Determining the appropriate adhesive for your project

[Robert_Fay]

Almost all of us have a project at one time or another that requires adhesive. Unfortunately being in the electronics field not many of us have an in depth knowledge of which adhesive is the best to use with your individual project.3M has an excellent guide to help with designing in their Adhesives and Tapes.

We will start by answering 2 questions.

1. What type of assembly is required?
2. What are the materials that are being bonded together?

Assembly

3M sorts assembly into 7 common categories

1. Panel to Frame / Stiffener to Panel
   • Panel to Frame: Decorative or load bearing panel that is applied
     to a rigid frame or support. Examples include trailer panels,
     elevator walls and sign boxes.
   • Stiffener to Panel: Stiffeners are applied to panels to give extra
     support and rigidity. Examples include trailer wall panels, traffic
     signs and large metal enclosures.
2. Small Joint Assembly
   • Small Joint: Small joints are typically irregularly shaped but only a few
     inches of overlap area. They may be insertion joints or overlap joints,
     or some combination. Examples include sporting goods (e.g., golf
     club heads to shaft), plastic casings, lens mounting for instrumentation,
     mortise and tenon furniture joints, thread locking or shaft retailing,
     magnet bonding and jewelry making.
3. Large Surface Lamination
   • Large Surface Lamination: Two surfaces (substrates) of similar size,
     either rigid or flexible, are bonded or laminated together where a
     majority of the surface is covered by the adhesive or tape in order
     to create the bond. Examples include high pressure laminate
     to tabletops, fabric to foam for furniture, veneers on wood
     and flexible transportation flooring.
4. Mounting and Trim Attachment
   • Mounting: Applying an object to a surface. Generally, static loads are
     prevalent and the mounted item is smaller than the surface to which it is
     bonded. Examples include small signs, mirrors and white boards,
     and panel-over-panel with partial adhesive coverage.
   • Trim: Decoration or identification added to a surface. Examples include
     nameplates, edge banding, bezels, rosettes and muntin bars.
5. Gasket Attachment
   • Gasketing: Attachment of a substrate typically, foam, rubber or paper that
     acts as an interface or seal between two surfaces. 3M offers solutions for
     attaching preformed gaskets, and also solutions which can replace gaskets or
     bond and seal simultaneously. Examples include air and liquid filters, fluid
     handling equipment, heat exchangers and ball joints.
6. Sealing
   • Sealing: Tape or sealant is applied over a seam to prevent fluid ingress or fluid
     egress. Examples include roof seams on vehicles, seams on metal enclosures
     and pipe sealing.
7. Potting and Encapsulation
   • Potting and Encapsulating: Adhesive flows over and around a component or fills
     in a chamber to protect components therein. Examples include heavy duty
     electrical cords and connectors, electronics in plastic cases, circuit boards
     and concrete repair.

Materials

Once you have determined your assembly we can look at the material you are using to help determine a family of products to look at using.Here is an example chart from the sealing, Potting and Encapsulating section. See the 3M solutions for you assembly guide at the bottom of the post for guides for each of the 7 assembly types.

Having an answer to these two questions, really helps to narrow down what 3M sticky product will work for your application. Remember to always look at the 3M Datasheets as they will provide you with a great deal of information on substrates.

So if your looking for Epoxy, Tape, Glue Sticks, Thermal Pads/Sheetsor liquid adhesives- we have them all here at Digi-Key.

Custom Products

Digi-Key can also help with your Custom Die Cuts as well.

Here is a link to the 3M Solutions for you assembly challenges.