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1、HOME Technical support Molding technology Molding technology for VECTRASafetyPredryingSelection of Molding MachineMolding ConditionsUse of RegrindSelection of Molding MachineMold Designing 1Safety1.1Safety PrecautionsThere is no danger in molding VectraTM so long as the general safety rules of moldi
2、ng operation are observed. However, like all other plastics, VectraTM produces decomposed substances when heated to a very high temperature. If ventilation is inadequate, such decomposed substances are built up to cause hazardous conditions to health. So, suitable ventilation is recommended.Do not r
3、aise the polymer temperature over 350 for VectraTM of A, B and C grades and 370 for E grades in order to prevent thermal decomposition, gas emission and pressure build up in the cylinder. These temperatures are much higher than the given molding conditions that it is normally unnecessary to heat the
4、 material at such temperatures. When molding is interrupted for a short time, it is possible to leave the material at the molding temperature, but when restarting, such a material must be thoroughly purged. When molding is interrupted for longer than 30 minutes, lower the temperature 50 below the mo
5、lding temperature.Before feeding pellets or starting the screw, allow sufficient time for cylinder heating, or wait until the temperature reaches the point 10 below the molding temperature of each grade. Operators must wear protective goggles (especially when purging). Wear hand gloves when handling
6、 a hot mold. When the machine is stopped, withdraw the injection unit to keep away from the mold to prevent solidification of the material in the nozzle section. 1.2Starting and Stopping the Molding Machine and Exchanging the Molding Material1.2.1Stopping the Molding MachineAfter purging VectraTM, a
7、nd while retaining the VectraTM molding temperature, the cylinder should be purged with a resin with the same molding temperature and good thermal stability. (Polypropylene, high-density polyethylene or acrylic type purging materials on the market are recommended.) If VectraTM is to be subsequently
8、molded, the cylinder can be purged with VectraTM. (Confirm the molding temperature ranges of the grades.)1.2.2Starting the Molding MachineIn starting up a machine containing another resin that is stable within the VectraTM molding temperature range, the cylinder temperature can be raised to this lev
9、el and purging can be done with VectraTM. VectraTM, however, has a very low melt viscosity, which makes purging difficult, so that very thorough purging is required. For efficient purging, first purge with glass fiber filled polycarbonate, then with VectraTM.When the resin remaining in the cylinder
10、has the different molding temperature range, the following steps should be carried out: Set the cylinder temperature at the molding temperature of the remaining resin.Purge the cylinder with purging material that has good thermal stability and can be used in the molding temperature ranges of both Ve
11、ctraTM and the remaining resin (for example, polypropylene, high-density polyethylene, or polycarbonate, as the case may be).Change the cylinder temperature at the VectraTM molding level and purge the cylinder again according to the instructions for a resin stable in the VectraTM molding temperature
12、 range.In most cases, when VectraTM is the resin remaining in the cylinder, it is possible to raise the cylinder temperature to the VectraTM molding level and to purge with VectraTM. However, as the molding temperature ranges of VectraTM grades differ, confirm the molding temperature ranges of remai
13、ning VectraTM grade and purging VectraTM grade prior to purging. If the remaining resin is VectraTM, but is of a different grade and has a different molding temperature range from the replacement VectraTM, purge the cylinder as with any other resin that has a different molding temperature range.1.2.
14、3Changing the Molding MaterialWhen the resin has the same molding temperature range as VectraTM, purge the cylinder at the molding temperature, following the same procedures used in starting and stopping the molding machine.When the resin cannot be placed under the same molding condition, it is reco
15、mmended to purge the cylinder with a resin that can be used at the molding temperatures of both VectraTM and the replacement, and has good thermal stability (e.g. polypropylene or high-density polyethylene).Then set the cylinder temperature at the replacement resin molding level.When the resin remai
16、ning in the cylinder has a higher viscosity than that of VectraTM, it is quite difficult to replace it with VectraTM. Very thorough purging is required.1.2.4OtherIf VectraTM remains in the cylinder for a long time, degradation and contamination may occur. Very thorough purging is required.When it is difficult to purge dark colored materials such as black coloring materials, purging should be done with glass
