Painting metal with powder paint and its features. Painting process technology The case is applied by powder painting

Powder paints were developed in the 60s of the 20th century due to the need to protect painted surfaces, give them an attractive appearance, reduce painting costs, and also to reduce environmental damage. At the same time, the electrostatic coating method and the anodizing system emerged. Coatings with a metallic effect and paints that are resistant to adverse external factors began to appear.

The polymer powder coating is first sprayed onto the product, and then polymerized in a special oven at a certain temperature. Painting technology powder paint involves the following steps:

• Surface preparation
• Powder paint application
• Polymerization

Surface pre-treatment

Pre-treatment of a product is the longest and most labor-intensive process, which is sometimes not given the necessary attention, while the durability, quality and elasticity of the coating depend on it. Preparing the surface for the painting process includes removing any contaminants, degreasing and phosphating in order to increase adhesion, as well as protect the metal from corrosion.

Cleaning the surface to be treated can be carried out mechanically or chemically. When mechanical cleaning steel brushes or grinding discs are used; grinding in with a clean cloth soaked in solvent is possible. As for chemical processing, it is carried out using acidic, alkaline or neutral substances and solvents, which are selected depending on the degree of contamination, material, size and type of surface being treated and other factors.

Application of a conversion sublayer prevents penetration under the coating various kinds contaminants and moisture, which cause peeling and subsequent destruction of the coating. Phosphating the surface with the application of a layer of inorganic paint makes it possible to increase adhesion, that is, the adhesion of the surface to the paint by 2-3 times, and protect it from rust. When removing oxides (scale, rust and oxide films), abrasive (mechanical, shot blasting, shot blasting) and chemical cleaning, that is, etching, are very effective.

• Abrasive cleaning is carried out using small particles (shot, sand), cast iron or steel granules, nut shells, which are fed to the surface at high speed using compressed air or centrifugal force. These particles break off pieces of metal with scale, rust or other contaminants, which significantly increases the adhesion of the coating.
• Pickling is the removal of oxides, rust and other contaminants using solutions based on hydrochloric, sulfuric, nitric, phosphoric acids or caustic soda. They contain inhibitors that slow down the dissolution of the cleaned surface. Advantages chemical cleaning before abrasive – this is greater productivity and ease of use. But after it, you need to rinse the cleaned surface from solutions, and this, in turn, necessitates the additional use of cleaning agents.
• The final stage of surface preparation is passivation. In other words, the treatment of the body with compounds of sodium nitrate and chromium. Passivation is carried out in order to prevent the appearance of secondary corrosion at any stage of surface preparation - after degreasing, phosphating or chromating.

Once the part has been rinsed and dried in the oven (curing section), the surface can be considered ready for powder coating.

Applying powder paint to the surface of the product

When the pre-treatment is complete, the item to be painted is placed in the spray chamber, where powder paint is directly applied to it.

The main purpose of this box is to catch powder particles that have not settled on the product being painted, dispose of paint, and prevent it from entering the room. Such a chamber is equipped with a filter system, cleaning means (vibrating sieve, bins, etc.) and suction systems.

There are dead-end and walk-through types of boxes. Products are usually painted in dead-end chambers small size, while large items are classified as long items. There are also automatic models, where powder coating is applied in a matter of seconds using manipulator guns.

The most common method of applying powder paint is electrostatic spraying, that is, applying an electrostatically charged powder to a grounded product using a pneumatic sprayer, also called a gun, applicator or spray gun.

Formation of coating

When the paint has already been applied to the product, it is sent to the next stage - coating formation, which includes melting the paint layer, obtaining a coating film, its hardening and cooling.

The reflow process is carried out in a special oven or chamber. There are many types of polymerization chambers; depending on the specifics of production, their design may vary. Speaking in simple language, such an oven is a kind of drying cabinet with electronic “stuffing”. Using the control unit it is possible to control temperature regime cameras and staining time, configure automatic shutdown at the end of the process. The energy source for the polymerization furnace can be electricity, natural gas or even fuel oil.

