May 24, 2013
ESD and Humidification
I am glad you made the distinction of handling completed
circuit card assemblies (CCAs) into systems (box level), as opposed ...
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May 3, 2013
Jumper Wire Gauge
Good answer, Leo. I would also like to point out two things. The IPC 7711/7721 standard also provides a chart ...
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Jan 9, 2013
Epoxy Wicking up Wire Insulation
You don't say how many wires per circuit board, or how many
circuit boards you need to do this to, ...
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Jan 9, 2013
Solder Paste Life on the Stencil
The printing process you describe is the one most commonly used
in most electronics assembly factories today. Dispense paste on ...
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Dec 5, 2012
Plating Lead Free Parts for Tin/Lead Assembly
Let me just point you to this article in Circuits
Assembly magazine. It will answer many of your questions.
http://www.circuitsassembly.com/cms/magazine/207-2010-articles/9439-a-novel-process-for-automated-lead-tinning ...
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Sep 26, 2012
Cleanliness After Coating Removal
Typically, depending on the type of CCA and the type of coating,
after the coating is removed for rework and ...
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Jul 23, 2012
Is Pre-Bake Standard for Rework?
Sorry to those who said no, but that is incorrect.
The correct answer is: it depends- on a lot of ...
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Jul 18, 2012
Cause of Cracking on SOT23 Components
It appears that there is some impact damage on the side
of the component near the horizontal crack, although it ...
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Jul 18, 2012
SMT Component Glue Strength
There IS a test procedure within the IPC-TM-650 standard,
which is an invaluable document but yours absolutely FREE at http://ipc.org/4.0_Knowledge/4.1_Standards/test/2.4.42.pdf; ...
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Jul 12, 2012
Inspection and Maintenance for Soldering Irons
From J-STD-001E:
3.9 Soldering Tools and Equipment
Tools and equipment shall [DID2D3] be selected, used and maintained such that no ...
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Jun 6, 2012
Wave Solder Pot Contaminated with Lead
You have all of the answers you need as to how
to dilute the pot with fresh lead-free solder (and ...
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May 30, 2012
Flux Aging Study
Refer to J-STD-004. This is the industry
standard for requirements for soldering fluxes, and has a lot of information on ...
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Apr 3, 2012
Conformal Coating in Low Humidity Environments
Dr. Pauls, could you expand on your answer slightly? We very much respect your knowledge on the subject of conformal ...
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Mar 7, 2012
Gold Edge Contact Flux Contamination Failures
A number of questions
came up as I read about your problem. I will attempt to touch on all of ...
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Feb 8, 2012
Idle Wave Solder Temperature
It depends
(ka-ching) on several factors.
Some wave solder machines contain 1800 lbs of solder, whereas others may only
hold ...
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Jan 25, 2012
Soldering Wires to SMT Pads
The pad, trace, and the wire size are determined by the
current-carrying capacity required of the circuit. This is determined ...
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Nov 7, 2011
Solder Paste Viscosity
It is probably not a good idea. It would be better to perform the viscosity check just prior to printing, ...
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Oct 31, 2011
CEM1 Laminate Issues
CEM1 is a paper-core material laminated with a thin layer of fiberglass. It is not usually able to withstand higher ...
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Oct 24, 2011
OSP Poor Wetting
The reason you see it on one particular PWB part number and not other PWB part numbers is probably because ...
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Oct 10, 2011
Components Jumping Out During Wave Soldering
It is not uncommon for through-hole parts to rise up out of their holes when coming into contact with the ...
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Oct 10, 2011
Contract Assembly in a Prison
Check with OK Industries, Hakko, AirVac (DRS24, DRS25or similar model). All of these companies (and others as well) have hot-gas ...
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Sep 30, 2011
Type 4 Solder Ball Use
At my client companies, we use type 4 for most products, type 3 for others, and for some special applications ...
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Sep 6, 2011
Rework or Repair
Gold edge contact re-plating is considered to be a Repair, not a Rework, and is detailed as such in IPC ...
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Aug 22, 2011
3D Solder Paste Inspection
Automated solder pasteinspection (SPI)systems are very common in the U.S. and abroad. There are many companies who make SPI equipment. ...
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May 31, 2011
Spec for Baking Assemblies Prior to Rework
You can completely dry any fully populated CCA at room temperature if you choose to, but there is an inverse ...
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May 9, 2011
Flux Recommendation for BGA Rework
Funny you should ask! Yesterday I went with my youngest son to the local game shop to return his Xbox ...
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May 9, 2011
Is Rework Unacceptable?
Well sure, if the assembly does not have any components, or else you have perfect processes and perfect operators. If ...
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Mar 21, 2011
Solder Paste Mixing After Storage
I think this is a good practice, except for one small detail. The vendor of solder paste centrifuges recommends going ...
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Mar 21, 2011
Uncontrolled Environment Causing Problems
Rather than repeating them here, see my response to another similar enquiry having to do with handling of solder paste. ...
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Mar 14, 2011
Lead Free Reflow Oven Zone Count
From my experience, most companies are quite comfortable with a 7-zone reflow oven, which I think has been the standard ...
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Mar 14, 2011
Water Washing Pressure
It's hard to answer this question without knowing what the delicate parts are, and what type of circuit card assembly ...
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Mar 2, 2011
Batch Reflow vs. In-line Reflow
You select cleaning methods and solvent chemistry based on the flux chemistry used, right?
Likewise, you select soldering processes based ...
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Feb 21, 2011
Soldering to Hard Gold
It takes special knowledge of chemical deoxidants, entirely different kinds of solders (not alloys), and special process expertise in order ...
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