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Robert "Bob" Lazzara
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President
Circuit Connect, Inc.
Bob has been in PCB design and fabrication since 1976. He has held elected positions with the SMTA, is a member of the MSD Council, has served as a committee member for various IPC standards and is a Certified IPC Trainer.

Robert "Bob" Lazzara has submitted responses to the following questions.
IPC-A-610 Class 3 - IPC-A-600 Class 2
"If the PCB Assembly inspection requirement is IPC-A-610 Class 3, does it mean that the PCB inspection IPC-A-600 also has ...
Bottom Terminated Components and Vias
Single sided via protection -- be it tenting, plugging or something other -- is to be avoided. Such features are ...
ENIG Solderability Issues
"The nickel thickness measured with an XRF is around 400 microinches." That is impressive thickness for electroless nickel. Are you ...
Manual or Automated Assembly?
Here's a different idea: Buy your PCBs pre-pasted. Pre-pasted PCBs come with assembly-thickness solder ready-to-go right out of the box. ...
V - Scoring PCB Question
You will generate post-assembly dust that will include metal (copper) particulates. Otherwise, going sufficiently deep to depanel with a 90-degree ...
Adhesion Problems with Conformal Coating
For your review and consideration: http://www.circuitnet.com/articles/article_102459.shtml ...
Proper method to bake PCB's
The IPC-1601, Printed Board Handling and Storage Guidelines, has 34 references on the subject of baking PCBs. The IPC answers ...
Concave Via Fillets Causing Problems
Maintain your pad size, but reduce the via size to the smallest diameter your board house can provide without driving-up ...
Reduce Glare During Assembly
Virtually all solder mask manufacturers offer matte and semi-matte formulations. In addition to mitigating glare these reduced-gloss masks arguably improve ...
Circuit Board Bow and Twist
Given that the circuit pattern and assembly processing are unchanged, bare board processing can be considered. If the manufacturer fails ...
Blow Holes and Disturbed Joints
In the case of multilayer PCBs it is unlikely that moisture trapped deep within the boards will be fully released. ...
Silkscreen as a Masking Layer?
Because you're re-purposing the material from Marking feature to Insulator function, you might first check with UL (presuming the end-product ...
HASL Surface Finish and Coplanarity
HASL coplanarity will vary by method (horizontal vs. vertical) and by alloy (Pb-free versus SnPb). I'm sure you want repeatability; ...
White Legend Ink Turning Pink
Gold salts (e.g., from ENIG surface finish) left on the surface (typically from a dirty final rinse) will react with ...
Issues with BGA Components Near PCB Edges
When the PCB is post-assembly separated from pallet/panel form to individual form, the various methods of "depanelizing" will load different ...
Delamination Causing Scrap
The #1 cause of delamination is moisture. And by-far. While other failure modes exist (e.g., inadequate bonding layer cure) they ...
Can Solder Joint Geometry Change Resistance?
Determine whether the intermetallic differs between two electrically-differing joints (micro-section analysis). If cross-sectional views indicates the intermetallic is visually thicker on the higher ...
Flux Oozing from Insulated Wires
Are your wires stranded or solid? Stranded wires have a higher propensity for wicking flux, which can later reflow at ...
Reflow Causing Warp
"We have a 20 layer PWB that is not balanced..."  That really says it all. Your only recourse will be ...
Gold Plated Hole Defects
There's a variety of causes for the solder not to fully wet to pads & hole walls, and none of ...
HASL vs. Immersion Gold
Immersion gold is not intended as a final finish. Rather, it's purpose is to preserve the solderability of the metal it ...