How Plasma Cleaning Solves Delamination Risks in Multi-Material Assemblies

When two materials don’t bond properly, failure is often only a matter of time. Delamination—where bonded surfaces separate under stress or environmental exposure—is one of the most frustrating and costly failure modes in advanced manufacturing.

Whether you’re overmoulding, potting, sealing, or assembling components with different surface properties, a weak interface can compromise the entire product.

But here’s the good news: many delamination issues can be prevented not by switching materials, but by treating the surface properly before bonding. Plasma cleaning plays a critical role in this process—not only by removing contaminants but by changing surface chemistry to improve material compatibility.

Why Delamination Happens

Delamination occurs when two bonded surfaces separate—not because of external damage, but because the bond was never strong enough in the first place.

1. You select two materials based on strength, conductivity, insulation, or durability

2. But at a molecular level, they’re chemically incompatible

3. You attempt to bond them—often using a moulding compound, adhesive, or coating

4. Under stress or heat, the bond fails and the layers separate

This failure may not be immediate. In many cases, it appears later—during vibration, temperature cycling, or environmental exposure. It’s a silent flaw until it becomes a critical one.

What Cleanliness Has to Do With It

Delamination isn’t just about chemical compatibility—it’s also about surface condition.

A. Even the most well-matched materials won’t bond well if surface contamination is present

B. Residues, oxides, or microfilms act as a barrier between materials, reducing bond strength

Plasma cleaning addresses both issues. First, it removes the invisible layers that interfere with adhesion. Then, depending on the gas chemistry used, it can modify the surface itself—introducing functional groups or altering surface energy to promote bonding.

This dual effect—cleaning and activating—is what makes plasma a reliable delamination prevention tool.

How You Know If Delamination Is the Problem

Sometimes delamination is obvious. Parts peel, coatings flake, or bond lines visibly separate. But in other cases, failure is internal and not visible until destructive testing is performed.

• One basic method is the break test: take a bonded part and snap it apart

• If the break is clean—two smooth surfaces—you likely have poor bonding

• If fragments of material A remain stuck to B (and vice versa), the bond is as strong as the base materials

There are also advanced diagnostic tools. One common one is C-SEM (Confocal Scanning Acoustic Microscopy), which uses sound waves to detect voids and weak bonds within assembled parts. It’s non-destructive and highly accurate—but requires proper process data to be meaningful.

How Plasma Actually Improves Bonding

Surface activation goes beyond removing dirt. Plasma can chemically alter a material’s surface to make it more compatible with the compound or adhesive it’s bonding to.

a) Different gases produce different reactions—argon for cleaning, oxygen or nitrogen for functionalisation

b) Treated surfaces become more reactive, increasing bond strength with moulding compounds or coatings

This means that plasma doesn't just make bonding possible—it makes it reliable, even when working with difficult or non-polar materials.

In applications like transfer moulding or overmoulding in semiconductors and electronics, this surface preparation can eliminate delamination entirely—even under thermal stress or in high-moisture environments.

The Outcome When It’s Done Right

When plasma is integrated properly before bonding, you get:

• Stronger, more durable bonds between dissimilar materials

• Fewer failures during thermal or mechanical stress testing

• Greater product consistency and reliability in the field

• Confidence that bonds will hold—internally, externally, and long-term

  
  

More importantly, you reduce rework, avoid hidden defects, and pass qualification testing with fewer delays.

The result is a process that holds up—not just on the bench, but in the real world.

Want to Prevent Delamination Before It Starts?

Delamination doesn’t have to be a recurring risk. With the right surface preparation, you can bond confidently across materials and reduce failures before they happen.

Plasma cleaning offers a proven way to clean, activate, and optimise surfaces for bonding—solving delamination issues before they appear in production or in the field.

Talk to SCI Plasma about surface treatment options for your moulding, bonding, or coating process—and build a more reliable product from the inside out.