(4)Should be no seriously collapsing problem and edges neatly after solder paste had been printed, the dislocation shouldn’t
be larger than 0.2 mm, for solder pad of fine pitch components, dislocation shouldn’t be larger than 0.1MM, pollution by
solder paste is not permitted to the PCB.
Inspection by 2~5 times magnifier or 3~20 times microscope.
12.3.3
The defects of solder paste printing, reasons andsolutions
Excellent printing graphics should be uniform in both vertical and horizontal direction, full, clean all round, solder paste fill
solder pad. Using above such printing graphics device, after reflow soldering, will get good welding effect then.
Problem
Reason
Issue
Solution
Solder paste
graphics
dislocation
Holes on the stencil not good
match with solder pad; No
enough precision of the Printing
machine
easily cause bridge
connection
Adjust the stencil position;
Adjust the printing
machine
Solder paste
graphics have
icicles and dents
Scraper pressure is too large;
Rubber scraper hardness is not
enough; Holes are too big in the
stencil
Solder paste required
volume is not enough,
easy to appear faulty
soldering; solder joint
strength is not enough.
Adjust the printing
pressure; Use metal
scraper; Improved holes
designing in the stencil.
Too much solder
paste
Holes are too big in the stencil;
The gap is too big between
stencil and PCB
easily cause bridge
connection
Check the holes size in
stencil; Adjust the
parameters of printing,
especially the gap between
PCB and stencil
Graphic uneven
(have
breakpoints)
Holes’ wall are not smoothness
enough; not wipe residual solder
paste in using for many times;
Solder paste’s thixotropy is bad
Easy cause no enough
solder paste, lead to the
problem such as faulty
soldering.
Wipe the stencil
Contamination of
the graphics
Not wipe residual solder paste in
stencil after using for many
times; Poor quality of solder
paste; Shake problem when
getting the stencil way
easily cause bridge
connection
Wipe and clean stencil;
replace solder paste; adjust
the machine
52
Zhejiang
NeoDen Technology Co.,Ltd.
Содержание K1830
Страница 6: ...1 3Working Area Structure Figure 3 Top view of main mounting area 6 Zhejiang NeoDen Technology Co Ltd ...
Страница 7: ...Figure 4 X axis Beam Figure 5 Main Placement Head Camera 7 Zhejiang NeoDen Technology Co Ltd ...
Страница 35: ...8 2 Component Positions Setup 35 Zhejiang NeoDen Technology Co Ltd ...
Страница 44: ...11 Structure and maintenance instruction 11 1 Feeder Brief Introduction 44 Zhejiang NeoDen Technology Co Ltd ...