The first step is to see if there are obvious distortions in the aluminum profile, whether the surface is smooth and smooth, there are no cracks or spots, scratches, burrs, and if it is found to be super good, do not buy it.
Secondly, it is necessary to carefully check whether the surface color of the aluminum profiles has different shades. A color difference means that the quality is not excessive. Of course, it is also possible to compare the profiles of the same model together for comparison. Of course, if the color difference is too obvious, the color difference should not be selected. To purchase, check whether the profile thickness of the aluminum profile is the same as the marked model.
Finally, you can use a smooth hard object to scratch the surface of the aluminum profile, leaving a white scratch, aluminum gently wipe and observe by hand, if you can not wipe, indicating that the material may be quality problems, but if Can be easily wiped off, indicating that the oxide film thickness on the surface of the profile is acceptable.