The industry masters who do injection molding must know that if you want to get a product, the craftsmanship is very important, but if you choose the materials well, it will make you twice the result with half the effort. Today I will summarize the temperature (control) of 36 common plastic raw materials. If you want to do a good job in injection molding, you must collect it!
ABS (acrylonitrile-butadiene-styrene copolymer)
1. Select the appropriate runner and gate according to the fluidity.
2. Select the appropriate fusion state for the corresponding gate position.
3. Due to high pressure forming, the retraction inclination must be above 2°.
4. The forming shrinkage rate must be around 0.5%.
5. Commonly used for gold-plated products, the precautions are as follows:
(1) The temperature of the material pipe should be high, about 220℃~250℃;
(2) The injection temperature should be slow (using the secondary pressurization method), and the injection pressure should be low;
(3) The mold release agent should be not available;
(4) There should be no traces of shrinkage, sinking and welding wire;
(5) There should be no wound on the surface of the finished product.
6. Heating temperature 180~290℃, mold temperature 50~80℃, material pipe temperature 200~230℃, spray material temperature 200~240℃, injection pressure 700~1500kg/cm2, and minimum operating temperature 260℃.
7. Use a hot air dryer, the drying temperature is 80~100℃, it takes 2~4 hours (below 0.3%), the first section of the pipe temperature is 220~240℃; the second section is 210~240℃; the third section is 180~230℃; the fourth section is 150~180℃; the mold surface temperature is 50~90℃, and the injection pressure is 500~2100kg/cm2.
8. Temperature setting: nozzle 203~295℃, front section 220~295℃, middle section 210~290℃, back section 180~210℃; screw speed 70~150rpm, mold temperature 10~80℃, holding pressure 30~60%, back pressure 100~250kg/cm2. 9. Density 1.04~1.06g/cc, deformation temperature 82~122℃, mold shrinkage rate 0.4~0.8%, specific gravity 1.0~1.2, linear expansion coefficient 0.00006~0.00013/℃, mold shrinkage rate 0.3~0.8%, thermal deformation temperature 66~107℃ (88~113℃).
PA (polyamide (nylon))
1. The injection temperature and drying temperature must be high; the injection pressure and holding pressure should not be too high or too long. The male mold should be injected at high speed, and there should be exhaust channels to avoid burning the glue; the back pressure is 50~150kg/cm2.
2. Plastics must not be placed in the melting glue cylinder before reaching the drying level. Because it contains very strong moisture, it is easy to get stuck in the rod groove of the feeding section, resulting in difficulty in feeding.
3. During forming, it is most likely to cool at the injection nozzle. If the injection pressure is increased during cooling, the check valve may easily rupture, so the temperature control at the injection nozzle must be appropriate. To prevent plastic from overflowing into the mold due to feeding, a controlled injection nozzle is suitable.
4. When using other plastics for injection, it should be noted that the original nylon heating temperature is above 270℃, while the general material heating temperature only operates at around 200℃. Therefore, the melting cylinder must be heated to the nylon heating temperature before operating, otherwise the check valve of the screw and the glue splitting head may be broken.
5. Pay attention to the molding method to produce good results.
6. To prevent waste edge formation, precision molds must be used.
7. Use molds for industrial products. When the temperature rises, attention should be paid to the crystallization of the forming materials.
8. The design of molded products must be prevented from being recessed and dimensional stability is taken into account.
9. The forming shrinkage rate is about 1.5~2.5%.
10. The heating temperature of nylon 6 (PA6) is 220~300℃, mold temperature is 100~160℃, pipe temperature is 200~260℃, spray material temperature is 220~300℃, injection pressure is 700~2000kg/cm2, minimum operating temperature is 225℃, melting point temperature is 215℃, molding temperature is 10~300℃, drying temperature is 75~100℃, it takes 2~6 hours, use a dehumidifier, injection pressure is 750~2000kg/cm2, the first section of the pipe temperature is 230℃; the second section is 230℃; the third section is 220℃; the fourth section is 210℃; the mold surface temperature is 25~70℃. The linear expansion coefficient is 0.000083/℃, the molding shrinkage is 0.6~2.1%, and the specific gravity is 1.1~1.4. The thermal deformation temperature is 67~70℃ (149~185℃).
11. The heating temperature of nylon 66 (PA66) is 250~380℃, mold temperature 30~100℃, pipe temperature 240~300℃, spray material temperature 250~310℃, injection pressure 600~2100kg/cm2, minimum operating temperature 260℃, melting point temperature 215℃, molding temperature 260~320℃, drying temperature 80~90℃, and 3~6 hours are required. Use a dehumidifier, linear expansion coefficient 0.00008~0.00013/℃, molding shrinkage rate 1.3~2.4%, specific gravity 1.1~1.4, and thermal deformation temperature 66~86℃.
