In addition to laser cleaning, there are many other processes for surface cleaning and stripping. We only offer laser cleaning systems ourselves. Therefore, we would like to show you the advantages and disadvantages as well as the possibilities of combining the different processes:
- Mechanical processes (e.g. blasting, sanding, grinding or particle beams)
- Thermal processes (e.g. burning by pyrolysis)
- Chemical processes (e.g. Washing, pickling, chemical treatment)
Depending on the process, the combination of different effects can also be used.
In particle blasting, a blasting medium is accelerated and “shot” at the surface. The mechanical impact mechanically removes the surface layers and dirt. Depending on the blasting material (from baking powder to steel shot), more or less abrasive removal and damage to the base material is possible.
The process can be installed quite easily and with a moderate investment volume and is very flexible. In addition to the disadvantage of surface roughening (which can also be an advantage depending on the application), particle blasting also has some basic disadvantages:
- High energy consumption costs (especially with compressed air blasting)
- No partial application possible, blasting medium can penetrate into critical component areas
- Depending on the technology, mixing of the blasting medium with the ablated layer leads to high waste quantities.
- High wear on blasting nozzles and blasting devices
- High noise and dust exposure requires sound insulation cabins
In dry ice blasting, (deep) frozen CO2 (ice pellets) is used as the blasting medium. In addition to the kinetic energy, a thermally induced shock wave/voltage is generated when the CO2 hits the surface, causing the coating to flake off.
Due to the “gaseous” blasting material, there is no need to worry about the disposal of the blasting material, but here, too, the advantages of simple application are countered by a number of disadvantages:
- Dry ice as blasting material must be stored cooled and insulated and is only “conditionally” durable
- Costs of the blasting material
- Considerable compressed air and energy consumption during the generation and application of the blasting medium CO2
- Costs of up to 100 €/hour are possible in some cases
- Very effective pellet blasting can produce noise emissions of up to 120 dB/A
- Limited possibilities of process protection
As a rule, washing processes serve to remove particle impurities and filmic contamination from components. The components are usually introduced into the system in batches by means of baskets and pre-treated in at least 3 stages (washing, rinsing, drying), but often also in further cleaning steps (up to 9 stages). The advantage of the process is the large-area application by immersion in the bath. Even hard-to-reach internal areas and boreholes/cooling channels can be reached and thus chips and particles can be removed very efficiently by combination with high-pressure pumps. Thus, the process offers fields of application which cannot be replaced by the innovative laser process. However, the wet-chemical process has some disadvantages, especially due to the limitations of the chemicals in the cleaning solutions that can still be used for environmental reasons:
- High energy consumption for temperature control of cleaning solutions (especially for degreasing applications) and for operation of high-pressure pumpsHigh space requirement (usually >20 m²)
- High running costs for bath care and maintenance of the chemicals
- Transfer of contamination through the baths
- No partial cleaning, the entire component is always cleaned
- Limited in-line capability
- Components become wet and must be dried and, if necessary, conserved again
- Process protection only possible to a very limited extent
Often the combination of two procedures can save a lot of money in the end. For example, the combination of an aqueous cleaning process (without temperature control) for cleaning chips and cooling channels with a partially and precisely effective laser cleaning step for pre-treatment of functional areas (e.g. degreasing for welding or adhesive pre-treatment) is significantly more cost-effective in terms of total costs compared to exclusively wet-chemical cleaning and degreasing and is much more space-saving.