Homemade powder paint polymerization oven. Oven for polymerization of powder paint: manufacturing technology
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The first plant for the production of non-traditional painting material, powder paint, was built in the United States in 1971 - 1974.
Therefore, the powder coating method is considered quite new. Recently, an increasing number of car manufacturers are switching to powder coating, recognizing the cost-effectiveness and practicality of the new technology. The powder painting booth allows the process to be carried out quickly and efficiently.
Powder painting booth - its structure
The basis of the equipment intended for powder coating is the painting chamber itself and the polymerization oven. In the first chamber a layer of powder paint is applied, in the second - surfacing. The paint is applied to the body surface with an electrostatic gun. In small-scale production, paint can be applied with a fairly compact hand gun.
In factory production, the coloring option often changes, therefore, chambers with cartridge cleaning are used. The powder is filtered from the air in the recuperator. This is a block of filters in which regeneration is carried out automatically, using the pulse blowing method.
Powder coating is now available in garage painting!
Currently, there are cameras on sale that are designed to work in small-scale production or with single products. The device is a complex of a working chamber and a filtration unit. The product enters the chamber through an opening located in the front part.
The powder painting booth is equipped with a mandatory control panel. The remote control is located outside the camera. This allows the operator to control the work while being at a safe distance from the equipment.
There is also a walk-through design. Products in such a chamber enter from one side and exit from the opposite. Some models make it possible to paint on both sides with a rotation. In other models, the operation is performed immediately.
In powder painting booths, instead of the usual paint materials, tinted powder is used. Powder paint is a finely dispersed powder with the necessary impurities. Powder grain size is approximately 10 - 100 microns.
Powder painting booth setup
The powder painting booth consists of two systems: air filtration and powder recovery. Before painting, the powder is magnetized, as a result of which it acquires a certain pole of the magnetic field. The car body is the second pole. The powder adheres to the metal in a dense and uniform layer.
After applying the powder, the layer is baked. To do this, the body is heated to a temperature of 160 - 200 degrees. The powder is melted and maintained at this temperature for 10 - 20 minutes.
In factory conditions, powder coating is used not only for painting the body, but also for painting wheel rims, bumpers, plastic parts, and headlight reflectors.
Currently, powder coating is used with a matte effect, semi-matte, under the skin, etc. The process uses ready-made powder, which does not require special dilution.
The main advantages of a powder coating booth
A powder painting booth significantly reduces the financial costs of painting products. The material remaining on the surface of the body and suspended in the air is collected using filters and returned to the production process. In this case, the powder undergoes additional purification to avoid contamination.
As a result, losses do not exceed 1 - 2%, while with conventional painting they are 50 - 60%. The use of powder paint makes it possible to widely regulate the thickness of the paint layer in the range from 35 to 250 microns. During accelerated climate tests, the service life of powder paint was determined to be 20 years. Painting in a powder chamber does not require additional drying of the surfaces to be painted.
A significant disadvantage of this type of car painting is the unprofitability of using cameras in a small repair shop. A powder painting booth is essentially a very complex and expensive piece of equipment. In addition, it is impossible to carry out the necessary tinting in the chamber.
Do you still want to make a powder coating booth with your own hands? This possibility exists. True, you will still have to buy branded equipment, without which the process will be impossible. In addition, you will have to carefully follow all stages of the painting process.
A powder painting booth at home will require you to:
- spray gun
- powerful compressor for supplying compressed air
- filter with pressure regulator
- powerful power grid
- ventilation
- vacuum cleaner equipped with a cyclone nozzle
- oven type oven
What is needed for a powder coating booth?
You can use a simple model of a paint gun in production by connecting a compressed air supply to two atmospheres. However, as work progresses, higher pressure may be required. In addition to a reliable compressor, take care of a filter with a mandatory pressure regulator.
When setting up a chamber, you cannot do without a powerful electrical network and ventilation. The recuperator will replace the vacuum cleaner. An ordinary household one will not work; it gets clogged in the first minutes. It is best to purchase a special vacuum cleaner with a cyclone attachment.
To illuminate the room, use sealed fluorescent lamps. Since they are not subject to heat, the paint that has settled on them will not melt and cleaning the lamps will not create problems. After installing the stove, place hangers nearby to cool the painted parts. The electrical network should be installed correctly, not forgetting the need for grounding. It’s easier to invite a specialist to do the work.
Work is carried out in tight overalls, specially designed for working with electrical equipment. The use of a respirator is mandatory. The finished parts should be removed from the oven using a special hook. The simplest powder painting booth is at your disposal.
The air duct is designed so that intense air flow passes through the protective covers. The air should come from below and pass through the suspended parts. The temperature will be evenly distributed throughout the entire volume of the device, which will ensure quality work. The furnace will be controlled using a control unit. He will set the parameters of the heating elements and start the fan. It will be easy for them to control the temperature in the chamber. The control cabinet must have:
- indicators and sensors of heated air temperature in the working chamber,
- automatic for starting the fan and heating element,
- automatic shutdown of the device in case of an accident.
