The following shows typical molding conditions such as recommended molding conditions and condition ranges for SUMIKASUPER LCP.
Resin temperature control is very important for SUMIKASUPER LCP. If there is a difference between the set temperature for the cylinder and the actual resin temperature, it is necessary to control it using the actual resin temperature.

Table 4-1-1 Standard Molding Conditions for SUMIKASUPER E5000, E4000, and E6000 series

		E5000 series		E4000 series		E6000 series
		Recommended	Range	Recommended	Range	Recommended	Range
Drying temperature (°C)		130	120-140	130	120-140	130	120-140
Drying time (hr)		5	4-24	5	4-24	5	4-24
Cylinder temperature (°C)	Rear	340	330-360	320	310-340	300	280-320
	Center	380	370-390	360	350-370	330	320-340
	Front	400	390-410	380	370-390	360	340-370
	Nozzle	400	390-410	380	370-390	360	340-370
Suitable resin temperature (°C)		400	390-410	380	370-390	360	340-370
Tool (Mold) temperature (°C)		70-90	60-160	70-90	60-160	70-90	60-160
Injection pressure (MPa)		120-160	80-160	120-160	80-160	80-160	80-160
Holding pressure (MPa)		40-60	10-80	40-60	10-80	10-40	10-80
Holding time (sec)		0.2-0.5	0.2-1	0.2-0.5	0.2-1	0.2-0.5	0.2-1
Back pressure (MPa)		0.5-1	0.5-5	0.5-1	0.5-5	0.5-1	0.5-5
Injection speed (mm/sec)		50-200	50-400	50-200	50-400	50-200	50-400
Screw rotation (rpm)		50-250	50-350	50-250	50-350	50-250	50-350
Sack back (mm)		1-2	0-2	1-2	0-2	1-2	0-2

Table 4-1-2 Standard Molding Conditions for SUMIKASUPER SV6000, SR1000, E6000HF, SV6000HF, SZ6000HF, and SR2000 series

		SV6000, SR1000 series		E6000HF, SV6000HF series		SZ6000HF, SR2000 series
		Recommended	Range	Recommended	Range	Recommended	Range
Drying temperature (°C)		130	120-140	130	120-140	130	120-140
Drying time (hr)		5	4-24	5	4-24	5	4-24
Cylinder temperature (°C)	Rear	300	280-320	300	280-320	300	280-320
	Center	330	320-340	330	320-340	330	320-340
	Front	360	340-370	350	340-370	350	330-370
	Nozzle	360	340-370	350	340-360	350	330-360
Suitable resin temperature (°C)		360	340-370	350	330-360	350	330-360
Tool (Mold) temperature (°C)		70-90	60-160	70-90	60-160	70-90	60-160
Injection pressure (MPa)		80-160	80-180	80-160	80-180	80-160	80-180
Holding pressure (MPa)		10-40	10-80	10-40	10-80	10-40	10-80
Holding time (sec)		0.2-0.5	0.2-1	0.2-0.5	0.2-1	0.2-0.5	0.2-1
Back pressure (MPa)		0.5-1	0.5-5	0.5-1	0.5-5	0.5-1	0.5-5
Injection speed (mm/sec)		50-200	50-500	50-200	50-500	50-200	50-500
Screw rotation (rpm)		50-250	50-350	50-250	50-350	50-250	50-350
Sack back (mm)		1-2	0-2	1-2	0-2	1-2	0-2

Pre-drying

SUMIKASUPER LCP has a very low water absorption rate of 0.02%, so it does not require a long drying time. However, it is recommended to dry it to 0.01% to obtain the best physical properties for molding. It is recommended to dry it using a hopper dryer between 4 to 24 hours at around 130°C. Use a dehumidification dryer or hopper dryer to prevent moisture absorption in the hopper during molding. If the drying temperature is too high, the resin may deteriorate, so make sure that the drying temperature is around 130°C.

