pad to drill size formulae

[v_kumar]

help
can anyone tell me whether there is any formulae for drill size to pad size
how to decide the pad size.

e.g

if drill - 24mil
than pad - ? (how to decide it any formulae?)

 

[IanP]

Pad size calculation
min. P = (2 x R) + FA + D

P = Pad size
R = Annular ring
FA = Fabrication allowance
D = Drill or tool diameter

Details at: https://www.brockstedt.de/en/desi/padsize.html

Used units:
40 mil approx 1.00 mm
10 mil approx 0.25 mm
4 mil approx 0.10 mm

Regards,
IanP

 

[Rame]

hi,

It again depends on the complexity of the board,for 24 mil drill min 10 mil more can be added,especially for via.

If it is for any components, then we need to add more say 15 r 20 mil depends upon the requirement,for reliabliity.

Hope this will help u.


Regards

Ramesh

 

[v_kumar]

Is there any similar formulae for
SOLDER MASK
AND PASTE MASK

THANKS

 

[IanP]

SOLDER MASK:

Swell solder mask 13 mil (.013) larger than the Pad, SMT or Non-Plated hole size.
If LPI (liquid photo image-able) solder mask is required swell to 5 mil (.005).

**broken link removed**

Regards,
IanP