Flowability

Flowability of SUMIKAEXCEL PES improves greatly as the cylinder temperature, injection pressure, and wall thickness of molded products increase. However, mold temperature does not have a major impact. If mold release failure, glass fiber floating or weld cracking occurs, it is recommended to increase the mold temperature to 160°C or higher.

Apparent Melt Viscosity

The apparent melt viscosity of SUMIKAEXCEL PES is as follows.

Molding of Relatively Thick-Walled Products

This section focuses on the flow characteristics at a wall thickness of 3mm.

Effect of Cylinder Temperature

When the cylinder temperature increases, the melt viscosity of the resin decreases and the flowability improves. The bar flow length improves by 30 to 60% when it is set 20°C higher.

Figure 4-2-3 Temperature Dependence of Bar Flow Length

Effect of Injection Pressure

The bar flow length improves by 10 to 20% when the injection pressure is set 20 MPa higher. High-pressure molding is generally recommended, but carefully check for mold release defects and residual stress due to overpacking. Select appropriate conditions by setting the secondary pressure.

Figure 4-2-4 Dependence of Bar Flow Length on Injection Pressure (4100G)

Effect of Injection Speed

Injection speed does not have a significant effect on the bar flow length.

Figure 4-2-5 Dependence of Bar Flow Length on Injection Speed (4100G)

Effect of Product Wall Thickness

Flow length increases sharply with wall thickness. When the wall thickness is 1.5mm or higher, flowability can be improved 40 to 70% by increasing the wall thickness by 0.5mm.

Figure 4-2-6 Effect of Wall Thickness on Bar Flow Length (4100G)

Molding of Thin-Walled Products

This section describes the flow characteristics at wall thickness of 0.1 to 0.7mm.

Effect of Cylinder Temperature

Flowability improves as the cylinder temperature increases, but this effect decreases when the wall thickness is 0.3mm or less. Considering the effects of thermal degradation, a temperature of up to about 380°C is suitable.

Figure 4-2-9 Cylinder Temperature Dependence
(Thickness: 0.3mm)

Effect of Product Wall Thickness

The flowability depends on the wall thickness, so please pay attention to this when designing your product.

Effect of Injection Pressure

Thin-wall flowability tends to be greatly affected by injection pressure. Injection pressure of at least 100MPa is recommended. However, it is required to determine the proper injection pressure by taking product appearance and residual stress into consideration.

Effect of Injection Speed

Thin-wall flowability is not affected by injection speed so much. If the injection speed is too high, it may cause defects such as burns.

Effect of Mold Temperature

Thin-wall flowability is not affected by mold temperature so much. However, it is recommended to raise the mold temperature to at least 160°C if problems such as sticking in the mold, poor surface appearance, or low weld strength occur.