Offset printing is the main printing method. The PS plate for offset printing is the most popular printing plate today. Aluminum base plate is the main raw material for PS plate production, accounting for 80% of total consumption.
Aluminum plate is not only a support for the PS plate, but also plays an important role in the performance of PS plate. The effect of trace metal elements in the aluminum base plate on the physical and mechanical properties of the PS plate is obvious.
When the manganese content increases to the extreme solubility (1.82%), the strength of the alloy will continue to increase. When the manganese content is 0.8%, the elongation reaches a maximum. The strengthening effect of magnesium on aluminum is obvious. For every 1% increase in magnesium, the tensile strength increases by 34Mpa.
A certain content of magnesium in aluminum plate for PS plate is good for improving the strength and toughness of aluminum plates. When aluminum plate in a solid solution state, silicon and magnesium exist as dimagnesium silicon to improve the strength and toughness of the aluminum plate.
The content of magnesium is generally 0.05% to 0.3%. When magnesium is less than 0.05%, the required strength and toughness cannot be achieved. It is easy to break during printing process. But if it exceeds 0.3%, the non-graphic parts are easy to get dirty in printing.
Copper and zinc also can improve the hardness of aluminum alloys. With the addition of lithium, it can improve the aluminum base plate’s corrosion resistance. Although we need to get a good physical performance, the addition of trace alloy elements should be first helpful for the electrolytic oxidation quality.