Figure 4-1-1 Drying Curve of SUMIKASUPER LCP

Measuring device : MS-70 Heating dry type moisture meter
(Manufactured by A&D Company, Limited)

Molding Temperature Setting

(1) Temperature of front part of cylinder and nozzle part

This is true for all resins, but it is necessary to properly control the resin temperature. Set the temperature at the front of the SUMIKASUPER LCP cylinder to 390 to 410°C for the E5000 series, 370 to 390°C for the E4000 series, 340 to 370°C for the E6000, SV6000, and SR1000 series, and to 330 to 360°C for the E6000HF, SV6000HF, SZ6000HF, and SR2000 series. When forming a complicated shape requiring high flowability, or a large item with a great difference between the long and short axes, set the front of the cylinder to a higher temperature. It is not recommended to set the temperature to more than 10°C above the applicable range because backflow to the hopper side tends to occur with the resin during injection.
Regarding the cylinder temperature, stable physical properties can be obtained at a molding temperature of 400°C or higher with the E5000 series, 380°C or higher with the E4000 series, 340°C or higher with the E6000, SV6000, and SR1000 series, and 330°C or higher with the E6000HF, SV6000HF, and SR2000 series. For some applications, it is possible to obtain non-problematic physical properties even when molding is performed at lower temperatures, but if the temperature is too low, physical properties may deteriorate.
It is very important to control the temperature of the nozzle since it can easily affect the resin temperature. Therefore, be sure to consider the position of the temperature control sensor and heat retention. If there is a difference between the set nozzle temperature and the actual resin temperature, it is necessary to control it using the actual resin temperature. If the nozzle temperature is too high, drooling and stringing can occur, and if it is too low, cold slag can occur.

(2) Cylinder rear temperature

The temperature at the rear of the cylinder for SUMIKASUPER LCP should be lower than that at the front of the cylinder. Set it to 330 to 360°C for the E5000 series, 310 to 340°C for the E4000 series, and 280 to 320°C for the E6000, SV6000, SR1000, E6000HF, SV6000HF, SZ6000HF, and SR2000 series. When the cylinder rear temperature is high, the resin tends to backflow to the hopper side, which makes it difficult to get a stable metering.

Figure 4-1-2 Dependence of Tensile Strength on Molding Temperature

Injection Pressure and Injection Speed

(1) Injection pressure

SUMIKASUPER LCP has low melt viscosity and excellent flowability, so it does not require an extremely high injection pressure. For example, with the E6000 series, by raising the molding temperature to at least 350°C, sufficient flowability is achieved even at a low pressure of about 40MPa. Since the resin quickly solidifies, there is almost no impact on tensile strength even if the holding pressure changes in the range of 65 to 160MPa.

(2) Injection speed

For thin-walled complicated shapes, it is better to perform moldings at medium to high injection speeds. When molding ultra-thin products (0.2mm or less), the resin may solidify at thin portions, and thus may not be possible to achieve a sufficient flow length. Therefore, it is recommended to use high performance injection molding machines that enable high speed and high response (refer to “High-speed molding”(High-Speed Injection Molding)).
SUMIKASUPER LCP can be molded even at a constant injection speed. However, in order to avoid jetting from the nozzle and the gate, it would be better to lower the injection speed while the resin passes through the sprue or runner, raise the injection speed after passing through the gate. Lowering the injection speed just before filling is completed can also be effective to ensure stable molding.
If there are problems related to the weldlines on relatively thick products, a medium/low injection speed of 20 to 60mm/sec with the appropriate air vent design in the mold would improve them.

Mold temperature

The molecular structure of SUMIKASUPER LCP is rigid rod-like even in the molten state, and its molecules are easily oriented in the flow direction by the shear flow during injection molding. When the molten LCP is cooled in the mold, it can solidify rapidly while maintaining its molecular orientation. Since the solidification rate of SUMIKASUPER LCP is very high, the mold temperature has almost no impact on its properties. Therefore, injection molding can be performed at a very wide range of mold temperatures.
When molding thin-walled products, it is recommended to set the mold temperature to 60 to 100°C if the priority is placed on the molding cycle, 100 to 150°C if the flowability and the weld strength for the thin wall are important, and set it to 160°C or higher if the smoothness of the molded product surface is important. When the product shape is complicated and there are issues with mold release, it is recommended to set the mold temperature to a lower temperature. The surface temperature of the mold is affected by various factors other than the cooling water, so be sure to measure and check it when starting up the injection molding machine or when making major setting changes.

