Al Cabral

Al Cabral has submitted responses to the following questions.

Is Rework Unacceptable?
The short answer is no, it's not practical but remains the customer's prerogative. As the service provider, this atypical requirement ...

Max Peak Topside Reflow Temperature
Dusting off the memory cells, I believe the maximum 150C topside board temperature relates to the nominal glass transition temperature ...

Options for Reballing BGA Components
There are a number of viable methods available for reballing BGAs and other area array devices. Ball count, pitch, diameter, ...

Legend Marking Discoloration
Ensure overheating is not taking place. Measure the temperature of the areas of interest with thermocouples. If OK, try reworking ...

Profiling for Double Sided BGA
If the component layout of the boards is not yet solidified, consider locating passives on the opposing sides of BGAs ...

What Causes Solder Balls During Rework?
One very common issue is the absorption of moisture, especially in environments with high humidity levels. The use of a ...

Need for Reflow Profiles
Even with the most forgiving reflow systems available, developing a "golden recipe" that produces adequate thermal results for all products ...

BGA Shifting During Reflow
Movement of a component could be caused by elevated mechanical vibrations stemming from a questionable conveyor system or blower motor. ...

What Is the Life Span for a Profile Board?
The short answer is "It depends." The material make up and physical attributes of the profile board, the thermocouples selected, ...

Small chip cap rework advise
Reworking sub-mm components requires either highly skilled operators with very reliable hand held equipment and vision assist or accurate semi-automated ...

Reworked BGA component bridging at the corners
Bowing or warping is typically caused by thermal gradients across components, boards or both. Components are comprised mostly of fiberglass, ...

Reflow oven testing and calibrating concern
Test boards can be created to illustrate specific characteristics of a reflow system, be it heating / cooling capacity, thermal ...

Re-certify a reflow oven
Despite what some folks may think, not all Reflow ovens are created equal. Consulting with the original equipment manufacturer will ...

Micro-balling with lead-free HASL and SAC alloy
Consider repeating the test following a baking cycle in a batch oven at 125C for 8 hours to determine whether ...

Reflow for leaded and lead-free assemblies
It's highly unlikely that dedicated Reflow ovens are required to process lead base and lead free alloys for traditional SMT ...

Remove and replace a 240 pin connector
The advise offered starts with the assumption that the Rework system used is operating properly and capable of Lead-Free processing. ...