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What are the faults in the process of plastic board processing

by:UNQ     2021-03-26

  The plastic plate processing overflows into the gap between the mold clamping surface and leaves the remaining material on the plastic part. Welding mark: a linear mark on the surface of a plastic part, flashing material: during plastic processing and molding. In the process of injection or extrusion, several streams of material flow and merge in the mold. The melts are not completely fused at the interface and cannot be fused into one body. This will cause fusion marks and affect the appearance quality and mechanical properties of the plastic parts. Wave flow mark: due to the improper flow of the melt in the mold cavity, the surface of the plastic part will have annual ring-shaped, spiral-shaped or cloud-shaped wave-shaped irregularities. Appearance turbidity: refers to the occurrence of cracks with voids on the surface of plastic parts and the resulting damage. The phenomenon that cracks occur on the outside or inside of the plastic part due to long-term or repeated application of stress lower than the mechanical properties of the plastic is called stress cracking; because the plastic part is subjected to a constant load for a certain period of time at a specific temperature and suddenly completely ruptures The phenomenon is called stress cracking; the cracks and ruptures that occur when certain thermoplastic parts are excessively exposed to higher temperatures are called thermal stress cracking. Fracturing: refers to the obvious cracks in the outer layer or layers of the reinforced material of the laminated plastic that can be seen through the resin layer covered on the outer surface.

   A defect in which the surface of the laminated plastic is cracked and clearly separated in the plastic board processing. Wrinkle: In the process of plastic processing, the appearance of creases or wrinkles on one or more layers of plastic parts. Cracking and bleaching: The relatively obvious micro cracks on the surface of the plastic part are called cracks, and the frost-like micro cracks similar to the cracks are called bleaching. Both cracks and bleaching are micro cracks without cracks. When plastic parts are exposed to a certain chemical environment or under stress conditions, environmental stress cracking will occur. Silver wire: needle-like silver-white frost-like fine lines on the surface of the plastic part along the direction of material flow. Streak: There are linear streak defects on the outside or inside of the plastic part. Streaks: due to poor dispersion or mixing of pigments and other reasons, mica flake-like dark spots occur on the surface of the plastic parts. Orange peel pattern: the appearance defect of the surface of the plastic part that is uneven like orange peel. Cell streak: refers to the cell layer in the foam plastic that is very different from its inherent cell structure. Black spots: In the process of plastic processing and molding, the melt is overheated and decomposed under high temperature and high pressure conditions, resulting in black carbonization spots on the surface of the plastic parts. White spots or bright spots: there are insufficiently plasticized particles in transparent or translucent plastic films, sheets or plastic parts, and red particles can be seen when light is transmitted. Such particles are called 'fish eyes'. When it is opaque or colored, such particles are called white spots or bright spots.

   The regular or irregular small craters appearing on the surface of plastic parts, usually their depth and width are roughly the same. Filling spots: The plastic parts are caused by the presence of fillers such as wood flour or asbestos. Obvious spots caused by dark spots: dark stains that appear in the laminate structure with fabric as the base material. Scorching and sticking spots: during plastic processing, under the conditions of high temperature and high pressure molding, the melt is carbonized due to overheating decomposition, the carbonized coke is mixed in the melt, and the plastic parts are formed on the surface and inside of the defects. Bubbles: plastic processing and filling During the process, if a large amount of gas remains in the melt or the air in the mold cavity is not completely exhausted, the plastic part will form defects of small volume or series of pores after molding. Cavitation or dark bubble: When the plastic part is cooled and solidified during plastic processing, due to the different cooling speeds of the inside and outside, sometimes the outer layer has cooled and solidified, but the inside is still in a hot melt state. Once the central part cools and shrinks, the inside of the plastic part will be Vacuum holes occur, which are generally called vacuum bubbles or dark bubbles, also known as shrinkage holes. Pinholes: There are pinhole-sized through-hole defects in the plastic sheet or film. 24 collapsed foam: the defect of local density increase caused by the destruction of the cell structure of the foam during the manufacturing process. Protrusion and shrinkage: In the cooling process of plastic processing, the surface layer of the plastic part is cooled and solidified first, and the inner or thick parts of the wall are cooled and solidified, so that when the volume shrinks, the shrinkage speed of the inside and outside is inconsistent, and the surface of the plastic part is stretched internally. Formation of depressions, shallow pits or dimples. Due to insufficient filling of the cavity, lack of injection: plastic processing. Lead to the phenomenon that the shape of plastic parts is complete and incomplete.

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