Figure 4-1-3 Dependence of typical properties on mold temperature

Metering (Plasticization) Setting

In order to ensure stable metering (plasticization) of SUMIKASUPER LCP, the temperature at the rear of the cylinder should be lower than that at the front of the cylinder. The recommended temperature range at the rear of the cylinder is 330 to 360°C for the E5000 series, 310 to 340°C for the E4000 series, and 280 to 320°C for the E6000, SV6000, SR1000, E6000HF, SV6000HF, SZ6000HF, and SR2000 series.
It is possible to shorten the metering time by setting a high screw rotation speed. However, if the screw rotation speed is too high, fillers such as glass fiber may be damaged. For small-diameter screws, the metering capacity is determined by the flight depth of the feed zone , and so refer to "Selection of Injection Molding Machine" and select the suitable screw.
Since the metering tends to be more stable when the back pressure is low, set this value as low as possible.

Suck-back

Suck-back (screw decompression) should be set to the minimum value when necessary. If the suck- back is too large, air can easily get caught in the nozzle, resulting in molding defects such as blisters. Drooling from the nozzle can be controlled by adjusting the drying temperature of the resin and the nozzle temperature, or, if necessary, using a dedicated nozzle for LCP.

Purging Method

Since SUMIKASUPER LCP has extremely low melt viscosity compared to other resins including purging materials, it is necessary to make sure there is no residual resins or purging materials in the cylinder or nozzle when replacing them by purging. To make it easier to replace the SUMIKASUPER LCP during purging, it is recommended to lower the cylinder temperature by about 20 to 30°C compared to normal molding condition in order to increase the melt viscosity of SUMIKASUPER LCP. When performing purging, especially for the E4000 series and E5000 series, please keep in mind that due to the high processing temperature, there may smoke or blow out of gas or resin from the nozzle.

Recommended Purging Material

Commercially available purging materials can be used for the purging of SUMIKASUPER LCP, and the following purging materials have been proven in use. Please note that purging material may decompose if it remains in a high temperature cylinder for a long time.

• ASACLEAN PX2 [Asahi Kasei Corporation]
• Z CLEAN S29 [Nissho Corporation]
• CELPURGE NX-HG [Daicel Miraizu Ltd.]

When the same grade is used after molding is suspended

If molding needs to be suspended for 15 minutes or more, discharge the resin from the cylinder and lower the cylinder temperature to about 250°C. When resuming molding, perform purging according to the following procedure. If the injection molding process is restarted using the same grade after the machine has been shut down for several hours, the following purging procedure can also be applicable.

Table 4-1-3 Purging procedure when injection molding is suspended or shutdown

1 End of molding	Discharge the prior resin completely from the hopper and inside the cylinder.
2 Purging material input	Purge with a purging material at molding temperature.
3 Purge continuation	Set the cylinder temperature to 20 to 30°C lower than molding temperature.
4 Resin replacement	Supply SUMIKASUPER LCP immediately after discharging the purging material. Replace the inside of the cylinder with SUMIKASUPER LCP.
5 Operation suspended	Set the cylinder temperature to 250°C, or Shutdown the injection molding machine.
6 Resume operation	Set the cylinder temperature to 20 to 30°C lower than molding temperature.
7 Pre-purging	Purge with SUMIKASUPER LCP (at least 5 shots) while maintaining the temperature 20 to 30°C lower than the molding temperature.
8 Start of production	Purge the cylinder with at least 5 shots of SUMIKASUPER LCP after the cylinder temperature has been raised to the molding temperature and start production. (Note) When only changing the color of the same grade, skip steps 5, 6, and 7 above.

When switching to SUMIKASUPER LCP from other resins

When molding of the prior resin is completed and changing it to SUMIKASUPER LCP, perform the following procedure.

Table 4-1-4 Purging procedure when switching materials to SUMIKASUPER LCP

1 End of molding	Discharge the prior resin completely from the hopper and cylinder.
2 Cylinder temperature set	Set the cylinder temperature to 20 to 30°C lower than molding temperature.
3 Purging material input	Purge with a purging material immediately after the temperature reaches to the above set point.
4 Resin replacement	Supply SUMIKASUPER LCP immediately after discharging the purging material. Replace the inside of the cylinder with SUMIKASUPER LCP.
5 Resume operation	Set the cylinder temperature to the molding temperature of SUMIKASUPER LCP.
6 Start of production	Purge the cylinder with at least 5 shots of SUMIKASUPER LCP after the cylinder temperature has been raised to the molding temperature, and start production.

Flash Characteristics

Figure 4-1-5 Comparison of the range of molding conditions that do not cause flash for LCP, PPS, and PBT

Molding machine : PS10E1ASE (Nissei Plastic Industrial Co., Ltd.)
Injection speed : 32cm3/sec
Injection pressure : 100% = 200MPa