A Solder Alternative Utilizing Integrated Solder Preforms.
Printed circuit boards containing both surface mounted and through-hole components are common in industry and, often, are referred to as "mixed technology" boards. Solder paste is used to attach the components on the surface, and wave solder is popular to attach the components that are inserted through holes in the board. Also, for low volume production, hand soldering is often utilized for the attachment of the through-hole components. Both of these methods require additional steps after the original reflow of the solder paste.
To save time and money, and to improve production, InTEGRATED® Solder Preforms have found a place in mixed technology boards. Integrated Preforms are connected washers that are designed to fit the pins of the through-hole component. The size of the washer delivers to each pin the required amount of solder that will fill the hole and give a good fillet to the joint. In some cases, to add an extra amount of solder, paste is deposited over the holes and the Integrated Preform is placed in the paste and the component is inserted through the holes in the preform. In other applications, TACFlux® that is compatible with the flux vehicle in the paste is applied to the preform before it is placed on the component over the pins or placed directly on the board and the component is inserted as mentioned above. Whichever method is used, only one reflow, and only one cleaning, are required.
Components with long pins are a special challenge because they are very difficult to attach without getting solder 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 for each specific application. The following information is required so the volume of solder and the washer spacing is correct for the pin configuration:
- Hole size
- Pin size
- Board thickness
- Center to center spacing of the pins (within the row and row to row)
- Is the preform going to be used to add to the volume of solder from the paste?
Separate washers can also be used in place of the connected Integrated Preforms. They can be designed to deliver the same consistent volume of solder required for the 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 connected washers are made 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 all the companies today driving to lower manufacturing costs, Integrated Preforms present an excellent opportunity. The biggest advantage of cutting cost with Integrated Preforms is the fact that quality can be improved at the same time whereas most cost reductions sacrifice quality in some manner. Integrated Preforms can be implemented into any manufacturing process from manual soldering steps to high volume automation. If you are looking for any easy way to cut costs, increase production, and improve quality, then consider using an Integrated Preform.