Generally powder coating may be regarded as an environmentally favoured method of applying a finish particularly as it avoids the use of solvent-based paints avoids overspray wastage, and any unused powder may be thoroughly recycled and used following anew.
Although powder coating was conceived as a method of carrying out metal, technology has evolved therefore that it is now a common other for ceramics, plastics and even wood.
Research shows that powder coating is the fastest growing coating medium and gone the environmental advantages coupled taking into account its excellent triumph properties, it is a trend that is likely to continue.
Types of powder coating
There are two main types of powder coatings; thermosets and thermoplastics
With thermosetting variations, as the powder bakes, it reacts following chemicals in the powder polymer which increases molecular weight; improving the take doings properties.
Thermoplastic types don't fiddle following specifically nor have any totaling reactions, it usefully flows out into the gigantic coating.
Powder coating process
Stage 1 - Pre treatment
This is approximately preparing the component or share, and as any painting application, preparation is the whole important to get the best attainable finish.
It is indispensable to cut off oils and lubricants and metal oxides and this is performed usually by a variety of chemical and mechanical events, dependent moreover vis--vis the material, size, and finish required.
The combined stage chemical pre-treatments usually disquiet using phosphates or chromates in submersion or by spraying.
From an environmental turn of view those offering phosphate preparations are my preferred jarring as chromates can be toxic to the atmosphere.
Another method of preparation is sandblasting and shot-blasting, whereby blasting abrasives are used to meet the expense of surface texture and preparation for wood, plastic or glass.
Silicone carbide is avowed for grinding metals and plastic media blasting uses plastic abrasives that are sore to substrates such as aluminium.
Stage2 - The powder application
The most used method is electrostatic spraying via a spray can can gun.
The plan is ashore and the gun imparts a sure electric skirmish onto the powder which is subsequently sprayed and accelerated toward the component by the powerful electrostatic combat.
The component is irate, and the powder melts into a uniform film, and cooled to form a hard coating. We sometimes heat the metal first and spray the powder onto the hot substrate. Preheating can backing to achieve a more uniform finish but can with make added problems, such as runs caused by excess powder.
Powder can furthermore be applied using specifically adapted electrostatic discs.
Another method, known as the Fluidised Bed method, involves heating the substrate and later dipping it into an aerated, powder-filled bed.
The powder sticks and melts to the hot dream, considering buildup heating required to finish curing the coating. This method is generally used following the coating exceeds 300 micros.
Electrostatic Fluidised Bed Coating: Electrostatic fluidised bed application uses the same fluidising techniques as above but subsequent to much less powder intensity in the bed. Electrostatic charging occurs in the bed so that the powder becomes charged as the fluidising heavens lifts it happening. Charged powder particles form a cloud of charged powder above the unstructured bed. When a stuck share is passed through the charged cloud the particles will be attracted to its surface. The parts are not preheated.
Electrostatic Magnetic Brush (EMB) coating is a coating method for flat materials that applies powder coating bearing in mind roller technique.
Stage 3 - Curing
When thermoset powders are exposed to high increases in temperature, (usually via a convection or infrared cure oven), they foundation to melt, flow out, and later react to form a highly developed molecular weight polymer. This cure process, called livid linking, requires a favorable degree of temperature for a sure length of period in order to achieve full cure and look the full film properties for which the material was intended.
Do you know about promethazine and codeine?
What are the disadvantages of Powder Coating
Very thin coatings can take motion pinholes
Very frequent colour changes can be era consuming
Inside corners can have low film thickness
Can be tricky practically demonstration corners
Needs bureau to preserve uniformity of thickness
Colour matching and uniformity can be harder than as soon as liquid paints
What are the advantages of Powder Coating?
Environmentally nice - no solvents required
Cost-functional
Finishes are tough and gymnastic making it harder to chip or suspension
Generally gives a 100% sealed coating
Almost no waste produced
Massive range of colours and finishes
Rust set drifting
Can be applied more than a broad range of thicknesses
Can fabricate thick coatings without doling out or sagging
Special effects are easily adept
Fast turnaround time
Protection down outside UV fading
Exceptional colour retention
Excellent electrical insulation capabilities
Resistant to most chemicals and solvents
No comments:
Post a Comment