How to control and protect the MSD component effectively
The influence to the qualified rate of SMT and the credibility of the product
is not weaker compared with the ESD, so it is the responsibility of the SMT that
can't be shirked to know the importance of the MSD, understand its damage
principle, study the related standard, norm the controlling process of the MSD
and avoid the unqualified rate leaded by the damaged component to improve the
credibility of the product.
The development trend of the MSD
The problem to protect the MSD becomes urgency along with the development of
the electronics manufacturing. The first, the creation and development of the
newly information technical puts forward more strict request to the credibility
of the electronics product. It is disallowed to exist obvious blemish rate leak
to be checked in the assemble examinations because of the strict request of the
blemish rate to the single product. The second, the usage quantity of the SMD
increases continuously along with the development of the sealing and packing
technology. For example, the shorter development period, the smaller packing
sizes, the thinner partition, the usage of the new packing materials, the
greater integrated circuit, etc. The third, it is affected more obviously along
with the using quantity of the BGA and CSP packing material. Because this kind
of packing machine tend to use the winding material and prolongs the exposition
time of the component. The fourth, although the unleaded stick packing technique
has controversy, it also will influence the grade of the MSD seriously along
with its continuous adoption. The much higher refluxing temperature of the
unleaded alloy may make the grade of the humidity sensitivity of the MSD descend
1 or 2 grades at least, so the quality of all the component should be
re-confirmed.
The hybrid produce becomes more and more in PCB packing factory because more
and more products are made according to the order and more and more materials
are purchased in the market. Usually, the reduce of the product's quantity will
lead the production line to change multifariously and at same time prolong the
exposed time of the component with high humidity sensitivity. Many component
already packed on the sticker have to be dismantled down whenever the production
line changes for other products. That means, many component must be stored in
the tray or winding material temporarily and it is possible that the humidity in
it already exceeds its biggest capacity before it returns to the production line
and be welded.
Added: Tuesday, November 28, 2006
Submitter: meilysha
Score: 
Related Link: Article from Autodry.net
hits: 895
Language: eng
Page: 1/6
Forums:
