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Session 16Scheduling System Examples

• The PAC Data Base

• Twin Disc Shop-Floor Control Report

• Finite Loading Example

• Steelcase Vendor Scheduling Report

• Concluding Principles

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The PAC Data Base

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Twin Disc Shop-Floor Control Report

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Twin Disc Example

The shop floor report at Twin Disc shows the six orders that are currently in the BH machine center. The report also shows the next nine orders that are set to arrive at the BH machine. What would the order processing sequence be at the BH machine center under the two following situations?

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Twin Disc Examplea. The first five orders in previous work centers arrive at machine center BH (i.e., 443C31

- 446A10) before any of the current orders are started on the BH machine.

ORDER # _OP #_ __PO__ __PI__

438C34 020 .436443C31 010 .437444C98 010 .462446A09 010 .742446A07 010 .907445C22 010 1.236446A10 010 1.388445C67 020 .430445B45 010 2.675445B45 020 2.675441B22 010 4.106

All jobs that are actual orders (PO’s) have priority over jobs that are for inventory (PI’s).

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Twin Disc Exampleb. The last four orders in previous work centers arrive at machine center BH (i.e., 445C90

- 446A08) before the other five, and no orders are started yet on the BH machine.

ORDER # __OP #__ __PO__ __PI__

438C34 020 .436445C22 010 1.236445C67 020 .430445C90 020 2.006446B17 010 2.215445B45 010 2.675445B45 020 2.675444A44 010 3.632446A08 010 4.105441B22 010 4.106

All jobs that are actual orders (PO's) have priority over jobs that are forinventory (PI's).

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Bedford Machine ShopThe Bedford Machine Shop's production scheduler has just received the following order:

Order no. 6243:Operation number 1 2 3 4Machine number 3 1 2 4Estimated time* 5 3 8 4*In standard hours.

a. Bedford allows two days between machine operations for queue time, material handling time, and so on. The shop works five days per week on a single work shift, and no overtime is planned for the near future. Given the following loads at each machine center, determined by finite scheduling in the machine shop, set up a schedule for each operation on the new job and indicate when this order can be shipped. (None of the currently scheduled jobs can be changed.)

WeekMachine # Capacity* 1 2 3 4 5 6 _7_ 1 40 40 40 30 20 15 10 5 2 40 40 25 40 40 35 30 40 3 40 20 15 10 5 2 - - 4 40 40 40 40 40 36 34 30*ln standard hours.

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Bedford Machine Shop: Solutiona. Order No. 6243

Operation Machine Estimated Week Start Finish MoveNumber Number Time* Scheduled Time Time Complete1 3 5 1 21 26 422 1 3 3 31 34 503 2 8 5 36 44 604 4 4 6 35 39*In standard hours

This order is completed at the end of the sixth week. It depends on thematerial handling and paperwork time whether it can be shipped in week six(only one hour remains in the week).

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Bedford Machine Shop: Solution (Continued)

b. Given the information displayed in the shop load table, what capacity recommendations would you make to management?

There are heavier loads at machine center 2 and 4 than at 1 and 3. Can these be made more equal (capacity expanded, alternate routing, etc.)?

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Steelcase Requirements

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Concluding Principles

• Production activity control system design must be in concert with the firm's needs.

• The shop-floor control system should support users and first-line supervisors, not supplant them.

• Vendor capacities should be planned and scheduled with as much diligence as are internal capacities.

• Lead times are to be managed.• Organizational goals and incentives must be congruent

with good PAC practice.• Discretion and decision-making responsibilities in

production activity control practice need to be carefully defined for both the shop and vendors.

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Concluding Principles

• PAC performance should be defined and monitored.• Feedback from PAC should provide early warning and

status information to other MPC modules.• Automated reading systems and distributed computers

should facilitate data acquisition and shop-floor decision making.

• Data base design and integrity must be assessed for PAC systems to be effective.

• The ongoing evolution in PAC systems as firms increasingly adopt world class manufacturing methods is reduced detail, smaller data bases, and simpler systems.