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Layout problem regarding OAR

Question asked by dhaval.shah on Dec 13, 2010
Latest reply on Dec 13, 2010 by jmatthews

hi everyone.

i am new in PCB Design..

I have made one design and when i make order for manufacturing they have some queries like.
         " Minimum OAR (Outer Annular Ring) in our  service is 0.125mm.Your design has OAR of 0.0mm for drill size of 0.30mm end size."         

i don't know how to correct it..

In my design drill size of the pad is 1.0mm and at TOP and BOTTOM it is 1.20mm as well as in PLANE its size is 1.40mm.
but i think this one is incorrect..



And they have suggest me to calculate OAR as per following formulas.. But I am too much confused from this.


Calculation of OAR:OAR = (Cupper pad diameter – TOOLSIZE)/2


TOOLSIZE = ENDSIZE + 0.10mm for all PTH holes of 0.45mm(ENDSIZE) and smaller

                              + 0.15mm for all PTH holes bigger then 0.45mm(ENDSIZE)

                                       + 0.05mm for all NPTH holes.


Example calculation for OAR in your design on the 0.30mm ENDsize drills:

    OAR = (0.4191mm – (0.30mm + 0.10mm))/2

             = (0.4191mm – 0.40mm)/2

= 0.0191mm/2

             = 0.0096mm



If Any one knows the formula to calculate OAR for different Drill sizes??


Please let me know if anybody knows solution.


They have provide me one documents showing my errors which i have attached.


So you can find that attached file more comfort.