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Automatic coating process and technology of kitchen utensils ------Application of automatic coating line in surface treatment of kitchen utensils

Release date:2019-05-22

With the sharp rise in prices in China, the wages of workers' labor have also increased substantially. The average wage has almost doubled compared with that in 2008. Although China has already had idle manufacturing processes and technologies, the previous production equipment in this industry is generally backward and needs A large number of low-level workers, such production methods have shifted to countries with lower labor and other labor force in Vietnam. 

Kitchenware non-stick pan (aluminum stretching pot die-casting pot) used to be manually sprayed before, labor-intensive and inefficient, artificial reasons, unstable quality..... I am currently the automatic coating process of non-stick stretching pot die-casting pot Say some opinions:

First, the traditional (aluminum) stretching pot die casting pot general process:

1 Stretching (die casting) - sand blasting (grinding) - soaking and degreasing (heating 60 ° C) - hand rubbing grease - manual hot water washing (heating 40 ° C) - manual cold water rinsing - pickling - manual cold water washing -- Handmade cold water rinsing - draining dry (rainy drying in the rain) - sand blasting - hand-wiping ash - hand-spraying inner coating - drying - hand-spraying inside --380 degree high temperature drying tunnel - External polishing - manual external spraying - medium temperature drying road - car side. ... loading and unloading times more labor.


     2 Problems:

  a Employees’ wages are large and workers are difficult to recruit.

b Manual spraying is uneven, paint is wasteful, and quality is unstable.

c The number of times of transfer is high, and the workpiece is easily scratched or scratched.


Second, in the last year, the company published the "new kitchen line washing machine" process ... has explained the pre-treatment process omitted here

Third, (aluminum) stretching pot, die-casting pot non-stick coating automatic internal coating process

1 Stretching (die casting)--cleaning machine cleaning--blasting (grinding)

Upper coating line:

Automatic dust removal--automatic preheating 40°C—4Q automatic primer—online automatic surface drying 160°C—automatic cooling 45°C-4Q automatic surface coating 1-4Q automatic surface coating 2--(transfer)--450°C high temperature drying Road—(outer polishing)—automatic external spraying—medium temperature drying tunnel 280°C-380°C


1 primer

The large number of applications of ceramic non-stick coatings greatly improves the performance of non-stick coatings and also changes the coating process.


   a rotary blowing dust:

In the automatic coating line, the workpiece is intelligently blown with 4.0-6.0kg/cm2 compressed air at a rotation speed of about 60-120r/min, which effectively solves the dust removal problem after the workpiece is blasted, and saves a manual hand wash or In an artificial ash cleaning process, intelligent dust blowing refers to the automatic control of the workpiece and the precise control of the blowing time and air flow. Of course, dust collection and treatment facilities are also included.


b preheating zone

The waterborne primer coating has good fluidity. In order to prevent the bottom oil from flowing, it is on the automatic coating line.

A far-infrared heating preheating drying tunnel process has been added, the temperature is controlled at about 40-60 ° C, and the preheating time is about 1-1.5 min, which can effectively solve the problem of low temperature primer coating in winter.


   C base oil spraying

   Automatically recognize multi-gun spray while the workpiece is rotating and moving at an average speed.

   The workpiece is rotated, and the rotating fixture is driven by a suitable wiper. The rotation speed can be continuously variable frequency regulation from 50~300r/min, so that the workpiece and the fixture rotate concentrically, creating energy-saving conditions for automatic spraying. Aluminum stretching pot die-casting pot automatic spraying generally 2 to 3 guns can be completed, but actually need to install 4, one as a spare gun.

When the first spray gun A (our company is currently using the Japanese Iwata WA-101-1.3 automatic spray gun), it will receive the induction signal to start the delay, and the delay time is accurate to 0.01-10S. When the workpiece is in the scope of the spray gun A, Start spraying the side of the pot, in order to ensure uniform spraying and energy saving effect, the general spray gun angle is adjusted at 35~45°, 1/4 is sprayed outside the pot, 3/4 spray pot, and the gun is installed above the water curtain. Place a grease pan at the 1/4 spray outside the pot to recover the paint. Of course, the same type of solvent should be placed on the oil pan for recycling.

When the second spray gun B approaches, the induction signal is received and the delay is started. When the workpiece is sprayed on the spray gun B, the spray wall is sprayed. In order to ensure uniform spray and energy saving effect, the spray gun angle is generally adjusted to 40~50°. All inside the spray pot. The spraying time is accurate to 0.01-10S, and the spraying time should be adjusted before the pot leaves.

When the third spray gun C approaches, the induction signal is received and the delay is started. When the workpiece is sprayed on the spray gun C, the bottom of the spray gun is sprayed. In order to ensure uniform spray and energy saving effect, the spray angle of the spray gun is generally 45~55°. All inside the spray pot. The spraying time is accurate to 0.01-10S, and the spraying time should be adjusted before the pot leaves.

According to the actual situation, adjust the spray flow, angle, position, etc. of the gun in time.