There are horizontal and vertical, continuous and dead-end, single and multi-pass furnaces. Melting and polymerization occur at a temperature of 150-220°C for 15-30 minutes, as a result of which a film is formed, that is, the powder paint polymerizes.

The main requirement for polymerization chambers is to constantly maintain set temperature for uniform heating of the painted product. The required mode for forming the coating is selected taking into account the characteristics of the product, the type of powder paint, the type of oven, etc.

At the end of polymerization, the part to be painted is cooled in air, and after it has cooled, the coating can be considered ready.

When processing large parts or large production volumes, a transport system is used. Thanks to it, painted products can be easily moved from one painting stage to another. The principle of operation is that the objects to be painted are supplied on a special suspension or trolleys moving on rails. Such a transport system makes it possible to continuously carry out the painting process, which, in turn, can significantly increase work productivity.

Benefits of Powder Coatings

Metal powder painting technology has many advantages:

• Excellent physical, chemical and decorative properties of coatings that cannot be achieved by other painting methods, including a rich palette of possible color solutions.
• Good operational properties coatings
• Durability of products painted with powder paints
• One-layer coating thanks to 100% dry matter content, which means the use of powder paints is economical
• Low porosity
• Improved impact resistance and anti-corrosion properties compared to other paints
• There is no need to control viscosity, since powder paints are supplied directly to the consumer in ready-to-use form
• Losses when painting with powder paints are 1-4%, and, for example, when using liquid paints - about 40%
• Coating hardens within 30 minutes
• No need for large rooms for storing powder paints
• Minimum damage to painted parts during transportation and reduced packaging costs
• Environmental safety of powder coating

In view of all the above advantages of this method of metal coloring, most industrialists today give their preference to it.

Powder coating- modern, environmentally friendly and harmless waste-free technology for obtaining high-quality decorative and protective coatings. The powder coating process can be divided into several stages:

— preparing the surface for painting;
— spraying polymer powder onto the surface;
— polymerization of the coating at temperatures from 140 degrees to 220 (depending on the type of paint) using special equipment. During polymerization, 2 conditions must be met:
1. required temperature;
2. strict adherence to time.

You will find on sale a large assortment installations, And . Our managers are professionals with extensive experience who will help you navigate among our offers and choose the most suitable equipment for organizing a painting area, taking into account the expected volume of work and in accordance with the type of process:
— semi-automatic lines;
— heat chambers (or polymerization ovens) of various designs;
— complex automatic lines.

The composition of semi-automatic and automatic lines includes the following equipment:
- spray chamber,
- polymerization oven,
— transport system.

You need to select equipment for a specific area depending on:
— the size of the production area;
— geometry of painted products;
- programs;
— frequency of paint color changes, etc.

Correctly selected complex different systems equipment and transport systems makes it possible to obtain polymer coating excellent quality, reduce costs to the optimal level, optimize production costs.

Preparing for coloring

To get a high-quality result and a well-painted surface, you must carefully prepare the base. Metal surfaces may contain contaminants: organic oils, greases, waxes, resins, oxides, inorganic deposits, etc. If you apply powder paint to the surface as it is without preparation, this will lead to the development of corrosive processes under the film, subsequent peeling, destruction of the coating.

That's why at the beginning staining Surface treatment is required. First you need to remove all contaminants from the surface. To do this, analyze their nature and composition, the degree of contamination, select a processing method, and an effective composition used for this type of contamination. It is necessary to take into account the conditions and service life of the surface.

Degreasing, abrasive cleaning, etching, applying a conversion layer - chromating, phosphating: all these methods are used to treat the surface to be painted before painting. The degreasing method must be used in all cases, the rest - depending on each specific case. When painting cars, for example, chromating or phosphating is required.

