sir , I am working in one product . its give good result after soldering but after few month i got dry soldering problem. tell me how to avoid this problem.

 

Welcome to AAC!
You haven't given us much to go on .
Something's wrong with your soldering technique, or else environmental factors (high humidity? vibration? temperature cycling?) are causing the problem.

 

Tell us what;s going on. Take a picture and post it. Since your new, it may take a day or so before you can upload one.

 

A delayed soldering defect is either an original defect that showed up later, like a crystallized solder joint caused by not enough heat, improper cleaning or fluxing, or movement during the plastic phase of cooling. A new defect after time is usually caused by heat. Some resistors get so hot they unsolder themselves.

See posts #2 and #3