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User Manual Line Computer UNIX 11 Production Tools / Optimization Software Version 501.xx 01/99 Issue 11.3 Setup Optimization 11 - 15 11.3.3.11 Handling of Dominant Vibration Times In some inst ances the plac ement time …
11 Production Tools / Optimization User Manual Line Computer UNIX
11.3 Setup Optimization Software Version 501.xx 01/99 Issue
11 - 14
11.3.3.8 Inclusion of Changeover Tables in Clustering
As soon as more than one setup is calculated, setup changeover operations on changeover tables play a role.
A changeover table denotes a feeder part that can be completely exchanged by means of a lift-truck. The
feeders are considered as being preset thus not causing any increase in the setup changeover effort.
Optimization proceeds from the assumption that the setup changeover time to be expended for feeder parts
that are identified as changeover table only consists of the changeover time of the changeover table irrespective
of the number of feeders whose setup is to be changed.
The identification of the feeder parts as changeover tables can be performed in the Configuration Editor for the
stations (see chapt. 12, section 12.1).
The setup changeover time can be entered together with the optimization parameters (see section 11.4.3.1).
Effects:
- Short setup changeover time: More feeders are set up in the fixed feeder part.
- Long setup changeover time: More feeders are set up on the changeover table.
11.3.3.9 Inclusion of a Basic Time in Clustering
As soon as more than one setup is calculated, the basic time plays a role in the setup changeover procedure.
The basic time comprises the time elapsing between the last placement from the predecessor setup and the
first placement of the follow-up setup. The changeover times are not taken into account.
Effects:
- Short basic time: More setups are created. The focus of the changeover procedures is placed on the
changeover tables.
- Long basic time: As few setups as possible are created. Setup changeover operations on fixed
feeder parts are permitted.
11.3.3.10 Handling of Dominant Components
If the placement time of a component on a given PCB type is so high owing to its high usage frequency that
the production of the PCB would result in an imbalance even if the fastest placement head were used, such a
component must be supplied in feeders on several stations of the line. The placement positions associated with
the component can be distributed among the stations thus preventing an imbalance of the line from occurring.
The number of feeders required for the dominant component depends on
- the proportion of the imbalance
- the number of placement positions
- and the number of heads by means of which the component can be placed.
However, if a dominant component is not to be set up any number of times, e.g. because a sufficient number
of feeders is not available, the number of feeders per component type can be restricted. This has the advantage
that a component type occupies only a limited number of feeder locations. However, this may result in an
increase of the production time since the components are not always located at the most advantageous
locations. Moreover, several setup clusters („families“) may under certain circumstances be calculated even
though one single setup would have sufficed.
This setting is to be set in the standard/job parameters by means of the „Maximum number if dominant“
parameter (see section 11.4.3.1).
User Manual Line Computer UNIX 11 Production Tools / Optimization
Software Version 501.xx 01/99 Issue 11.3 Setup Optimization
11 - 15
11.3.3.11 Handling of Dominant Vibration Times
In some instances the placement time largely depends on the vibration times of the feeders. This is always the
case if the turret head needs to place the same component type very frequently. In this case, the turret head
accesses the same feeder compartment several times in succession. Owing to the fact that in most instances
the pick-up speed of the turret head is greater than the feeding speed of the feeder, waiting times are likely to
occur. To prevent this from happening, components with a high usage rate are set up at several locations.
Prerequisite: If the percentage of the placement positions of a particular component is larger than or
equal to 20% compared with the total placement positions to be populated by the turret
head, and if the vibration time of the feeder is longer than the the cycle time of the turret
head, the component is set up a second time provided the capacity of the feeder part
concerned is sufficiently large.
However, if a dominant component is not to be set up any number of times, e.g. because a sufficient number
of feeders is not available, the number of feeders per component type can be restricted. This has the advantage
that a component type occupies only a limited number of feeder locations. However, this may result in an
increase of the production time since the components are not always located at the most advantageous
locations. Moreover, several setup clusters („families“) may under certain circumstances be calculated even
though one single setup would have sufficed.
This setting is to be set in the standard/job parameters by means of the „Maximum number if dominant“
parameter (see section 11.4.3.1).
11.3.3.12 Nozzle Minimization
In „nozzle minimization“ the number of nozzles per head and PCB type is used for the calculation.
● For the IC-head, nozzle minimization is carried out per PCB type.
● Also for the turret head, a nozzle minimization run is performed for each PCB type.
Furthermore, the particular nozzle configuration at the head is determined which results in a minimum of
placement cycles.
NOTE
The nozzle configuration can be displayed with the producibility check results.
11.3.3.13Times Taken Into Account
For setup optimization the times listed in the following are taken into account:
● Time required for one movement of the IC-head or turret head, respectively.
To be able to calculate the placement times as accurately as possible, time functions were recorded
at selected placement machines. These times were measured separately for SIPLACE 80S/80F and
HS-180 machine types.
11 Production Tools / Optimization User Manual Line Computer UNIX
11.3 Setup Optimization Software Version 501.xx 01/99 Issue
11 - 16
In addition to the machine type, the time functions are also dependent on the different head types such as
turret head and IC-head as well as the 3 axes x, y and z.
The time functions determined at the placement machines are directly included in the calculation of the
placement times.
● Non-productive times of IC head and turret head
ROPT takes non-productive times into consideration.
For the IC head, the non-productive times for the following operations are allowed for:
● external optical centering dependent on sensor system type
● coplanarity measurement dependent on sensor system type
The non-productive times for the 2 operations listed above are contained in the package form description
(.gf). They are added as additional constant time values to the placement time of each component to be
centered optically, or to be subjected to coplanarity measurement.
The times are computed automatically upon saving the GF-file and entered irrespective of the sensor system
type; they cannot be changed.
This added time is extra time to be expended as compared to the normal placement time.
● Measurement of local fiducials
● Waffle-pack magazine exchange
dependent on the required nozzle types (i.e. the exchange of waffle-pack trays has priority over the
nozzle change)
● Times required for nozzle change
For the turret head, the non-productive times for the following procedure are taken into account:
● Measurement of local fiducials
● Waffle-pack magazine exchange