Indium Corporation has two options available for connector pin soldering: standard individual washers and InTEGRATED™ Preforms.
If you are using individual washers in your process, there are several things to keep in mind:
- The ID (inner diameter) of the washer will be the most critical dimension. It needs to fit over the pin. If your washers are flux-coated, be sure to allow for the added flux in your calculation.
- Some IDs are too small for flux coating as the flux coating can easily obscure the ID and make it difficult to smoothly place a washer over a pin.
- When you are flux coating your washers, less is more. In other words, 0.5% to 1.5% flux by weight is sufficient to reduce the surface oxides and prepare the surface for wetting.
- Solder volume can be adjusted by adjusting the thickness. Contact us to help determine the best inner and outer dimensions for your application. Next we'll need to know the board thickness, hole size, and pin size. Then we can recommend the proper thickness for your washer.
- Here are some common washer sizes:
- 0.020" x 0.031"
- 0.022" x 0.050"
- 0.025" x 0.040"
- 0.027" x 0.043"
- 0.030" x 0.049"
- 0.032" x 0.052"
- 0.033" x 0.060"
- 0.035" x 0.060"
- 0.043" x 0.058"
- 0.045" x 0.060"
- 0.045" x 0.080"
- 0.060" x 0.100"
- Washers are available in a variety of alloys, including indium-based alloys which allow for soldering to ceramics or other non-metallics.
Pin soldering to ensure a reliable solder joint on each pin can be challenging. Spacing, quantity, size, and location of the pins on a board, as well as the board thickness can make it difficult to get individual washers over the pins.
Manual placement includes hand-placing individual washers over each pin. This is viable for larger washers and simple pin design. However, as the pins get smaller, more complex, or larger in number, manual placement becomes more problematic.
The solution? InTEGRATED™ Preforms.
InTEGRATED™ Preforms are linked washers that can be cut to the configuration of the connector and placed in one simple motion, saving time and money.
Saves time - no need to place each washer individually.
Saves money - by eliminating the need for special pick and place equipment or extra fixtures.
InTEGRATED™ Preforms are washers (or other shapes) that are linked together to allow for placement of multiple washers in one single motion. In virtually the same time it takes to place ten washers on one connector, by hand, one at a time, up to ten connectors can be ready for reflow.
InTEGRATED™ Preforms washers are joined in a matrix by fine, precise strands of solder. These strands melt and flow to the adjacent pads during the reflow process, providing for a complete separation of the washer preforms.
InTEGRATED™ Preforms require an even heating process - vapor phase and convection reflow are ideal. If the job is small enough a hot air gun will work, provided you apply the heat evenly.
InTEGRATED™ Preforms are sold in single, patterned sheets. The pattern for each connector will be cut from the sheet. To determine the pattern, we need to know:
- Hole size
- Pin size
- Board thickness
- Pitch of the pins (between the row and row-to-row)
InTEGRATED™ Preforms are best suited for smaller volume applications that are not easily automated.
Tips for using InTEGRATED™ Preforms:
- Flux must be applied separately to both sides
- Preforms must be flat in the application
- Uniform reflow heat is required
- Minimum thickness is 0.002" and maximum thickness is 0.018", but they can be stacked to achieve greater solder volume
Not all alloys are suited for InTEGRATED™ Preforms. Contact us for technical advice about your application.
Connector Assembly Technical Documents
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Safety Data Sheets
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Indium Corporation Blog Posts
A paper presented at SMTAI 2016 on reducing voids in bottom-terminated components...
A preform is a piece of solder (available in a wide variety of shapes).
Indium metal has a positive environmental impact in our customers' applications.
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