12. Temperature setting: nozzle 235~265℃, front section 235~245℃, middle section 210~240℃, rear section 195~230℃; screw speed 100~105rpm, mold temperature 35~40℃, back pressure 5-10kg.
13. Density 0.94~1.14g/cc, deformation temperature 35~121℃, molding shrinkage rate 0.7~2.5%.
POM (polyformaldehyde)
1. Pay attention to the temperature management during molding. The POM material should not stay in the melting cylinder for too long, otherwise it will be prone to overfire and yellowing.
2. The melted gas is very thick, and the contact points of the nozzle and flange are most susceptible to corrosion, so good materials should be used.
3. Heating temperature 190~220℃, mold temperature 80~120℃, material pipe temperature 170~225℃, spray material temperature 190~210℃, injection pressure 800~1500kg/cm2, pressure maintenance depends on the plastic part wall, and the minimum operating temperature is 180℃.
4. Use a hot air dryer, the drying temperature is 100~120℃, it takes 1~4 hours, the first section of the material pipe temperature is 190~215℃; the second section is 195~215℃; the third section is 180~205℃; the fourth section is 150~180℃; the mold surface temperature is 60~120℃.
5. Temperature setting: injection nozzle 185~215℃, front section 190~200℃, middle section 175~190℃, rear section 170~190℃; screw speed 80~200rpm, mold temperature 30~80℃, injection forming temperature 195~250℃, 700~1500kg/cm2, back pressure 100~200kg/cm2.
6. Density 1.30~1.45g/cc, deformation temperature 70~125℃, molding shrinkage rate 0.8~2.0%, specific gravity 1.4~1.6, linear expansion coefficient 0.000081/℃.
PC (polycarbonate resin (polyhydroxyester, bulletproof glue))
1. When the injection pressure is large, the temperature in the tube is too high or the retention time is long, it is prone to thermal decomposition, discoloration and physical properties. Pay attention to the mold temperature based on 85℃~120℃.
2. It is especially difficult to form a finished product with thickness, because the finished product is prone to residual stress and will cause future rupture. Therefore, it is advisable to use powdered silicone as the mold release agent, and do not use liquid mold release agent.
3. The forming must be high temperature and high pressure, and a screw forming shuttle must be used.
4. The materials are pre-dried before use.
5. Gate and runner design should have a smaller flow impedance.
6. The molded product design should be close to the thickness of flesh to avoid inlaid metal parts. Furthermore, the retraction tilt must be above 2°.
7. The molding shrinkage rate is 0.4~0.7%, and the specific gravity is 1.2~1.5.
8. Heating temperature 260~320℃, mold temperature 80~120℃, material pipe temperature 260~310℃, spray material temperature 280~320℃, injection pressure 800~1500kg/cm2, and minimum operating temperature 260℃.
9. Use a dehumidifier, the drying temperature is 105~120℃ (below 0.02~0.03%), it takes 2~4 hours, the first section of the feed pipe temperature is 260~270℃; the second section is 260~270℃; the third section is 240~250℃; the fourth section is 220~230℃; the mold surface temperature is 40~60℃.
10. Temperature setting: injection nozzle 275~305℃, front section 270~275℃, middle section 265~275℃, rear section 250~270℃; screw speed 50~115rpm, mold temperature 60~120℃, injection pressure 700~2100kg/cm2, back pressure 5-15kg.
11. Density ~ 1.20g/cc, deformation temperature 120~146℃, linear expansion coefficient 0.000066/℃, thermal deformation temperature 129~135℃ (141℃).
PBT (saturated polyester (thermoplastic polyester))
1. The temperature of the melting cartridge should be controlled at 230~270℃, and the mold temperature should be set at 40℃~90℃.
2. When you want to get a good surface, it is advisable to heat up and sufficient preparation and drying is required if necessary. The required injection pressure is about 500~1300kg/m2.
3. Temperature setting: nozzle 250℃, front section 245℃, middle section 235℃, back section 230℃; screw speed 80rpm, mold temperature 40~120℃, back pressure 10kg, material pipe temperature 230~270℃, injection pressure 300~1000kg/cm2, drying temperature 100~140℃, and it takes 2~8 hours.
