What should be considered when designing PET preforms?

The temperature of the PET preform mold is precisely controlled to prevent warping. Deformation is an important factor, therefore the use of a hot runner mold is recommended. The tool temperature should be high, otherwise there will be poor surface gloss and difficulties in demolding.

What are the material properties of PET preforms?

What should be considered when designing PET preforms?

How do I set the temperature when using PET preforms?

What are the material properties of PET preforms?

1.When the PET preform is formed, the returned material should be completely dried and not thermally degraded, and the amount added should not exceed 20% .

2.The rheology of the PET preform in the molten state is non-Newtonian, and the temperature has little influence on the melt viscosity. The pressure can be adjusted to increase the shear stress or shear rate.

3. PET has an obvious melting point. The processing temperature range of PET preform mold is narrow, 270 to 290 ℃, and thermal deterioration occurs when it exceeds 300 ℃.

4.The pressure holding time during PET molding should not be too long, otherwise the internal tension will increase, generally 20 to 50 seconds.

5.Since the solidification of the PET preform mold melt is fast, high-speed injection should be used to prevent the melt from filling the mold cavity as quickly as possible.

6.PET, like PBT, is very sensitive to sharp corners and notches. These areas tend to stress concentrations, which greatly reduce the load-bearing capacity and tend to break under force or impact. Therefore, an arc transition should be used as far as possible at these points.

What should be considered when designing PET preforms?

To prevent poor backflow or uneven cooling, resulting in poor plastic forming, surface defects and deterioration; In general, the following points must be considered when designing tools:

1.The wall thickness should be as uniform as possible and the deformation tendency large enough;

2. The transition part should be gradual. Smooth transition to avoid sharp corners and burrs, especially PC products must not have gaps;

Third goal. The sprue should be as wide and stubborn as possible, the sprue position adjusted according to the shrinkage and condensation process and, if necessary, the sprue position should be adjusted. be supplemented with a cold well;

4.The surface of the PET preform should be smooth and of low roughness (preferably below 0.8);

5. Exhaust holes. The tank must be sufficient to remove air and gas in the melt in time;

6.Except for PET, the wall thickness should not be too thin, generally not less than 1mm.

How do I set the temperature when using PET preforms?

①Temperature setting: Nozzle: 280~295℃, front section 270~275℃, medium forging 265~275℃, rear section 250-270℃; Screw speed 50~100 rpm, mold temperature 30~85℃, amorphous type The mold is below 70℃ and the back pressure is 5-15 kg.

② Try the dehumidification dryer, the temperature of the material pipe is 240,280 ℃, the injection pressure 500,1400 ℃, the injection molding temperature 260,280 ℃, the drying temperature 120,140 ℃ and the time 2~5 hours.

With 16-years export experience, our company is a professional manufacturer and exporter engaged in the design, development and production of PVC raw materials.