Injection Molding Conditions for SUMIKASUPER LCP

General Molding Conditions

  E5000
Series
E4000
Series
E6000
Series
E6000HF
Series
Pre−drying Temperature about 130 deg C
Time 4 to 24 hours
Cylinder temperature(deg C) Rear 350~370 330~350 280~320 280~320
Center 370~390 350~370 320~350 320~340
Front 390~410 370~390 340~370 340~360
Nozzle 390~410 370~390 340~370 340~360
Suitable resin temperature(deg C) 400 380 360 350
Tool Temperature(deg C) 40~160
Injection pressure(MPa) 120~160 80~160
Hold pressure(MPa) 40~60 20~40
Screw back−pressure(MPa) 1~5
Injection speed Middle~High
Screw revolution(rpm) 50~100

If the cylinder temperature setting differs from the actual resin temperature, product molding should be controlled by the actual resin temperature.

Pre−drying

It is not necessary to dry SUMIKASUPER LCP for a long time, as it has extremely low water absorption of 0.02%. In general, the drying time required is between 4 hours and 24 hours, when a hopper dryer is utilized at a temperature of approximately 130 deg C.

Molding Temperature

The temperatures for the front of the cylinder and the nozzle area must be set as follows; 390~410 deg C for the E5000 series; 370~390 deg C for the E4000 series; 340~370 deg C for the E6000 series; and 340~360 deg C for the E6000HF series. The temperatures of these areas should not be greater than these values, as resin will tend to backflow toward the hopper during injection. In particular, when molding products that have complex shapes requiring high moldability, or when molding products with a high L/T, the temperature of the nozzle area must be set higher than that of the front cylinder area. Furthermore, if the metering time does not stabilize, decrease the temperature at the rear of the cylinder by 10~20 deg C. As proper control of nozzle temperature is extremely important, ensure that the temperature adjustment sensor is correctly positioned and that the appropriate temperature is always maintained.
If a discrepancy exists between the nozzle temperature setting and the actual resin temperature, then molding must be controlled at resin temperature.
In order to ensure consistent physical properties of SUMIKASUPER LCP, the ideal molding temperature for each product type is as follows: 400 deg C or greater for the E5000 series; 380 deg C or greater for the E4000 series; 340 deg C for the E6000 series; and 340 deg C or greater for the E6000HF series. Even if molding is performed at temperatures lower than these guidelines, it is still possible to obtain physical property performance levels that are adequate for effective product use, depending upon the particular application. However, if the molding temperature is reduced excessively, physical properties will also become degraded (Figure 1 and Figure 2).

Figure 1 :
Tensile Strength Dependency on Molding Temperature
Figure 1 : Tensile Strength Dependency on Molding Temperature
Tool Temperature : 130 deg C
Injection pressure : ca. 130MPa (ca. 1300kg/cm2)
Injection speed : Medium
Figure 2 :
Mold Shrinkage Dependency on Molding Temperature
Figure 2 : Mold Shrinkage Dependency on Molding Temperature
Tool Temperature : 130 deg C
Injection pressure : ca. 130MPa (ca. 1300kg/cm2)
Injection speed : Medium

Mold Temperature

As the molecules of SUMIKASUPER LCP are rigid, there does not happen the entanglement of each molecular. The polymer chains become oriented in the flow direction due to shearing forces at the time of molding. In addition, as solidification occurs extremely rapidly, this orientation is maintained throughout the setting process. Therefore, the mechanical properties are only slightly affected by the temperature of the mold.
When molding thin−walled products and when greater importance is placed on the molding cycle, the tool temperature should be set to 70~100 deg C. When the weld strength and moldability of thin−walled products is to be considered, it is recommended that the temperature be set to 120~150 deg C. When priority is placed on surface smoothness of moldings, it is recommended that the temperature be set to 160~190 deg C.

Figure 3 : Mold Temperature vs Physical Properties

Figure 3 : Mold Temperature vs Physical Properties

Injection Pressure and Injection Speed

SUMIKASUPER LCP does not require high injection pressures, as it possesses low melt viscosity and high moldability. Using the E6000 series products as an example, raising the molding temperature to 350 deg C or greater enables the products to demonstrate adequate moldability, even under a low pressure of approximately 40 MPa. In addition, even if injection pressures are changed through the range from 65-160 MPa, changes to resulting tensile strengths are minimal.
The ideal injection speed for products having thin walls and complex shapes is a medium to high speed. However, when molding products that have thicker walls where weld sections are critical, a medium to low speed of 20-40 mm/sec is recommended for use, along with the consideration of air venting within the mold.

