EUKYX-199-4110_G5S2_Instruction_Vol4_E - 第358页
EUKYX 5-10 199-4100 3.1 Cause and Remedy of Placement Errors (2) Missing Component s on PCB (2 - 1 ) Situational Grasp of Error Generation The fol lowi ng three symptoms can be assumed regardi ng why some components are …
EUKYX
5-9199-4100
3.1 Cause and Remedy of Placement Errors
(1-3) Positional or Angular Deviation in Process D through E
When a positional deviation is not generated on the double-faced tape, it indicates that positional
and angular deviations occur in Process D through 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 fixation of PCB.
It is required to check these conditions and take individual countermeasures.
Positional/Angular deviations of component placement (2)
Vacuum nozzle
X
Vacuum nozzle is
moved down.
Component shifts in X-direction
during placement.
Positional/Angular deviations
PCB
PCB
F4E8
EUKYX
5-10199-4100
3.1 Cause and Remedy of Placement Errors
(2) Missing Components on PCB
(2-1) Situational Grasp of Error Generation
The following three symptoms can be assumed regarding why some components are missing.
• Some components were lifted up during placement.
• Some components sprang out due to vibrating PCB or vacuum break during placement.
• A component sprang out while the PCB is being discharged after placement.
The smaller the touch area with the PCB (solder paste) is in comparison with the component size,
the more frequently this type of failure occurs.
This applies commonly to these symptoms.
As shown in Fig. “F4E9”, power enough to hold a component will be given when square
components (resistors, capacitors, etc.) are used. However, the above symptoms may appear more
frequently when leaded components (transistors, diodes, etc.) are handled because of the small
touch areas.
Note
Square Component Leaded Component
The hatched area above shows the contact surface between component and solder paste.
PCB
Solder Paste
F4E9
EUKYX
5-11199-4100
3.1 Cause and Remedy of Placement Errors
(2-2) Machine-Based Factors
Shown below are the assumable main factors based on the machine.
When trouble occurs in some of the components (the components of the same type that have been
used in the past actual production), check for the following factors.
• Worn, Clogged, or Dirty Vacuum Nozzle
• Vacuum Nozzle Up/Down Movement Error
• Flow Rate of Broken Vacuum and Performance Error
• Improper Placement Height Level
• Imperfect Holding Power for Z Clamping
• Dirt and/or Nicks on Side View Camera
(3) Other Factors
The factors other than the machine-based ones are assumed to be the shape of the component, the
condition of the PCB, or the condition of solder paste or glue.
The factors are shown in the table below.
Check each item and take measures if necessary.
If no quick improvement can be made due to the condition of the PCB or solder paste, failures can
be avoided by slowing down the speed of the component placement or the PCB transfer.
Component
A foreign object exists on the upper surface of a
component and adheres to the vacuum nozzle.
There is a protruding portion on the upper surface of a
component, causing the lower surface of the vacuum
nozzle to wear out and an error during the teaching
operation through component recognition lighting.
Oil or mold lubricant adheres to the lower surface of a
component.
PCB Some PCBs vibrate during component placement
because the warpage is great.
Some PCBs are fixed imperfectly due to variations in
shape.
Glue
Shortage of Applied Glue
Solder Paste
Shortage of Applied Solder Paste
Shortage of Adhesion