Views:8 Author:Jia Hua Aluminium Co., Ltd Publish Time: 2019-08-16 Origin:Site
Aluminum profiles is the main material of the windows and curtain wall, which is widely use around the world. The surface of the aluminum profiles without the surface treatment is vulnerable to corrosion. In order to increase the decoration, corrosion and lifetime, the aluminum profiles needs the surface treatment. Anodized, Powder coating, wooden grain is the common use surface treatment.
Powder coating aluminum profiles is the green building material which has colorful surface. This time, let’s see how Jia Hua produce the Quality powder coated aluminum profiles.
The processing of spraying powder:
Extrusion – size check - Pre-treatment (Degrease – Wash – drying – Wash – Wash – Chromizing – Wash – Wash) - Spray powder – Solidification – Quality check – Packing
1. Pre-treatment of powder coating
The aluminum profiles will be cleared the oil and dust on the surface. And it will comes a layer of Zinc phosphating film which can increase the adhesion of the powder and the corrosion.
The details requirement of pre-treatment
Degreasing removes oil, grease, and other contaminants from the surface of the work piece prior to erosion to form a clean surface.
Temperature: 50°C -70°C
Time: 5-10 minutes
After the degreasing, it needs be washed by the water in few times. But at the last we will use the Ionized water for washing to prevent the adhesion and corrosion. The water can not exceed 50 °C after chromizing. It musts have the wash after every processing of the pretreatment.
Time: Three times wash. 1- 3 minutes in once time
C. Alkali etch
Some insoluble pickling residues can be removed during the neutralization stage. Some oxides such as magnesium oxides, metal oxides and the like are present in these residues. These materials are insoluble in alkaline solutions and can be removed by immersion in nitric acid or sulfuric acid.
For aluminum, chromium is the most commonly used method of chemical conversion. The chrome film improves the adhesion between the aluminum and the coating and improves the corrosion resistance of the coating. If the chrome film is too thick, it will greatly improve the corrosion resistance. If the chrome film is too thin, it can produce very good adhesion, but the coating has less corrosion resistance than the thick chrome film. There are two forms of chromium chrome in general: yellow chrome and green chrome.
Chromizing concentration 25- 35 g/L. PH is 1.5-3.0. Time: In 1-3 minutes. 5-10 degree of slope.
The profiles should be dry before spray the powder. If not the moisture will affect the quality. 65°C – 80 °C. Less than 85°C. The time of drying is 30- 60 minutes. No any water droplets on the surface.
2. QC Checking
After the pretreatment of the aluminum profiles, the QC will check the quality of aluminum profiles. Only the qualified aluminum profiles can be sent to do the powder coating. And before the powder coating, we need to punching a hole so that the aluminum profiles can be handled on the vertical machine and send to do the powder coating.
3. Powder coating
The aluminum profiles will be handled on the vertical powder coating machine. And the production will be automatic controled by the computer. But onething we need clear it before the spraying is the decoration surface of the aluminum profiles. We need to make sure which suface of the aluminum profiles must have the powder coating and the requirement of the powder coating.
Usually, there is the standard of the powder coating which is aggreed by the seller and buyer. Such as, AAMA 2603, GB5237.4, etc. Usually, we will follow the GB standard. But if you have other requirement, please feel free to contact us. Looking forward to received your requirement.
4. QC Checking
After the powder coating, there also have a testing. The QC will check the powder coating thicknes of the profiles. And they check the surface whether it has the Blisters, Marks, Cracks(oxide) Or Scratches Found In The Coating Surface. If the aluminum profiles have the accessories, we will check the assemble.
The most important is that our quality test center will take few pieces of finished powder coating aluminum profiles to do the impact test, boiling test, etc.
The qualified powder coating aluminum profiles will be directly send to packing. That can help the aluminum profiles reduce the scracth on the surface.
Our Jia Hua with the advance aluminum extrusion profiles powder coating machine and the professional technology can help our customer get the 100% qualified products. Contact us now! Then you can know our price of powder coating.