Hi Balan,





There is, at least,  three factors when finding the right choice of alloy

for the particular application and product requirement



1. Cost



2. Performance (e.g. hole-fill at wavesoldering process)



3. Reliability (Thermal cycle, drop shock etc)





Just in terms of raw material cost, tin / copper alloy should be the

cheapest one.  The addition of silver would add the cost.  However, it is

not the "only" criteria when selecting the alloy as indicated above.



High silver alloy is proved to have the good reliability in terms of

thermal cycle test comparing to tin / copper alloy.  However, the cost is

considerable.  As a result, certain balance point when considering the

above three factors as a whole.  Therefore, the silver content is needed to

lower but still satisfy the performance and reliability requirement.

SACX0807 (Silver 0.8%, 0.7% copper) is one of the choice when considering

the product which is needed to meet these factors



Jackson Chan

Technical Services Manager

Cookson electronics - Alpha Metals



Low cost, reliable alloy- SACX0807







                                                                           

             "Qualitek"                                                    

             <qualitek@qualite                                             

             ksolution.com>                                             To 

                                       "Asia Committe Task Group Forum"    

             2008/07/27 下午           <[log in to unmask]>, "Jackson Chan"    

             10:01                     <[log in to unmask]>      

                                                                        cc 

                                                                           

                                                                   Subject 

                                       Re: [TGA] Immersion gold thickness  

                                       enquiry                             

                                                                           

                                                                           

                                                                           

                                                                           

                                                                           

                                                                           









  Hi Jackson,



  Using SACX0807, will this become best choice to replace SN100C in terms

of

both

  1)Pricing

  2)Joint finishing compare to SAC305



  Appreciate your sharing on the above matter.



  Rgds,

  Balan