Control sensors are mounted so that one is on top, the other is on bottom. They must be equally distant from the heating elements. It is advisable to buy a factory unit that will control the processes in the chamber. The device will be more functional. A thermostat with automatic control will set a more accurate operating mode.
Good afternoon
I wrote about problems with the high voltage block for powder coating, see Post #7:
In the description of making a spray gun:
in Post #11 Aldar Kose wrote:
at the same time very good I wanted to understand how a 30 kV power supply works.. and how to make it..
Here's what I got.
In those days I did not have the Internet, PCAD and time. I had to quickly come up with something. I think I found an idea in Radio magazine.
I assembled the diagram:
and it worked.
ATTENTION:
The circuit is galvanically connected to the supply network. To ensure correct connection of the phase and neutral wires of the power supply network, there is a power cord with three contacts.
To isolate from the network, you can use a 220V to 220V transformer.
Circuit operation:
When the unit is connected to the network, the left LED lights up. When the circuit is switched by the foot switch, both LEDs light up and the circuit begins to work.
With a negative half-cycle of the supply voltage, current cannot pass to the collectors of the transistors and the output voltage switch VR1 (closing diodes). The diode in the circuit of transistor VT1 protects the base junction of the transistor from a negative voltage at a level of about -0.6V.
After the supply voltage passes through 0 to the positive half-cycle and reaches approximately 0.6V at the base, transistor VT1 opens and the voltage at the collector decreases to the saturation voltage of the transistor. At the same time, capacitor C5 and capacitors C6, C7 are charged. When the point of maximum positive amplitude of the supply voltage (+311V) is reached, C5 is charged to the maximum (311V minus the voltage drop across the two open diodes). C6, C7 are charged to a voltage determined by voltage divider VR1 and accompanying resistors and diodes. After the maximum amplitude of the supply voltage has passed, capacitor C5 begins to gradually discharge through the VT1 circuit and the resistance in the collector circuit is M16. Since VT1 is open, transistor VT2 is closed. When the supply voltage passes through 0 to the negative region, transistor VT1 closes, transistor VT2 opens and the capacitor quickly discharges through VT2 and opens the thyristor. In this case, the charged capacitors C6, C7 are discharged through the primary winding of a six-volt ignition coil for a motorcycle. A high voltage pulse appears on the secondary winding of the ignition coil. The KD202D diode allows several oscillations after the thyristor is opened in the circuit of the primary winding of the coil. After the voltage multiplier, a negative high-voltage DC voltage arrives at the output of the unit. This voltage is supplied through a shielded high-voltage wire to the electrode of the sawing gun. The metal part of the gun body is grounded through the wire shield. The part to be painted is connected to the block body by a separate wire.
Display oscillograms at different points.
The oscillograms are displayed from top to bottom:
1. Supply voltage output.
5. Voltage on capacitors C6, C7 when the output voltage switch is in the lower position.
6. Voltage on capacitors C6, C7 when the output voltage switch is in the upper position.
(Misunderstanding (forgotten) about 4. - it seems like the voltage at the control terminal of the thyristor, but then at the 4V location there should be approximately 3.5V).
Design.
1. Photo of a buried block
2. Photo without cover and front
3. Photo from behind.
The most convenient way to paint small items is to use powder paint. With it you can do coloring at home. But this will require maintaining the required temperature conditions. The main one is drying. And here the polymerization furnace will help us. This will be more economical than purchasing professional equipment. And we will do it with our own hands.
Powder painting oven setup
Powder paint has been produced since the early 1970s, so this method of painting is considered quite new. It is economical and durable, which is why it is preferred by a large number of people.
The powder coating oven includes a polymerization oven and a painting chamber. Powder paint is applied in the painting booth, and it is melted in a polymerization oven. Powder paint should be applied special pistol, professional or manual.
Nowadays a painting booth can be purchased for working with single elements. It consists of a filtration unit and the working chamber itself. Products penetrate into it through the hole at the top.
You can control the powder furnace using the remote control. This is very convenient from a security point of view.
Among the varieties of powder furnaces, there are also walk-through designs. This means that the elements to be painted enter from the right and exit from the opposite side.
Coated powder is used in a powder painting oven. Powder paint consists of finely dispersed powder. The required additives are added to this powder, and thus we get powder paint.
Painting booth
It includes a powder recovery system and an air filtration system. First, the powder is magnetized. After this, the magnetized powder is distributed evenly on the surface, adhering to it. Heating occurs so that the powder can bake. It is necessary to heat for no more than twenty minutes at a temperature of up to two hundred degrees.
Share:There are several ways to paint car body parts, and powder painting is the most modern among them. However, this technology is very complex, as it requires the use of special equipment, represented by powder coating chambers, the features of which are discussed in this article.
What is powder coating?
This term refers to the creation of high-quality decorative and protective polymer coatings by using a high-voltage electrostatic field. Powder paint is a tinted fine powder with impurities with a grain size of 10-100 microns.
