Rick Perkins

Rick Perkins has submitted responses to the following questions.

Full Aqueous Clean or Local Spot Clean
The amount of cleaning you do on your parts depends on the level of reliability that you are building your ...

Conformal Coating Bubbles
Fun times! Yes, bubbles are a defect. Bubbles in your conformal coating is a result of one of two things. ...

Water Wash vs. No-clean
If the contract does not specify a cleaning process, but does specify a solder paste / flux system, then the ...

Contamination From Anti-static Foam
Without knowing the types of materials on this board, it sounds like the advice you have been given is good. ...

What's Causing Cloudy Conformal Coating
I imagine that this is a 2-part polyurethane conformal coating this is cloudy in the "cured" state. If so, the ...

Cleaning Under Low Clearance Components
Yes, more than likely, you are jeopardizing the reliability level of your product by not removing residues from a water-based ...

Is Solder Mask Considered an Insulator
While I cannot speak to the IPC standard requirements, it depends on what reliability specification you are working as to ...

Out-gassing and Cleaning
Outgassing from the solvents will not be an issue if you use one solvent, or a blend of solvents, that ...

QFN Test Failures Caused by Flux
Great question! You have learned the hard way that "No Clean" does not entirely mean "do not clean". The process ...

Removal of Coatings from PCBs
Coating removal from a PCB depends on several factors: 1) type of coating, 2) type of substrate, 3) type of ...

Contamination Using Solvent Dispensers
The first point you must understand is that you are not "actually" cleaning the boards when you use an acid ...

Trichloroethylene Alternative
My response might sound crazy to many in the USA, but I'm taking into account that you are primarily using ...

ESD Grounding - 1 Meg Ohm Resistor
A resistor is used as a safety precaution. Since electrical equipment is also connected to ground ... (some companies do ...

Mixing Silicone and Acrylic Conformal Coatings
The mixing of the two conformal coatings is not ideal and if there is away to avoid using the acrylic ...

Conformal Coating Recommendation
There are two best options for an outdoor conformal coating. One is a silcone-based product that can also withstand high ...

ESD Conductive Floor Tile Worry
I have been involved in specifying, installing, and verifying conductive ESD floor tile in several high reliability manufacturing areas. I ...

Challenging Cleaning Problem
For this critical unit, the obvious cleaning method is vapor cleaning. Vapor cleaning uses a nonflammable hydrocarbon that is boiled ...

Stencil Cleaning Procedure
In this process you have many variables that need to be optimized dependent upon the acceptable reliability level of the ...

Solder Paste Life on the Stencil
Yes, you need to remove the solder paste on a regular schedule, possibly every 4 hours, and clean the stencil ...

Un-cleaned PCB Assemblies Potted
There are many variables associated with your question. For example, was this "washable flux" a water-based OA type of flux ...

Cleanliness After Coating Removal
This is a situation where you have to prove to yourself (and to your customer) that your rework cleaning process ...

Zip-lock Bags vs. Heat Sealed Bags
No. Zip lockbags are made from polyethylene, which moisture and other gases can transpire. ...

Class 3 Cleaning Requirements
It is unclear as to what specification you are working under. There is no general specification for "Class 3" cleanliness. ...

Tacky Substance Under Zero Clearance Parts
If the contaminant is causing you a reliability problem, then it needs to be eliminated or controlled. It would be ...

Flux Oozing from Insulated Wires
When I have seen flux oozing from between the wire insulation and the wire, the reason has been attributed to ...

Dendritic Growth and Contamination at BGA Sites
Obviously this was an error as all active flux residues must be cleaned. The question is, what type of active ...

Gold Edge Contact Flux Contamination Failures
Boards that have been manufactured with "No-Clean" flux may still require cleaning prior to delivery to service. This depends on ...

Ways to Remove Silkscreen Ink from Pads?
Removing ink is not different than removing solder paste, that is, if the ink is UNcured. However, if the ink ...

DI Water Resistivity Check
A simple conductivity / resistivity probe is all that is needed to make the measurement, and that is about as ...

Fumes from Baking
An oven used to demoisturize the boards would typically operate in the 250 F temperature range. Some nonmetallic materials will ...