First of all, of course, is to look at the aluminum profile in the appearance of any obvious distortion, touch the surface is smooth, there are no cracks or bubbles, scratches, burrs and other non-smooth
local. If found, it is best not to buy, this is the most obvious quality problems.
Second, it is necessary to carefully check the aluminum surface color, whether there is color. A color that does not mean the quality of the pass. Or you can put the same type of profiles together for comparison, if the color is too obvious is best not to buy. Also check the cross-sectional thickness of the aluminum and marked with the same model, the existence of physical and not marked.
Finally, it is possible to draw a smooth hard object to the surface of the aluminum profile, which will leave a white scratch. We gently wipe the hand and observe, if you can not erase, indicating the quality of the material may have problems, if you can easily wipe, then the profile of the oxide film thickness is qualified.
