Emery (sanding) paper has a fairly wide application. It is used to clean surfaces before painting, gluing, to insure against slipping (for example, in skateboards), to remove dirt, etc. The use of sandpaper in many industries and repair enterprises provides huge demand for this product. The business of manufacturing grinding, with the correct organization of production and established sales channels, of course, will be profitable.
Sandpaper device and material
Sandpaper consists of a base and abrasive (grinding material). Its main characteristics are granularity and grain . The last parameter refers to the size of the abrasive particles covering the base of the paper. Granularity refers to the density of the abrasive covering the base, i.e. the number of particles per square inch. According to this characteristic, the following types of paper are described, described in GOST 6456-82:
- sandpaper with a grain size of 40-60. It is the coarsest, has large abrasive particles located far from each other. Used for primary processing of material.
- 80-120 - paper with medium grain. Smoothes the surface, removes bumps.
- 150-180 - thin sandpaper. It is applied at final polishing.
- 220-240 - very thin sandpaper. It is used for grinding material for stripping before coating with paint.
- 280-320 is already extra-thin paper. She removes dust specks and marks at the final stage of coating the material.
- 360-600 is the thinnest sandpaper. It is used very rarely to remove light impurities.
The following types of paper are distinguished, depending on the basis:
- sandpaper on a paper basis. Paper is a cheap and convenient material for production, but it is not strong enough and non-waterproof. Although, due to its subtlety, the smallest abrasives can be applied to it.
- fabric-based sandpaper (coarse cotton, polyester). The fabric is very durable and waterproof, but expensive and can be lengthened when working.
- paper on a mixed basis (fabric glued to paper).
- on a fiber basis. Usually used for the manufacture of fiber disks.
Various materials are also used for the abrasive. The most widely used is alumina. It has a high cutting ability, resistant to high pressure. It is a brittle material - when used, its granules are easily broken, but this only increases its shelf life. The hardest ceramic abrasive, used for rougher surfaces. The second hardness is silicon carbide, it is used in the processing of glass, plastic, metal. The softest material is pomegranate. It is used at the final stages of polishing or for easy softening of the surface.
By the type of application of abrasive sanding paper is released:
- with open and half-open filling. It has gaps between particles that cover from 40 to 60% of the surface of the base. It is used for grinding soft materials;
- with a closed bulk (solid). Abrasives cover the entire surface of the paper. Grinds hard materials well.
Sandpaper is made in several stages. First, it is passed through a machine with a printed press, where the drums with rubber stamps held on magnets display technical information on the fabric. Then the base is impregnated with water-resistant substances (latex, rubber). The fabric passes under a full-blown press, where other drums apply thermosetting glue to the side that is free of inscriptions. Coating density is controlled by a computer system. Phenol-formaldehyde and urea-formaldehyde resins, a glue based on varnish, an adhesive based on epoxy resins, and glue are used as a bonding layer. After that, the step of applying the abrasive occurs. There are several ways.
Mechanical. Abrasive particles fall in a chaotic order from a bulk machine with a hopper-feeder, excess material is removed. With this type of application, less aggressive particles are obtained.
Electrostatic. The base is pulled underground to the electrostatic section, where a hot and humid atmosphere is maintained. Particles are poured onto a conveyor moving in a container that moves particles under a rotating fabric between the electrodes and the base. An electric field is created that causes a mini sandstorm. Under the influence of an electrostatic field, negatively charged abrasive particles are uniformly pressed into the base. This method produces a more aggressive sandpaper.
A piece for testing quality is cut from almost finished paper.
Next, the paper is dried in special furnaces. The temperature depends on the bond (glue): formaldehyde resins - 100 ... 120 ° С, glue SFI-3039 or SFZh-3038 require several drying stages (20 ... 70 ° С, 70 ... 100 ° С and 100. ..120 ° С), pentaphthalic and oil varnishes - 120 ° С, glue - 25 ... 45 ° С.
After applying the fixing layer of the ligament and dried again. Finished paper rolls are sent to the warehouse to wait for cutting. Some rolls are cut into huge sheets: they will go for use in heavy engineering. On special machines, emery discs, tapes to protect the skateboard, etc. are cut.
To service the entire production workshop, you will need to hire about 10-15 people.
Equipment and raw materials (cost)
To produce grinding, the following raw materials and equipment should be purchased:
- glue. It will cost somewhere in the 200-250 rubles per kg;
- silicon carbide - $ 500-2400 per ton;
- cotton fabric - 18-30 rubles. per linear meter;
- electric furnace - from 78 thousand rubles - up to 450 thousand rubles;
- drying chamber - from 60 thousand to 500 thousand rubles;
- coating machine (for applying glue, marking) - about 450 thousand rubles;
- hoppers-dispensers (for filling abrasive) - from 5000 rubles;
- belt conveyor - from 23 thousand rubles per linear meter;
- drive station and return station - from 124 000 rubles.
The initial investment in the annual production of sandpaper will be about 3.5 - 4 million rubles. If you sell 5, 000 meters of paper per year at an average price of 280 rubles per linear meter, the business will pay off in 4-5 years.
According to GOST 6456-82, the following information should be applied on the back of sandpaper:
- product designation;
- what material the base is made of;
- abrasive used, its content and size;
- type of material used for gluing the abrasive;
- waterproof or non-waterproof;
- release date and batch number;
- stamp of technical control;
- image of the State Quality Mark according to NTD for a grinding skin;
The winding of the sandpaper in rolls should be even and dense, with the working layer facing out, preventing the formation of wrinkles, folds and wrinkles. Each roll of sandpaper should be wrapped with a double layer of paper according to GOST 18277-72, GOST 2228-81 or GOST 10127-75.
The roll should be sealed at the seam. Layers of packaging paper should cover the ends of the roll and ensure its safety during transportation.
Transportation of materials is subject to the following conditions:
- the product should not be subjected to strong shock, shock, moisture;
- during transportation, the material should be protected from the effects of precipitation;
- the goods are accompanied by the necessary documents.
Store sandpaper in a dry, ventilated area. Its rolls are stacked in dense rows, alternating in the longitudinal and transverse directions. Store at a temperature not lower than plus 2 ° C. Shelf life is 12 months (more on GOST sites).
The ways of selling polishing should be sought based on its purpose. It can be industrial enterprises, shops of goods for repair, goods for wood processing, however, sandpaper is sold in every hardware store. Therefore, the main goal will be the production of high-quality, cheap goods and establishing contact with buyers.
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