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A table to understand molding conditions of injection molding materials

Time：2022-01-15 21:35:11 / Popularity： / Source：

Raw material name Molding conditions
ABS 1. Select proper runner and gate according to fluidity.
2. Select appropriate fusion state corresponding to gate position.
3. Due to high pressure forming, retreat tilt must be above 2°.
4. Forming shrinkage rate must be around 0.5%.
5. Commonly used for gold-plated products, precautions are as follows:
(1) Temperature of material pipe should be high, about 220℃~250℃
(2) Injection temperature should be slow (using secondary pressurization method), and injection pressure should be low;
(3) Unusable release agent;
(4) There should be no shrinkage, sinking, and welding line flow marks;
(5) There should be no scars on the surface of finished product.
6. Heating temperature 180~290℃, mold temperature 50~80℃, material tube temperature 200~230℃, ejection temperature 200~240℃, injection pressure 700~1500kg/cm², minimum operating temperature 260℃.
7. Use a hot air dryer, drying temperature is 80~100℃, it takes 2~4 hours (less than 0.3%), temperature of material pipe is 220~240℃ for the first stage; 210~240℃ for second stage; Section is 180~230℃; fourth section is 150~180℃; mold surface temperature is 50~90℃, and injection pressure is 500~2100kg/cm².
8. Temperature setting: nozzle 203~295℃, front section 220~295℃, middle section 210~290℃, rear 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℃, molding shrinkage rate 0.4~0.8%, specific gravity 1.0~1.2, linear expansion coefficient 0.00006~0.00013/℃, molding shrinkage rate 0.3~0.8%, heat distortion temperature 66~107℃ (88~113℃).
AS (SAN) 1. If molded product is likely to crack, pay attention to design of molded product. In special circumstances, use a retreat tilt of more than 1°, and pay attention to mold not to have a recessed part.
2. Molding shrinkage rate is about 0.45%, heating temperature is 170~310℃, hot air dryer is used, drying time is 2~3 hours (less than 0.1%), drying temperature is 80~100℃, and material tube temperature is 180~290℃.
3. Temperature setting: nozzle 205~240℃, front section 190~235℃, middle section 180~230℃, rear section 180~210℃; screw speed 70~150rpm, mold temperature 35~80℃, injection pressure 700~2300kg /cm², holding pressure 30~60%, back pressure 100~200kg/cm².
4. Linear expansion coefficient 0.00006~0.00008/℃, molding shrinkage rate 0.2~0.7%, heat distortion temperature 91~93℃ (88~99℃), glass transition temperature 125℃, conductivity coefficient 0.0003cal.cm.s.sm/ ℃, density 1.06~1.08g/cm³, tensile strength 650~800kgf/cm², stretch rate 2~3%, elastic coefficient 32000~37000 kgf/cm², 2.1~3.2kgf.cm/cm, Rockwell hardness M80, Transparent, water absorption 0.2~0.3%.
CA 1. Material must be pre-dried, drying temperature is 75~80℃, drying time is 2~6 hours, and specific gravity is 1.29.
2. Molding shrinkage rate is about 0.5%.
3. Heating temperature is 170~265℃, and mold temperature is 20~80℃.
CAB 1. Heating temperature 170~265℃, mold temperature 20~80℃.
2. Drying temperature is 75~80℃, and drying time is 2-6 hours.
CP Heating temperature is 170~265℃, mold temperature is 20~80℃.
EVA 1. Temperature setting: nozzle 185℃, front section 166℃, middle section 160℃, rear section 150℃; maximum screw speed, mold temperature 35~45℃, back pressure 10kg.
2. Material pipe temperature 150~180℃, nozzle 150℃, first stage 150℃, second stage 140℃, third stage 120℃, mold temperature 30~40℃, injection pressure 600~800kg/cm², molding shrinkage rate is 0.7~2%, drying temperature is 40~50℃, and drying time is 2~4 hours.
FR-PET 1. UL has a long-term heat resistance of 140℃ and a heat distortion temperature of 225℃.
2. Crystallization rate is slow, and the drying and processing conditions are demanding.
3. Drying: 140℃ for 3 hours or 120℃ for 5-8 hours.
4. Injection temperature: 235℃~250℃
5. Mold temperature: 40℃~80℃.
HDPE 1. Temperature setting: nozzle 210℃, front section 200℃, middle section 200℃, rear section 195℃; screw speed 140rpm, back pressure 15kg.
2. Linear expansion coefficient is 0.00010~0.00013/℃, molding shrinkage rate is 1.2~5.0%, and specific gravity is 0.93~0.97. Heat distortion temperature is 43~49℃ (60~82℃).
