7.Printed Circuit Board Cropping
1. After mounting a capacitor on a printed circuit board, do not apply any stress to the capacitor that caused bending or twisting the board.
1-1. In cropping the board, the stress as shown may cause the capacitor to crack.
Cracked capacitors may cause deterioration of the insulation resistance, and result in a short.
Avoid this type of stress to a capacitor.
[Bending]
[Twisting]
2. Check the cropping method for the printed circuit board in advance.
2-1. Printed circuit board cropping shall be carried out by using a jig or an apparatus (Disc separator, router type separator, etc.) to prevent the mechanical stress that can occur to the board.
Board Separation Apparatus
Hand Separation
Nipper Separation
Board Separation Method
1) Board Separation Jig
2) Disc Separator
3) Router Type Separator
Level of stress on board
Recommended
Medium
Medium
Low
◯
High
×
△*
△*
· Board handling
· Layout of slits
· Design of V groove
· Arrangement of blades
· Controlling blade life
Hand and nipper
separation apply a high
level of stress.
· Board handling
· Board bending direction
· Layout of capacitors
Notes
Board handling
Use another method.
ꢀꢀ * When a board separation jig or disc separator is used, if the following precautions are not observed, a large board deflection stress will occur and the capacitors may crack.
ꢀꢀ Use router type separator if at all possible.
ꢀ(1) Example of a suitable jig
ꢀꢀ [In the case of Single-side Mounting]
An outline of the board separation jig is shown as follows.
Recommended example:
Stress on the component mounting position can be minimized by holding the portion close to the jig, and bend in the direction towards the side where the capacitors are mounted.
Not recommended example: The risk of cracks occurring in the capacitors increases due to large stress being applied to the component mounting position,
if the portion away from the jig is held and bent in thedirection opposite the side where the capacitors are mounted.
[Outline of jig]
[Hand Separation]
Recommended
Not recommended
Printed Circuit Board
Direction of
load
Load point
Direction of load
V-groove
Printed circuit
board
Component
Components
Printed circuit
board
Load point
Board Cropping Jig
[In the case of Double-sided Mounting]
Since components are mounted on both sides of the board, the risk of cracks occurring can not be avoided with the above method.
Therefore, implement the following measures to prevent stress from being applied to the components.
(Measures)
(1) Consider introducing a router type separator.
ꢀIf it is difficult to introduce a router type separator, implement the following measures. (Refer to item 1. Mounting Position)
(2) Mount the components parallel to the board separation surface.
ꢀ
ꢀ
(3) When mounting components near the board separation point, add slits in the separation position near the component.
(4) Keep the mounting position of the components away from the board separation point.
GRM188R61H684KA75-01A
MURATA [ muRata ]
