The roving is a bundle of parallel or parallel monofilaments. The roving of the roving can be divided into: alkali-free glass roving and medium-alkali glass roving. The glass fiber used to produce the glass roving has a diameter of 12 to 23 μm. The number of rovings is from 150 to 9600 (tex). The roving can be directly used in some composite material forming methods, such as winding and pultrusion processes. Because of its uniform tension, it can also be woven into a roving fabric. In some applications, the roving is further chopped. .
(1) The roving for jetting is suitable for the spun yarn used for FRP injection molding. It has the following properties: 1 good cutting property, less static electricity generated during continuous high-speed cutting; 2 roving without roving after being cut into raw yarn The efficiency is high, that is, the beam splitting rate is high, usually requires more than 90%; 3 the chopped strands have excellent overmolding property and can cover all corners of the mold; 4 resin is soaked quickly, easy to be flattened by roller rolls Easy to drive air bubbles; 5 original wire cylinder has good decomposing performance and uniform density of coarse yarn, suitable for all kinds of spray guns and fiber conveying systems. The roving for jetting is made up of multiple strands of silk, each strand containing 200 glass filaments.
(2) SMC swarf roving SMC is a sheet molding compound, which is mainly used for pressing automobile parts, bathtubs, water tank plates, septic tanks, various seat gingham fabrics, and the like. SMC uses roving to cut the length of lin (25mm) in the SMC sheet and disperses it in the resin paste. Therefore, the requirement for SMC roving is good short cut, less wool and excellent antistatic property. The chopped strand does not stick to the knife roll during cutting. For colored SMC, the roving is to be impregnated with resin in a high pigment content resin paste. Usually SMC roving is generally 2400 tex, and in some cases 4800 tex is also useful.
(3) The roving winding method for winding is used to manufacture glass steel pipes and storage tanks of various calibers. The number of rovings used for winding is from 1200 to 9600. The large pipes and tanks tend to be directly roving, such as the 4800 tex direct roving. The requirements for the roving for winding are as follows: 1 is good in banding, and is in the form of a flat ribbon; 2 the roving of the roving is good, and it does not detach from the bobbin, and does not form a "bird's nest"-like chaotic yarn; 3 Uniform tension, no drape; 4 line density is uniform, generally less than ± 7%; 5 æ» roving has good permeability, easy to wet and soak the resin when passing through the resin tank.
(4) Pultrusion The pulverized roving is used to manufacture various profiles with the same cross section, which is characterized by high glass fiber content and large unidirectional strength. The pultrusion roving may be a combination of a plurality of strands of yarn or a straight roving having a linear density ranging from 1100 to 4400. The various performance requirements are generally the same as for twisted rovings.
(5) An important use of roving roving for weaving is to weave woven fabrics of various thicknesses or unidirectional roving fabrics, which are mostly used in hand lay-up FRP forming processes. The following requirements are imposed on the roving for strong making: 1 good wear resistance; 2 good banding; 3 roving for weaving requires forced drying before weaving; 4 uniform tension of roving roving, drape should be Meet certain standards; 5 æ» roving decomposability is good; 6 æ» roving permeability is good.
(6) Preformed roving in the pre-form process, the roving is short-cut and sprayed on a predetermined shape of the net, while spraying a small amount of resin to fix the fiber web, and then moving the formed fiber web into In the metal mold, the resin is injected into a hot press to obtain a product. The performance requirements for the roving for this process are essentially the same as for the roving without jetting.
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