Frequently Asked Questions

 Solder Paste Printing Process

• What's the best practice for handling solder paste
• What's the best solder paste quality control?
• Type 3 or Type 4 Solder Paste
• What's the best way to clean a misprinted PCB?
• What factors affect solder paste transfer efficiency?
• What is the difference between aspect ratio and area ratio of stencil apertures?
• What stencil thickness should be used?
• What squeegee speed should be used?
• What squeegee pressure should be used?
• What the differences between 'on-contact' printing and 'gap' printing?
• What separation speed should be used?
• What are the benefits / challenges of using halogen-free solder paste?
• What is the best stencil aperture shape for solder paste transfer efficiency?

Pick and Place Process

• What's the best way to support a PCB during assembly?
• How are components transferred from tray to tape and reel?
• What is 'Package on Package' (POP)?
• What methods are there for stock control and monitoring component attrition?

Reflow Soldering Process

• Why do PCB's delaminate during reflow soldering?

• What are the different types of reflow profile?
• What does the term voiding mean?
• How is void percentage calculated?
• How to reduce voids in QFN device ground connection?

Cleaning

• What are the differences between 'Water-soluble' and 'No-clean' flux?
• What causes electrochemical migration (ECM)?
• What is the difference between ionic and non-ionic contamination?
• Why clean a PCBA that has been soldered using no-clean flux?
• How do engineered cleaning fluids such as Zestron and Kyzen work?
• How do engineered cleaning fluids affect surface tension and wetting angle?
• How does the pH level affect engineered cleaning fluids?
• How do mixed-bed and carbon filters work in PCB cleaning systems?
• What are the risks of using ultrasonics to clean PCBA's?
• What is ROSE (Resistivity of Solvent Extract) testing?
• How do you validate a PCBA cleaning process?

Conformal Coating

• What are methods of masking before conformal coating?
• How to apply conformal coating by brushing?
• How to apply conformal coating using dipping?
• How to apply conformal coating using spray/aerosol?
• How do selective robots apply conformal coating?
• What is the best method to dry/cure conformal coating?
• What concerns are there when demasking?
• What should be checked when inspecting after conformal coating?
• How to check the adhesion of conformal coating?

General

• What is a Teflon PCB?
• What is a Rigid Flex PCB? Examples, Cost, and Uses
  
• Wiring Harness Manufacturing: A Detailed Guide
  
• What's the preferred PCB finish within the industry?
  
• What is the 'floor life' for the different moisture sensitivity levels?
• Is there a quick way of comparing bills of material to find differences when up issuing an assembly?
• Comparison of SAC305 and SAC387 Lead-Free Solder Alloys
• What is a 'Eutectic' solder alloy?
• What does 'SMT' stand for?
• What do you think of low temperature lead free solder paste?
• What software is available to view Gerber data?
• What software is available for PCB design?
• How do you extract CAD data from PCB design software?
• How are PCB's manufactured?
• What are the IPC standards that govern electronics manufacturing processes?
• What are the differences between SMEMA and HERMES?