The Department of Clothing Design and
Technology The Department of Clothing Design and
TechnologyOnce the possible allocations have been obtained from the DSS, each solution can be examined in more detail using simulation (COATS).
The user selects the appropriate Team/style configuration and determines the simulation length (here, one day).
The image shows the coats display after about an hour of production. The screen shows the 16 workstations and 4 operators. At this stage, 17 garments have been produced and the line efficiency is 76.3%. Most of the operators are near the end of their pitches.
The image below shows production a minute later. The final operator completed the garment on workstation 16, placed it on the output buffer, then moved clockwise to take work from operator 3. Operator 3 then takes work from operator 2 and operator 2 takes from operator 1. Operator 1 brings new work into the line. This screen shows all operators near the beginning of their pitches.
At the end of the simulated day, which takes a few seconds of computer time, the user can access a Summary Report. Looking first at the TALLY VARIABLES, the average team performance is 83% and the number of garments produced (the number of observations) is 158. Additional infomation on machine and worker utilisations is available on screen, as displayed in the table below.
TALLY VARIABLES
Identifier Average Variation Minimum Maximum Observations
____________________________________________________________________
PRODUCTION RATE 179.08 .14115 131.90 251.07 157
TIME IN SYSTEM 822.48 .03563 628.99 891.57 158
Team Performance 82.891 .10483 25.157 87.020 158
DISCRETE CHANGE VARIABLES
Identifier Average Variation Minimum Maximum Observations
____________________________________________________________________
Machine.1 util. .24640 1.7488 .00000 1.0000 .00000
Machine.2 util. .33388 1.4214 .00000 1.0000 .00000
Machine.3 util. .39306 1.2426 .00000 1.0000 1.0000
Machine.4 util. .15961 2.2945 .00000 1.0000 .00000
Machine.5 util. .38066 1.2755 .00000 1.0000 .00000
Machine.6 util. .11527 2.7704 .00000 1.0000 .00000
Machine.7 util. .16721 2.2317 .00000 1.0000 .00000
Machine.8 util. .26330 1.6727 .00000 1.0000 1.0000
Machine.9 util .08282 1.6727 .00000 1.0000 .00000
Machine.10 util. .21331 1.9204 .00000 1.0000 .00000
Machine.11 util. .03088 5.6022 .00000 1.0000 .00000
Machine.12 util. .33299 1.4152 .00000 1.0000 .00000
Machine.13 util. .05123 4.3033 .00000 1.0000 1.0000
Machine.16 util. .28153 1.5975 .00000 1.0000 .00000
Worker.1 util. 1.0000 .00000 .00000 1.0000 .00000
Worker.2 util. .85561 .41081 .00000 1.0000 1.0000
Worker.3 util. .82159 .46599 .00000 1.0000 1.0000
Worker.4 util. .98008 .14257 .00000 1.0000 1.0000
Looking more closely at the Worker Utilisations:
Operator 1 is used 100%; Operator 2 is used 86%; Operator 3 is used 82%; Operator 4 is
used 98%
This suggests the redesign of the layout to enhance the utilisation of operators 2 and 3.
Table 1. TEAM/STYLE: 3/7/905
_____________ ____________________________________________________
| | | |
|Solutions | Operations allocated to | Simulated |
| | Operator (Utilisation %) | Production |
| |--------------------------------------| |
| | 301 | 302 | 303 | 304 | (garments) |
|_____________|________|________|_________|__________|_____________|
| | | | | | |
|1st Solution | 1 to 4 | 4 to 8 | 8 to 12 | 12 to 16 | 158 |
|by DSS | (100) | (86) | (82) | (98) | |
|_____________|________|________|_________|__________|_____________|
| | | | | | |
|2nd Solution | 1 to 4 | 4 to 8 | 8 to 12 | 12 to 16 | 156 |
|by DSS | (100) | (91) | (88) | (98) | |
|_____________|________|________|_________|__________|_____________|
Table 1
This table summarises the results of an experimental programme with simulation to
investigate two solutions proposed by the DSS. In both cases, the pitches are identical:
pitch 1 comprises workstations 1 - 4, pitch 2 comprises workstations 4 - 8, and so on.
Both of the solutions proposed by the DSS show low operator utilisations on pitches 2 and 3 when simulated. We shall consider improvements to Solution 1 (which is the better of the two).
Table 2. TEAM/STYLE: 3/7/905
______________ ____________________________________________________
| | | |
|Solutions | Operations allocated to | Simulated |
| | Operator (Utilisation %) | Production |
| |--------------------------------------| |
| | 301 | 302 | 303 | 304 | (garments) |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|1st Solution | 1 to 4 | 4 to 8 | 8 to 12 | 12 to 16 | 158 |
|by DSS | (100) | (86) | (82) | (98) | |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|2nd Solution | 1 to 4 | 4 to 8 | 8 to 12 | 12 to 16 | 156 |
|by DSS | (100) | (91) | (88) | (98) | |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|1st Suggestion| 1 to 3 | 3 to 8 | 8 to 12 | 12 to 16 | 168 |
| | (100) | (99) | (92) | (98) | |
|______________|________|________|_________|__________|_____________|
Table 2.
By moving the overlap station to Workstation 3, more work should pass to operators 2 and
3. This revised layout has been simulated, and the result is 168 garments in the day, and
higher operator utilisations.
Table 3. TEAM/STYLE: 3/7/905
______________ ____________________________________________________
| | | |
|Solutions | Operations allocated to | Simulated |
| | Operator (Utilisation %) | Production |
| |--------------------------------------| |
| | 301 | 302 | 303 | 304 | (garments) |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|1st Solution | 1 to 4 | 4 to 8 | 8 to 12 | 12 to 16 | 158 |
|by DSS | (100) | (86) | (82) | (98) | |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|2nd Solution | 1 to 4 | 4 to 8 | 8 to 12 | 12 to 16 | 156 |
|by DSS | (100) | (91) | (88) | (98) | |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|1st Suggestion| 1 to 3 | 3 to 8 | 8 to 12 | 12 to 16 | 168 |
| | (100) | (99) | (92) | (98) | |
|______________|________|________|_________|__________|_____________|
| | | | | | |
|2nd Suggestion| 1 to 3 | 3 to 8 | 7 to 12 | 12 to 16 | 170 |
| | (100) | (99) | (98) | (98) | |
|______________|________|________|_________|__________|_____________|
Table 3.
The 1st suggestion was certainly an improvement, but the utilisation of the 3rd operator
is still low. By broadening the overlap between pitches 2 and 3, the utilisations of all
operators is 98% or more and the production total 170. Here, simulation is being used as a
tool for improving the pre production design.
Next: 5. Overview
1. The Database 2. Production Scheduling 3. Decision Support System 4. Coats Simulation 5. Overview