The product is fixed on the transport system and delivered to spray booth. This is where the powder coating takes place. For this the product to be painted an electric charge is imparted, creating a high-voltage electrostatic field. Then the product is sent under voltage to a polymerization oven, where the powder melts, forming an airtight coating, penetrating even the small pores of the base. Then the part cools and the coating polymerizes.

KRASTECH company produces and supplies equipment to all regions of the Russian Federation

The Krastech company has been producing high-quality equipment in this area of ​​production for many years. By contacting the Krastec company, the buyer does not overpay extra money to intermediaries, but purchases equipment directly from the manufacturer. All equipment is supplied of exceptionally high quality; the Krastech company values ​​the reputation accumulated over years of impeccable work and responsibly treats the fulfillment of contractual obligations.

Spray Booth Operating Instructions

1. 1. General requirements

1.1. This operating manual is a document certifying the basic parameters and characteristics of the chamber for spraying products with polymer powder paints, guaranteed by the manufacturer.

1.2. The powder paint spraying chamber (PC) is designed for applying polymer powder paints (PC) in it.

1.3. The spraying chamber is equipped with an air suction system to prevent powder paint from entering the room, as well as to capture the PC for the purpose of its recycling.

1.4. The chamber for applying polymer powder paints is designed to work in enclosed spaces at temperatures environment 15-20 degrees C and relative humidity no more than 80%.

1. 2. Specifications

• Power supply – 380 V 50 Hz.
• Power 2.2 kW
• Exhaust ventilation capacity is no more than 3500 m 3 /hour.

1. 3. Delivery contents

• Cabin, pcs. - 1
• Operating manual – 1 copy.

1. 4. Design and principle of operation

4.1. The technological process of applying PC is based on transferring electrostatically or tribostatically charged PC onto the product, sprayed with a special pneumatic powder paint sprayer (spray gun) and held on the surface of a grounded painted product by the force of electrostatic (tribostatic) voltage.

4.2. The process is carried out in a spraying chamber, which is equipped with an air suction system to prevent PC from entering the room and a combined system for collecting PC that has not settled on the part for its recycling or disposal.

4.3. A charged PC ejected from a powder paint sprayer forms a torch of one shape or another depending on the spray nozzle (nozzle) used, moves towards the grounded part to be painted under the influence of air jets and the force of electrical attraction and settles on the surface, being held by the same forces.

4.4. Powder application chamber polymer paint made of galvanized sheet metal with a window for the operator, filtration, exhaust and lighting systems.

1. 5. Indication of safety measures

5.1. In installations for applying PC coatings, the most dangerous process is the process of applying a layer of PC to the product, since during operation there are constantly several places with a higher concentration of PC in the dust-air mixture lower limit explosiveness.

5.2. Attention! It is strictly prohibited to operate the powder coating spray booth without grounding it.

5.7. It is prohibited to allow persons under 18 years of age to work who have not undergone training in safety and fire safety.

1. 6. Preparing the product for use

6.1. Install the KN on a flat horizontal surface at a distance of at least 1 m from other equipment and 0.5 m from the wall.

6.2. Re-preserve the equipment.

6.3. Connect lighting and chamber exhaust.

6.4. Connect the ground bolt to the ground loop.

1. 7. Operating procedure

7.1. Place the products prepared for painting on the hanger and move the hanger to the KN.

7.2. Turn on the exhaust ventilation in the KN.

7.3. Enable PC application installation.

7.4. PC should be applied from a distance specified by the spray gun manufacturer.

7.5. When switching to a different color, you must perform following works:

• Use a brush to remove the PC from the walls of the cabin.
• Blow out the guides and ceiling with compressed air.
• Wipe the guides, walls and floor with a damp cloth.
• You must have a separate filter element for each paint color.

7.6. At complete cleaning cabins to perform the following work:

• Sweep the PC from the walls onto the cabin floor.
• Collect and dispose of PCs in specially designated containers.
• Blow out the cabin with compressed air.
• Turn off the exhaust ventilation.
• Wipe the cabin with a damp cloth and let dry for 5-10 minutes.

