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Brian Smith
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General Manager - Electronic Assembly Americas
DEK International
Mr. Smith has been supporting customers in the electronics assembly industry since 1994. His expertise is focused on solder paste printing and reducing soldering defects. He holds a BS in Chemical Engineering and an MBA in Marketing. He has authored several papers in trade magazines and at industry conferences. He is an SMTA Certified Process Engineer.

Brian Smith has submitted responses to the following questions.
Components Jumping Around During Reflow
Lead-free solder does not have the same surface tension capability as leaded solder. The "self-centering" behavior of lead-free solders is ...
Solder Paste Alloy Check
The easiest way to check the approximate alloy composition is through XRF (x-ray fluorescence) technology. This equipment can non-destructively analyze ...
Transfer Efficiency Greater Than 100%
It is possible to actually have greater than 100% transfer efficiency, but the most likely scenario to cause this is ...
Mixing SAC305 and SACX0307 Solder Alloys
These alloys really should not be mixed together.  The benefits of the SAC305 system are a little different than those ...
Flux Aging Study
For most cases, the most measurable difference over time is acid number. This is particularly relevant for low-solids, no-clean fluxes. ...
Tacky Substance Under Zero Clearance Parts
The term "cure" really doesn't apply to solder paste fluxes -- curing generally applies to polymers and cross-linking behavior with ...
Bromine Free PWBs
Bromine and lead-free are connected, in some ways, because both are targeted by the RoHS legislation.  Bromine itself it not ...
Gold Edge Contact Flux Contamination Failures
It really depends on what the gold pads will be used for when the product is in use.  Most typically, ...
Wave Solder Pot Contaminated with Lead
The only way to lower the amount of lead contamination is to dump at least a portion of the pot ...
Is Rework Unacceptable?
Without knowing the end use application, I would suggest that this is quite unusual and impractical. Reworked boards can be ...
Intermittent BGA Test Problems
This sounds like a typical "head-in-pillow" (or "ball-in-socket") defect that is a common issue with BGAs. In this case, the ...
Flux Cored Wire Solder Shelf Life
Cored wire solder is generally very shelf-stable. The core flux is a nearly solid material and therefore is not prone ...
Need for Reflow Profiles
I think that there are a lot of SMT facilities that have an optimized profile for every board they are ...
Solder Paste Volume
The expected solder paste volume should be calculated based on the dimensions of the stencil openings. We would expect the ...
Advantages Using OSP Surface Finish
The biggest advantage of an OSP finished board is the price. OSP boards tend to be cheaper than those fabricated ...
Cleaning No-Clean Solder Paste
Cleaning boards that have been soldered with no-clean paste can be a challenge. To some extent, it depends on the ...
Soldering lead-free component, with tin-lead solder
There should be no reliability issue with the soldering application that you are suggesting. The use of Sn63/Pb37 solder paste ...
Hot or Cold DI Water Rinse
In nearly every circumstance, hot water (120-150F) will be better than room temperature water (70-80F) in terms of removing residues ...
Concerns with High Humidity
Solder pastes can be affected by high humidity in the plant. The traditional upper limit where pastes may start to ...
Solder Joint Void Limit for BGA Components
The void requirement is that the sum of all of the voids cannot equal more than 25% of the cross-sectional ...
Pin-in-Paste Hole Fill
Paste-in-hole processes are somewhat more complex than traditional SMT from a process control standpoint, but with good engineering practices and ...
Problem with 'No Clean' Solder Flux Residue
It is extremely likely that this white residue from a no-clean flux is perfectly safe. However, it is suggested that ...
Type III vs. Type IV solder paste
Type 3 solder paste is generally considered to be the industry standard that will work for most printing applications. The ...
Cleaning No-clean Flux
This approach is not a good practice for one obvious reason and one less obvious reason. The more clear-cut bad ...
Lead Free Flux
From the wording of your question, it isn't clear if you are referring to a lead-free flux for a surface ...
Humidity and Corrosion
It sounds as if your product is subjected to a condensing environment in its end application. In such cases, the ...
BGA Voids
Changing from Sn63 to Sn62 should have minimal impact on the amount of voiding. The degree of voiding is far ...
Optimize Temperature Profile for High Mix Boar
Profiling a high-mix board can be challenging, but these pointers can help you through it. It is critical to pinpoint ...
Best Paste for Gold Finished Surfaces
More than likely, this is related to the dissolution of Gold into the solder joint. Gold is easily dissolved by ...
Wave Solder fluxing
This may have more to do with the choice of flux than any particular wave soldering parameter. When you identify ...
Cleaning tin-lead and lead-free boards
The only thing that would force a user into unique cleaners for leaded and lead-free assemblies would be if the ...
Flux residue after baking
This depends on the type of flux that is being used. If you are using a no-clean rosin-based flux, these ...
Cleaning an assembled board with IPA
With a no-clean residue, it is best to either leave the residue uncleaned or insure that the residue is removed ...
Reflow oven profilers
I would rate a reflow profiler as a "must-have" for process control of the soldering process (and I have no ...
Alcohol based fluxes
There has been no mention of a complete ban on alcohol-based flux products to my knowledge. However, some local governments ...
Aqueous Cleaning Process
It depends on what types of residues you are trying to remove.  If you are trying to clean rosin-based or ...
0201 capacitors creating process problem
The types of process problems that you are having aren't clear, but I will guess that you are experiencing problems ...
Hand soldering process for lead-free
Hand soldering with the lead-free alloy SAC305 is most commonly done in the range of 700-750 F. Some have pushed ...
Problems with solder paste stencils
The rule of thumb for printing small round and small square apertures can be helpful in determining the proper stencil ...
Can we pour left over paste into the solder pot?
Solder paste scrap should never be placed in a solder pot. The solvents in the solder paste may flash and ...
Average Temperature/Humidity for an Electronics Assembly Facility?
Of course, it is best to have a temperature and humidity controlled environment for any electronics assembly environment. Ideally, the ...
Pre-wash boards prior to conformal coating
It sounds like you are using no-clean soldering materials (pastes, liquid fluxes and cored wires) for assembly and asking if ...