What Exactly are Solder Preforms?

Being that Array Solders specializes in manufacturing solder preforms, we feel compelled to explain what they are exactly. Preforms are engineered shapes of solder that are used in numerous applications across a wide swath of industries. Available in numerous alloys with varying melting points, they deliver a precise amount of solder volume to your assembly. You can view a list of typically available alloys here.

Commonly Available Preforms

Washers

Array Solders - Solder Washers
Array’s solder washers can be used in applications such as connector and thru-hole assemblies.

The inside diameter or ID is the most important dimension of the solder washer. If it is too small, it will not fit over the intended pin. When the application calls for the solder washer to be flux coated, please be aware that the ID will be smaller than the specified ID dimension. You must compensate for the added flux material. Solder washers are referred to by the following: Outside diameter (OD) x Inside Diameter (ID) x Thickness (T) There may be some instances when the washer may be too small to be flux coated. If that is the case, Array Solders can also fabricate washers with internal flux. Internal flux percentages can range from 1-3%. When you are using a flux coated solder washer, less is more. In other words, 0.5% to 1.5% flux by weight is more than enough to reduce the surface oxides and prepare the surface for wetting. The thickness will determine the solder volume. Our engineers will work with you to determine the best inside and outside dimensions for your application.

Rectangles

Array Solders - Solder Rectangle
Solder rectangles are a commonly available type of preform Array solders offers.

Rectangles are solder preforms measured length x width x thickness. Tolerances are kept tight for precise solder volume. Also available flux coated or cored.

Squares
Squares are solder preforms utilized in numerous applications across a wide spectrum of industries. Squares are measured by length x width x thickness. Dimension tolerance is kept tight for soldering volume.

Discs

Disc Preforms
Disc shaped preforms in a brazing alloy.

Discs are measured by diameter and thickness. Available plain, flux coated and in some cases, flux cored.

Custom Designed Preforms

Array Solders - Customized Solder Preforms
Array Solders will work with you on your more challenging applications. In some cases, your assembly calls may call for a customized solution. We stand ready to assist you.

We also realize that your application may be complex. It is with that in mind that Array Solders offer customized preforms. Custom designed preforms can be fabricated specifically to meet your application’s intricate demands in various alloys. Our engineering staff will work with you to develop a solution. You can find more information on Array Solders customized solder preforms here.

Flux Coated and/or Cored

Array Solders - Flux Coated Washers
Flux coated preforms eliminate the additional steps of flux application and cleaning.

Array Solders also offers our preforms flux coated and flux cored. Flux coated and flux cored preforms are offered in various weight percentages. The typical percentages range from 1%-3% with a tolerance of +/- 0.5%. Adhering to IPC J-STD-004 (ROL0, ROL1, ROM1, ROH1), available flux coatings are rosin mildly activated (RMA), rosin activated (RA), rosin (R), or no clean (NC).

Applications
Preforms are used in applications such as PCB assembly, thermal fuses, die-attach, connectors, cables, sealing and thermal interfaces. Preforms are the perfect solution for these applications because they deliver the exact amount of solder required.

Pre-Fluxed Advantages
Pre-fluxed preforms, whether coated or cored, deliver the precise amount of required flux and solder volume to the exact area where it is needed. They leave behind little to no residue. As a result, you are able to skip the additional steps of applying flux and cleaning therefore saving time and money.

Solder Preform Packaging

Array Solders - Tape and Reel Preforms
Array Solders offers various packaging solutions for many of its preforms.

Solder preforms are usually bulk packed. In addition, they may also be tray packed or placed on tape and reel for automated applications. There are instances when solder preforms are in need of more secure packaging. Depending how delicate or brittle the preform may be, they can be layered and pressed packed to maintain integrity during shipping and handling.

Storage
In order to maximize the shelf life, preforms should be stored in dry areas. It would be best to store preforms at or just below room temperature.

Download our technical data sheet here: Array Solders – Solder Preform Technical Data Sheet

To conclude, we hope this overview helped. If you are ready to move forward and start using preforms for your application, our engineering staff stands ready to work with you. Contact us to get the ball rolling.