7.7. Attention! All work in the spraying booth should be carried out with the exhaust ventilation turned on.

1. 8. Maintenance

8.1. To ensure uninterrupted and long work CN must strictly follow the recommendations set out in the operating instructions.

8.2. Carry out daily inspection of the control unit to identify minor faults.

8.3. Regularly check that the grounding wires are securely fastened.

8.4. Check the reliability of the connection to the KN of the exhaust ventilation system.

8.5. Before starting work, regularly wipe the lamps to improve the illumination of the products being painted.

8.6. Clean the contacts of the attachments from paint, dust and dirt.

8.7. Attention! To avoid contamination of the surface of the product being painted, do not allow the product to be painted. different colors without first removing paint of other colors from working surfaces.

1. 9. Possible faults and ways to eliminate them

10. Acceptance information

Spray booth matches technical specifications requirements for installations of this type and is recognized as suitable for operation.

11. Warranty

11.1. The warranty period for operation of the spray chamber is 24 months from the date of commissioning of the product by consumers.

11.2. During the warranty period, the manufacturer undertakes to carry out free repairs of the AC and faulty electrical equipment, provided this passport is available.

11.3. Claims regarding the quality of work of the spraying booth are not accepted and warranty repair is not performed in the following cases:

• Failure by the consumer to comply with the operating rules of the spraying booth.
• Careless storage and transportation.
• Repair of the cabin by a person who does not have the right to carry out this work.
• Use of the spray booth for purposes other than its intended purpose.
• The manufacturer does not accept claims regarding the completeness of the product after its sale.

Powder coating is becoming increasingly popular today. What is it? This modern technology, designed to produce high quality decorative and protective coatings. The work uses polymer powders (hence the name “powder”). They turn into coating due to exposure to high temperatures. Because of this peculiarity of the procedure, powder coating of metal and glass is most common.

Advantages

This process has a number of positive aspects. These include:

Economical. The fact is that such paint can be reused if it does not settle when sprayed
on the treated surface. Thus, material loss is no more than 5%. By the way, this figure for conventional paints will be 8 times higher - about 40%. Also in this case there is no need for solvents.

Easy to use. Materials for this type of work are produced completely ready-made. This guarantees stable high quality coatings In addition, cleaning the equipment after use is very simple, because the powder is easily removed from the parts.

Speed. Powder coating does not require drying of products before placing them in the oven. If surfaces coated with conventional paint need to dry for quite a long time, then in this case the process is reduced significantly.

Durability. The technology of these works involves the polymerization of a layer of elastic plastic, which has fairly high adhesion, directly on the surface that is being painted. The result is durable coating, which boasts excellent electrical insulation and anti-corrosion properties, as well as resistance to various substances.

Environmental friendliness. As already mentioned, solvents are not used in this case, which has a beneficial effect on the environment. Waste-free production also plays a role.

Decorative. Powder paints make it possible to obtain a surface of any shade. The palette of materials presented today includes more than 5 thousand colors and shades with various textures. If desired, you can get a glossy or matte surface, as well as granite, moire, etc.

Powder painting as a business idea

If we take into account all the advantages of this type of work, it becomes obvious that such a business will be quite profitable. If you do not have the opportunity to immediately invest a large sum in your business, it is advisable to at least simply learn how to do powder coating with your own hands.

But it is worth considering that you will still have to spend money. First of all, you will need to take care of the availability of special equipment and separate room. For the latter, a simple garage is quite suitable, but provided that there is enough space in it to accommodate all the tools and carry out the actual work. What equipment is needed for powder coating?

Camera

Carrying out the work will be impossible without a special camera. It is in it that it is carried out most of the whole process. The powder coating chamber is needed for air purification (recovery process), in addition, it is due to it that the material can be reused. Here, paint that does not reach the surface being treated is sent to filters and then discarded.

Such equipment may have various sizes. Which one to choose should be decided individually in each case, having previously determined which products you plan to work with.

