are parts grouped based on similarity of part characteristics.

16. The method of claim 1 wherein said machine availability information is indicative of availability of said machines for processing said items during a time interval, and wherein said allocating comprises allocating at least some of said machines to process, during said time interval, at least some of said items.

17. A method of assessing the sufficiency of a plurality of work centers for processing a plurality of jobs during a time interval, each work center having a group of machines for performing an operation, each job having a job priority and including one or more operations to be performed upon a set of like items, each machine having a preference level for processing the items associated with each job, said preference level being one of a range of machine preference levels, the method comprising:

determining which jobs of said plurality of jobs have an operation that is associated with a work center having an available machine whose preference level for processing the items associated with the job matches a current machine preference level, said current machine preference level having been selected from said range of machine preference levels in decreasing preference order, said determining resulting in a set of candidate jobs;

selecting from said set of candidate jobs a job whose job priority is at least as high as the job priority of any other job in said set of candidate jobs, said selecting resulting in a selected job, the items associated with said selected job being referred to as selected items; and

at each work center associated with an operation of the selected job, allocating one or more machines having either said current machine preference level or a lower machine preference level in respect of the selected items to process a chosen number of units of the selected items, said allocating of machines being performed in decreasing order of machine preference level in respect of the selected items.

18. The method of claim 17 further comprising, prior to said allocating:

calculating, for each work center associated with an operation of the selected job, a maximum number of units of the selected items that the work center is capable of processing during said time interval, said calculating being based on availability of machines having said current machine preference level or a lower machine preference level in respect of the selected items and on a processing rate of said machines when processing the selected items, said calculating resulting in a set of numbers, each of said numbers being a maximum number of units capable of being processed by a work center; and

choosing a minimum value from said set of numbers, said minimum value defining a bottleneck number of units of the selected items to be processed during the time interval,

and wherein said chosen number of units is said bottleneck number of units.

19. The method of claim 17 further comprising, prior to said determining, identifying jobs from said plurality of jobs for which no machine has yet been allocated to perform any of the one or more operations associated with the job, said identifying resulting in identified jobs, and wherein said determining is limited to said identified jobs.

20. The method of claim 19 further comprising repeating said identifying, said determining, said selecting, said calculating, said choosing and said allocating until either a machine has been allocated to perform each operation of each one of said plurality of jobs or until said allocating cannot be performed for an operation of one of said plurality of jobs.

21. The method of claim 17 wherein said job priority is determined based on one or more of an importance of a customer associated with said job, an importance of a product associated with said job, or a deadline for completing said job.

22. A method of assessing sufficiency of a plurality of work centers for processing a plurality of jobs during a time interval, comprising:

choosing a machine preference level as a current chosen level, said current chosen level being a highest level of all levels not yet chosen as a chosen level;

selecting as a current job a highest priority job of a set of jobs having at least one operation requiring said current chosen level at a work center having an available machine; and

allocating machine capacity to said current job across all work centers.

23. The method of claim 22 wherein said job comprises operations to be performed on a set of items and wherein said allocating comprises:

determining, for each work center, a maximum number of said items that can be processed; and

selecting a minimum one of each said maximum number as a number of items of said job to be allocated.

24. The method of claim 22 further comprising repeating said selecting and said allocating until either no further job in said set of jobs remains to be chosen as a current job or no further items in jobs in said set of jobs can be allocated.

25. The method of claim 24 further comprising, after concluding said repeating said selecting and said allocating, repeating said choosing, said selecting, and said allocating.

26. A machine-readable medium including code for assessing the sufficiency of a plurality of machines for processing a number of items, comprising:

machine-executable code for obtaining machine availability information indicative of availability of said machines for processing said items;

machine-executable code for obtaining machine capacity information indicative of a capacity of each of said machines for processing said items;

machine-executable code for obtaining machine preference information indicative of a preference of each of said machines for processing said items;

machine-executable code for determining a capacity constraint based on said machine availability information, said machine capacity information and said machine preference information; and

machine-executable code for allocating at least some of said machines to process at least some of said items based on said machine availability information, machine capacity information and machine preference information, subject to said capacity constraint.

27. The machine-readable medium of claim 26 wherein said machine availability information comprises, for each of said machines, a timeline indicative of the availability of said machine.

