The surface of the large core board should be flat, without warping, deformation, no blistering or dent; the core strips are evenly arranged, the gap is small, and the core strip has no decay, breakage, wormholes, thrift and so on. Some blockboards cut corners, and the gap between the solid wood strips is large. If nails are nailed in the gap, there is basically no nail holding force. Consumers can look at the sun when they choose, and the gap between the solid wood strips will be white. If the glue strength of the blockboard is not good, it will have a "å±å±" opening sound when it is self-financing. If the large core board emits a fragrant wood smell, it means that the formaldehyde emission is less; if the smell is pungent, it means that the formaldehyde is released more.
The quality of the large core board varies greatly, so check it carefully when purchasing. First of all, see if the core material is dense, whether there are obvious seams and decaying wood strips, there may be eggs in the decaying wood strips, and insects will occur in the future; then see if there is any glue or greasy putty around. It is to compensate for cracks or voids inside; then use a sharp-nosed instrument to strike the surface of the board to see if the sound is very different. If the sound changes, there is a hole inside the board. These phenomena will weaken the overall bearing capacity of the board, and the uneven long-term stress will cause the sheet structure to be distorted and deformed, which will affect the appearance and use effect.
FR4 is not a material`s name, but a kind of grade of fire-resistant, which represents resin materials can self-extinguish when firing. Now there are all kinds of FR4 materials using as PCB, but the majorities are composite made of epoxy resin, filler and fiberglass.
G10 FR4 Sheet mainly used as insulation structure parts in electrical, electronic and other industries.
Key Features :
• Flame resistance
• High dielectric strength
• Moisture resistance
• Heat resistant
• Temperature resistance: 180-200℃
• Under the normal temperature 150 ℃, it still has high mechanical strength.
Fr4 Sheet,Fr4 Epoxy Fiberglass,Fr4 Epoxy Glass Sheet,Green Fr4 Sheet
SHENZHEN XIONGYIHUA PLASTIC INSULATION LTD , http://www.xyhplastic.com