Ultra-thin double-sided tape for earbud housings
Double-sided tape just 50 microns thick that bonds firmly to PC/ABS plastic is an increasingly popular choice for bonding earbud housings, replacing liquid adhesives that are hard to meter and prone to squeezing out at the edges.
Wireless earbud housings usually consist of two or three plastic parts joined together, sometimes with a metal or glass decorative panel. The requirements are a strong joint with no gaps, no visible adhesive and the ability to be disassembled for repair when needed. Thin double-sided tape meets these requirements well.
Another rarely mentioned advantage is repairability: when the battery or circuit board needs replacing, a tape-bonded housing can be separated with gentle heat, whereas a housing bonded with liquid adhesive usually has to be destroyed.
Advantages over liquid adhesives
- Uniform thickness that does not affect assembly tolerances.
- No adhesive squeeze-out, keeping product surfaces clean.
- No curing time needed, so parts move to the next station immediately.
- Easy to automate with pick-and-place machines.
- Precisely die-cut to match the housing contour.
Properties to consider
High-strength acrylic adhesive layer
PC/ABS plastic has medium surface energy, which suits modified acrylic adhesives. 180-degree peel strength on PC typically reaches 8–12 N/25 mm after 24 hours, sufficient for lightly loaded positions.
Thin carrier
A thin PET carrier makes the tape just stiff enough for die cutting and handling, while carrierless tapes offer better gap filling on textured surfaces.
Impact resistance
Earbuds are dropped frequently. The tape must maintain its bond after repeated drop tests from heights of 1–1.5 m. Some grades have a damping adhesive layer that absorbs impact energy better.
Tips for maximum bond strength
- Clean surfaces with IPA, avoiding oil residue from the molding process.
- Press at about 0.5–1 MPa for 3–5 seconds.
- Allow 24 hours to stabilize before peel or drop testing.
- Store tape at 20–25°C with humidity below 60%.
For housings with soft-touch coatings or plastics containing flame retardants, real-world testing is recommended because adhesion can vary significantly.
Designing tape parts for automated lines
For pick-and-place machines to run reliably, tape parts should be supplied on continuous rolls or sheets with locating holes, with liner pull tabs in convenient positions. The part profile should leave a 0.2–0.3 mm clearance from the housing edge to compensate for assembly tolerances and avoid visible adhesive. For curved housings, the tape can be split into several short segments to follow the curve without wrinkling. These small details directly affect line speed and the rate of misaligned placements.
AMS supplies ultra-thin double-sided tapes from leading manufacturers along with die-cutting services to customer drawings. Contact AMS Vietnam to receive samples.
