Question: Is it acceptable to “shave” or cut solder joints?
Example 1: If you have a castellation with excess solder, is it acceptable per IPC to cut the “belly” off with an Exacto knife?
Example 2: If you have a “lumpy” solder joint on a SMT transistor, is it acceptable to “shave” the lumps off with an Exacto knife?
This is something I’ve never seen before and I couldn’t find any criteria on cutting solder joints except for when you are lead cutting, which I know when you do, you are not supposed to cut into the solder joints.
Answer: I’ve seen this type of trimming done a couple of times before and I can’t find anything that states it is not acceptable.
I’ve never seen it used to trim a solder joint and would not recommend this at all as this is not good workmanship practice to trim solder joints to reduce the excess solder. The potential of creating stress risers in the cut surface is enormous and this could help create the initiation of cracks in the solder joint.
You may also want to check the reasons for having excess solder. The way to fix this is to remove the solder from the joint with a solder braid, or something equivalent and resolder the joint.