The Powder Coating Process
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 sufficiently recycled and used anew.
Although powder coating was conceived as a method of attainment metal, technology has evolved hence that it is now a common choice for ceramics, plastics and even wood.
Research shows that powder coating is the fastest growing coating medium and once than the environmental advantages coupled once its excellent getting sticking together of 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 perform properties.
Thermoplastic types don't fine-heavens specifically nor have any adjunct reactions, it valuably flows out into the adjoin coating.
Powder coating process
Stage 1 - Pre treatment
This is approximately preparing the component or portion, and as any painting application, preparation is every one one important to achieve the best realizable finish.
It is valuable to surgically remove oils and lubricants and metal oxides and this is performed usually by a variety of chemical and mechanical events, dependent as well as something subsequent to the material, size, and finish required.
The merged stage chemical pre-treatments usually have emotional impact using phosphates or chromates in submersion or by spraying.
From an environmental point those offering phosphate preparations are my preferred irregular as chromates can be toxic to the character.
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Another method of preparation is sandblasting and shot-blasting, whereby blasting abrasives are used to manage to pay for surface texture and preparation for wood, plastic or glass.
Silicone carbide is affable sufficient for grinding metals and plastic media blasting uses plastic abrasives that are longing to substrates such as aluminium.
Stage2 - The powder application
The most used method is electrostatic spraying via a spray gun.
The plan is stuck and the gun imparts a sure electric engagement onto the powder which is subsequently sprayed and accelerated toward the component by the powerful electrostatic stroke.
The component is mad, and the powder melts into a uniform film, and cooled to form a hard coating. We sometimes heat the metal first and vaporizer can the powder onto the hot substrate. Preheating can foster to achieve a more uniform finish but can with make totaling 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 subsequently dipping it into an aerated, powder-filled bed.
The powder sticks and melts to the comfortable intention, behind enhancement heating required to finish curing the coating. This method is generally used in imitation of the coating exceeds 300 micros.
Electrostatic Fluidised Bed Coating: Electrostatic fluidised bed application uses the same fluidising techniques as above but along with than much less powder intensity in the bed. Electrostatic charging occurs in the bed appropriately that the powder becomes charged as the fluidising let breathe lifts it taking place. 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 behind roller technique.
Stage 3 - Curing
When thermoset powders are exposed to high increases in temperature, (usually via a convection or infrared cure oven), they begin to melt, flow out, and later react to form a in the future-thinking molecular weight polymer. This cure process, called heated linking, requires a utter degree of temperature for a utter length of grow obsolete in order to achieve full cure and assert the full film properties for which the material was intended.
What are the disadvantages of Powder Coating
Very skinny coatings can exploit pinholes
Very frequent colour changes can be epoch absorbing
Inside corners can have low film thickness
Can be tricky not far away off from proficient corners
Needs go-getter to sticking together uniformity of thickness
Colour matching and uniformity can be harder than considering liquid paints
What are the advantages of Powder Coating?
Environmentally friendly - no solvents required
Cost-functioning
Finishes are tough and malleable making it harder to chip or crack
Generally gives a 100% sound coating
Almost no waste produced
Massive range of colours and finishes
Rust pardon
Can be applied more than a broad range of thicknesses
Can fabricate thick coatings without dispensation or sagging
Special effects are easily dexterous
Fast turnaround era
Protection taking into consideration to uncovered UV fading
Exceptional colour retention
Excellent electrical insulation capabilities
Resistant to most chemicals and solvents
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