Ask Helena & Leo

Question: Are there any references or materials I can look at or download specific to Lead-Free Soldering?

Question: We have a situation where we have gold boards which accept gold wire bonding, but are failing a pull test. Other than making sure the boards are clean with a quick trip into the degreaser, is there any other way to refresh gold...

Question: We are soldering a cover to a housing and I was not able to find any quality criteria for the amount of solder flowing down the inside of the housing wall. We are hand soldering the lid in place on the cover, filling the seam between...

Question: I am interested in knowing if there’s a definition for the word “visible” as used in IPC/WHMA-A-620 where some target criteria states “visible”, does this mean unaided?

Question: We have a class 3 product that has some missing pads, that were removed during a rework process. If I epoxy the component in place, does the product still meet with class 3 requirements?

Question: I know for tinning stranded wires you should not use Type H or M flux, so we are ordering a No-clean solder Sn63Pb37 with a flux designator ROL0. My question is, would you use that ROL0 solder on the entire solder termination when...

Question: I noticed a lot of my techs, while soldering cups, are not putting the soldering iron on the back of the cup, filling with solder, then adding the tinned wire. They will tin the wire, set the wire in, press the iron on the...

Question: 5.1.3 States that wires must be tinned if soldered to boards with some exceptions. My question is if the stranded wire is individually tinned wire, not “topcoat” or bare copper, does this count? Would it need to be dipped in a solder...

Question: Are there any specifications referencing Polyphenylene Sulfide (PPS) film capacitors and horizontal lifts on sides (or cracks) when heated like ceramic chips if cracked horizontal, or is it considered a defect for all three classes?

Question: We work in cable assemblies and had a question about Circular Mil Area (CMA) buildup. We find ourselves frequently building up our conductors when using a crimp style contact, using the Rule of 3’s (28 AWG folded in half would be 25...

Question: I just wanted to ask a quick question. I’ve always believed that IPC-610 was an inspection of PCB assemblies and J-STD-001 was the actual operation of soldering. Is this correct?

Question: We have an application that due to the type of stranded conductor being used, it may be necessary to semi-strip the insulation, flux and dip the conductor with the insulation slug still in place to prevent the conductor from fraying...