3. Material tube temperature 160~310℃, nozzle 190℃, first stage 190℃, second stage 180℃, third stage 160℃, mold temperature 10~70℃, injection pressure 300~1400kg/cm², molding shrinkage rate is 1.5~5%.
HIPS 1. Temperature setting: nozzle 220~240℃, front section 210~230℃, middle section 200~230℃, rear section 190~215℃; screw speed 135~215rpm, mold temperature 25℃, back pressure 5-10kg specific gravity 1.05g/cc.
2. Linear expansion coefficient is 0.000034~0.00021/℃, molding shrinkage rate is 0.2~0.6%, and heat distortion temperature is 96℃.
LCP Ⅱ 1. Density is 1.35~1.45g/cc, deformation temperature is 198~310℃, and molding shrinkage rate is 0.1~1.0%.
2. Fast curing speed, resin temperature 300℃, mold temperature 100℃, injection pressure 300kg/cm², fast injection speed, short molding time, pre-drying 150℃, more than 4 hours, glass fiber reinforcement 170, fluidity 210.
LCP Ⅲ 1. Density is 1.35~1.45g/cc, deformation temperature is 198~310℃, and molding shrinkage rate is 0.1~1.0%.
2. Fast curing speed, resin temperature 260℃, mold temperature 100℃, injection pressure 300kg/cm², fast injection speed, short molding time, pre-drying 140℃, 3 hours required, 230 glass fiber reinforced.
LDPE 1. Temperature setting: nozzle 140~190℃, front section 140~200℃, middle section 135~195℃, rear section 130~180℃; screw speed 210~220rpm, mold temperature 10~70℃, barrel temperature 150 ~310℃, back pressure 5-10kg, mold temperature 30~50℃, injection pressure 360~500kg/cm².
2. Linear expansion coefficient is 0.00010~0.00020/℃, molding shrinkage rate is 1.5~5.0%, specific gravity is 0.91~0.93, heat distortion temperature (38~49℃).
PA 1. Injection temperature and drying temperature must be high; injection pressure and holding pressure should not be too high or too long, high-speed injection of male mold, and exhaust channels should be provided to prevent rubber from scorching; back pressure is 50~150kg/cm².
2. Plastic must not be put into melt cylinder before it reaches dry level. Because of strong water content, it is easy to get stuck in rod groove of feeding section, which will cause difficulty in feeding.
3. When forming, it is the easiest to cool down at nozzle. If injection pressure is increased during cooling, it is easy to cause check valve to rupture, so temperature control at nozzle must be appropriate. In order to prevent plastic from overflowing into mold due to feeding, it is advisable to use a controlled nozzle.
4. When changing to other plastics for injection, it should be noted that heating temperature of original nylon is above 270℃, and heating temperature of general materials can only operate at about 200℃. Therefore, melting cylinder must be heated to nylon heating temperature before operation. Otherwise, it is easy to break check valve and the dispensing head of screw.
5. Pay attention to molding method to produce good results.
6. In order to prevent formation of waste edges, precision molds must be used.
7. When using industrial molds, pay attention to crystallization of molding materials when temperature rises.
8. Design of molded products must prevent dents and consider dimensional stability.
9. Forming shrinkage is about 1.5~2.5%.
10. Nylon 6 (PA6) heating temperature 220~300℃, mold temperature 100~160℃, material tube temperature 200~260℃, ejection temperature 220~300℃, injection pressure 700~2000kg/cm², minimum operating temperature 225℃, melting point temperature 215℃, molding temperature 10~300℃, drying temperature 75~100℃, takes 2~6 hours, use dehumidification dryer, injection pressure 750~2000kg/cm2, the first stage of material pipe temperature is 230℃; second stage is 230℃; third stage is 220℃; fourth stage is 210℃; mold surface temperature is 25~70℃. Linear expansion coefficient is 0.000083/℃, molding shrinkage rate is 0.6~2.1%, and specific gravity is 1.1~1.4. Heat distortion temperature is 67~70℃ (149~185℃).
11. Nylon 66 (PA66) heating temperature 250~380℃, mold temperature 30~100℃, material tube temperature 240~300℃, ejection temperature 250~310℃, injection pressure 600~2100kg/cm², minimum operating temperature 260℃, melting point temperature 215℃, molding temperature 260~320℃, drying temperature 80~90℃, 3~6 hours when necessary, using dehumidifying dryer, linear expansion coefficient 0.00008~0.00013/℃, molding shrinkage rate 1.3~2.4% , specific gravity 1.1~1.4, heat distortion 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%.
PAR 1. Density 1.17~1.31g/cc, deformation temperature 95~175℃, molding shrinkage rate 0.8~1.0%.
2. Glass transition point 190℃, fast curing speed, resin temperature 370℃, mold temperature 130℃, injection pressure 1000kg/cm², fast injection speed, normal molding time, pre-drying 140℃, takes 6 hours, glass fiber reinforced 35 , Liquidity 50.
