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4OM-1603 5-1 1.ClassicationofFailureSymptomsandHelpfulHintsonCountermeasuresagainstFailure:Chap.5 1012-005 1. ClassicationofFailureSymptomsandHelpfulHints on Countermeasures against Failure 1.1 Cl…

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4OM-1603
1012-005 5-B
4OM-1603
5-1
1.ClassicationofFailureSymptomsandHelpfulHintsonCountermeasuresagainstFailure:Chap.5
1012-005
1. ClassicationofFailureSymptomsandHelpfulHints
on Countermeasures against Failure
1.1 ClassicationofFailureSymptoms
The machine processes can be classied into Processes A, B, C, D, and E as
shown below.
Reference
Refer to "4. Surface Mounting Mechanism" in "Chapter 1 (Vol. 1: Guide)" for
the outline of actions.
Process A : The placement head moves to the feeder base and picks up a
component.
Process B : The head moves to the area where the component recognition
camera is installed and a component recognition process is
taken there.
Process C : The placement angle is corrected while the head is moving to
the PCB positioning section.
Process D : The component is placed on the PCB.
Process E : The component-placed PCB is discharged.
1
2
3
Feeder Base Section
Component Recognition Camera
PCB Positioning Section
Process A
Process B
Process C
Process D
Process E
F4E1
Based on these processes, failures can be divided roughly into the following two
types.
Failure before Component Placement : This type of failure occurs mainly in
Processes A, B, and C.
Failure after Component Placement : This type of failure occurs mainly at
Processes D and E.
4OM-1603
5-2
1.ClassicationofFailureSymptomsandHelpfulHintsonCountermeasuresagainstFailure:Chap.5
Failures can further be classied as shown in the table below.
Classicationof
Failures
Contents of
Failures
Symptom of Failures
Failure before
Component
Placement
Component Pickup
Error
Components cannot be picked up.
Components are turned vertically.
A recognition error occurs.
Components fall down.
Others
Failure after
Component
Placement
Component
Placement Error
The positional and angular deviation of
component occurs.
Components are turned over and placed.
Some components are missing.
Some components are cracked or nicked.
Others
T4E1
1.2 Helpful Hints on Countermeasures against Failure
•
The rst helpful hint on countermeasures against failure is to catch precisely
what kind of symptom is produced and how frequently the symptom appears.
•
The second helpful hint is to grasp the tendency (environment and condition) of
a failure.
Shown below are the concrete items to be checked.
(1) Check if the failure occurs on specic components.
(2) Check if the failure occurs on a specic production lot.
(3) Check if the failure occurs on a specic machine.
(4) Check if the failure occurs at a limited stage.
•
The third helpful hint is to nd in which process the failure occurs.
In normal cases, a failure after component placement is found in the nal
inspection process. In such a case, it is required to track the failure by checking
all processes and specify the process in which the failure has occurred.
It is very important to grasp a failure symptom precisely on these helpful hints.
Precise capture of a failure symptom makes it possible to track the factor and
make a plan to take countermeasures against the failure.
In the case that the present status is not grasped correctly, the countermeasure
for the error takes time due to the execution of ineffective measures.
In particular, for the errors with low occurrence rate, it is required to collect the
data accurately, estimate the factors based on the data collection results, and
take the countermeasure.
1012-005