Carlos Bouras

Carlos Bouras has submitted responses to the following questions.

Challenge Wetting Solder to Brass Pins
In general brass is a difficult base metal to solder since it is an alloy of copper and zinc, with ...

Challenges Placing RF Shields During SMT Assembly
Very often when components lift during reflow the root cause is due to various factors including solder paste outgassing caused ...

Pick and Place Machine Calibration
We would suggest you follow your manufacturers guidelines for the frequency of calibration. It is also recommended to conduct a ...

Baking After Cleaning Hand Placed Parts
Baking of moisture sensitive components is generally required before reflow soldering where the component body is exposed to elevated reflow ...

Assembly Question for Soldering USB Connectors
Straddle mount connectors are typically attached with reflow soldering after solder paste deposition by either stencil printing or solder paste ...

Hand Sanitizer Contamination
Quaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly found in cleaning solutions used in residential, commercial, medical settings, restaurants and ...

How To Measure Solder Paste Rolling Diameter
Solder paste is typically dispensed across the entire squeegee blade length and maintained at a 15mm rolling diameter assuming the ...

Critical Part Fixture During Reflow
Since little information is given about the board assembly or component in question, it's difficult to provide a specific suggestion. ...

Aluminum Trays and Rapid Static Discharge
In order to be in compliance with an ESD program all operators should wear wrist straps or ESD shoes when ...

Water Wash vs. No-clean
In general the decision as to whether to use a post soldering cleaning process or a no-clean process is driven ...

Solder Contamination Sources
It is generally recommended that solder baths containing lead-free alloys be analyzed once every 3-6 months or every 8,000 boards ...

How Do You Calculate Solder Paste Volume?
The issue that makes this complicated is the coplanarity variations between the tabs on the connector and the PCB itself. ...

Maximum Allowable Time Prior to Washing When Using Water Soluble Paste
It is difficult to provide guidance without knowing more information such as is the factory environment such as temperature and ...

Shelf Life Limit for Soldering Old Components
The IPC standard J-STD-002C, Solderability Tests for Components Leads, Terminations, Lugs, Terminals and Wires, addresses solderability testing that should be ...

Looking for Long-term Component Storage Options
Storage of components for ten years or longer is generally not a normal practice since most components are consumed on ...

Is There a Spec for LDI Mask thickness?
The generally accepted spec for LDI mask thickness is dependent upon the copper thickness within the circuit. For example these ...

Question About Dry Storage of PCBA's
Since you’re hand soldering the through-hole components it would appear your production volumes are relatively low. To avoid using a ...

Competing Reflow Oven Zones
Since most thermal profiler manufacturers have an extensive library of solder paste profiles, my first suggestion would be to contact ...

Exposed Copper Defect
Leaving exposed copper on a printed circuit board assembly is not recommend for any end application environment since copper quickly ...

BGA reballing question
While a single dynamic wave can be used to remove lead-free BGA solder balls before the re-balling process, it is ...

Depaneling circuit board that contain BGA components
Random or intermittent opens can occur within BGA or micro-BGA components during the de-paneling process if the devices are located ...

Tarnished OSP Circuit Boards
Even though OSP over bare copper has a significant cost benefit compared to other SMOBC board finishes, OSP is not ...

Pad Missing ENIG Plating
The most common reason for this to occur is that the fabricator could have micro-etch solution remaining in the holes. ...

IPC SOIC Defect Question
Ceramic components such as ceramic quad flat pack (CQFP) or other similar ceramic devices have a very low CTE (coefficient ...

Adding Chlorine to a DI (Deionization) Water System
We assume you're talking about a deionized reservoir for an aqueous cleaner. Adding chlorine will remove bacteria from the cleaner ...

Reflow Profile for Mixed Lead-Free and Leaded
It is highly recommended to follow the profile for the solder paste being used, so in this case one should ...

OA Flux Turning Blue
Since organic acid (OA) fluxes have a high activity level they are generally used for component lead tinning but are ...

Baking Concerns for Stacked Trays of Components
All moisture sensitive devices (MSDs) such as QFPs, TQFPs, TSOPs, etc. need to be baked before soldering based on their ...

Allowable Bow and Twist on Round PC Fab
The geometric tolerances specified in the IPC-A-600 standard should apply even if the board is routed in the shape of ...