4. Density 1.29~1.50g/cc, deformation temperature 50~110℃, molding shrinkage rate 1.3~2.4%, specific gravity 1.3~1.6.
PMMA (polymethyl methacrylate (acrylic))
1. This material has strong toughness and poor flow, so it is suitable for low-temperature molding. The speed should be slow so that the temperature inside the tube cannot rise.
2. When designing molds, it is advisable to increase the runner and nozzle hole.
3. Acrylic molding is technical processing and molding. During operation, you must set up a clean room to isolate dust. The funnel should be clean, and the mold should be light and white gloves should be worn to keep it clean.
4. General type: the pipe temperature is 180~240℃, the injection pressure is 750~2400kg/cm2, the mold temperature is 40~70℃, the drying temperature is 70~75℃ (below 0.1~0.2%), 4 hours, and the shrinkage rate is 0.4~0.8.
5. Heat-resistant type: the pipe temperature is 220~260℃, the injection pressure is 750~2400kg/cm2, the mold temperature is 40~70℃, the drying temperature is 70~75℃ (below 0.1~0.2%), it takes 4 hours, and the shrinkage rate is 1.1~1.2.
6. The drying temperature is 80℃, which takes 3 to 4 hours. The first section of the material pipe temperature is 200 to 220℃; the second section is 190 to 220℃; the third section is 170 to 200℃; the fourth section is 150 to 180℃; the mold surface temperature is 20 to 90℃.
7. Temperature setting: nozzle 185~215℃, front section 190~200℃, middle section 175~190℃, rear section 170~190℃; screw speed is 80~200rpm, mold temperature is 30~80℃, high-pressure injection pressure, pressure holding is 2~3 minutes, back pressure is 150~400kg/cm2.
8. Density 1.14~1.20g/cc, deformation temperature 76~116℃, molding shrinkage rate 0.2~0.8%.
9. Linear expansion coefficient is 0.00005~0.00009/℃, thermal deformation temperature is 68~99℃ (74~107℃).
PP (polypropylene)
1. PP material will deteriorate from around 280℃, so the heating temperature should be operated below 270℃. Its molecular orientation is very strong. When forming at low temperature, it is prone to warp and distortion due to molecular alignment. It should be paid attention to.
2. A high-pressure forming machine must be used during high-pressure forming.
3. The retreat tilt may be enlarged. The runner and gate must be designed according to the flowability. Pay attention to controlling the material temperature and model modulus.
4. The forming shrinkage rate is about 0.35%, the heating temperature is 180~300℃, the mold temperature is 20~80℃, the pipe temperature is 220~270℃, the spray material temperature is 210~280℃, the injection pressure is 400~1000kg/cm2, and the minimum operating temperature is 200℃.
5. Gate design must pay attention to the adhesion of the formed product. The molded product design must prevent depression and deformation. The forming shrinkage rate is about 0.8~1.5%.
6. Use hot air to dry the drying temperature is 60~90℃, it takes 1 hour, the first section of the material pipe temperature is 240~250℃; the second section is 190~250℃; the third section is 170~230℃; the fourth section is 150~210℃; the mold surface temperature is 20~60℃.
7. Temperature setting: injection nozzle 200~220℃, front section 190~215℃, middle section 190~210℃, rear section 185~200℃; screw speed 120~maximum rpm, mold temperature 20~70℃, injection pressure 700~1800℃, pressure holding extreme length 30~70%, back pressure 120~200kg/cm2.
8. Density 0.90~0.91g/cc, specific gravity 0.9~0.92 linear expansion coefficient 0.000058~0.0001/℃, molding shrinkage rate 1.0~2.5%, thermal deformation temperature 57~63℃ (96~110℃).
PPS (polyphenylene sulfide)
1. Density 1.34~1.40g/cc, deformation temperature 110~265℃, molding shrinkage rate 0.4~1.4%.
2. The material tube temperature is 290~360℃, the injection pressure is 500~1400kg/cm2, the mold temperature is 120~150℃, and the injection forming temperature is 300~370℃.
3. Burning point 288℃, glass transfer point 90℃, curing speed, resin temperature 320℃, mold temperature 150℃, injection pressure 600kg/cm2, injection speed fast, forming time short, preparation drying 140℃, taking 3 hours, forming shrinkage rate 1.6%, and glass fiber reinforcement 100.
4. Use a hot air dryer, with a drying temperature of 130~150℃, and it takes 2~3 hours.
5. Use a dehumidifier, the drying temperature is 120~140℃, and it takes 2~4 hours.
PS (polystyrene)
1. Easier to form.
2. When ejecting from the mold, pay attention to the crack and select suitable switching mold mechanism.
3. If the molded product is in danger of being cracked, pay attention to the molded product design.In special cases, use a retraction inclination of above 1°, and be careful that the mold must not have a low-sinking part.
