Come see Indium Corporation's new AuLTRA™ ThInFORMS™ at SPIE West in San Francisco, CA Feb. 4-6, 2020. AuLTRA™ ThInFORMS™ improve thermal transfer and the overall operational efficiency of die-attach applications.
Solder Preforms come in standard shapes such as squares, rectangles, washers and discs. Typical sizes range from .010" (.254mm) up to 2" (50.8mm). Smaller and larger sizes, as well as custom shapes, are also available. Dimensions can be held to tight tolerances to assure volume accuracy.
Alloy selection should be based on strength and other required physical properties, as well as the preferred soldering temperature and the operating temperature of the device being soldered. A general rule is to select an alloy that melts at least 50°C higher than the operational temperature of the part being soldered.
Next, consider the materials being soldered and what solder is most compatible with them. For example, tin-based solders will scavenge the gold from gold-plated parts, forming brittle intermetallics, so indium-based solders are generally recommended in these cases.
Metals and alloys have different characteristics that can affect the ease with which they can be made into different shapes and thicknesses. It is important to consider the shape of the final preform in the alloy selection process.
The operating environment of the completed assembly is also an important consideration for alloy selection. Will it operate in very high or very low temperatures, or be subjected to vibration? If so, you need to select an alloy that will stand up to these conditions.
Our Application Engineers will work with you to determine the best alloy for your application.
The location of the solder joint and the volume of solder needed will determine the size and shape of the preform. Once the flat dimensions (diameter, length, width) have been determined, the thickness can be adjusted to achieve the desired volume of solder. Generally, for through-hole connections, add 10-20% to the calculated volume for a good fillet. For pad to pad joints, figure about 5% less surface area than the pad.
Each Solder Preform should have a burr tolerance specified. You should stay as close to standard tolerances as possible to avoid adding cost and lead time to your Solder Preforms.
Indium Corporation has an extensive library of sizes and shapes from which you can choose, or we can create a set-up specifically for your application. Using an existing preform size can eliminate the additional time associated with creating a new set-up.
Dimensional Specification Recommendations
Width/length or diameter:
Up to .100" (2.54mm)
Over .100" (2.54mm)
± .005" (± .127mm)
Up to .001" (.025mm)
± .0002" (.005mm)
.001" (.025mm) to .002" (.050mm)
± .0003" (.0076mm)
> .002" (.050mm) to .010" (.254mm)
± .0005" (.0127mm)
> .010" (.254mm) to .020" (.508mm)
± .0010" (.0254mm)
> .020" (.508mm) to .050" (1.27mm)
± .0025" (.0635mm)
> .050" (1.27mm)
Burr Tolerances (Discs, Squares & Rectangles):
>.050" (1.27mmm) to .500" (12.7mm)
Burr Tolerances (Washers & Frames):
When thickness ≥ 2/3 of I.D.
Packaging and Storage
Solder Preforms come in a variety of packaging options, including tape and reel. To minimize excessive handling, and exposure to air and subsequent oxidation, Solder Preforms should be packaged according to the quantity used during a typical work shift.
Store in the original container, closed securely, in 55% RH or less and at temperatures less than 22°C. Solder Preforms can also be stored in an inert atmosphere, such as a nitrogen dry box.
The shelf life of Solder Preforms is dependent on the alloy composition. Pb-free alloys, and alloys with lead content of less than 70%, have a shelf life of 1-year from the date of manufacture (DOM). Alloys with lead content >70% have a shelf life of 6-months from the DOM.
Flux-Coated Preforms eliminate the costly production step of separate fluxing and increase throughput yields. Flux Coatings for Preforms are available in no-clean and rosin-based chemistries with a variety of activity levels to suit your substrate metallizations.
Indium Corporation is a leading joining and bonding materials innovator for medical, aerospace, optoelectronics, and automotive applications. When even 10 ppm of contamination can cause process and application failures – quality counts. Indium Corporation casts our alloys, which enables us to closely control the process from start to finish and ensure purity.
Solder Tubes – Precise Solder for Electrical Connection in Heat Shrink Solder Sleeves
Indium Corporation’s Solder Tubes provide a precise, controlled amount of solder for heat shrink electrical joint termination within solder sleeves.
While Solder Tubes are similar in shape to standard washers, the tight wall-to-height/thickness ratios of 3 or more is a key distinguishing feature. Solder Tubes can be customized to meet your heat shrink solder sleeve requirements and are ideal for a number of applications including:
EMI shield to ground termination
Wire to wire splicing, and more
Flux coating is available to facilitate the soldering process. Typically, flux coatings can be applied in the range of 0.5%–2% by weight and are available in no-clean, RMA and RA
Visual Reflow Indicators
There are two options available for visual verification that the reflow temperature for the solder has been reached:
Thermochromic indicator dye which disappears when the proper temperature has been reached. This dye is added to the flux coating and does not interfere with reflow.
External indicator ring which is made of an alloy that melts at a higher temperature than the base tube. Once the outer ring is reflowed, it is an indication that the base tube has also reflowed.
Wall-to-height/thickness ratios of 3 or more
Visual reflow verification
Flux coatings can be applied in the range of 0.5%-2% by weight
Available in the most frequently used solder alloys, including:
Non-standard alloys are also available, depending on the alloy.