Ask Helena & Leo

Question: We were looking over the J-STD-001 and the Space Addendum requirements for partially visible or hidden solder connections 4.18.3. Why does the space addendum give you the option to x-ray the parts in Note D, but in the J-STD-001 book there is no option for inspection if you don’t meet the 3 criteria? It almost seem a bit backwards. I would assume there should also be the option of some type of NDE for non Space Addendum assemblies. Can you enlighten me on this?

I also have a question pertaining to 4.18.3 note C. My opinion is that hand soldering is not a controlled process. Is there any IPC direction that states hand soldering SHALL not be considered a controlled process, or do they leave that decision up to the manufacturers/customers to decide?

Answer: First of all the list of conditions listed in 001F in 4.18.3 are not notes, but conditions of the criteria and for the condition to be acceptable, the solder joint has to meet the criteria of each one listed a, b and c. If they don’t then the condition is [A1P2D3]. In the 001 ES document, the criteria is all Class 3 and the Space Folks have decided that the three conditions are not enough to guarantee a good solder joint, therefore are asking for the joints to be inspected under an X-Ray system.

This does not imply that X-Ray cannot be used for the requirements in 001F as part of the process controls.

As for your second question, you are correct, hand soldering does involve lots of variables and the only things that are controlled are the wire solder used and the soldering iron system. I would also consider solder experience as being a big issue with the process controls. IPC will not define the process to be used but what the end results should be regardless of the process used, so if there are lots of hand soldering joints to be created, the automation of the process should be investigated, such as mass soldering systems like a wave solder system, or localize soldering system or solder past, part placement, and reflow processes of the surface mount technologies. This would define the methodology for reducing the variables as well as reducing cost, plus reducing the manufacturing defects.