Precautions in molding

Injection molding and drying conditions for U polymers,
and precautions in molding

Brand	Cylinder temperature (°C)				Limit temperature (°C)	Mold temperature (°C) (actual surface temperature)	Back pressure (kgf/cm²) (gage pressure)	Drying temperature (°C)	Drying period (hr)
Brand	Nozzle	Front	Middle	Rear	Limit temperature (°C)	Mold temperature (°C) (actual surface temperature)	Back pressure (kgf/cm²) (gage pressure)	Drying temperature (°C)	Drying period (hr)
U-100	350~ 370	350~ 370	340~ 360	310~ 330	390	120~140	5~15	140	6~24
UG-100-20	350~ 370	350~ 370	340~ 360	310~ 330	390	120~140	5~15	140	6~24
UG-100-30	350~ 370	350~ 370	340~ 360	310~ 330	390	120~140	5~15	140	6~24
P-1001	350~ 370	350~ 370	330~ 350	310~ 330	390	120~140	5~15	140	6~24
P-3001	330~ 350	330~ 350	320~ 340	290~ 310	370	110~130	5~15	140	6~24
P-5001	310~ 330	310~ 330	300~ 320	270~ 290	350	100~120	5~15	140	6~24
P-1001A	350~ 370	350~ 370	330~ 350	310~ 330	390	120~140	5~15	140	6~24
P-3001S	330~ 350	330~ 350	320~ 340	300~ 320	380	100~120	5~15	140	6~24
L-1003PA	350~ 370	350~ 370	330~ 350	310~ 330	390	120~140	5~15	140	6~24
PT-3020	330~ 350	330~ 350	320~ 340	290~ 310	370	110~130	5~15	140	6~24
C300VN	300~ 320	300~ 320	280~ 300	260~ 280	330	100~120	5~15	130	6~24
U-8000	270~ 290	270~ 290	260~ 280	250~ 270	300	70~90	5~15	110	10~24
U-8400H	250~ 270	250~ 270	240~ 260	230~ 250	290	50~70	5~15	100	10~24
L-8005	270~ 290	270~ 290	260~ 280	250~ 270	300	70~90	5~15	110	10~24
LM-8503-10	250~ 270	250~ 270	240~ 260	230~ 250	290	70~90	5~15	100	10~24
FUN-8000	280~ 300	280~ 300	270~ 290	260~ 280	310	70~90	5~15	120	8~24
UM-8400-20	250~ 270	250~ 270	240~ 260	230~ 250	290	70~90	5~15	100	10~24
UM-8430RG	250~ 270	250~ 270	240~ 260	230~ 250	290	70~90	5~15	100	10~24
AX-1500	250~ 270	250~ 270	240~ 260	210~ 230	290	70~90	5~15	100	10~24
AXG-1500-30	250~ 270	250~ 270	240~ 260	210~ 230	290	80~120	5~15	100	10~24
AXF-1500-05	250~ 270	250~ 270	240~ 260	210~ 230	290	70~90	5~15	100	10~24
AX-1500W	230~ 250	230~ 250	220~ 240	200~ 220	290	40~60	5~15	100	10~24

* If the cylinder temperature indicated above is not high enough to provide the material with desirable flowability, the temperature may be raised up to the limit temperature to improve flowability.
* Proper setting of the screw back pressure is effective for improving blending efficiency and for removal of gases, and thus make sure to set a suitable back pressure.
* If a hot-air-circulating tray drier is used, place and dry the pellet in a layer with a thickness of 3 cm or less under the condition above.
* Use of a dehumidifier, reduced-pressure or vacuum type drier allows more efficient drying.
* The water content of the resins other than the AX series should be less than 200 ppm, and those of the AX series, less than 2000 ppm.
* Make sure to heat the hopper immediately above molding machine, for example, by employing a hopper drier, for the purpose of raising the temperature of the pellets therein to the drying temperature and preventing them from absorbing moisture.
* As the resins are ester resins, presence of excessive water leads to hydrolysis of the resins during heat processing, decrease in the molecular weight of the resins, and consequently decrease in the quality of molded products. Comply strictly with the drying condition indicated above, and take notice of reabsorption of water during molding.
* Lower mold temperature may result in residual strains at the sharp edge and gate portions of the molded products, which may results in cracks. Make sure to raise the mold temperature (mold surface temperature actually determined) into the range of temperature indicated above as standard.
* Select a suitable molding machine so that the amount of resin injected per shot is equivalent to 30 to 70% of its cylinder capacity.
* If a resin remains in the molding machine for 10 minutes or more, remove the resin thoroughly form the molding machine and then restart molding. If not, products in poor appearance such as burns and silver may result.
* Note that antirusts and other oils remaining adherent to the mold may cause cracks in the products.
* If there remains hazes on the surface of molded products of AX series resins, raise the temperature of mold and cylinder and make sure to remove gases in the mold thoroughly.

Extrusion molding of U polymers
See the table above for the settings of barrel temperature and the conditions of drying resins.
Contact our sales department for details.

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