DGC ZM-DGC900 Скачать руководство пользователя страница 5

 

point is that the welding spots can still be welded on the pad. The ideal situation is 
no poor welding. Poor welding may be caused by pollution or the uneven 
distribution of flux paste. What's more, warped PCB may also lead to poor welding. 
Open-circuit welding spot may exist, too.  

The quantity and size of poor welding are the key factors to decide whether it 

will be accepted. Generally the size of single poor welding should be less than 50% 
of the solder ball's diameter. If the ball is surrounded by reflow solder, BGA is able 
to work. It is a very critical standard. The electrical properties may meet the 
requirements but the mechanical strength will be affected. 

PCB with BGA must use X-ray evaluation systems that can decern holes of less 

than 100 µm diameter. The X-ray must be able to observe from top-down and tilt. 
X-rays is a reliable guarantee of successful BGA welding, 
b. Proposed inspection criteria 

The inspection criteria will help X-ray inspection system confirm some typical 

welding problems, which is related with the use of BGA device. It includes the 
following factors: 
(1)Poor welding 

Poor welding results from the expansion of compounds in solder during the 

heating of BGA. BGA with poor welding may cause some problems such as 
ineffectiveness. The inspection criterias are as follows: the size of single poor 
welding should be no more than 20% of the solder ball's diameter, with no single 
poor welding on the surface; if many poor welding may exist, the total should be no 
more than 20% of the solder ball's diameter. 
(2)Desoldering spots 

No desoldering spots. 

(3)Bridging and short-circuit. 

When there is extra solder or the solder is not put on the right place, bridging 

and short-circuit may happen. So no bridging or short-circuit. 
(4)None paraposition. 

The X-ray image will show very clearly whether the BGA solder ball is aimed 

at the welding pad on PCB. 
(5)Broken circuit and cold welding 
When solder don't touch the relevant pad or the solder doesn’t flow very well, there 
will be broken circuit or cold welding. It is absolutely not allowed. 
 

4. BGA rework process  

Most of the semiconductor device’s heat-resistant temperatures are between 

240°C and 600 °C. Therefore, the control of the temperature and uniformity are very 
important to BGA rework systems. BGA rework process as follows: 
a. Printed Circuit Board and BGA preheating

 

Printed Circuit Board and BGA’s preheating is meant to wipe off the moisture. If 

the moisture was little, this step can be omitted.  
b. Remove BGA 

 

If the BGA will not be reused, and the PCB can endure high temperature, we can 

use high temperature (shorter heating period) to remove it. 
c. Clean the pad. 

Pad cleaning is mainly clearing the solder paste and scaling powder remained on the 

surface of PCB after BGA removal. For that process, it must use standard cleaning agent. To 
ensure the reliability of the BGA solders, generally we cannot use the remained solder 
paste in the pad, and we must clear away the used solder paste, except that solder balls reform on 
the BGA. Because of the small size of BGA, especially CSP (or µBGA smaller), it is always 
difficult to cleaning the pad, so when reworking CSP, it needs to use Rinse-free Flux if 

 

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Содержание ZM-DGC900

Страница 1: ...1 BGA Rework Station ZM DGC900 SOFTWARE SOLUTIONS Address Office 12D Fuxin Building 318 Fuhua Road 558000 Shenzhen China Telephone 86 0755 88360496 Fax 86 0755 83292149 Http www dragongroupchina com...

Страница 2: ...BGA Rework Station C Installation D Safety Cautions E Introduction of Structure F Operation Steps G PLC Programmable logic Controller H Curve Program Controller I Related information J Tips for opera...

Страница 3: ...ll Grid Array It is a kind of package method which use organic carrier in IC It has the following features Small package area Greater functions and more pins Self centerize while PCB puddle welding ea...

Страница 4: ...welding paste will flow from the welding pad to the rabbet then leads to short circuit between welding pad and rabbets nearby The geometric shape and diameter of welding pad The compactness of pins ha...

Страница 5: ...no more than 20 of the solder ball s diameter 2 Desoldering spots No desoldering spots 3 Bridging and short circuit When there is extra solder or the solder is not put on the right place bridging and...

Страница 6: ...and time For example reflux temperature of CBGA BGA should be higher than that of PBGA choose the higher reflux temperature For no clean solder paste its activity is lower than non no clean solder pa...

Страница 7: ...fire or an electric shock 7 There are high pressure parts in the circuit box Don t disassemble it 8 If some metals fall in the rework station when it is working turn off the power immediately After i...

Страница 8: ...positioning Max PCB size 280 320mm mm 8 Weight 20kg Features 1 Choose imported high precision materials temperature sensor PLC heater to control BGA desoldering soldering procedures precisely 2 Top bo...

