Murata LLA219C70G475ME01 Series Reference Sheet page 16

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
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
Printed circuit
board
(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
Recommended
JEMCAC-00640B
V-groove
Board cropping jig
Top blade
Printed circuit board
Top-bottom misalignment
Top blade
Bottom blade Bottom blade
Twisting
Recommended
Printed circuit
Components
board
Load point
Principle of operation
Top blade
Bottom blade
V-groove
Not recommended
Left-right misalignment
Top blade
Bottom blade
16
Not recommended
Direction of
Load point
load
Printed circuit
board
Components
Cross-section diagram
Printed circuit board
V-groove
Front-rear misalignment
Top blade Top blade
Bottom blade
! Caution
Direction of
load