Lacking hole fill during THT-soldering?

What options support hole fill during your soldering process?

With THT-soldering it can happen that the hole fill does not form properly. In this case the solder does not completely perforate the hole and the counterminiscus is not formed 100%.

First check that the diameter of the hole in relation to the pin ratio and the joint geometry are correctly selected. If this is the case, you have the following options to optimize the process:

Mini wave or selective soldering:

  • Increase the temperature of the solder bath and check for the desired temperature at the process point.
  • Increase contact time between mini-wave and product
  • Increase preheating temperature, activation or preheating time
  • Check the optimal flux quantity
  • Verify that the correct flux is used in accordance to solids and other activators
  • More about the EUTECT IW1 & 2 module

Laser solderings

  • Use of a preheater to apply heat to the joints, thus facilitating hole fill
  • Position of the laser focus in the right angle and in relation to the product geometry, solder feed and overall product geometry
  • Test feeding speed of the solder wire
  • Additional energy input after fusing of wire
  • Test the optimal flux content and the correct alloy in the solder wire
  • More about EUTECT laser soldering


If you still have problems with hole fill, please contact us, we will help you to optimize your soldering process.

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