7.Printed Circuit Board Cropping
1. After mounting a capacitor on a printed circuit board, do not apply any stress to the capacitor that is
caused by bending or twisting the board.
1-1. In cropping the board, the stress as shown right may cause the capacitor to crack.
Try not to apply this type of stress to a capacitor.
Bending
Twisting
2. Check of 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 to prevent the
mechanical stress which can occur to the board.
(1) Example of a suitable jig
Recommended example: the board should be pushed as close to the near the cropping jig as possible
and from the back side of board in order to minimize the compressive stress applied to capacitor.
Not recommended example* when the board is pushed at a point far from the cropping jig and from
the front side of board as below, the capacitor may form a crack caused by the tensile stress applied
to capacitor.
Outline of jig
(2) Example of a suitable machine
An outline of a printed circuit board cropping machine is shown as follows. Along the lines with the
V-grooves on printed circuit board, the top and bottom blades are aligned to one another when
cropping the board.
The misalignment of the position between top and bottom blades may cause the capacitor to crack.
Outline of machine
Principle of operation
Cross-section diagram
Top blade
Top blade
Top blade
Top blade
Bottom blade
Bottom blade
Bottom blade
Bottom blade
Caution
Recommended
Not recommended
Top-bottom misalignment
Left-right misalignment
Front-rear misalignment
Recommended
Not recommended
Printed circuit
board
V-groove
Board cropping jig
Printed circuit board
Top blade
V-groove
Bottom blade
Load point
Direction of
load
Components
Printed circuit
board
Direction of
load
Load point
Components
Printed circuit
board
Top blade
Printed circuit board
V-groove
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JEMCNC-0012L
18
