Epoxy Adhesive Preforms define custom parts that are cut out of an adhesive film material that can come either thermally conductive or electrically conductive. However, oftentimes they come as both. In addition, some of these films are supported by carriers such as fiberglass to ease in handling and assembly. Epoxy preforms offer an alternative to conductive thermal pastes that can be difficult for assembly in a few ways.
Benefits of Epoxy Films
Cleanliness and Cleanup
With epoxy films, since these films can be preformed to shape it minimize the amount of post-cleaning that is required to be done before and after bonding is completed.
Consistency of Application
Conductive Thermal Pastes can be inconsistent for the sole reason of how its applied. Depending on who/how it is applied. On the other hand premade epoxy preforms are made the same way every-time. The thickness, cut-outs, and tolerances of the preform can all be held to +/- .002” in some cases.
No Mixing Time
Since Epoxy Preforms are 1 part pre-cut parts, there is no need to mix anything unlike some of the conductive thermal pastes available.
Overall, epoxy preform film materials add a lot of consistency and can lower cost per unit production.
Preforming the material allows for more uniform bond lines, and consistent application of the adhesive across the assembly. When there is many cut-outs and close tolerancing using automated machines can offer an incredible amount of consistency. Applications such as bonding to heat-sinks are common for these films. These epoxy films can be laser-cut or die-cut.
Availability of Epoxy Film Materials
Henkel manufactures a number of assembly film options that may be a fit for different applications that require epoxy preforms:
Electrically/Thermally Conductive Films
Thermally Conductive Films
Typical thicknesses of epoxy preform materials range from .002-.006’’, however depending on the material that may change. Thickness tolerancing is also very tight on these materials ranging from +/- .001’’ to +/- .0005’ depending on the material. These tight thicknesses help control the bond-line during assembly to ensure a high level of consistency.
It is wise to consulate about epoxy film sheet sizes before determining sizes of preforms. With these materials tightly controlled performance characteristics and thickness tolerances availability of size can be tricky.
Storage is an important consideration with these films. Oftentimes these films are required to be stored at temperatures at freezing or sub-freezing in order to maximize the shelf life. This includes when shipping these materials that they are shipped at temperatures required by their datasheets. Our team generally refers to two different types of ice. There is Blue Ice and there is Dry Ice. Blue Ice keeps the package at around 30-45°F, and Dry Ice keeps the package sub-zero fahrenheit.
At NEDC, we laser-cut or die-cut epoxy preforms to many different custom shapes for our customers. Epoxy Preforms are usually very intricate with many twists, and turns in the cuts. With these challenges, choosing between die-cutting or laser cutting is a tough choice sometimes.
The delineation between laser-cutting or die cutting is often stratified by a number of factors including:
-Complexity of the cut-outs
-How many preforms are being manufactured
-How big/small the preform is
-Tolerance requirements(recommended +/- .003’’ for cutouts, +/- .005’’ for locations)*
If you have an application that you believe could utilize preforms or assembly films, please contact firstname.lastname@example.org.