On the structure of landscape lighting product waterproof
Luminaires based on structural waterproof design need to be tightly matched with silicone sealing ring. The outer casing structure is more precise and complicated. It is usually suitable for large-sized lamps, such as strip floodlights, square and circular floodlights, etc. Lighting.
The structural waterproof luminaire is only assembled with pure mechanical structure, the use of tools is simple, the assembly process and process are few, the assembly cycle is short, and the repair of the production line is convenient and quick. The luminaires can be packaged and shipped through electrical performance and waterproof testing, and are suitable for engineering projects with short lead times.
However, the structure of the waterproof design of the luminaire has higher requirements for machining, and the dimensions of each component must be precisely matched. Only the right materials and constructions can guarantee the waterproof performance, the following design points.
(1) Design silicone waterproof ring, choose the material with the right hardness, design the appropriate pressure, and its cross-sectional shape is also very important. The cable entry line is a channel for water seepage. The waterproof cable should be selected. The strong cable waterproofing head (PG head) can prevent the water vapor from penetrating from the gap of the cable core, but the long-term strong extrusion of the wire insulation layer in the PG head. Press without aging and no cracking.
(2) Under normal temperature, the difference between the two is large. Care must be taken when the outer dimensions of the luminaire are large. Assume that the length of the luminaire is 1 000 mm, the case temperature is 60 ° C during the day, the temperature drops to 10 ° C in the rain or night, the temperature drops by 50 ° C, the glass and aluminum profiles shrink by 0.36 mm and 1.16 mm, respectively, and the relative displacement is 0.8 mm. The sealing element is repeatedly pulled during the repeated displacement process, which affects the airtightness.
(3) Many medium and high-power outdoor LED lamps can be installed with waterproof and breathable valves (respirator). The waterproof and breathable functions of the molecular sieves in the respirator can be used to balance the internal and external air pressure of the lamps, eliminate the negative pressure, prevent the inhalation of water vapor, and ensure the internal drying of the lamps. This cost-effective waterproof device can improve the waterproof performance of the original structure design. However, the respirator is not suitable for burying lamps, underwater lights, and the like that are often in the water.
The long-term stability of the waterproof structure of the luminaire is closely related to the design, performance, processing accuracy and assembly technology of the selected lamp material. If the weak link is deformed and seeps, it will cause irreversible damage to LEDs and electronic devices, and this situation is difficult to predict during the factory inspection process, which is very sudden. In this regard, to improve the reliability of structural waterproof lamps, it is necessary to continue to improve the waterproof technology.
About the LED product material waterproof
The waterproof design of the material is made of filling and sealing glue to achieve insulation and waterproofing. The sealing glue is used to bond and seal the joint between the structural parts, so that the electrical components are completely airtight and achieve the waterproof function of the outdoor lighting.
Outdoor Landscape Lighting potting glue
With the development of waterproof material technology, various types and brands of special potting glues have appeared constantly, such as modified epoxy resin, modified polyurethane resin, modified organic silica gel and so on. Different chemical formulas, the physical and chemical properties of potting rubber, such as elasticity, molecular structure stability, adhesion, anti-uV, heat resistance, low temperature resistance, water repellency and insulation properties, are different.
Elasticity: The gel is soft and the modulus of elasticity is relatively small, so the adaptability is better. Among them, the modified organic silica gel has the smallest elastic modulus.
Molecular structural stability: Under the long-term action of uV, air and high and low temperature, the chemical structure of the material is stable, without aging and no cracking. Among them, modified organic silica gel is the most stable.
Adhesion: When the adhesion is strong, it is not easy to be peeled off. Among them, the modified epoxy resin has the strongest adhesion, but the chemical structure stability is poor, and it is easy to age and crack.
Water repellency: Indicates the ability of the colloid to resist water penetration. Among them, the modified organic silica gel has good water repellency.
Insulation: Insulation is related to product safety indicators. The special filling glues of the above materials are all good materials and special potting glues are good.
From the above comprehensive physical and chemical properties, the modified silicone material performs best.
Landscape Lighting sealing adhesive
Sealant is usually a tubular package, suitable for glue application, and is generally used for bonding and sealing of indirect seams of wire ends and outer structural parts. It is a commonly used one-component formula that reacts with air vapor at room temperature and naturally solidifies.
Special attention: Some lighting manufacturers use neutral curtain wall glue for construction instead of professional electronic sealant, which easily decomposes harmful substances and damages the lamps.
Some types of potting and sealant will decompose a small amount of chemical liquid or gas during the solidification process. For example, the colloidal decomposition product of the lamp bead damages the lamp phosphor, causing color temperature shift or invading the LED chip. Or decompose substances that chemically react with transparent PC plastics, destroy PC structures, and so on. This is a potential hazard in colloidal applications. The colloidal manufacturer must be fully aware of its chemical and physical properties and tested for compliance.
In the seal of the structure of the lamp housing, the sealant is most affected by thermal expansion and contraction, especially for large lamps. The coefficient of linear expansion of different materials is quite different, and the thermal expansion and contraction are continuously pulled, which is prone to cracks. Therefore, the waterproof ability of the material waterproof design is mainly based on the circuit board potting.
The production process of material waterproofing is long, and the curing cycle of one filling glue takes 24 hours. Some products are more complicated in design, and even require 2 to 3 filling cycles, resulting in a long shipping cycle and a large occupation of the production site. The production environment is dirty. Product rework after solidification of the colloid is troublesome.
The structural design of the material waterproof lamp does not need to be too precise, as long as the gel potting area is reserved during the design, the liquid does not leak, and the waterproof performance is very intuitive. Therefore, the material waterproofing process is more suitable for small outdoor lighting, indoor moisture-proof lamps. It is usually used in a large number of low-end and low-cost public mold products. Small lamps such as soft light strips, small strip lights, and buried lights are listed.