Adhesive surface preparation

Efficiency, sustainability and quality in surface pretreatment

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Adhesive surface preparation

Laser processing to prepare surfaces before bonding offers enormous advantages. This ensures that the bond is of high strength and correspondingly durable.

Industrial joining technology is no longer conceivable without reliable adhesive bonds. Particularly in sectors such as the automotive industry, aerospace and mechanical engineering, optimum preparation of the bonding surfaces plays a decisive role in the quality and durability of the bond. In this context, laser cleaning offers a modern, environmentally friendly and extremely precise alternative to conventional cleaning processes such as sandblasting, grinding or chemical pickling.

Basics of laser cleaning

Laser cleaning (also known as laser ablation) uses short, high-energy laser pulses to selectively remove unwanted layers - such as oxides, grease, dust, paint or corrosion - from the surface without damaging the base material. The process is based on physical principles:

Ablation by thermal energy: Impurities absorb the energy of the laser beam, vaporise or decompose.
Pulsed laser: Short pulses prevent excessive thermal stress on the substrate.
No mechanical stress: In contrast to abrasive processes, the surface remains structurally intact.

Advantages of laser cleaning for adhesive surfaces

Advantage	Description of the
Residue-free cleaning	Removal of oil, grease, oxide, paint and much more - without the use of chemicals
Microscopically precise machining	Ideal for geometrically complex workpieces and selective cleaning
Improved adhesion	Increase in surface energy → better wettability through adhesives
Can be automated	Easy integration into existing production lines and robot solutions
Environmentally friendly	No use of solvents, no abrasive waste
Cost reduction	Less consumables required, shorter set-up times, reduced reworking

Process parameters and material compatibility

The effectiveness of laser cleaning depends largely on the parameters used:

Laser power (watts)
Pulse duration (ns - fs)
Wavelength (typically 1064 nm, Nd:YAG or fibre laser)
Scan speed and line spacing
Material type and degree of contamination

Suitable materials:

Metals (e.g. aluminium, steel, titanium)
Plastics (with restrictions - test required)
Composite materials (carbon, GFRP, CFRP)

Application scenarios

Automotive industry
- Preparation of car body components before bonding
- Cleaning of aluminium die-cast parts before seal application
Aerospace industry
- Cleaning of CFRP components for structural bonding
- Removal of release agents and oxide layers
General industry
- Replacement of chemical cleaning in series production
Selective cleaning of repair areas

Quality assurance and auditability

Laser cleaning can be validated using various methods:

Contact angle measurement (wettability)
XPS / Auger analysis (surface chemistry)
Microscopy (impurities / surface structure)
Destructive tests (e.g. tensile tests of bonded samples)

Consistent cleaning quality can be guaranteed through the use of inline monitoring systems, e.g. plasma lights or camera monitoring.

Economic consideration

The initial investment in laser systems can be quickly amortised through savings on consumables, disposal costs and reduced rework. Process stability and traceability also increase production reliability - an increasingly important factor in certified industries.

Conclusion

Laser cleaning is a future-orientated technology for preparing adhesive surfaces. It combines maximum precision with environmental friendliness and offers high automation potential. Companies that rely on durable, reproducible bonded joints benefit considerably in terms of both quality and cost-effectiveness.