Steve Stach

Steve Stach has submitted responses to the following questions.

BGA Ball Sheer Testing
I have pulled and sheered many BGAs from assemblies to access flux removal under devices. I commonly see both pad ...

Tiny Solder Balls After Reflow
In my experiences I have seen several causes you could check out.Wiping the board with alcohol can leave water on ...

Solder Paste Prep Before Use
It is a good ideato let the solder paste come to room temp before opening the container toprevent water from ...

Cleanliness Testing
The newest cleanliness test methods are focusing on the time it takes to create and electrical event (defined short) in ...

Cleaning No-clean Flux with Tap Water
What happens is; the no clean flux is coatedwith a surface layer of what ever ions were present in the ...

Cleaning Water Soluble Flux
To answer your question; cleaning a watersoluble flux with a flux cleaning chemistry at a concentration of 5% is arelatively ...

Solution for Grape Effect
Switching solder paste formulas is your best bet. Ask your solder paste suppliers for a formula with a high temperature ...

Method for cleaning boards after misprint
The best procedure for cleaning solder misprints is to;Do not attempt to hand wipe the assembly. Hand wiping forces the ...

Is lead contamination during cleaning of PB-free stencils possible?
The short answer is "yes, it is possible to crosscontaminate leaded and no-lead stencils when cleaning in a common stencilcleaner." ...

Water Washing Pressure
The best way I have found to measure maximum impactpressure at the board surface is to fabricate what we call ...

Circuit Board Exposed to Rain
It really comes down to if power was applied when it was exposed to the rain water. Since most circuit ...

BGA Rework Residue Concern
My guess is that this polymerized flux residue. If you clean after initial soldering, thisresidue was there after cleaning and ...

Conformal Coating Over No-Clean Flux
Doing this without the proper control is very dangerous. The controls are necessary to prevent encapsulating ionic/conductive materials under the ...

Spotting After DI Water Cleaning
DI resins will only remove ionizable material and it looks like you are building a concentration of non-ionic compounds in ...

Cause of Green/Blue Oxide Buildup
I believe you problem is caused by the marine environment providing a little salt which will catalyze and accelerate base ...

Is Baking Required After Aqueous Cleaning?
If your boards are wet with liquid water you must dry them to pass electrical test. If your boards are ...

What Causes Black Pad?
Black pads are not created in the assembly process, they are revealed. They actually come from your board vendor in ...

Cleaning to Remove Solder Balls
Don't even think about using anything but airspray for removing post reflow solder balls. You will need the physical energy ...

Hot or Cold DI Water Rinse
Heating the final rinse water is a waste of energy and is not needed in most modern inline cleaners. If ...

Class 3 Cleaning Requirements
It is really comes down to your company having data showing you can meet and control your process to the ...