PTFE, PFA, FEP, PVDF Fluoroplastic products industry experts
Analysis of the relationship between the extrusion process and quality of the fep tube
Classification:
Industry dynamics
Author:
PFA tube little sister
Source:
PFA tube little sister
Release time:
2008-04-19
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The full name of FEP is Fluorinated ethylene propylene, which translates as fluorinated ethylene propylene copolymer (perfluoroethylene propylene copolymer). FEP is a copolymer of tetrafluoroethylene and hexafluoropropylene. The FEP crystals had a melting point of 304 ° C. and a density of 2.15g/cc. FEP can be applied to soft plastics, the tensile strength, wear resistance, creep resistance is lower than many engineering plastics.
Figure 1 fep Spiral Pipe Source: Teflon Pipe Little Sister
FEP has good processing performance. The insulation layer of the wire and cable may be coated by a common extrusion method. The following is the FEP tube extrusion needs to be prepared:
1) Feeding: Before FEP extrusion, it is advisable to pre-bake at 120 ℃ for about 3h. Kan
2) Preheating of conductive wire core: In order to ensure uniform temperature inside and outside of the extruded FEP insulation layer, the conductive wire core should be preheated to 300-350 ℃. Kan
3) the temperature distribution of the extruder: the extruder is generally 280 ℃ (feed inlet) to 380 ℃ (head) linear temperature distribution is good;
4) The draw ratio of the mold sleeve: it should be selected in the range of 50-200. Kan
5) Screw speed: After the screw speed is adjusted in coordination with the temperature, do not change frequently during FEP resin extrusion processing, and slightly adjust if necessary.
6) Mold die heat preservation: The heat preservation area should be covered with the entire stretching area, and the heat preservation temperature should be 350-380 ℃, so as to avoid the formation of stress due to surface quenching before the cone of FEP is formed, resulting in insulation cracking.
7) Insulated wire cooling: The wire extruded from the extruder is water-cooled. The distance between the die and the water tank should be closer, and it is recommended that it is not more than 20cm.
The product forms before FEP resin processing and molding are:
1. Pellet, used for extrusion molding and injection molding;
2, dispersion, used for impregnation and coating;
3. Powder for electrostatic spraying.
Below we mainly understand the FEP under several molding processing methods.
1, Melt extrusion molding
2. Molding: heating, pressurizing and plasticizing; cooling, pressurizing and shaping
3. Blow molding
4. Vacuum forming
5. Injection molding
6. Coating processing
7. Electrostatic spraying
(insert fep spiral tube video)
FEP hose extrusion quality and the following related parameters also have a certain relationship, a factor may lead to FEP tube extrusion quality and ideal difference.
1. Temperature
Extrusion molding temperature has barrel temperature, plastic temperature, screw temperature, generally we measure the barrel temperature. The temperature is controlled by the heating and cooling system. Due to the instability of the screw structure, the heating and cooling system, and the change of the screw speed, the temperature of the extruded material fluctuates in the radial and axial directions, which affects the quality of the product. The strength of each point of the product is different, resulting in Residual stress, and the surface is gray and dull. In order to ensure the quality of products, the temperature should be stable.
2, the pressure
Due to the structure of the screw and the barrel, the resistance of the head, the filter screen, and the filter plate, there is pressure inside the plastic. As shown in the figure, the pressure also fluctuates.
3. Extrusion rate
The mass or length of plastic extruded by the extruder die per unit time. Factors affecting the extrusion rate: head resistance, screw and barrel structure, screw speed, heating, cooling system, plastic properties. But when the product has been set, the extrusion rate is only related to the screw speed. Extrusion rates also fluctuate, affecting article geometry and dimensions.
In order to ensure the quality of products, the screw should be designed correctly, the heating and cooling system and the stability of the screw speed should be controlled to reduce the parameter fluctuation.
Shenzhen Dankai Technology Co., Ltd. (ShenZhen DanKai Technology Co., Ltd.), whose predecessor was the Fluoroplastic Material Factory of Dongguan Dandi Insulation Material Co., Ltd. established in 1998, specializes in the research and development, production and sales of FEP, PFA, PTFE and other fluoroplastic tube rod sheet membrane products and other insulation materials. The company has international standards of senior R & D team and the introduction of foreign fluorine plastic products production line. Some fluoroplastic products through ISO9001, SGS, FDA certification, Huawei, Foxconn, the United States, ZTE, Intel, AirTAC and other domestic and foreign cooperation customers fully affirmed. The company's main products are: ① pipes: Ptfe pipes, Fep pipes, Pfa pipes, Pvdf pipes; ② Heat shrinkable tubes: Ptfe heat shrinkable tubes, Fep heat shrinkable tubes, Pfa heat shrinkable tubes, Pvdf heat shrinkable tubes; ③ Plate rod film: Ptfe plate rod film, Feep plate rod film, Pfa plate rod film, Pvdf plate rod film, etc. PE: PE, special, spiral tube, spring tube, rotary cutting tube, welding rod, tee, straight, gasket, joint, cone rod, flared tube, sealing tube, braided tube, corrugated tube, etc. At the same time can be customized according to customer requirements processing production of various specifications of fluorine plastic products.
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