1. Understand the window types in the local market, and then see if the manufacturers have such window types, because the extrusion dies for different window types are the same, and the assembly dies are different when making finished windows.
2. Understand the fluctuation law of aluminum ingot futures. Because aluminum ingots are in the form of futures, if you don't know the price trend, you will often buy at a high price and sell at a low price. Grasp it well, just earning the difference between aluminum ingots is very powerful.
3. Looking at the grade of local market, the quality and price of aluminum are different, so it is necessary to set a good position. Is garbage popular or national standard popular? It is popular when the thickness exceeds 1.2, and it is popular when it is below1.2 mm.
All of the above should be understood and well known.