QUALITY CONTROL FOR SMT LINE

 

 

“AOI”

 

1.   Post Reflow Inspection

      -     This inspection process is extremely difficult.  It requires tight control of data input during inspection in order to achieve higher detection.  However, human being might over look such defects during eye-sight checking  resulting in increase of higher leakage.

-          If we input sweet data, the machine  will leak out more NGs.

-          It is therefore, vital that before any inspection is done, we must remember to preset the correct threshold of data for input so as not to jeopardize the leaking situation.

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(To create the data well) 

(1)        Do not expect 100% detection by M/C.

-     Those Ngs that M/C cannot be detected or overlooked so often or those NGs cannot be stopped without any tight control of data must be clarified and determined.

   -     AOI surely has a tendency of being suitable or unsuitable against various PCBS –  many tall component or different circuit design.

 

         (2)    -     Listen to Inspector’s opinion well.

               -     Due to their daily experiences and careful observation of “NG” pictures, Inspector normally understand well the NG/OK of  PCB and soldering tendency.

     

      (3)    Rely on inspector.

-          Inspite of severe fine tuning, the component eventually also becomes False NG. In such a situation, it is better to rely on human visual checking.

(4)        Taking Care of “Data”

-     AOI resembles a spoiled child.

-     With new component lot, new solder lot, and new pcb lot will creates many “NGs” 

-     Proper care of Data  must be  maintained always for it to stay  in top condition for inspection.

-     If the above steps have been dutifully taken and observed, then there is no possibility of experiencing NGs leakage during inspection.        

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2.      These steps must be carefully taken before inspection.

      -     By using actual PCB to determine whether m/c really detects NGS or not.

-          Due to various reasons such as using different components lot, pcb lot or the data being altered, etc, and also if you did adhere to the above steps, it will hinder detection. 

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3.   Selection of AOI

      -     There’s no so big difference in function by every principals’ AOI.

      -     To analyze and identify what is really the issues of inspection process before purchasing AOI.

      -     With this analysis, it will help you to select better AOI. On the contrary, only the price-conscious purchaser will not be able to enjoy and utilize it fully  due to the m/c lack of information.

      -     To check the missing fillet only.  Also, to check fillet height – AOI purpose must be clarified.

      -     Although AOI is cheaper in price compared to that of the chip for shooter, it can be used  like chip shooter for many years.

      -     It is better to select suitable model which can solve your concern and fits into your factory.           

 

 

 

 

(QUOTED BY MR. RISING DRAGON)