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Technical cleaning of new painting production line workshop

In the newly built coating production line workshop, the pre-treatment tank and drying room need technical cleaning before debugging and at the beginning of operation. After the completion of the painting production line workshop, it is forbidden to visit, not only foreign personnel are not allowed to enter, even the company's personnel are also non-public, even if entering, they must change special shoes and clothes through the wind shower door to enter. All these are for one purpose, to prevent dust from entering and affecting the quality of paint.


 In fact, from the first day of painting production line workshop planning, always consider how to prevent dust everywhere. For example, the air entering the workshop should be filtered for several times, sealed throughout the workshop and maintained relative positive pressure with the outside world. Logistics process should go through the double door, personnel in and out need to pass through the air shower door, into the high clean area through the double air shower door.  Workshop management is also trying to prevent dust entry, the selection of materials to dust-free or as little as possible, work clothes to be made of non-woven fabric. Spray room coated with sticky materials. But dust is a formidable enemy. It is everywhere, and the average amount of particles in the atmosphere is about 10 to 40 million per m3. A coating production line with an annual output of 30,000 MPVS can produce 1.5 to 6 billion dust particles in 150,000 m2, which is why coating production line workshops regard dust as their biggest enemy. In view of the above reasons, this paper discusses the problem of the first deep cleaning of the new coating production line before the tank and during the trial operation of the drying room. 

1. Clean the groove of the pretreatment line  
The internal cleaning quality of the pre-treatment line groove directly affects the quality of the body surface, so before cleaning, we should consider the material of the groove and whether it is coated with anti-rust layer and the order of cleaning the groove.  The steel beams and the top of the trough should be cleaned first, from top to bottom. And when cleaning the several places, the general floating dust should be removed for the first time (specific method: first use a vacuum cleaner, and then repeatedly wipe with sticky gauze), and the second cleaning should find the sanitary dead corner that is difficult to clean last time or not clean to clean (acceptance standard: After two times of cleaning, do not spend too much time on the steel platform at the top of the tank body, just go over it briefly before acceptance, wipe 1m with a clean sticky gauze on the steel platform or steel beam, and the sticky gauze does not change color.

When cleaning the main body of the tank, professional detergent must be added with a low pressure water gun of about 100KPa to remove the sediment and oil stains on the inner wall (the supplier of pre-treatment chemicals will also use a special solvent to remove unrelated impurities before the tank). In this cleaning cleaning company's main task: prior to the big tank cleaning, to reach the water supply pipeline in the sediment or rust out; Remove oil stains from the inner wall of the tank;  Remove internal sundries - balls, ballasts, etc. When cleaning the tank, safety stairs should be set up in each large tank before treatment. The equipment needed in the cleaning process is often heavy, which brings great security risks to the personnel in and out of the tank. In this cleaning project, it is difficult to clean once, at least 3 to 4 times to basically remove the sediment at the bottom of the tank.  In short, cleaning companies should not stop cleaning large tanks before the pre-treatment tank, in order to meet the high requirements of chemical suppliers for the environment in the tank.

2. Drying room during the trial run of cleaning
The cleaning requirements of the drying room during the trial operation are higher than those of other cleaning items.  Different types of drying rooms have slightly different cleaning methods. The drying room cleaning in the initial stage of new construction is divided into three stages. The first two stages can be carried out after the completion of construction, and the last stage is carried out during the trial line. The first stage is called the rough cleaning stage, in which the cleaning company always cleans all parts of the drying room from the inside out and from the top down. The purpose is to clear out the relatively large balls or excessive welding rods and other sundries. Then clean each corner with a vacuum cleaner again, the oven wall board and the dust in the corner of the general first clean again. The cleaning order is as follows: air curtain suction in the drying room → air outlet in the drying room → internal cleaning of heat exchanger → ceiling in the drying room → air chamber wall on both sides of the drying room (or the surface of Angle steel of baking lamp, etc.) → air duct in the first insulation section → ground in the drying room → debris cleaning in the pit on both sides of the drying room track.

The following are the cleaning methods for the first stage of two different ovens:  
Method 1: The internal cleaning of the oil-type drying room is more difficult than that of the baking lamp type drying room, because the space is relatively narrow when cleaning the air room on both sides, and it is not easy for people to move inside, so the cleaning is also slower. Materials, personnel and other related auxiliary facilities required for cleaning:  

Method 2: It is more troublesome to clean the air-supplied drying room. Because the air room space is relatively narrow and it is difficult for personnel to move inside, it is difficult to clean the ventilated indoor part. It takes two days to clean the air-supplied drying room. Clean the interior air chamber from top to bottom on the first day. The next day, the inside of the oven is cleaned from top to bottom again, and the material required is also 30% more than that of the oven.

In the second stage, the air particles at three points in the drying room were recorded after cleaning. After this cleaning, both ends of the drying room should be sealed with film to prevent secondary pollution caused by air convection and to prohibit irrelevant personnel from entering.  

The third stage is called the ventilation stage, which is carried out synchronously with the workshop trial run. Two hours before the trial production every day, the cleaning company smears the car body (commonly known as toothpaste car) with the special sticky paint for the oven through the oven. Toothpaste car in the radiation section and the first insulation section stay for a period of time can absorb more dust and particles.  There are many reasons affecting the quality of painting, among which the particle dust is the main reason, but also a difficult problem. To solve the problem of body particles to consider from all aspects, plant, equipment, personnel wearing, coating and so on.

Post time: Jan-17-2022