(1) Precautions before installation
1. Clean the metal frame, and there must be no chemical substances such as metal elbow oil or pickling liquid remaining on the frame.
2. Reserve expansion space, the size of the expansion space can be calculated by the following formula:
Expansion value = linear expansion coefficient × length × maximum temperature change value
The coefficient of linear expansion is a fixed value=7×10-5(cm/cm/℃)
Example: If a PC board with a length of 100cm is installed in an environment with a temperature difference of 40°C between day and night, the reserved expansion space is: expansion value=7×10-5(cm/cm/°C)×100(cm)×40°C= 0.28 (cm), so the reserved expansion space should be at least 0.28cm.
3. The plasticizer (DOP) in the PVC gasket and the chemical substances in some rubber gaskets will migrate to the surface of the gasket, and will destroy the PC board after contacting with the PC board, so it must not be used. The recommended materials for gaskets are EPDM rubber (ethylene propylene diene monomer), Siliconer rubber (silicone rubber) and Neoprene rubber (neoprene rubber). If there is no suitable gasket, it is better not to use it than to use a gasket that will damage the PC material.
4. For sealed installation, neutral Silicone (silicon) series sealant, double-sided waterproof tape and rubber bead can be selected.
5. In addition to being used for waterproofing, the double-sided waterproof tape can also be used as a gasket material between the PC board and the frame. Some double-sided tapes are damaged on the surface of the PC board, so they are also used during construction.
6. Electric tools must be used when cutting. The saw blade should be made of tungsten carbide. Before cutting, the plate must be fixed to avoid vibration.
7. The PC board is easily scratched, so do not tear off the protective film when cutting. Before cutting, it is necessary to mark the line and mark it on the protective film as much as possible. If it must be marked directly on the board, please use a crayon and avoid contact with sharp tools.
8. Before the cement is completely dry, the new building should not be in direct contact with the PC board, otherwise the alkaline substances in the cement will damage the PC board material.
9. If the PC board needs to be bent, the construction radius must be greater than the allowable curvature radius. The calculation method of the allowable radius of curvature is as follows: The allowable radius of curvature (R) for outdoor use must exceed 180 times the thickness of the plate. The allowable radius of curvature for indoor use
(R) Need to exceed 150 times the thickness of the plate
Example: For example: 3mm PC board is used outdoors, its radius of curvature should be: 3mm×180=540mm=54cm, so the designed radius of curvature must be at least greater than 54cm, see the minimum bending radius table.
10. When the radius of curvature (R) is less than 180 times the thickness of the plate, thermoforming must be used for bending construction. For example, vacuum forming is one of the thermoforming methods, but if the temperature of thermoforming is higher than 120°C, the protective The film is torn off and then thermoformed.
11. Allowable deflection angle θ: As shown in the figure on the right, the bending central angle θ must be less than or equal to 90°. If it is greater than 90°, a reinforcing frame must be added at the part less than 90°.
12. Dust and dirt on the surface of the PC board are generally wiped with a soft cloth or sponge dipped in a neutral detergent, and then rinsed thoroughly with water.
Finally dry with a soft cloth.
13. If you need to use solvents to clean, remember that most solvents, such as toluene, acetone, gasoline, carbon tetrachloride, etc., will damage the PC board and must not be used. The recommended solvent is alcohol, such as alcohol or isopropanol etc.
(2) Correct installation method
1. Embedded installation method
(1) The protective film on the PC board will affect the adhesion with the seal, so the protective film on the embedded part should be removed before the PC is embedded. 5-10mm.
(2) When the PC board is embedded, there must be an appropriate amount of embedding and expansion space. If the embedded amount is too small, the PC board may fall off due to wind pressure or other heavy pressure; if the expansion space is not enough, the PC board may also be stressed due to expansion, resulting in damage.