Stove and gun

You will also need a reflow oven. This is a prefabricated structure consisting of panels (their thickness is 100 mm). Thermal insulation material– basalt fiber. If you are just trying your hand at this type of work, it is not necessary to immediately buy a special oven. For this purpose, it is quite possible to use a conventional oven. However, to build a business, it is still recommended to purchase professional equipment.

Powder coating technology also requires a spray gun that allows the use of compressed air. You can also use a compressor as this. If you choose the latter, please note that it must have a high-pressure filter installed.

Recuperator and transport system

The remaining powder paint is collected using a recuperator. Instead, at first you can use a cyclone-type vacuum cleaner. In this case, you need to first check the power of the electrical network in the room and make sure that there is grounding.

If you plan to work with large-sized products, then you should also consider purchasing transport system. In it, the workpieces are moved on special trolleys that move on rails. This is how a powder coating line is built. Such equipment improves the productivity of the process, ensuring its continuity.

Powder coating technology

The process of doing the work itself is divided, as you can already understand, into several stages:

1. Let's talk about each stage separately. Preparing the product, or rather its surface, for processing.
2. Application of paint in powder form.
3. Polymerization, i.e. heating the product in an oven.

Preparatory stage: cleaning, degreasing

We can say that this stage is the most labor-intensive. And it depends on it how high-quality and durable the coating will be. In the process of preparing the surface, it is necessary to remove all contaminants from it and degrease it.

Cleaning is carried out by mechanical or chemical method. The first option involves using steel brushes or a grinding disc. You can also grind in with a clean cloth, after moistening it in a solvent.

The second cleaning option involves the use of alkaline, neutral or acidic composition, as well as solvents. Their choice depends on how dirty the surface is, what material the product is made of, what type it is and what dimensions it has.

Phosphating and Chromating

Next, a conversion sublayer can be applied to the product, which will prevent moisture and dirt from getting under the coating. Phosphating and chromating procedures provide better adhesion and protect the surface from rust. For this purpose, iron phosphate (for steel), zinc (when working with galvanic cells), chromium (for aluminum) or manganese and chromic anhydride.

Then you will need to remove the oxides, which is done using abrasive and dry cleaning. The first is produced using abrasive particles (shot, sand), nut shells. These substances are supplied with compressed air at a fairly high speed. As a result, the particles “crash” into the surface of the product and bounce off it along with the contaminants.

Pickling (chemical cleaning) is the removal various contaminants using special etching solutions, the main components of which are sulfuric, hydrochloric, nitric, phosphoric acid or caustic soda. This method is considered more productive, however, after such treatment, the product must be rinsed from solutions.

Passivation

This is the final step in the surface preparation stage. It is necessary to treat the part with sodium and chromium nitrate compounds. This is done in order to prevent secondary corrosion.

After everything has been done preparatory work, the product is rinsed and dried in an oven. Now the surface can be directly powder coated.

Applying paint

What is powder coating technology itself? The prepared product must be placed in the chamber. Here the powder (paint) will be applied to it. If you have a dead-end box, then only small parts can be painted in it. Large products can only be processed in long chambers.

The most commonly used method for applying paint is electrostatic spraying. In this case, powder coating guns are used. These tools are also called sprayers or applicators. This device is a pneumatic sprayer that applies an electrostatically charged substance to a previously grounded part.

Formation of coating

Let's move on to next stage work. The paint is applied, now you need to form the coating. First of all, the product is sent to the oven for polymerization. Such chambers can be different: vertical, horizontal, again, dead-end or pass-through, single-pass and multi-pass.

The mentioned equipment for powder coating ensures heating of the surface to a certain temperature - 150-220 o C. The treatment lasts about half an hour, as a result of which a film is formed. At this stage, it is important that the part is heated evenly, which is only possible if the temperature in the chamber is stable.

Which mode to choose for processing a particular part depends on the part itself, the type of paint and equipment. After polymerization is completed, the product must be cooled in air. That's it, job done.

