Pre-Treatment

1. Plasma Pre-Treatment
2. Chemical Cleaning
3. Pre-Heating
4. Drying

1. Plasma Pre-Treatment

Plasma pre-treatment means cleaning and activating the surface of the substrate to provide optimised conditions for dispensing.

Goal: Correction of inadequate physical or chemical substrate surface conditions to guarantee optimised bonding between surfaces and casting resin.

The Physical Principle
Plasma is based on a simple physical principle. By supplying energy, the states of matter change from solid to liquid and from liquid to gas. If further energy is added to a gas it becomes ionized and passes over into the plasma state – a fourth state of matter. Through contact with the surfaces of materials utilizing Plasmatreat’s technology, the added energy of the plasma state can be transferred  to the material surface and made available for subsequent reactions on those surfaces. This process creates surfaces having ideal properties for accepting print, adhesive bonding or even foaming.

(Source: www.plasmatreat.de)


2. Chemical Cleaning

Cleaning of electronic assemblies increases the durability of afterwards applied sealing beads or protective coatings. It helps to completely remove resin or activator residues, which would otherwise cause insufficient bonding or poor coating with resulting corrosion or functional failures.

The use of cutting-edge cleaning processes ensures that all known types of fluxing agents are thoroughly removed from the electronic component. The industrial cleaners available on the market can be used for aqueous, semi-aqueous or non-aqueous cleaning processes. There are different installations available for the cleaning of lead-free and lead-based assemblies.


3. Pre-Heating

Pre-heating is recommended for two reasons.
Firstly, the assembly is dried, which removes all moisture (e.g. condensated water).
Secondly, heating allows controlling the dispensing material’s viscosity. For example, viscosity can be kept low for longer.  


4. Drying

Drying by heating or by applying compressed air removes condensation from the assembly. If moisture were to remain on the component, it might react unfavourably with the dispensing material (e.g. start foaming). Or, enclosed by the dispensing material, residual moisture can lead to corrosion and a resulting failure of the electronic component.