28. The machine-readable medium of claim 26 wherein said availability of said machine is based on one or more of a preventative maintenance schedule for said machine, a scheduled break for an operator of said machine, or a down time of said machine due to day of week or day of year.

29. The machine-readable medium of claim 26 wherein said machine capacity information comprises, for each of said machines, an indication of a processing rate of said machine for processing said items.

30. The machine-readable medium of claim 29 wherein said processing rate is based on a type of said items.

31. The machine-readable medium of claim 26 wherein said machine preference information comprises, for each of said machines, an indication of a preference of said machine for processing said items.

32. The machine-readable medium of claim 31 wherein said indication of a preference is based on a type of said items.

33. The machine-readable medium of claim 31 wherein said indication of a preference is a preference level selected from a range of preference levels.

34. The machine-readable medium of claim 33 wherein machine-executable code for allocating causes said allocating to be performed for machines having a high preference level before it is performed for machines having a low preference level.

35. The machine-readable medium of claim 26 wherein said capacity constraint is an upper limit to the number of items capable of being processed.

36. The machine-readable medium of claim 35 wherein said upper limit is based on limited availability of one of said plurality of machines for processing a type of said items.

37. The machine-readable medium of claim 36 wherein said one of said plurality of machines is in a first work center having one or more machines for performing a first processing operation, wherein at least one other of said plurality of machines is in a second work center having one or more machines for performing a second processing operation, and wherein said machine-executable code for allocating causes said allocating to be limited to allocating capacity of said machines of said second work center sufficient for processing no more than said upper limit of said type of said items at said second work center despite availability of machines at said second work center for processing more than said upper limit of said type of said items at said second work center.

38. The machine-readable medium of claim 26 further comprising machine-executable code for obtaining job priority information associated with each of said items, and wherein said machine-executable code for allocating causes said allocating to be performed based on said job priority information.

39. The machine-readable medium of claim 38 wherein said job priority information includes a job priority for each of said items, said job priority being based on one or more of an importance of the item to be processed, an importance of a customer for the item, or a deadline for completion of processing.

40. The machine-readable medium of claim 26 wherein said items are parts grouped based on similarity of part characteristics.

41. The machine-readable medium of claim 26 wherein said machine availability information is indicative of availability of said machines for processing said items during a time interval, and wherein said machine-executable code for allocating comprises machine-executable code for allocating at least some of said machines to process, during said time interval, at least some of said items.

42. A machine-readable medium including code for assessing the sufficiency of a plurality of work centers for processing a plurality of jobs during a time interval, each work center having a group of machines for performing an operation, each job having a job priority and including one or more operations to be performed upon a set of like items, each machine having a preference level for processing the items associated with each job, said preference level being one of a range of machine preference levels, comprising:

machine-executable code for determining which jobs of said plurality of jobs have an operation that is associated with a work center having an available machine whose preference level for processing the items associated with the job matches a current machine preference level, said current machine preference level having been selected from said range of machine preference levels in decreasing preference order, said determining resulting in a set of candidate jobs;

machine-executable code for selecting from said set of candidate jobs a job whose job priority is at least as high as the job priority of any other job in said set of candidate jobs, said selecting resulting in a selected job, the items associated with said selected job being referred to as selected items; and

machine-executable code for, at each work center associated with an operation of the selected job, allocating one or more machines having either said current machine preference level or a lower machine preference level in respect of the selected items to process a chosen number of units of the selected items, said allocating of machines being performed in decreasing order of machine preference level in respect of the selected items.

43. The machine-readable medium of claim 42 further comprising machine-executable code for, prior to said allocating:

calculating, for each work center associated with an operation of the selected job, a maximum number of units of the selected items that the work center is capable of processing during said time interval, said calculating being based on availability of machines having said current machine preference level or a lower machine preference level in respect of the selected items and on a processing rate of said machines when processing the selected items, said calculating resulting in a set of numbers, each of said numbers being a maximum number of units capable of being processed by a work center; and

choosing a minimum value from said set of numbers, said minimum value defining a bottleneck number of units of the selected items to be processed during the time interval,

and wherein said chosen number of units is said bottleneck number of units.

44. The machine-readable medium of claim 42 further comprising machine-executable code for, prior to said determining, identifying jobs from said plurality of jobs for which no machine has yet been allocated to perform any of the one or more operations associated with the job, said identifying resulting in identified jobs, and wherein said machine-executable code for determining limits said determining to said identified jobs.