Areas of application

As you can see, powder coating is a rather labor-intensive job that requires certain investments. What products are exposed to it? The painting method in question is ideal for processing aluminum or forged products, as well as galvanized surfaces.

Powder paints are finding more and more “fans” these days. Now they are used in instrument making, construction, automotive industry, as well as in other areas. They are used to paint medical equipment, roofing materials, household appliances, objects made of ceramics, plaster and glass, furniture. Powder coating of wheels is becoming increasingly popular among car enthusiasts.

Business organization

These works in specialized centers today are quite expensive. If you want to try yourself in this business, then if you have financial resources, you can start. Of course, the powder coating line ( automated system) is not affordable for everyone, but thanks to our recommendations you will be able to replace some elements with other tools at first.

Start with small items. These can be plaster figurines, ceramic dishes and much more. Try painting something in your home first (start with something you don't mind ruining). Gradually you will develop the necessary skills and dexterity, then you will be able to accept orders from friends. However, you shouldn’t expect much income if you rely only on one-time orders from individuals.

The best case scenario involves the presence of large start-up capital. In this case, you can immediately purchase necessary equipment and hire workers. Clients should be sought among enterprises engaged in the production of metal products. Only the presence of such customers will allow your business to exist and develop.

But the quality of the painted surface left much to be desired. Paint and varnish materials are sometimes simply ineffective. But there is another way, or rather not even a method, but a whole technology. So, powder painting - what is it? Let's try to find out the answer to this question.

What does it represent?

So, paint of this type called a powder of very fine dispersion, which is obtained by melting film-forming components, various pigments, and special additives. Then all the ingredients are mixed, and then the melt is extruded, resulting in a thin plate. This plate is then crushed, ground and fractionated.

As for film-forming materials, these are often polyester or epoxy resins or any mixtures thereof. Acrylate and urethane materials are used somewhat less frequently. One particle of such powder has a size from 10 to 100 microns.

Powder painting - what is it?

It is believed that such paints are completely environmentally friendly, and the technology for painting with them is completely waste-free. The result is the highest quality decorative, as well as decorative and protective polymer coatings.

This coating is formed from polymer powder.

It is applied to the surface to be treated. For this there is special method. The layer of powder is very thin. This layer is then melted at temperatures ranging from 160 degrees. And then the most uniform and continuous coating is formed.

Since the technology involves high temperatures, powder painting is used only for metal or glass products. For the last 10 years this innovative technology was able to make its way into many areas where more traditional coatings based on paints and varnishes were previously applied.

Today, about 15% of all products are painted using powder paints. And this figure is increasing every day.

Benefits of technology

Powder painting, what is it, why is this method so popular? It's simple. This technology is very economical. There is no large number operations, the polymerization rate is very high. differs in compact sizes. It should also be said that the paint is hard. The composition does not contain any solvents. The utilization rate is more than 95%. This is true thanks to a special recovery system for such compounds. So, the unused part of the powder is returned back to technological processes and it can be reused.

If we talk about traditional liquid paint and varnish products, then approximately from 40 to 60% coloring matter remains in the solvent, but it does not remain on the coating. This means that traditional paint makes up only 40-60%. This is if you do not take into account the various losses that sometimes occur during coloring.

High savings, low cost

Low cost is another advantage. The price depends on the surface area, as well as the complexity of the item. The price is also determined by the type of paint. What are the savings?

Powder painting - what is it? This is a dyeing without solvents, which in liquid analogues act only as a carrier for the film-forming substance. Thanks to the energy savings for heating and ventilation, and the fact that there is no need to expend money or energy on the process of evaporating solvents, the cost of the technology is very, very affordable.

There is also no need for large premises - the equipment can be located in a small workshop.

Work speed

The technology can significantly reduce the time for hardening of treated coatings. So, the film forms very, very quickly, so you only need to dry the layer once, and not repeatedly, as is the case with conventional paint and varnish materials. Powder painting of metal, for example, car parts, is a very popular service today.

