We offer services of:
- powder-coating; Prisma Ltd. also has an equipment of mobile painting with liquid paint
- compression services performed with hydrostatic and power presses
- plate cutting with sizes up to 1 m length and 80 cm width
- sandblast cleaning
- transport of goods up to the weight of 3,5 t
It is a simple method of cleaning any kind of surfaces (metal, plastic, Wood, glass, brickwork, etc.) followed by a protection technique (electrochemical coating, painting, enamelling, oiling, etc.) of surfaces.
The principle of method
It consists in bombing the surfaces with a compressed air flow under pressure which by impact cleans surfaces of contaminants (scale, rust, dust, etc.) .
Depending on the initial state of surface as well as of the finite elements degree aimed as sandblast agent, the following can be used: quartz sand, lead shots, electro-cordon, glass pearls.
The sandblast cleaning operation is performed in a sandblast sealed cabin provided with ventilation, using a sandblast pistol with quartz sand. Prismainfo Ltd. also has a mobile sandblast station suitable for sandblasting big surfaces at customer’s place of residence. Besides other specific procedures the sandblast workshop also provides a method of high quality restoration of car wheels with various sizes, made of plate as well as of aluminium alloy. After restoration wheels are powder-coated.
Advantages of method
This method is characterized by a little degree of pollution since no solvents are used.
The dispersed powder is gathered, flittered and reused; therefore this method is one of the most efficient painting method.
The painting layer shows a high degree of resistance to bad weather and chemical agents, as well as to abrasion.
This method is applied for protecting metallic surfaces in metallic constructions, car industry, exhaust systems, consumer goods, domestic goods, etc.
There is a high diversity of colors.
The powder-coating represents a method of protecting metallic surfaces, it ensures a high quality of the finite product, both regarding the mechanical strength, durability to corrosion as well as regarding its commercial character.
- Technological phases
The painting method includes the following phases and technological facilities:
1. The preparation of surfaces on the line of surface preparation.
2 The electrostatic spray painting with powder painting performed using a painting nozzle in the powder-coating cabin.
- the polymerization of powders performed in the automatic polymerization oven.
- the quality control of the covered surface, packing and delivery of painted half-finished goods performed using the proper equipment.
. The principle of powder-coating.
Between an electrode charged at high voltage and the antipole an electrical field with lines oriented according to the principles of physics. The field intensity depends on the difference between the potential and the distance existent between the two poles, as well as on the environmental features. The particles found in the proximity of electrodes are charged with electrons, they are rejected by the electrode and attracted by the antipole along the field lines. In case the antipole is earthed, the captured electrons would be discharged, maintaining constant the difference between the field potential and intensity. According to these principle features the material sprayed is transported on the surface of the covered piece.
The surface painting with powder paint is achieved using a special pistol containing an electrode inside, which allows the charging of the paint particles (electron charging).
Due to the polymers quality to charge electrostatically and to “keep” the electrical charge, the powder-paint particles are attracted by the surface of the piece (which is connected to the antipole, more exactly to the earth) and subside on its surface.
Therefore the strictly necessary conditions for a uniform subsidence of powder-paint particles on the piece in electrostatic field are the following:
- the pistol should be equipped with electrode.
- the piece should be earthed.
- the electrical field should be produced between the two elements.
For the technology of powder-coating the painting workshop is equipped with a painting cabin provided with powder-coating painting pistol and a polymerization electrical oven.
1. SURFACE PREPARATION
The surface preparation has a decisional role in achieving the performances of covering, influencing features such as adherence, resistance to shock, to humid warmth and salt fog.
The selection of a method of surface preparation shall be done according to the nature of metal and surface state. The method election is very important as regarding the improvement of adherence and anticorrosive qualities of the layer.
A superficial preparation of surface leads to the procurement of a layer with low attributes no matter the quality of powder paint.
Normally, the preparation of painting surface is achieved by the removal of organic or non-organic impurities from the surface.
The phases of the preparation process are the following: removal of rust, alkaline degreasing, water washing, application of cover by chemical conversion (phosphate-passivation), water washing, drying.
The removal of organic impurities (oil wastes, vaseline, cupping solutions, etc.) derived from previous mechanical treatments is performed using alkaline degreasing solutions.
The removal of non-organic impurities (dust, rust, boring dust, slag, etc.) derived from previous mechanical treatments is performed using mechanical polishing, sandblasting, chemical cleaning, etc.
The preparation of surfaces destined to painting may be performed within:
- the painting workshop on the preparation department (department made of degreasing bath, phosphating, drying).
- the galvanization workshop on the line of frames and barrels.
- the sandblasting workshop using Quartz sand.