45. The machine-readable medium of claim 44 further comprising machine-executable code for repeating said machine-executable code for identifying, said machine-executable code for determining, said machine-executable code for selecting, said machine-executable code for calculating, said machine-executable code for choosing and said machine-executable code for allocating until either a machine has been allocated to perform each operation of each one of said plurality of jobs or until said allocating cannot be performed for an operation of one of said plurality of jobs.

46. The machine-readable medium of claim 42 wherein said job priority is determined based on one or more of an importance of a customer associated with said job, an importance of a product associated with said job, or a deadline for completing said job.

47. A machine-readable medium including code assessing sufficiency of a plurality of work centers for processing a plurality of jobs during a time interval, comprising:

machine-executable code for choosing a machine preference level as a current chosen level, said current chosen level being a highest level of all levels not yet chosen as a chosen level;

machine-executable code for selecting as a current job a highest priority job of a set of jobs having at least one operation requiring said current chosen level at a work center having an available machine; and

machine-executable code for allocating machine capacity to said current job across all work centers.

48. The machine-readable medium of claim 47 wherein said job comprises operations to be performed on a set of items and wherein said machine-executable code for allocating comprises:

machine-executable code for determining, for each work center, a maximum number of said items that can be processed; and

machine-executable code for selecting a minimum one of each said maximum number as a number of items of said job to be allocated.

49. The machine-readable medium of claim 47 further comprising machine-executable code for repeating said machine-executable code for selecting and said machine-executable code for allocating until either no further job in said set of jobs remains to be chosen as a current job or no further items in jobs in said set of jobs can be allocated.

50. The machine-readable medium of claim 49 further comprising machine-executable code for, after concluding said machine-executable code for repeating, said machine-executable code for selecting and said machine-executable code for allocating, repeating said machine-executable code for choosing, said machine-executable code for selecting, and said machine-executable code for allocating.

51. A computing device comprising a processor and persistent storage memory in communication with said processor storing machine readable instructions for directing said device to assess the sufficiency of a plurality of machines for processing a number of items, the device comprising:

means for obtaining machine availability information indicative of availability of said machines for processing said items;

means for obtaining machine capacity information indicative of a capacity of each of said machines for processing said items;

means for obtaining machine preference information indicative of a preference of each of said machines for processing said items;

means for determining a capacity constraint based on said machine availability information, said machine capacity information and said machine preference information; and

means for allocating at least some of said machines to process at least some of said items based on said machine availability information, machine capacity information and machine preference information, subject to said capacity constraint.

52. A computing device comprising a processor and persistent storage memory in communication with said processor storing machine readable instructions for directing said device to assess the sufficiency of a plurality of work centers for processing a plurality of jobs during a time interval, each work center having a group of machines for performing an operation, each job having a job priority and including one or more operations to be performed upon a set of like items, each machine having a preference level for processing the items associated with each job, said preference level being one of a range of machine preference levels, the device comprising:

means for determining which jobs of said plurality of jobs have an operation that is associated with a work center having an available machine whose preference level for processing the items associated with the job matches a current machine preference level, said current machine preference level having been selected from said range of machine preference levels in decreasing preference order, said determining resulting in a set of candidate jobs;

means for selecting from said set of candidate jobs a job whose job priority is at least as high as the job priority of any other job in said set of candidate jobs, said selecting resulting in a selected job, the items associated with said selected job being referred to as selected items; and

means for, at each work center associated with an operation of the selected job, allocating one or more machines having either said current machine preference level or a lower machine preference level in respect of the selected items to process a chosen number of units of the selected items, said allocating of machines being performed in decreasing order of machine preference level in respect of the selected items.

53. A computing device comprising a processor and persistent storage memory in communication with said processor storing machine readable instructions for directing said device to assess sufficiency of a plurality of work centers for processing a plurality of jobs during a time interval, the device comprising:

means for choosing a machine preference level as a current chosen level, said current chosen level being a highest level of all levels not yet chosen as a chosen level;

means for selecting as a current job a highest priority job of a set of jobs having at least one operation requiring said current chosen level at a work center having an available machine; and

means for allocating machine capacity to said current job across all work centers.