Purging Methods

Purging methods for SUMIKASUPER LCP are explained here.
Recommended purging agents : Amte Clean AP series [manufactured by Amtec corporation]

The following precautions must be taken when performing purging operations:

  • Please note that E4000 and E5000 series grades require high processing temperatures, thus may cause fuming, gas emission and resin scattering.
  • Ensure that none of the purging agent is left in the cylinder.

When Using the Same Grade

1 End of molding Shoot out all remaining resin (from within both hopper and cylinder).
2 Feeding of purging agent Perform purging while maintaining the cylinder temperature at the molding temperature.
3 Continuation of purging Set the cylinder temperature to a temperature 20-30 deg C lower than the molding temperature.
4 Displacement of resin As soon as all purging agent has been shot out, immediately feed in the SUMIKASUPER LCP, to displace the cylinder contents with SUMIKASUPER LCP.
5 End of operation Turn OFF the power. (It is OK to power down while the temperature is decreasing.)
6 Resumption of operation Turn ON the power.
Set the cylinder temperature to a temperature 20-30 deg C lower than the molding temperature.
7 Pre-purging Perform purging using SUMIKASUPER LCP (5 shots) at a cylinder temperature that is 20-30 deg C lower than the molding temperature.
8 Start of production Raise the cylinder temperature to the molding temperature.

Note) When using different colored resins from the same SUMIKASUPER LCP grade, please omit the above procedures 5, 6 and 7.

Switching to SUMIKASUPER LCP

1 End of molding Shoot out all preceding resin (from within both hopper and cylinder).
2 Raising of cylinder temperature Set the cylinder temperature to a temperature 20-30 deg C lower than the molding temperature for SUMIKASUPER LCP.
3 Feeding of purging agent As soon as the temperature has risen to the above temperature setting, immediately begin feeding the purging agent.
(Note) Once the temperature has increased, ensure that the rotation prevention mechanism does not become actuated.
4 Displacement of resin As soon as all purging agent has been shot out, immediately feed in the SUMIKASUPER LCP, to displace the cylinder contents with SUMIKASUPER LCP.
5 Resumption of operation Set the cylinder temperature to the molding temperature for SUMIKASUPER LCP.
6 Start of production After the cylinder temperature has risen, purge with at least 5 shots of SUMIKASUPER LCP prior to starting production.

Flashing Defect

SUMIKASUPER LCP produces minimal level of flash. This property makes it suitable for the molding of compact electronic components that have thin walls. Figure 5 depicts evaluations of flashing defect for SUMIKASUPER LCP, using the tool shown in Figure 4. Figure 5 indicates both narrow and broad molding window (i.e., areas where short shots defect and flashing defect occur). SUMIKASUPER LCP has a broad "molding window" where short shots defect and flashing defect do not occur. However, with PPS and PBT, flash is often occurred and the molding window is quit narrow when molding thin-walled products.

Figure 4 : Tool for Evaluation of Flash Properties

Figure 4 : Tool for Evaluation of Flash Properties

Figure 5 : Flash Properties of Various Engineering Plastics (0.5/0.3mm Double Thicknesses)

(a)SUMIKASUPER LCP E6008

Figure 5 for SUMIKASUPER LCP E6008 : Flash Properties of Various Engineering Plastics (0.5/0.3mm Double Thicknesses)

(b)PPS(40%)

Figure 5 for PPS(40%) : Flash Properties of Various Engineering Plastics (0.5/0.3mm Double Thicknesses)

(c)PBT(30%)

Figure 5 for PPS(30%) : Flash Properties of Various Engineering Plastics (0.5/0.3mm Double Thicknesses)
Molding machine : JUshi Kogyo PS10E1ASE
Injection speed : 32cm2/sec.
Injection pressure : 100%=2015kg/cm2
Inquiries about SUMIKASUPER LCP