smt pcb assembly process

smt pcb assembly process
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Product Details

Technical Detail for smt pcb assembly process :

XD Electronic Technology Co.,LTD

Seq

Item

capability

1

Base Material

FR-4, High TG FR-4 , Halogen Free material ,CEM-3,CEM-1,PTFE,Rogers ,Arlon ,Taconic,Aluminum base,Teflon,PI ,etc

2

Layers

1-38 ( ≥30 layers needs review )

3

Finished inner/outer copper thickness

0.5-12OZ

4

Finished board thickness

0.2-7.0mm(≤0.2mm needs review),≤0.4mm for HASL

Board thickness≤1.0mm: +/-0.1mm
1<Board thickness≤2.0mm: +/-10%
Board thickness>2.0mm: +/-8%

5

Max panel size

≤2sidesPCB: 600*1500mm
Multilayer PCB: 500*1200mm

6

Min conductor line width/spacing

Inner layers: ≥3/3mil
Outer layers: ≥3.5/3.5mil

7

Min hole size

Mechanical hole: 0.15mm
Laser hole: 0.1mm

Drilling precision: first drilling       First drilling: 1mil
                                                     Second drilling: 4mil

8

Warpage

Board thickness≤0.79mm: β≤1.0%
0.80≤Board thickness≤2.4mm: β≤0.7%
Board thickness≥2.5mm: β≤0.5%

9

Controlled Impedance

+/- 5 % Ω(<50Ω),+/-10%(≥50Ω),≥50Ω+/-5% (needs review)

10

Aspect Ratio

15:01

11

Min welding ring

4mil

12

Min solder mask bridge

≥0.08mm

13

Plugging vias capability

0.2-0.8mm

14

Hole tolerance

PTH: +/-3mil
NPTH: +/-2mil

15

Outline profile

Rout/ V-cut/ Bridge/ Stamp hole

16

Solder mask color

Green,yellow,black,blue,red,white,matte green

 

17

Component mark color

white,yellow,black

18

Surface treatment

OSP: 0.2-0.5um
HASL: 2-40um
Lead free HASL: 2-40um
ENIG: Au 1-10U’’
ENEPIG: PB 2-5U’’/ Au 1-8U’’
Immersion Tin:0.8-1.5um
Immersion silver: 0.1-1.2um
Peelable blue mask
Carbon ink
Gold plating: Au 1-150U’’

19

E-Test

Flying probe tester : 0.4-6.0mm,max 19.6*23.5inch

Min spacing from test pad to board edge : 0.5 mm

Min conductive resistance :   5 Ω

Max insulation resistance : 250   MΩ

Max test voltage : 500 V

Min test pad diameter : 6 mil

Min test pad to pad spacing : 10 mil

Max test current   :   200 MA

20

AOI

Orbotech SK-75 AOI : 0.05-6.0mm,max 23.5*23.5inch

Orbotech Ves machine :   0.05-6.0mm,max 23.5*23.5inch

 

PCB SMT Assembly Procedure


 


Advantage of PCB SMT Assembly in Design

1.The most important benefits in Design section are significant savings in weight and real estate and electrical noise reduction.

The SMT component can weigh as little as one-tenth of their common thru-hole equivalents. Because of this reason significant decrease in weight of the Surface Mount Assembly (SMA).

SMT components occupy small because of this only one-half to one-third of the space on the printed circuit board.

Since every electronic part are not accessible in surface mount, the real area reserves on a board will depend on the ratio of through-hole components changed by surface mount parts.


Benefits of PCB SMT Assembly in Manufacturing

There are major benefits provide also in manufacturing section.

The important advantage of SMT in manufacturing includes reduced board cost, reduced material handling costs, and a controlled manufacturing process.

Routing of traces is reduced, the size of the board is reduced, and number of drilled holes are also reduced.

If the functions on the surface mount board are not expanded, the expanded between inter-package spacing made possible by littler surface mount parts and a decrease in the quantity of bored gaps may likewise reduce the quantity of layer counts in the printed circuit board. This will again bring down the board cost.

The above benefits of Surface Mount Technology don’t necessarily means that SMT assembly will always cost less. It depends when and how SMT is used.



Disadvantages of smt pcb assembly process

• The small lead spaces can make repairs more difficult.

• It cannot assurance that the solder connections will withstand the compounds used during potting application. The connections may or may not be damaged when going through thermal cycling.

• Components that generate a lot of heat or bear a high electrical load cannot be mounted using SMT because the solder can melt under high heat.

• The solder can also be weakened due to mechanical stress. This means components that will be directly interacting with a user should be attached using the physical binding of through-hole mounting.


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Foreign Sale :Rainbow

Email:sales5@xdpcba.com

Skype:xingdapcbsales5

Tel:86-0755-29621535 Ext:817

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