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Spraying assembly line production process



Release time:

2021-06-17 19:40



The spraying line is mainly composed of pre-treatment electrophoresis line, sealed bottom coating line, intermediate coating line, top coating line, finishing line and its drying system


Engineering process layout of spraying assembly line:

1. Plastic spraying line: upper conveyor chain-spraying-drying (10min, 180℃-220℃)-cooling-lower part

2. Painting line: upper conveyor chain-electrostatic dust removal-primer-leveling-top coat-leveling-drying

(30min, 80℃)-cooling-next part

Paint spraying mainly includes oil shower spray booths and water curtain spray booths, which are widely used in the surface coating of bicycles, automobile leaf springs, and large loaders.

Attention factors for spraying assembly line design:

1. Master the economic principles of less input and more output

2. Reasonably choose the annual time base

3. Reasonable selection of materials and reasonable determination of supporting equipment

4. Reasonable layout and accurate selection of the size of non-standard equipment

5. Save energy

Precautions for spraying line

1. Attention should be paid to the installation of the painted objects on the spraying line. Pre-dip test to design the hanger and object mounting method on the spraying line to ensure that the workpiece is in the best position during dipping. The largest plane of the object to be coated should be close to vertical, and the other planes are at an angle of 10°-40° with the horizontal, so that the remaining paint can flow out smoothly on the painted surface.

2. In order to prevent the solvent from spreading in the workshop and dust falling into the paint tank when painting on the spraying assembly line, the dipping tank should be protected.

3. After the large objects are dipped in the spraying assembly line, they should be sent to the drying room after the solvent is basically volatilized.

4. When painting, pay attention to the determination of the viscosity of the paint. The viscosity should be measured 1-2 times per shift. If the viscosity increases by more than 10% of the original viscosity, the solvent should be added in time. When adding solvent, the dip coating operation should be stopped. After stirring evenly, measure the viscosity, and then continue the operation.

5. The thickness of the paint film is mainly determined by the rate of object lifting on the spraying line and the viscosity of the paint solution. After the viscosity of the paint solution is controlled according to the above requirements, the spraying line should be based on the maximum speed of the paint film about 30um, and the appropriate lifting rate should be determined by experiment according to different equipment. At this rate, the coated object is evenly lifted. The lifting rate is fast and the paint film is thin; the lifting rate is slow, and the paint film is thick and uneven.

6. During the dip coating operation on the spraying line, sometimes the thickness of the paint film to be coated and the lower part of the paint film is different, especially the thick accumulation on the lower edge of the coated object. In order to improve the decoration of the coating, use a brush to manually remove the excess accumulated paint drops when dipping in small batches, or use centrifugal force or electrostatic attraction equipment to remove these paint drops.

7. When dipping wooden parts on the spraying assembly line, pay attention to the time not to be too long, so as to avoid the wood from inhaling excessive paint, causing slow drying and waste.

8. Strengthen ventilation equipment to prevent the harm of solvent vapor; pay attention to the arrangement of fire prevention measures and regularly check the spraying line. Oven Oven is one of the important equipment in the spraying line, and its temperature uniformity is an important index to ensure the quality of the coating. The heating methods of the oven include: radiation, hot air circulation and radiation + hot air circulation, etc. According to the production program, it can be divided into single room and through type, etc. The equipment forms have straight-through and bridge types. The hot air circulation oven has good heat preservation, uniform temperature in the furnace, and low heat loss. After testing, the temperature difference in the furnace is less than ±3oC, which meets the performance indicators of similar products in advanced countries.

Heat source system

Hot air circulation is a common heating method, which uses the principle of convection conduction to heat the oven to dry and solidify the workpiece. The heat source can be selected according to the user's specific situation: electricity, steam, gas or oil, etc. The heat source box can be determined according to the situation of the oven: placed on the top, bottom and sides. If the circulating fan that produces the heat source is a special high-temperature resistant fan, it has the advantages of long life, low energy consumption, low noise, and small size.

Electric control system

The electrical control of spraying and spraying assembly line has centralized and single-row control. Centralized control can use a programmable logic controller (PLC) to control the host, and automatically control each process according to the programmed control program, data collection and monitoring alarms. Single-row control is the most commonly used control method in the spraying assembly line. Each process is controlled in a single-row. The electric control box (cabinet) is set near the equipment, with low cost, intuitive operation and convenient maintenance.

Suspended conveyor chain

Suspension conveyor is the conveying system of industrial assembly line and spraying line. The accumulation type suspension conveyor is used in L=10-14M storage racks and special-shaped street lamp alloy steel pipe spraying lines. The workpiece is hoisted on a special hanger (load bearing capacity of 500-600KG), the entry and exit of the switch are smooth, and the switch is opened and closed by electric control according to the work instruction, which can meet the automatic transportation of the workpiece in various places of science and technology, in the strong cold room and the lower part area Parallel accumulating and cooling, and set up the identification and traction alarm and shutdown devices in the strong cold area. The so-called spraying line refers to covering the surface of metal and non-metal with a protective layer or a decorative layer. With the development of industrial technology, spraying has been developed from manual to industrial automation, and the degree of automation is getting higher and higher, so the application of spraying lines has become more and more extensive, and has penetrated into many areas of the national economy.