00191017-01 - 第320页

11 Production Tools / Optimization User’s Manual Line Computer UNIX 11.4 Optimization Dial og Software Version 403.xx Edition 06/97 11 - 26 - Maximum number if dominant This param eter all ows you to define th e maximum …

User’s Manual Line Computer UNIX 11 Production Tools / Optimization

Software Version 403.xx Edition 06/97 11.4 Optimization Dialog

11 - 25

SETUP CHANGEOVER TIMES

Set-Up Optimization requires a basis for the calculation of the changeover times. The parameters listed in

the following can be set to specify how much time is required for setup changeover operations.

Basic time for set-up changeover [sec]:

The basic time refers to the time that elapses between the

last placement from the predecessor setup and the first placement of the follow-up setup. The actual

setup changeover times are not included in the calculation. The default setting is 600 sec.

Trolley changeover time [sec]:

Estimated time required for the removal and installation of a compo-

nent changeover table. While the placement process continues, the feeders are prepared, away from

the line, on a second changeover table. The changeover table is then exchanged completely during the

changeover procedure. The default setting is 180 sec (= 90 sec for taking down + 90 sec for setting up).

To be able to use this parameter, a feeder part must be defined as component changeover table in the

Configuration Editor (see chapt. 12).

Feeder changeover time [sec]:

Estimated time required for the removal and installation of a feeder

on a fixed component table. The feeders are prepared outside the line with the placement process

continuing. They must be changed over individually; this is why the time required for the setup

changeover increases with the number of machine components to be changed over. The default set-

ting is 60 sec (= 30 sec for taking down + 30 sec for setting up).

COMPONENT TYPE

The following parameters can be set for the component supply units. They will affect - with one exception -

the entire setup optimization.

WPC refilled 100%

In a setup, not all levels of the Wafflepack Changer need necessarily to be occupied by

components.

This parameter permits you to specify that Optimization is to assign components to all empty trays as

well, i.e. in accordance with their usage frequency rate across all PCBs of a lot file.

Using the nozzle changer configuration

This parameter permits you to specify that the current configuration of the respective nozzle changer

is to be used and not to be changed by Set-Up Optimization.

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.

11 Production Tools / Optimization User’s Manual Line Computer UNIX

11.4 Optimization Dialog Software Version 403.xx Edition 06/97

11 - 26

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.

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: program run time per lot).

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. 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.

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.

User’s Manual Line Computer UNIX 11 Production Tools / Optimization

Software Version 403.xx Edition 06/97 11.4 Optimization Dialog

11 - 27

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.

Effect:

From the initial setup a follow-up setup is computed in the shortest possible amount of time, having the

following features:

●

A minimum changeover time from the initial setup to the follow-up setup is achieved.

●

Every component is set up only once. The dominance of components is suppressed.

●

Feeders with two compartments that are taken over from the initial setup and integrated into the

follow-up setup remain set up on the exactly same tracks as before.

●

Components of the initial setup that are not required remain at their location.