The intelligent automatic identification control circuit can be a PC or a discrete component, and the sensor is preferably capacitive.


d table

An incubator is arranged on the automatic painting line, and the assembly line track is installed at the bottom of the box. In order to install the process, the third track is generally rotated. The drying time is generally designed to be 3~5min, and the track length of the drying zone can be designed to 20~30M. The far-infrared heating tube and the reflector are installed directly above the track and heated by radiation. The temperature is automatically controlled at around 150 °C, which ensures fast drying on the assembly line.


E cooling

In order to have a good uniform brightness of the inner coating oil and a wet spray effect of the inner coating oil, the workpiece temperature should be lowered to below 40 °C. It is best to use a rotary blast cooling to make the workpiece temperature more uniform. The cooling air here must be filtered through 5 million grades of air.


F inner coated oil 1, inner coated oil 2

The working principle is the same as that of the base oil spraying. Here, only 4 automatic spray guns (8 in total) are added. When wet spraying, it is best to have a leveling distance of 1-2M, which can take into account various indicators.


g manual transfer area

The workpiece is manually transferred to a high temperature curing (furnace) drying tunnel after 3-5M line leveling.

Only 4 workers were used in this process, and the output can reach 800-1400 pieces/hour.

Fourth, non-stick coating internal coating curing sintering

     The non-stick coating sintering must follow the curing temperature curve (figure) to achieve the desired physical effect.

     In order to have a good temperature profile, two heating zones are generally required, namely a preheating volatile zone and a high temperature solidified sintering zone; a cooling zone.

Preheating the volatile zone, the temperature is too high and too low, it is easy to foam, because too high will cause the solvent to evaporate too quickly and foam; too low solvent volatilization is slow and not clean, it will be easy to foam when it enters high temperature sintering, preferably controlled at 220. Around °C, the time is controlled at 5-10min.

In the high temperature curing sintering zone, this temperature and sintering time are very important, directly reflecting the chemical and physical properties of the paint, mainly in the hardness, wear resistance, brightness and other indicators. A flat high temperature curve of more than 10-15 min. is required, and the temperature is about 427 °C (ceramic non-stick coating). In order to ensure good surface brightness, it is necessary to have a good smoke exhausting function in each zone, and to save energy and Smoke is taken care of. In particular, the exhaust pipe should be well insulated. Otherwise, the temperature curve of the drying tunnel will appear in the exhaust port, which will affect the curing effect of the drying tunnel and cause waste of energy.

Cooling zone; using dust-free strong wind cooling.

The filtered air is passed through a fan to a programmable air shower nozzle that is evenly mounted above the cooling zone line to cool the workpiece. The fan pressure is preferably ≥1200pa, and the air shower nozzle adjusts the middle of the workpiece. Design cooling design ≥ 3-5 min (according to the actual thickness of the workpiece), so that the workpiece surface temperature ≤ 45 ° C.

The next step is external polishing, which requires external polishing before the outer coating in order to improve the adhesion. It will not be described in detail here.

Five, automatic overcoating process

Generally, the stretching pot and the die-casting pot are only used for one painting. Now, the high-demand products are also used for two-coating. The two coatings are all sprayed with wet spray, and the wet spray distance should be greater than 2M.

Since most of the outer coatings use oily coatings, it is very easy to cause equipment pollution during spraying. This has been an industry problem for many years, and now the outer coatings are generally sprayed manually.

Now the professional external spray automatic spray booth developed by our company has fundamentally solved this industry problem and is shared with you here.

Other technical indicators about the automatic spray booth are not here.

Displacement automatic spraying: It is to displace the pollution of the oil-based paint equipment, and spray the paint, rails, chains, etc., which are contaminated by the original spraying, and discharge the waste paint directly into the water curtain of the sink to ensure that the track and the chain work. In a non-polluting environment, but other properties and stability remain unchanged.

The working principle of the automatic coating of the outer coating is basically the same as that of the inner coating, and the workpiece is automatically recognized for multi-gun spraying under the condition of rotating and moving at a constant speed. Refer to automatic internal coating. The outer coating is different from the inner coating. The automatic top pot system is added to the inner coating. The principle is to prevent the outer coating from being accidentally sprayed into the inside of the sprayed pot body, and the outer coating is applied, so the automatic top pot system is helped. These are all done with mechanical structure.


Sixth, external coating curing sintering

      Sintering of the outer coating must follow the curing temperature profile of the paint to achieve the desired physical effect.

      In order to have a good temperature profile, two heating zones are generally required, namely a preheating volatile zone and a medium temperature solidification sintering zone; a cooling zone. The temperature curve is different from the inner coating (figure), and the drying tunnel structure is basically the same.


Seven automatic coating production line application

      The application of the automatic coating production line greatly improves the work efficiency and product quality. As long as 6 workers can guarantee the mass production of 1000/hour in the production of coating.



The kitchen utensils realize automatic coating and solve the difficult problems of kitchen surface treatment coating equipment. We will continue to work hard on the development of automatic coating equipment, and continuously use the digital intelligent automatic control management system to make our painting equipment more humanized. .