<li id="jugbo"><object id="jugbo"></object></li>

  • <dd id="jugbo"><noscript id="jugbo"></noscript></dd>
      <th id="jugbo"></th>
      <dd id="jugbo"></dd>
      <button id="jugbo"></button>
        1. <dd id="jugbo"></dd>

              1. Pro Classification  

                 

                  Address: West City Industrial Park Dinghai,Zhoushan City,Zhejiang,China

                  Tel: +0086-580-2363797

                  Fax: +0086-580-2364972

                  Mobile: +86-13906804927

                  E-mail: sales@zstaisu.com

                >>News

                 

                zstaisu.com

                Screw is the main factors affecting the quality of plastics
                Views: 7404 AddFavoritePrint

                The main factors affecting the quality of plastics are: aspect ratio, compression ratio, back pressure, screw speed, barrel heating temperature.

                1, aspect ratio: for the effective working length of the screw and screw diameter ratio.

                a, large aspect ratio is even easy to eat the material;
                b, better thermal stability of the plastic can be used to improve the longer screw without mixing of the burning, poor thermal stability of the plastic can be shorter end of the screw or screw without thread. Plastic properties to consider, such as under the general stream length: thermosetting 14 \ '16, rigid PVC, PU and other heat-sensitive high viscosity of 17 \ '18, usually plastic to 18 \ '22, PC, POM and other high-temperature stability of plastic 22 \ '24.

                2, compression ratio: the feed section of a spiral groove depth of the last paragraph with the measurement of the ratio of the depth of a spiral groove.
                a, consider the compression of material, filling level, back and other affected products to be dense, heat and exhaust;
                b, the appropriate compression ratio can increase the density of plastic, so that the molecules and between molecules more closely to help reduce the air absorb and reduce the stress generated due to temperature rise and affect the output of the difference, inappropriate compression than would destroy the physical properties of plastics;
                c, the higher the compression ratio, the plastic tube in the plastics material produced during the higher temperature, the plastic in the plastics results in better mixing uniformity, greatly reduced relative to the fluxes.
                d, high compression ratio for easy melting plastic, especially a low melt viscosity, thermal stability of plastics; low compression ratio suitable for fusible plastic, especially with high melt viscosity, heat-sensitive plastic.

                3, the back pressure
                a, increase the back pressure can increase the screw on the work done by the molten resin to remove the plastic particles without melting, increasing raw material tube density and uniformity;
                b, back pressure is being applied to improve the barrel temperature, the effect is most significant;
                c, back pressure is too large, the higher the heat-sensitive plastic decomposition, the low viscosity of the plastic may cause salivation phenomenon, back pressure is too small, injection molding of the finished product may be air bubbles.

                4, screw speed
                a, screw rotation speed directly affects the plastic shear in the screw slot;
                b, small screw groove shallow absorption heat quickly enough to promote plastic softening in compression time, the screw and barrel wall of the lower heat of friction, suitable for high-speed rotation, increased plasticizing capability;
                c, large screw rotation is not fast, so as not to cause excessive friction plastics and uneven heat;
                d, the higher the heat-sensitive plastic, screw speed too much, then, the plastic can easily break down;
                e, usually of a certain size screw speed range, the general speed of 100 \ '150rpm; too low you can not melt the plastic, too much plastic will be burned.

                5, the heating temperature setting
                a, so stay in the barrel and screw the screw rotation chilled molten plastic in order to facilitate and provide molten plastic to obtain the necessary part of the heat;
                b, set the temperature lower than the melt 5 \ '10 ​​(provided in part by the friction heat);
                c, the adjustment of the nozzle temperature can also be used to control salivation, condensed material (plug Tsui), pull wire and other issues;
                d, crystalline plastics are generally temperature control:

                Plastic types
                 Barrel temperature
                 Injection Pressure kgf/cm2
                 
                HDPE (High Density Polyethylene)
                 180 \ '210
                 500 \ '1500
                 
                PP (polypropylene)
                 200 \ '270
                 400 \ '1000
                 
                PA6 (Nylon 6)
                 225 \ '280
                 700 \ '1000
                 
                PA66 (nylon 66)
                 260 \ '280
                 600 \ '1500
                 

                e, non-crystalline plastic

                Plastic types
                 Barrel temperature
                 Injection pressure kgf/cm2
                 
                PS (polystyrene)
                 180 \ '240
                 400 \ '1300
                 
                ABS (acrylonitrile butadiene styrene)
                 200 \ '230
                 800 \ '1500
                 
                PMMA (polymethyl methacrylate)
                 180 \ '220
                 700 \ '1500
                 
                PC (polycarbonate)
                 260 \ '310
                 800 \ '1500
                 
                Modified PPO (Noryl)
                 240 \ '280
                 850 \ '1400
                 
                Rigid PVC (rigid PVC)
                 165 \ '185
                 1000 \ '1500
                 

                Note: a, do not add more to the non-glass fiber reinforced plastic.

                b, the barrel melt temperature is usually higher than the tube outside the control of the temperature.

                久在线中文字幕乱码免费,tube性老少配bbwxxxx...,理论片免费ā片在线观看,老师亲自示范性课h