4. The forming shrinkage rate is about 0.45%, the heating temperature of the general type is 160~310℃, the mold temperature is 40~70℃; the impact-resistant type is 180~310℃, and the mold temperature is 40~70℃.
5. Use a hot air dryer, the drying temperature is 60~80℃, it takes 1~2 hours, the pipe temperature is 180~260℃, the first section is 190~215220~240℃; the second section is 210~240℃; the third section is 180~230℃; the fourth section is 150~180℃; the mold surface temperature is 10~70℃. It takes 2 hours.
6. Temperature setting: nozzle 190~225℃, front section 180~225℃, middle section 160~220℃, back section 150~200℃; screw speed 70~160rpm, mold temperature 20~80℃, back pressure 10~20kg.
7. Density 1.04~1.06g/cc, deformation temperature 65~106℃, molding shrinkage rate 0.4~0.8%, specific gravity 1.0~1.1.
8. Flow length 200~500L/t, linear expansion coefficient 0.00005~0.000083/℃, glass transfer temperature 85~110℃, load bending temperature 68~105℃ (50~95℃), conduction coefficient 0.0003cal.cm.s.sm/℃, density 1.03~1.05g/cm3, tensile strength 350~550kgf/cm2, elongation rate 1.2~3.6%, elastic coefficient 22000~32000kgf/cm2, 2.1~3.2kgf.cm/cm, impact strength 1.9~2.4kgf.cm/cm, Luo style hardness M60~84, transparency, water absorption 0~0.03%.
PE (polyethylene)
1. High-density PE material has obvious crystallization temperature, and it is best to increase the ejection speed.
2. For thick meat products, it is particularly important to increase the injection speed: it can improve the surface gloss of the product, prevent warping, reduce molding shrinkage, etc.
3. The screw design and reverse control equipment need to be precise. If there are losses and scars, it will gradually slow down when adding feed. (The amount of injection into the mold is reduced due to the countercurrent of plastics, and the melt is retracted to the metering part, causing the new material in the feed section to remain, causing metabolic failure, resulting in the phenomenon of unsolid quality of the molded product, strong shrinkage, and high defect rate.)
4. The mold design (gate, runner) has a fast material filling speed.
5. Use a cooling method with uniform cooling speed.
6. It is better to use a screw forming machine and have good fluidity; there is no need for high-pressure injection pressure, and the holding pressure should be longer than 30~60%.
7. The forming shrinkage rate is 2.5%, and the right angle is 2.0%.
8. The design of molded products should be prevented from warping and deformation.
9. Under low pressure, the heating temperature is 140~300℃ and the mold temperature is 30~65℃; under high pressure, the heating temperature is 150~300℃ and the mold temperature is 50~70℃.
10. The material pipe temperature of high-density PE is 210℃, the discharge temperature power supply can be turned off in the next section, the injection pressure is 500~1500kg/cm2, and the minimum operating temperature is 180℃.
11. The drying temperature is 85℃, it takes 1 hour, the first section of the material pipe temperature is 220~240℃; the second section is 200~220℃; the third section is 180~190℃; the fourth section is 160~170℃; the mold surface temperature is 30~70℃.
12. Temperature setting: nozzle 210~265℃, front section 200~255℃, middle section 200~250℃, back section 190~240℃; screw speed 110~140rpm, mold temperature 45~50℃, back pressure 150~250kg/cm2.
13. Density 0.91~0.97g/cc, deformation temperature 32~95℃, molding shrinkage rate 0.5~2.5%.
PEEK (polyphenylether ether ketone (polydiether ketone))
1. Density 1.30~1.45g/cc, deformation temperature 151~300℃, molding shrinkage rate 1.0%.
2. Burning point 334℃, glass transfer point 134℃, fast curing speed, resin temperature 400℃, mold temperature 180℃, injection pressure 1000kg/cm2, fast injection speed, long forming time, preparation for drying 150℃, taking more than 3 hours, glass fiber reinforcement 30, fluidity 55.
PES/PESF (polyether)
1. Density 1.24~1.37g/cc, deformation temperature 174~214℃, molding shrinkage rate 0.5~1.0%.
2. Glass transfer point 225℃, resin temperature 370℃, mold temperature 160℃, injection pressure 900kg/cm2, injection speed is normal, forming time is normal, preparatory drying is 150℃, it takes 3 hours, glass fiber reinforcement 55, fluidity 70.
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