Rodney Miller

Rodney Miller has submitted responses to the following questions.

Pad Missing ENIG Plating
I would agree... Adding OSP would most likely be on the Nickel or Bare Copper. Assuming these are solder pads. ...

BGA Solder Ball Collapse
It is a function of the Alloy and the liquidus phase you want for the solder to fully wet. With ...

What Caused SMT Pads to Oxidize After Reflow
Most likely, this is the infamous "Black Pad" where the Nickel plating was not properly prepped prior to Immersion Gold ...

Recommended Fiducial Shape
In making some assumptions about your board design.... we can only speculate from this photo/question. The PCB should not be ...

Is Solder Mask Considered an Insulator
Solder mask primary function is to protect copper of the PCB laminate during manufacturing process and also provide bare copper ...

Reduce Glare During Assembly
Glare from direct task lighting can be a myriad of issues. Facility Lighting, Ambient light direction, Solder Finish, Solder Mask ...

Conformal Coating Recommendation
Conformal coatings come in 4 primary liquid types and 1 polymer type and are generally only single part of a ...

Confused About IPC-A-610 Class 2 vs. Class 3
IPC classes, with regard to the Assembly Standard 610 are used to standardize the acceptability levels of electronics. Class 1 ...

HASL Surface Finish and Coplanarity
This is acceptable, but you will need to be placing the BGA with "Paste Additive"process. You should also ensure you ...

Dam & Fill vs. Conformal Coating
Dam and Fill is generally an encapsulant that utilizes epoxy. This is generally used when product has mechanical or thermodynamic ...

Removal of Non-functional Pads from Inner Layers
Non-functional copper, is generally used to balance plating. On inner layers, with non-functional copper, this would be a very sophisticated ...

Toe Fillet Requirements on Gull Wing Components
There is a requirement to have the pad extend past the toe of the lead... however, the solder presence cannot ...

Coating Scored Panels Prior to Separation
This depends on the thickness and uniformity of the panels... To properly conformal coat this assembly, we would recommend a ...

Voids with Back to Back BGA Components
Yes, it is quitepossible to have voids form, grow and move, if the BGA balls are reflowed asecond time. Good ...

Conformal Coating Over Heat Sinks
Selective coating will prevent over spray and allow you flexibility and consistent results. If you are using an acrylic, it's ...

BGA Reflow on HASL PCBs
Very feasible... youcan specify the land/land flatness you want on the BGA pattern and also,specify the lead-free HASL you wish ...

Fastening Surface Mounted Connectors Before or After Refow?
The PTH Connectors should be torqued down prior to reflow, when applicable. Mainly due to stress incurred, if you torque ...

Reflow Causing Warp
You can take the following precautions.Check that the PCB House is giving the board a 'slow cool' or secondary 'annealing'.Review ...

Acceptable Conductor Repair
I would not accept this repair on a production, sold as new component. The IPC specification for rework is specific ...

Gold Edge Contact Flux Contamination Failures
Find a new EMS supplier. Flux residues on the laminate will cause premature failures and also promote ionic migration, pending ...

Gold Plated Hole Defects
It's not uncommon for this effect, and probably more common on all solder joints... but due to dissimilar colors, you ...

Glued SMT Components Falling Off
This could be a function of your glue placement.... Cap's 'pop' off the boards generally because of voids in glue. ...

HASL vs. Immersion Gold
ENIG is a good candidate for High Phosphoric Corrosion resistance. This is the plating of choice for Printers, TeleCom and ...

Insufficient Plated Hole Fill with Electrolytic Capacitors
Solder fill is dependent on Thermal balance, lead-to-hole ratio, solder tension and cleanliness. To check thermal balance, ensure you have ...

How To Mask Areas During Conformal Coating
Conformal coating is more an art than science, in its application. Even the automated spray systems require some technique to ...

Cleaning No-Clean Solder Paste
We use Zestron products, but if you are hand cleaning, this is not recommended. The type of NC flux and ...

Solder Thieving Explanation
Solder Thieving? or Theiving pattern for Solder Plating... If the latter, a pattern may be introduced to a PCB with ...

Long Term Concerns with Disturbed Solder Joints
This policy, is pending the PCB Solder finish. Eutectic Solder, itself, will not be affected by heat cycling performed during ...

Epoxy Bonding Problems on RoHS Boards
Depends on the surfaces you are bonding to. If the bonding is to the green soldermask, there could be a ...

Hand Soldering Alternative
We have assemblies with wires that are located around assembly which are mixed technology. We terminate the wires with griplets, ...

Concerns with High Humidity
High Humidity will affect solder finish specifically longtermand paste deposition/solder wetting during production shortterm. You should determine what solder finish/system ...

Solder Joint Rework Question
IPC has an entire rework standard which will directly specify the proper method of PTH rework. In most cases, you ...

Mysterious Solder Balls
This could be attributed to couple things: Is the solder finish HASL? As solder finish may not be applied to ...

Delamination dilemma
Delamination is generally a result of moisture content, PCB lamination controll problems with Epoxy system and/or inherent stress that is ...

Reworked BGA component bridging at the corners
The component package should be considered when reballing/reworking BGA. Is the BGA a ceramic, FR4 laminate system or some other ...

Ultrasonic Cleaning Causing Damage
We use a semi-aqueous cleanser that works very well at removing "no-clean" residues when we are required to do so. ...

What is the Proper DI Water Resistivity
Resisitivity of a rinse water is a function of surface area being cleaned. We rinse to a resisitivity of 200 ...

Recommended lead to hole ratio
For consideration of a good solder joint, you will need to consider the following. Solder Finish,Component Lead Mass, Auto or ...

Ideal humidity for circuit board assembly
...

Problem with 'No Clean' Solder Flux Residue
The white rsidue is typically not Halites. I'm not a chemist but we believe the white to be a type ...

Set up for lead-free wave soldering
Wave soldering setup is dependent upon the materials used, and the configuration of the PCBA. Considerations for Leadfree Soldering: * ...