The essence of painting work is to apply a powder material charged during the spraying process by electrification through friction or from an external source onto an oppositely charged metal surface.
This ensures uniform application of paint to the object being processed. Powder painting involves the use of a polymerization chamber for drying and final fixing of the paint.
Sequence of work
The powder coating process includes several stages. The first of these is surface preparation, which involves removing any contaminants from it. In case of repainting, it is necessary to clean the surface of the original paint and primer. These works are carried out after drying is completed using sandblasting, using various abrasives. Coarse ones are designed to quickly remove paint and varnish material, while inorganic materials are used to level the surface.
Next, powder primer is applied to the prepared work surface. This process is carried out in a spray chamber using an electrostatic sprayer. The workpiece must be grounded first. Powder primer, like regular primer, serves as anti-corrosion protection. After the soil has melted in the spraying chamber, powder paint is applied. This work is also carried out with an electrostatic sprayer. To create a smooth, uniform coating, the paint should be applied in several layers (usually 2-3).
After each layer, the product to be painted is placed in a polymerization chamber for 15-30 minutes, where, under the influence of a high temperature of 180-200 ° C, powder paint particles are fixed on the surface of the part due to melting. Upon completion of drying and polymerization, the part to be painted is removed from the chamber and left for some time - this is necessary so that it cools to room temperature.
Upon completion of paint application, the part is coated with powder varnish, which performs protective and decorative functions. It gives the coating additional stability and protects it from fading under the influence of ultraviolet rays. In some cases, varnish is applied to metal that is not covered with paint and primer in order to preserve its texture. In addition, in this case it plays the role of an anti-corrosion agent.
Advantages of the method
Powder painting is considered an alternative to applying liquid paints and varnishes. Moreover, the method under consideration is much more advanced, since it has some advantages over the use of liquid paints:
- Powder coating is of higher quality and monolithic.
- Powder paint particles that have not settled on the working surface are captured in the spray booth and can be used for re-spraying, resulting in significant material savings. This increases the profitability of factory painting and reduces costs when doing the work yourself. Thanks to these measures, material loss during operation is 1-2%, while when working with liquid paints and varnishes, 50-60% of paint is lost.
- Powder paints are superior to liquid paints and varnishes in terms of bending and impact strength.
- The materials under consideration are more resistant to factors such as temperature changes, exposure to chemically active substances, corrosion and abrasion.
- Powder paints have higher adhesion to the surface.
- Do-it-yourself powder painting is simplified due to the absence of drips on vertical surfaces.
- The use of powder paints allows you to vary the thickness of the applied layer within a wide range (from 35 to 250 mm).
- The powder coating is characterized by high durability, which according to test results was estimated at 20 years.
However, powder painting also has some negative qualities, mainly due to the complexity of the work. Since they require equipment such as a spray booth, powder coating is a very complex and expensive procedure, so it is not cost-effective to do it yourself at home. In addition, such work is very lengthy, since it takes time not only to apply the paint and varnish material, but also to carry out drying and polymerization, as well as cooling.
Equipment
The equipment necessary for do-it-yourself powder painting is represented, first of all, by a spray booth and a polymerization oven. An electrostatic gun is required to apply the paint. When doing work at home, a compact hand gun is usually used.
Models of powder coating booths are available for sale, designed for small-scale production or for processing single products. These powder coating booths are most suitable for DIY work. The devices under consideration are represented by complexes consisting of a working chamber and a filtration unit. The powder coating booth may have one or two openings. The product enters through the opening in the front part, and it can exit through the opening on the back side or through the inlet.
Painting booths are divided according to painting technology: some devices paint parts on both sides with rotation, other models simultaneously. The powder painting booth has powder recovery and air filtration systems.
The polymerization oven is used to heat processed products to a temperature of 160-200ºC and maintain them in such conditions for 10-20 minutes in order to dry and bake the applied layer of material.
Both in factory conditions and when doing DIY work, powder materials are used not only for painting the body. They are also used to process wheels and plastic body parts, such as bumpers, moldings and other elements.
To create a paint booth with your own hands, you will need the following equipment:
- spray gun;
- filter with pressure regulator;
- compressor for air supply;
- electrical network;
- ventilation;
- oven type oven;
- a vacuum cleaner equipped with a cyclone-type nozzle.
A simple model of a paint gun can be used as a spraying tool. It is supplied with compressed air under a pressure of two atmospheres, although for some work this value may not be enough. In any case, for painting you will need a compressor, as well as a filter with a pressure regulator.
The spray booth must be equipped with a ventilation system. The recuperator can be replaced with a vacuum cleaner, but household models are not suitable for such use, as they quickly become clogged. It is advisable to use a vacuum cleaner with a cyclone attachment.
As for the electrical network, it must be installed by a specialist. A hanger should be placed near the polymerization oven for drying and cooling the parts. It is necessary to provide bright lighting - sealed fluorescent lamps are best suited for a powder coating booth. This is explained by the fact that they are easy to clean, since they do not heat up, as a result of which the paint that gets on them does not melt.