Ease of use

The dyeing process is very simple. There is no need for constant monitoring of paint viscosity and constant adjustments to the desired consistency. This ensures not only savings, but also high stability of the treated surfaces. Removing powder from spray devices is much easier.

Variety of colors and shades

Powder painting - what is it? This is an opportunity to use more than 5000 various colors, their shades, as well as a wide variety of textures. Any surface can acquire properties that, when traditional technologies dyeing is simply impossible or very expensive.

For example, powder painting of metal in silver or aluminum metallic, such as with an “antizik” effect, imitating moiré or granite - all this is available. In addition, you can make the surface more glossy or, conversely, more matte.

Durability and surface strength

Powder coating differs from traditional ones in its increased chemical resistance, as well as excellent physical and mechanical characteristics. Thus, in order to damage the layer, an impact requires a force of more than 500 Nm, and the bending strength is 1 mm.

The resulting coating is quite impact resistant.

This has already been appreciated by cyclists, motorcyclists, and car owners. Powder coating of a bicycle is a popular service for those who prefer to ride in extreme disciplines and at the same time want to keep the frame in a new condition at all times.

High environmental friendliness

This coloring method various surfaces helps get rid of various environmental problems. Thus, there is no need for flammable and rather toxic solvents. The process is completely waste-free. Powder that has not settled on the surface can be reused. In addition, the working conditions of the personnel who work in such a site are much better than if they used conventional materials.

Advantages of powder technology

This is an opportunity to get a fairly thick single-layer coating. In the case of paints and varnishes, several layers would have to be applied.

Powder painting metal products, glass and others are fully automated. The film practically does not shrink after painting works. There are no negative effects due to the absence of any solvents.

Any drips and wrinkling can be completely eliminated.

Powder paint has good temperature resistance.

How is it applied?

There are several methods for applying such coatings. The most popular of them are electrostatic and tribostatic. If you want to see what powder coating is, there is a photo of it in this article.

Electrostatic spray painting

This method involves charging with a corona charge. This is industrial technology. It is quite popular due to its high efficiency. Many powder paints can be charged. The method is quite productive - it is used to work on large surfaces.

Along with the advantages, this electrostatic spraying also has some disadvantages.

Strong is being created electric field between the sprayer and the part. This can make painting a little more difficult in corners and deep recesses. In addition, incorrect settings can sometimes degrade the quality of the surface.

Tribostatic spraying method

What is this type of powder coating? What is tribostatic spraying?

This is friction charging. Unlike electrostatics, there is no high voltage generator, which is necessary for the atomizer.

Teflon is used for this method. This material allows you to perfectly charge many powder paints. Nebulizers for this technology do not require strong electric fields. Charged particles are able to penetrate even the most hard to reach places. You can apply paint in several layers.

Paint at home

Do-it-yourself powder coating requires complete set equipment.

As for surface preparation, it is the same as in the case of paints and varnishes.

Painting something at home using this technology is an expensive and difficult task. If you need to paint one or two parts, it’s easier to contact companies that offer this service.

Powder coating of metal was invented back in the 60s of the last century and very quickly became widespread. This is due to the many advantages of this technology, such as efficiency, environmental friendliness, attractive appearance coverings.

General information

So, the meaning of this technology is that a polymer powder dye is sprayed onto the surface to be painted. That is why this method and got that name. After applying the dye, the surface is subjected to heat treatment, as a result of which the powder melts and forms a continuous, uniform film.

The coating obtained by this method has the following properties:

• Corrosion protection;
• Good adhesion to the base;
• Resistant to temperature changes;
• Resistance to mechanical damage, including impact resistance;
• Moisture resistance;
• Resistant to chemical influences;
• Excellent decorative properties;
• Durability.

Advice!
Thanks to good adhesion, this method is the most the best option painting stainless steel.

Special mention should be made about decorative properties such a coating, which is distinguished by a variety of colors and textures, which is achieved through the use of various additives.

