Common PCB Soldering Problems to Avoid

How do you know if you have a problem with solder applications in SMT manufacturing? We've put together information on the most common PCB soldering problems to avoid, helping you troubleshoot your SMT equipment and your PCB assembly line overall.

Keeping Your Components Together

SMT assembly is all about creating PCBs that work in today's electronics. That means attaching small components to compact board designs, rather than relying on bulky wiring.

The right PCB soldering equipment can mean the difference between a lot of rework time and excellent reliability from your assembly line.

What Does A Perfect Solder Application Look Like?

Although you may hear it described like a Hershey's Kiss in shape, the ideal solder joint also looks somewhat like a volcano (think Mount Fuji or Mount St. Helen's) or a cone with concave sides. You also want to see a smooth, shiny surface on the cured paste.

Signs You Have A Problem

  • Domed Paste Application
  • Frosted, Lumpy, Rough, Or Crystalline Surfaces
  • Cracked Or Weak Joints
  • You See Burnt Flux
  • Poor Bonds Between Components & Boards
  • Conductivity Issues

PCB Contamination Causes Problems

Minimizing pollution or impurities throughout the PCB assembly process is essential — whether it's on your boards, components (like transistors, resistors, capacitors, or integrated circuits), or around your machinery. The quality of your solder paste and flux, too much handling, dusty environments, and too much moisture can all cause contamination problems in SMT manufacturing.

  • Insufficient Wetting On The Pad
  • Webbing, Splatters, Or Splashes
  • Balls Or Blobs
  • Blow Holes Or Pinholes

Causes Of Weak Solder Joints

Weak joints may result in PCBs that test fine initially but will crack or fail eventually. If your screen printer, wave solder machines, or reflow oven are acting up, the fluctuations in application amounts, placement, and temperature can result in weak joints that need to be reworked, costing you both time and money.

  • Cold Joints
  • Overheated Joints
  • Insufficient Wetting
  • Not Enough Solder
  • Lifted Pads
  • Tombstoning

PCB Conductivity Issues

If you notice poor conductivity, shorts, or burnouts on your circuit boards, you may have a PCB soldering problem. Not enough or too much fixative, skipped joints, and temperature can all cause connectivity issues.

  • Opens Or Skips
  • Too Much Solder
  • Untrimmed Leads
  • Bridging
  • Component Shifts

Have Solder Equipment Problems?

Sometimes you can fix PCB defects from the start by getting your board design right, your contamination issues figured out, and your equipment configurations set correctly. Over time, an efficient SMT manufacturing line can start producing duds, which might indicate machines that are failing.

Affordable SMT Equipment For Sale

When you're ready to invest in quality SMT machines, save big with used PCB assembly equipment. New or replacement machinery may be your key to minimizing PCB soldering problems. If you need a few repairs, we may even be able to help you with the parts you need.

Contact Capital Equipment Exchange today for more information on inventory and availability.