Indium Blog

Mixed Technology Boards: A Solder Alternative Utilizing InTEGRATED PREFORMS®

Printed circuit boards containing both surface mounted and through-hole components are common, and are often referred to as "mixed technology" boards.  In mixed technology assembly, solder paste is used to attach the components to the surfaces and wave soldering attaches the components that are inserted through holes in the board.  For low volume production, hand soldering is often utilized - for the attachment of through-hole components.  Both of these methods require additional steps after the original reflow of the solder paste.

To increase your profits (saving you time and money while improving your quality and productivity) InTEGRATED PREFORMS® have found a place in mixed technology assembly.  InTEGRATED PREFORMS® are interconnected solder washers, designed to fit the pin pattern of a through-hole component.  These arrayed solder washers are sized to deliver the precise solder volume required to fill the holes and to produce excellent solder fillets at each joint. 

In some cases, to add even more solder, solder paste is deposited over the holes and the InTEGRATED PREFORM® is placed into the paste. The component is then inserted through the solder preform, the solder paste, and the hole. 

In other applications, TacFlux® (that is compatible with the solder paste's flux vehicle) is applied to the preform before it is placed on the component's pins, or is placed directly on the board, and the component is inserted as described above.  Whichever method is used, only one reflow step and only one cleaning step are required.

In traditional wave soldering, components with long pins are a special challenge because they are very difficult to attach without getting alloy on the pins during wave or hand soldering.  InTEGRATED PREFORMS® can be applied to the top or bottom side of the board and are reflowed along with the components held down with solder paste.

InTEGRATED PREFORMS®  are designed and built to address the unique characteristics of each specific application.  To build your InTEGRATED PREFORMS® we require the following information, so the solder volume and washer spacing are correct for your specific pin configuration:

  • Hole size
  • Pin size
  • Board thickness
  • Center to center spacing of the pins (within the row, and row to row)
  • Solder Alloy
  • Is the preform going to be used to add to the volume of solder from the paste?


Separate (individual) solder washers can also be used in place of connected InTEGRATED PREFORMS®.  They can be designed to deliver the same consistent volume of solder required for each joint.   Care must be taken, however, to place only one preform on a pin, and not miss any.  This is what makes InTEGRATED PREFORMS® desirable.  The solder washer array is designed and manufactured to fit the pin configuration so only one washer goes on a pin.  If extra solder volume is required, InTEGRATED PREFORMS® can be easily stacked.


With today's drive to optimize profits, InTEGRATED PREFORMS® present an excellent opportunity.  The biggest advantage of InTEGRATED PREFORMS® is the fact that quality can be improved while costs are reduced.  If you are looking for any easy way to cut costs, increase production, improve quality, improve customer satisfaction, and, ultimately, increase your profits, talk to me about InTEGRATED PREFORMS®.

Paul Socha

BONUS: Read our white papers regarding InTEGRATED PREFORMS® .