Страница 9: ...d down and the damage caused by temperature difference is less To use some flux paste when cleaning the pad can increase the solder activity and achieve better cleaning effect Be careful to not to des...

Страница 10: ...of 1 2 3 4 5 0 and the temperature graphs choose NO X from ten groups take NO 1 group as an example D I S P S E L E S E T P R O G R U N P R O G P T N P A R S E T H A N D A U T O P V S V P C 4 1 0 P T...

Страница 11: ...R O G P T N P A R S E T H A N D A U T O P V S V P C 4 1 0 P T N S T E P P R O R U N O U T 1 O U T 2 S V A L 1 M A N M V T I M E C O M A L T E C 1 L 1 1 6 0 0 0 4 Preheating section time d set Press th...

Страница 12: ...L 1 M A N M V T I M E C O M A L T E C 1 L 2 1 8 5 7 Enter the second section constant temperature time set press UP DOWN to modify Press the PAR to define D I S P S E L E S E T P R O G R U N P R O G...

Страница 13: ...OWN to modify Press the PAR to define D I S P S E L E S E T P R O G R U N P R O G P T N P A R S E T H A N D A U T O P V S V P C 4 1 0 P T N S T E P P R O R U N O U T 1 O U T 2 S V A L 1 M A N M V T I...

Страница 14: ...1 M A N M V T I M E C O M A L T E C 1 d 4 3 5 14 Enter the fifth section heating up speed set press UP DOWN to modify Press the PAR to define D I S P S E L E S E T P R O G R U N P R O G P T N P A R S...

Страница 15: ...ND AUTO P V SV P C410 P TN ST EP PRO RUN O UT1 OUT2 SV AL1 MAN M V TIME C OM ALTEC 1 r8 End Remarks if you need to increase the temperature then press the UP to open 18 Set finished then it will show...

Страница 16: ...set to prog TIME shows the remaining time of certain period of procedures While the meter is set to constant temperature controller TIME shows cent code In some special type of instrument TIME shows t...

Страница 17: ...SELECT button the lower screen shows settings value the output value or the remained time of operation the corresponding indicator SV MV TIME are on AUTO HAND is the automatic manual switch button Whe...

Страница 18: ...measured value is not vibrating After 1 5 periods of vibration the PID self setting is completed Then the AT lamp is off The meter can calculate the best PID parameter and save it in the meter accordi...

Страница 19: ...state of auto control f Software configuration code and meaning of function parameters Set the configuration password as 808 the parameter code Loc when the meter shows PV press button PAR and for 3 s...

Страница 20: ...sistance signal Distant transmission pressure resistance signal with decimal 8 Rddr Local address 0 99 9 bRud Communication baud rate 600 1200 2400 4800 9600 19 2KB 10 Ctrl Regulation On of PLd rSP Pr...

Страница 21: ...should be no less than 20s Regulation parameter ProP ln dEr rEL C ProP ln dEr rEL C are the four regulation parameters directly affecting control precision RL02 on Second alarming output Action suctio...

Страница 22: ...proportion then mutiplied by cooling coefficient Control mode parameter Rc When Rc is set at rEu the control mode is reverse acting control It means that as the input signal of the meter increases the...

Страница 23: ...varies according to different objects PID is over AT go out P I D parameters which have been set before will be kept in the meter automatically If we need to examine P I D parameters after setting we...

Страница 24: ...d for 3s the meter can enter the menu of curve program menu the upper screen display the code of the first parameter and the bottom one display the value of parameter Then we can change the value by a...

Страница 25: ...s the basic setting 2 Modification of parameters when the curve procedure runs a When the meter runs we can t modify the curve program parameter LC r1 L1 d1 r2 L2 d2 But other parameters can be modifi...

Страница 26: ...26...

Страница 27: ...use IR because the ceramic heater can t cool down very quickly thus it is difficult to control the time of higher reflow temperature However the convection can control strictly and it is conductive to...

Страница 28: ...he standard choice in USA Components manufacturers consider the using of lead free balls as the standard b Setting of temperature difference The temperature difference on the surface of components is...

Страница 29: ...te are necessary because the melting point of soldering balls on CBGA is much higher than common paste such as Sn63 and pb27 4 Removal of residual soldering tin and mounting of BGA Besides the tempera...

Страница 30: ...time The upper main heater arises to 8 10mm from the surface of BGA and pauses for 30 40s Or after the working light is off move the main heater away and take PCB away from the positioning bracket 5 B...

Страница 31: ...meet the fast increasing demand of BGA circuit assembly the manufacture companies need to choose safer faster and more convenient assembly and rework technology Appendix packing list Order Name Speci...

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