4OM-1603-007_w.pdf - 第371页
4OM-1603 5-8 3. T roubleshooting on Placement Errors : Chap.5 3. T roubleshooting on Placement Errors 3.1 Cause and Remedy of Placement Errors (1) Positional and Angular Deviations of Component Placement (1-1) Situationa…
4OM-1603
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2. Troubleshooting on Pickup Errors : Chap.5
Sprocket
Dirt and/or
Component Adhesion
Suppressor
Lifting, Deformation,
and/or Component
Adhesion on
Inner Side
Front Hook
Deformation
Cover Tape
Take-Up Gear
Dirt and/or
Component Adhesion
Clearance, Deformation,
and/or Dirt
Pickup Position
Peeling Area
Positioning and/or
Elimination of Positional Deviation
F4E5
Cover Tape
Take-Up Gear
Dirt and/or
Component Adhesion
Threading of Cover Tape
This should be mounted
correctly.
F4E6
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3. Troubleshooting on Placement Errors : Chap.5
3. Troubleshooting on Placement Errors
3.1 Cause and Remedy of Placement Errors
(1) Positional and Angular Deviations of Component Placement
(1-1) Situational Grasp of Error Generation
Positional and angular deviations may be generated in either Process C or D
and E.
See Fig. 4E1.
By placing a component on the PCB where a double-faced adhesive tape is
afxed, it can be checked and determined in which process positional and
angular deviations are generated.
When a positional deviation is generated on the double-faced tape, it
indicates that positional and angular deviations occur in Process C.
When no positional deviation is generated, it means that positional and
angular deviations occur in Process D or E.
(1-2) Positional and Angular Deviations in Process C
When a positional deviation is generated due to the movement of the head
after component recognition or a rotational deviation by placement angle
correction, the deviation may be caused mainly by the following two factors.
•
Deterioration of Vacuum Suction Force
•
Vibration or Shock during Nozzle (Head) Movement
When one of the above factors exists, unstable components (components that
cannot be picked up in stable condition) such as those shown in F4E7 are
directly affected.
When a positional deviation is generated on the components (the components
of the same type that have been used in the past actual production), check for
the above-described factors.
As for vacuum suction force, check the nozzle and the vacuum line.
As for vibration during nozzle movement, check the related spots in the
range of Process C.
Easily-Dislocated Components during Placement (Example 1) F4E7
Note
When there is a protruding portion on the upper surface of a component,
the lower surface of the vacuum nozzle may be worn out, causing an error
during the teaching operation through component recognition lighting.
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3. Troubleshooting on Placement Errors : Chap.5
(1-3) Positional or Angular Deviation in Process D or E
When a positional deviation is not generated on the double-faced tape, it
indicates that positional and angular deviations occur in Process D or E.
As a symptom at this time
•
The component is dislocated right after it is placed.
•
The component is dislocated during operation subsequent to the placement.
•
The component is dislocated during PCB discharge operation subsequent
to the placement.
The causes in the above cases lie in the factors affected commonly by the
shape of the component, the condition of the PCB, or the condition of solder
paste or glue.
F4E8 is an example, which shows that a component is dislocated right after
it is placed due to the upper and lower surfaces of the component not parallel
to each other.
A force is generated and moves the component in the X direction at the
moment when the lower surface touches the PCB during placement.
This leads to the positional and angular deviations of the component
placement.
When this type of component is used, this failure may be avoided by slowing
down the placement speed or slightly increasing the nozzle descent level for
the placement.
Some components may be dislocated easily during the backup base
movement or a PCB discharge operation after they are placed.
The factor may be weak holding power of solder paste or glue or imperfect
xation of PCB.
It is required to check these conditions and take individual countermeasures.
Easily-Dislocated Component during Placement (Example 2) F4E8
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