Ask Experts Submit a Question
Submit your question to our Expert's panel using the form below. This is not the typical forum where anyone can post an answer to the questions submitted.
Your question will be forwarded to a distinguished panel of industry experts. Those experts that have a comment or suggestion to pass along will forward them to us for posting.
Look for new questions and answers posted each week.
Please keep your questions short, although it's important that you include all the information our panel may need to provide an answer.
Recent Ask the Experts Questions
March 19, 2019
Using Solder Paste Beyond the Expiration Date
We assembled a batch of PCBs using a water soluble paste that was beyond the expiration date. After cleaning we are seeing a white powder residue. Do you think it is because the paste used was beyond the expiration date, or is it likely to be something else?
March 18, 2019
SMT Target Component Placement
I'm having trouble obtaining accurate placement for an IR SMT LED on a PCB during the SMT soldering process. Despite meeting the IPC standard, which allows for some shift of the component with respect of the pad, I would like to reduce the shift, and obtain a maximal displacement (post reflow) of less than 0.2 MM in both directions, X and Y.
Can you advise about ways to improve the placement accuracy for the location of the IR LED compared to the ideal target placement?
March 15, 2019
Manual or Automated Assembly?
We are a new start-up assembling wireless sensors. All assembly is now manual, we have no automation. We are at a point where we are experiencing large reject rates due to hand soldering of components. The PCB is a 2 layer board and we are not using anything smaller than a 0805 package.
We were looking at whether we should get better soldering tools or upgrade to small prototype bench-top stencil printing, placement and reflow. We now assemble 10-15 boards per day.
Should we upgrade our soldering equipment, or go for automation?
March 14, 2019
Cleanliness Standards for Electronic Components
I work as a supplier engineer in our automotivedivision and we are very concerned about cleanliness for electroniccomponents. We have a very stringent humidity and temp test from oneof our OEM's that causes dendrites almost every time we run the test.
I have been looking for cleanliness standards forelectronic components but the only thing I have been able to find is for PWBcleanliness. To date I have not been able to find any standardsregarding cleanliness specifications for ionics for electronic componentsspecifically.
Are there forelectronic component cleanliness in the industry currently or are there plansto review cleanliness requirements for components?
March 13, 2019
Solder Splashing During Wave Soldering
We are experiencing solder splash during wave soldering while using both adjustable and dedicated pallets resulting in the splash on the boards creating ICT failures.
The solder splash is popping up from the solder flow. What is the likely reason for this?
March 12, 2019
Solution for Warped PCBAs
From a large lot we have 20 populated boards with components on both sides that are warped. Components vary in height. What method can we use to flatten them?
March 11, 2019
Initial Screen Print Test Board
Is it recommended to print one cycle before printing the first production board? I could use a scrap board or blank plastic card for the first print.
March 8, 2019
Ultrasonic Cleaning and Surfactants
I've heard that deionized water is a poor conductor of ultrasonic cavitations. Can we add a small amount of a surfactant to improve the ultrasonic effectiveness?
March 7, 2019
What are the latest techniques/methods for testing the cleanliness of an assembled PCB after going through our in-house cleaning process?
March 6, 2019
Stainless Steel Benches and ESD
I do some contract work for a company that uses stainless steel benches in both their assembly area and test lab. I'm having trouble making the case to replace them with non-conductive surfaces and ESD mats.
Is anyone aware of any standard, or industrial best practices to help me highlight the various concerns with using stainless steel benches when handling ESD sensitive components?