Ask Helena & Leo

Question: If there is a bubble in the conformal coating that covers two traces, but both traces are covered with soldermask is this rejectable? Also, how do you avoid bubbles in the coating?

Question: I have a customer who seems to be having issues making acceptable solder connections using the vapor phase process. Can you tell me if there are any specific issues related to vapor phase soldering to immersion tin plated pads on...

Question: We are having certain batches of PC boards exhibiting micro voiding at the copper-lead free intermetallic region after thermal stress. Can you give me some background on this issue, as we are trying to determine the root cause of...

Question: Are there any benefits to using deionized water versus tap water on the solder iron sponges? What is the best type of water to use?

Question: IPC-610 has many areas that are left to ones interpretation. The area for solder touching glass body components is one of them. The IPC mentions this along with the subject of maximum fillet height and the image that sets in some...

Question: Once a wire is pre-tinned with lead free – no clean solder, can it then be considered solid wire and then be soldered to a PCBA using water soluble flux?

Question: I’m looking for the corrections that are supposed to be online for the IPC-A-600H CIS Training Program. Do you know the direct link or where I can find it?

Question: In IPC-A-610 section 9.4 on page 9-8 component damage there seems to be a lack of class three acceptable requirements for nicks or chip-outs in ceramic bodied components that are not in the termination area. Could you elaborate on...

Question: We did some cross sectioning of solder joints on a PCB assembly and found some air bubbles trapped in the solder joints. Do you know if there is an IPC standard to specify the maximum allowable air bubbles or voids in a solder joint?

Question: Can you tell me where I can purchase training standards, IPC certificates and soldering kits now that I am an instructor, to train our employees?

Question: Very simply, do you wear one or two foot straps to protect against ESD?

Question: IPC-TM-650, 2.4.18.1 is the method for testing in-house plating for tensile strength and elongation, but where can I find the IPC requirements for results? For example, military standard MIL-PRF-31032 states copper elongation shall...