Application: Precisely apply liquid coatings to coil and strip material
What this application is about
For coil material, spray technology is particularly useful for partial functional coatings, edges, narrow strips, special batches, repairs and pilot processes. High-speed full-surface coatings are often applied by roller or curtain coating, so the suitability of spraying must be assessed for each project.
What the coating must achieve in the process
The application mainly concerns steel strip, aluminium strip, coated sheets and flexible technical tracks. The required effect occurs only when coating material, substrate, layer thickness and subsequent drying or curing fit together. The spraying process must therefore be adapted to the concrete material system and the real production conditions.
Alongside surface quality, material consumption, cleaning effort, system availability and reliable repeatability also matter. A sound technical solution therefore combines controlled atomisation with a stable material supply that is easy to regulate.
Challenges in spray application
Even small fluctuations in material pressure, viscosity, distance or movement control can change the coating visibly or functionally. Typical requirements include:
- even application quantity with continuous movement
- Adaptation to changing belt speed and width
- sharp limitation of partial coatings
- Avoidance of overspray outside the tape
- Stable material pressure over long run times
- quick change between media or product variants
Synchronising continuous application with strip speed
In the case of coilware and running metal belts, the material application must remain constant over the entire width and at changing line speed. Spray width, overlap and number of apparatuses are adapted to bandwidth and desired surface performance.
The spray application is particularly suitable for partial surfaces, primers, protective media, oils or supplementary coating steps. For classic large-volume coil coating lines, roller processes can be more economical; the spray application is used where flexibility, selective application or frequent format changes are required.
- Bandwidth and line speed
- overlap of multiple spray patterns
- Border and sub-area limits
- Wet layer at start, stop and speed change
- Protection of the plant against spray mist and deposits
Krautzberger application technology for this application
Krautzberger treats application and material supply as a connected system. Depending on the task, manual and automatic spray guns, suitable air and material nozzles, material pressure tanks, diaphragm pumps, pump and lifting stations, and material pressure regulators can be combined.
In automated processes, spray guns can be integrated into mounts, lifting devices, axes or robots. Material changeover valves and flushing equipment support applications with several colours or media. The specific selection depends on viscosity, solids content, application quantity, cycle time and component geometry.
For fine surface finishes, various XLINE nozzle combinations and spray patterns are available. With highly viscous, abrasive or sedimenting media, sufficiently large flow cross-sections, suitable material combinations, agitators and pressure-stable delivery become more important.
The focus is on automatic spray guns with defined beam width, traversing axes, pumps or material pressure vessels, material pressure regulators as well as material change and rinsing devices. The technically and economically suitable combination is selected for the specific medium, components and required production output.
Typical components and areas of application
The application is used in different industries and component groups. Typical examples are:
- partial protective or functional coating
- Edge and edge zone coating
- Primers and adhesive agents on narrow bands
- Repair and post-coating stations
- Pilot and development lines
- Special coatings after the main coil coating process
From manual application to automated installation
The spraying technology is synchronized with belt speed and web guidance. For wide surfaces, several apparatuses or a traversing movement may be required. High-speed full-surface coil coating often remains a roll application; the suitability of spraying must therefore be tested project-specific.
In addition, component feed, extraction or ventilation, cleaning, media change and accessibility for maintenance work must be taken into account during the system integration. This keeps the process stable not only in the pattern run, but also in everyday production.
Advantages of a coordinated spray solution
- flexible application to selected areas of the strip
- fast adaptation to different widths and media
- suitable for special batches and development
- precise coating of edges and edge zones
- Integrable material change and rinsing concepts
- Scalable automation
Application trials at the Krautzberger technical centre
Liquid media and coating materials with similar names can differ considerably in viscosity, solids content, solvent base, wetting and drying. A reliable choice of spray gun, nozzle and material supply should therefore be made using the original material and a representative component.
Band speed, beam width, overlap and quantity of material are coordinated under realistic movement conditions.
On this basis, the spray pattern, material quantity, pressure, distance, movement and cleaning sequence can be defined. The result is an application solution suited to the medium, the geometry and the intended production process.
Related products
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Matching solution for your process
Looking for a spray gun, an automatic spray gun or a complete material supply for this process? Krautzberger helps you select and design suitable spray technology, nozzle configurations, delivery and regulation.
Contact Krautzberger to discuss your medium, component, production volume and desired result. Together, we assess how the process can be implemented safely and economically.
Industries for this application
For coil material, spray technology is particularly useful when edges, narrow zones or special batches need targeted processing. The material, subsequent processing and production environment determine which coating is appropriate.
