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User Manual Line Computer UNIX 11 Production Tools / Optimization Software Version 501.xx 01/99 Issue 11.4 Optimization Dialog 11 - 27 - DETERMINATION OF RUN TIME: Optimiza tion ru n time incre ases exp onentiall y with …
11 Production Tools / Optimization User Manual Line Computer UNIX
11.4 Optimization Dialog Software Version 501.xx 01/99 Issue
11 - 26
- Filling up changeover tables
This parameter permits you to specify that on the changeover tables components from the initial setup
are to be included in the follow-up setup, even if they are not required. The setup changeover effort
can thus be kept to a minimum.
Note: This parameter only affects Clustering.
- Fixed set-up components to be set up only once
This parameter is only relevant where a fixed setup is defined. It is possible to define whether or not a
component already contained in the fixed setup is allowed to be set up by Optimization at another or
several other locations that may be more advantageous.
- Allocate components to empty feeder compartments
Activation of this parameter causes empty compartments or feeders to be removed from the fixed
setup so that they are available for reallocation by the setup optimization. New feeders will only be set
up if required.
- Remove components that are not required from fixed set-up
This parameter is used to define that components that are not contained in the PCB types to be opti-
mized will be removed from the fixed setup and made available for reallocation by the setup optimiza-
tion. New components can only be added to the fixed setup if the button "Allocate components to empty
feeder compartments" is activated in addition (see above).
Dynamic changeover procedures are supported. If a setup family was formed by, let’s say, five pro-
ducts, such setup family can be used as a fixed setup for a new setup optimization run if two products
were removed and two new products were added. No changeover procedures need therefore be per-
formed for the three remaining products, and hence no tests have to be performed. This results in
considerable time savings. The two new products will be optimally integrated into the ’stripped down’
fixed setup thus allowing for a continuous dynamic setup optimization process.
- Maximum number if dominant
This parameter allows you to define the maximum number of times a dominant component type may
be set up. If only a minimum of setups is to be created, the number of feeders in the case of domi-
nance should be limited to 1. With the setting of 0, Set-Up Optimization can decide on its own how
often the component type at issue is to be set up.
User Manual Line Computer UNIX 11 Production Tools / Optimization
Software Version 501.xx 01/99 Issue 11.4 Optimization Dialog
11 - 27
- DETERMINATION OF RUN TIME:
Optimization run time increases exponentially with the number of jobs. The quality of the setup can be set
via the run time: long run time -> good setup, short run time -> poor setup. The run time of Optimization
can be limited. Once the preset run time is exceeded, or the preset number of iteration steps completed,
Optimization is aborted. The best solution hitherto found continues to be used.
Optimization can produce reproducible (parameter: no. of iteration steps) and non-reproducible results
(parameter: Board Booster: Program run time per lot).
- Board Booster: Program run time per lot [sec]
This parameter allows you to define how long Optimization is to run for a given job. By multiplication
with the number of jobs contained in a lot file it is possible to determine the total run time of Optimiza-
tion for that lot file. A more optimized setup is computed requiring, however, more computing time. The
optimization results are not reproducible.
- No. of iteration steps
This parameter allows you to define how many Optimization runs (iteration steps) are to be performed
until a setup is established. Thereafter, Optimization is aborted and the best setup selected. The opti-
mization results are reproducible, however the time required for optimization cannot be precisely pre-
determined.
Meaning of the buttons
- Reset
This button is used to reset the standard values to the default values. They are deleted when so doing.
- OK
This button is used to accept the modified values.
- Cancel
This button is used to discard the modified values and to restore the previous state.
11 Production Tools / Optimization User Manual Line Computer UNIX
11.4 Optimization Dialog Software Version 501.xx 01/99 Issue
11 - 28
11.4.3.2 Examples of Parameter Settings
The parameter settings for Set-Up Optimization greatly depend on the frequency of setup changeover
operations taking place during a production run.
Three examples have been selected to show how the parameters can be set in different production situations:
● highly flexible production: many different jobs are processed in a very short time with the setup
changeover operations required.
● flexible production: frequent setup changeover operations are carried out whereby identical jobs are
also processed over and over.
● inflexible production: only one single setup is used for production over a long period of time.
Example 1: Highly flexible production
Setup problem:
In the case of a highly flexible production, setup changeover operations are performed daily in order to
produce new products. Setup changeover is carried out job-specifically.
Objective:
A setup is to be calculated for a given job as fast as possible. As little time as possible is to be expended
on the setup changeover. Production time plays is of minor importance.
Parameter settings:
● Clustering according to the Sequence method.
● Maximum number (feeders) if dominant: 1.
● No. of iteration steps: 1
(With a setting of 0 one single setup is created. It is, however, not optimized. This is the fastest
method for obtaining a setup.).
Lot file setting:
● Set the lot size to 1 so that only the setup changeover time is of importance.
● Enter an initial setup, i.e. the current setup of the line.