1, wooden blackboard
The wooden blackboard is mainly made of fiberboard, density board or plywood, and the treated board surface is black. The blackboard made of this material is light in weight, easy to move, and the board size can be processed as required. The treatment method of black coating on board surface is simple and has high blackness. After the surface treatment, the friction and adhesion of chalk are very strong, and the contrast of writing with chalk is obvious, and the words on the blackboard feel smooth and smooth.
Disadvantages: The wooden blackboard is easy to get wet. If it is not well maintained, it will be deformed, coated and peeled, and the interlayer will be stuck.
2. Cement blackboard
Attached to the wall, made of sand and cement. Usually prefabricated on indoor or outdoor walls, there is no uniform standard for production specifications.
Disadvantages: the grain particles formed on the blackboard surface are uneven and uneven, and the black paint brushed out is easy to fade, crack and sand, so it is more troublesome to brush the paint frequently.
3. Glass blackboard
Made of a glass plate of more than 5 mm, the surface of the glass is polished with emery or etched with hydrofluoric acid to form ground glass, and the back is painted with black paint or set off with black material. The size of the blackboard depends on the size of the glass. If the size is large, it needs to be spliced.
Disadvantages: the glass blackboard is not easy to move, easy to break, the blackness of the board surface is not enough, the board surface can not be treated, the friction adhesion of chalk is poor, the color contrast of chalk handwriting is not obvious, and the background color of the blackboard is easy to be exposed.
4, metal steel blackboard
Generally, it is made of magnetic color-coated steel plate, and the thickness of the plate is mostly between 0.2 mm and 0.4 mm. This material has the characteristics of wear resistance, no falling off, no fading, durability, good writing feel, clear handwriting and easy writing and erasing. The inner core is made of seven layers of sound-proof and moisture-proof corrugated paper, the back plate is rust-proof hot-dip galvanized sheet, and the frame is made of high-strength electrophoretic aluminum alloy with fragrant seaside color, which is beautiful and generous.
How to choose the right blackboard
1, magnetic blackboard
Magnetic strips and bars are arranged inside the blackboard, or magnetic particles are attached to the surface. When in use, small teaching tools or pictures can be fixed with magnetic nails, magnetic blocks, etc., which is convenient for display.
Step 2 Push and pull the blackboard
Push-pull blackboard can be divided into up-and-down push-pull and left-and-right push-pull. The push-pull blackboard consists of two blackboards. When the writing space of the front blackboard is exhausted, the lower blackboard can continue to write, which greatly reduces the frequency of erasing the blackboard in class and enables teachers to teach the course more coherently.
3. Arc blackboard
Curved blackboards are usually used for blackboards with large widths, and their sides are slightly inclined, which is similar to the styles of curved displays and curved televisions in our daily life. The main purpose is that because the writing area is too wide, it is easy to refract light from different angles, resulting in unclear reflection, and a slight arc can reduce the visual impact caused by reflected light.
4. Green eye protection blackboard
Compared with the traditional pure black blackboard, dark green blackboard can reduce the contrast between colored chalk and blackboard, and has the functions of protecting eyes and reducing visual fatigue. At present, the education bureaus in some areas have issued regulations on using green blackboards to protect children's eyesight.
Generally speaking, although the materials and functions of various blackboards are different, it does not affect the use requirements, so we mainly consider the use feelings when buying, such as writing feel, durability, the feelings of viewers and so on. From the perspective of cost performance and use, the green blackboard of composite board is recommended, which is also the most mainstream product classification at present.