In particular, powder coating of metal allows you to obtain following types surfaces:

• Matte;
• Glossy;
• Flat or voluminous;
• Imitating gold;
• Imitating wood texture;
• Marbled;
• For silver, etc.

Advantages of powder painting technology

In addition to the possibility of obtaining a coating with high performance qualities, this technology has a number of other advantages, such as:

• Possibility of applying the coloring composition in one layer, which is unacceptable when painting with liquid paints and varnishes.
• No need to use solvent and control the viscosity of the material.
• High dye efficiency, since the powder that has not settled on the surface to be painted can be reused. To do this, spraying is performed in a special chamber, which allows you to collect all unspent powder. As a result, the cost of powder painting of metal is lower than applying paintwork using other methods.
• The painting process takes a little time, and after applying the paint, you don’t have to wait for it to dry.
• Environmental Safety, since the dye does not contain toxic organic compounds. As a result, there is no need to use powerful ventilation systems.
• Highly automated dye application technology, which simplifies the process of learning how to operate the equipment.

Flaws

Like any other technology, powder coating metal has some disadvantages:

• It is impossible to eliminate local coating defects - if they occur, it is necessary to completely repaint the surface.
• It is impossible to do the painting yourself, as this requires special equipment and workshop conditions.
• The dimensions of painted surfaces are limited.
• – it is allowed to use only powder paints for metal from manufacturers.
• It is impossible to paint parts that will later be welded, since burnt areas of the coating cannot be restored.

Powder painting technology

Preparing the base

Pre-treatment is the most time-consuming and labor-intensive stage of painting. However, it needs to be given Special attention, since the elasticity, durability and quality of the coating depend on preparation.

Preparing a part for painting involves removing any contaminants, degreasing the surface, and phosphating to improve adhesion and protect the metal from corrosion. The surface to be treated is cleaned mechanically or chemically.

To remove oxides, rust and scale, effective method cleaning is shot blasting. They are realized using sand, steel or cast iron granules.

Under the influence of compressed air or centrifugal force, these particles are fed at high speed onto the surface being treated and crush it. As a result, scale, rust and other types of contamination break off from the metal, which significantly improves adhesion.

The chemical cleaning method is called etching.

In this case, the removal of rust, oxides and other contaminants is carried out using compounds based on the following types acids:

• Solyanoy;
• Nitrogen;
• Sulfur;
• Phosphoric.

The advantage of etching over abrasive cleaning is greater productivity and ease of use. However, after this procedure it is necessary to rinse the surface thoroughly. Accordingly, costs arise for the use of additional cleaning products.

In the photo - painting a small part

Applying paint

After completing the pre-treatment of the metal, the part is placed in a special chamber where coloring powder is sprayed. As mentioned above, the camera is needed to catch unused material. In addition, it prevents paint particles from entering the room.

Such chambers are equipped with cleaning means such as hoppers and vibrating screens, as well as suction systems.

It must be said that there are two types of cameras:

• Walkthroughs - for painting large-sized products;
• Dead-end – for painting small objects.

In addition, there are automatic models in which the coating is applied with automatic manipulator guns. Of course, the price of such equipment is the highest, however, its productivity is also much higher - in this case, powder coating is applied literally in a matter of seconds.

As a rule, paint is applied electrostatically, i.e. Electrostatically charged powder is sprayed, which envelops the grounded part and adheres to it. The spraying itself occurs using a pneumatic sprayer, which is either simply a pistol.

After spraying the powder, the product is moved into the oven chamber, where it is subjected to heat treatment. Under influence high temperature the powder goes into a viscous-fluid state, after which the melted particles form a monolithic layer.

Note!
To obtain a high-quality coating result, the operating instructions for the equipment must be strictly followed.
Therefore, this work should be carried out by a specialist.

Conclusion

Powder painting metal surfaces much more advanced than painting liquid paints. However, in some cases its use is limited. In addition, it can only be performed using expensive professional equipment, so it is not applicable at home.

For more information on this topic, watch the video in this article.