2. WORK-STATION PRODUCTION MODELS:
FILE NAME: FLOW1
FUNCTION: Scheduling a single work station
OVERVIEW: Four alternative macros are available to develop job schedules.
1. <CNTL> A schedules jobs in first-come, first-served (FCFS) order, almost always the worst thing you can do.
2. <CNTL> B develops a schedule that minimizes average flow time, defined as the time from the kick-off date until the last job is complete.
3. <CNTL> C minimizes the maximum number of days that any job is late.
4. <CNTL> D minimizes the number of late jobs. This is done by sorting the jobs in due date order and then moving "barrier" jobs to the end of the schedule as necessary to that other jobs can be done on time. It is important to understand that objectives B, C, and D usually cannot be met at the same time.
For example, the schedule that minimizes flow time may result in an unacceptable number of jobs late.
INPUT: Enter the kickoff date (the first work day) in cell E10 (C8 for Lotus Windows version). The date is entered as follows:
=DATE(year, month, day); March 1, 1993 is entered as
=DATE(93,3,1). Instead of typing the entire command, you can place cursor on cell, press F2, and backspace over the numbers you need to correct. Enter job names, order dates, due dates, and work days (processing time) beginning at row 20 in columns C-G. In column C, staring at row 31, enter a 1 opposite each off day (when no work is to be scheduled).
OUTPUT: Hold down the <CNTL> Key and press one of the letter keys A - D. When the macro stops, the jobs are in the correct sequence in rows 20-25. Average flow time, the maximum number of days any job is late, and the number of late jobs are computed in range H11..H13. Range N20..N25 lists the number of days late for each job. A negative number in this range means the job is early. The calendar in rows 31-68 shows the job in progress on each day. You can enter notes in Column I, rows 31 and below. Pressing <F10> produces a bar chart showing which jobs are early, on-time, and late. Another graph of same data is on separate sheet, you can click on tab to view additional bar chart.
MODIFYING THE WORKSHEET:
To add more jobs, place the cursor at any row between the first job and the last and insert one new row for each additional job. Then, copy the formulas in columns H..R from the row above the first blank row to all newly inserted blank rows. For example, in the example place cursor at row 21 and insert one new row for each additional job. Then copy formulas in range H20..R20 to row containing the last job. You must also extend the calendar to cover sufficient days for the schedule. Proceed in same manner as above, copying formulas in columns C..G to blank entries. It is easy just to insert at the second to last entry. You will then need to verify column C has the right values for the newly inserted rows. You can make the calendar as long as you wish, the worksheet simply ignores days beyond the end of the schedule.
1. Get Started
2. Workstation Production Models
3. Scheduling 2 Workstation in Series
4. Scheduling 3 Workstation in Series
5. Scheduling 4 and more Workstation in Series
6. Scheduling 2 Workstation in Parallel
7. Project Management - Daily Schedule
10. Gantt Charting