L22 Cleaning and Coating

What is the aim of cleaning?

To remove unwanted substances (impurities or contaminations) from the surface of workpieces to the required and agreed level of cleanliness.

Name the five different processes of cleaning.

Thermal processes, Mechanical processes, Wet processes, Blast processes, Special processes.

What factors should be considered selecting the appropriate cleaning process?

Component properties (material, geometry), contamination status (type, quantity, adhesion), cleanliness requirements, plant data (costs, capacity), and environmental/company policies.

Which cleaning method do you choose for removing thin layers in sub-millimeter range?

Laser beam cleaning, plasma cleaning, or fine blasting processes are suited for removing thin surface layers.

What are the advantages and disadvantages of a visual inspection as an analysis method?

Advantages: low cost, fast, simple. Disadvantages: subjective, not reproducible, limited accuracy.

What is the aim and purpose of coating?

To protect, enhance surface properties, restore damaged surfaces, or apply functional properties (e.g., corrosion protection, wear resistance).

List at least five states of coating agents that are available.

Liquid, solid, mushy, plastic, gaseous, and ionized.

What is the difference of sizing compared to avivages?

Sizing provides a functional layer (adhesion, protection), while avivage enhances fiber processability during spinning or weaving.

How is the fiber changed by adding sizing or avivage?

The fiber gains better bonding properties to the matrix, improved protection during processing, and potentially modified surface energy.

Explain the trade-off by sizing fibres?

Better fiber-matrix adhesion and protection, but may reduce recyclability or alter fiber properties negatively if not optimized.