PBT 1. Temperature of melt cylinder should be controlled at 230~270℃, and mold temperature should be set at 40℃~90℃.
2. If you want to get a good gloss surface, temperature should be raised, and if necessary, sufficient pre-drying should be carried out. Required injection pressure is about 500~1300kg/m².
3. Temperature setting: nozzle 250℃, front section 245℃, middle section 235℃, rear section 230℃; screw speed 80rpm, mold temperature 40~120℃, back pressure 10kg, barrel temperature 230~270℃, injection pressure 300 ~1000kg/cm², drying temperature 100~140℃, 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.
PC 1. When injection pressure is high, temperature in tube is too high or residence time is long, it is easy to cause thermal decomposition, discoloration and reduce physical properties. Please note that mold temperature is 85℃~120℃.
2. It is especially difficult to form thick finished products, because finished products are prone to residual stress, which will cause future cracks. Therefore, it is advisable to use powdered silicone as a release agent instead of liquid release agents.
3. Forming requires high temperature and high pressure, and screw-type forming shuttle must be used.
4. Material is fully dried before use.
5. Gate and runner design should have small flow resistance.
6. Design of molded product should be close to thickness to avoid inlaid metal parts. Furthermore, retreat tilt must be above 2°.
7. Molding shrinkage rate is 0.4~0.7%, specific gravity is 1.2~1.5.
8. Heating temperature 260~320℃, mold temperature 80~120℃, material tube temperature 260~310℃, ejection temperature 280~320℃, injection pressure 800~1500kg/cm², minimum operating temperature 260℃.
9. Use a desiccant dryer, drying temperature is 105~120℃ (0.02~0.03% or less), it takes 2~4 hours, and temperature of material tube is 260~270℃ in the first stage; 260~270℃ in second stage; third stage is 240~250℃; fourth stage is 220~230℃; mold surface temperature is 40~60℃.
10. Temperature setting: 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/℃, heat distortion temperature 129~135℃ (141℃).
PCTFE 1. Design gates and runners with proper flow.
2. A high-pressure injection molding machine must be used.
3. Choose molding conditions that can prevent discoloration.
4. Use anti-rust molds and materials to implement surface treatment.
5. Molding shrinkage is about 0.5%.
PE 1. High-density PE material has obvious crystallization temperature, it is best to increase injection speed.
2. For thick meat products, increasing injection speed is particularly important: it can improve surface gloss of product, prevent warpage, and reduce molding shrinkage.
3. Screw design and anti-reverse equipment are especially required to be precise. If there is wear and tear, it will slow down when feeding. (Due to reverse flow of plastic, amount of injection into mold is reduced, and molten material is poured back into metering section, so that new material in feeding section is retained, causing metabolism to fail, thus forming phenomenon of unstable quality, strong shrinkage, and high defect rate.)
4. Mold design (gate, runner) has a fast material filling speed.
5. Adopt a cooling method with uniform cooling rate.
6. It is better to use screw molding machine and good fluidity; high pressure injection pressure is not required, and holding pressure should be 30~60% longer.
7. Forming shrinkage rate is 2.5%, and right-angle direction is 2.0%.
8. Design of molded product should prevent warping and deformation.
9. Under low pressure, heating temperature is 140~300℃, mould temperature is 30~65℃; under high pressure, heating temperature is 150~300℃, mould temperature is 50~70℃.
10. Material pipe temperature of high-density PE is 210℃, power supply for spraying temperature of next section can be turned off, injection pressure is 500~1500kg/cm², and minimum operating temperature is 180℃.
11. Drying temperature is 85℃, it takes 1 hour, temperature of material pipe is 220~240℃ for the first stage; 200~220℃ for second stage; 180~190℃ for third stage; 160~170 for fourth stage ℃; surface temperature of mold is 30~70℃.
12. Temperature setting: nozzle 210~265℃, front section 200~255℃, middle section 200~250℃, rear 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 1. Density 1.30~1.45g/cc, deformation temperature 151~300℃, molding shrinkage rate 1.0%.
2. Burning point 334℃, glass transition point 134℃, fast curing speed, resin temperature 400℃, mold temperature 180℃, injection pressure 1000kg/cm², fast injection speed, long molding time, pre-drying 150℃, it takes more than 3 hours, glass fiber reinforced 30, fluidity 55.
PES/PESF 1. Density 1.24~1.37g/cc, deformation temperature 174~214℃, molding shrinkage rate 0.5~1.0%.
2. Glass transition point 225℃, resin temperature 370℃, mold temperature 160℃, injection pressure 900kg/cm², normal injection speed, normal molding time, pre-drying 150℃, 3 hours required, glass fiber reinforcement 55, fluidity 70 .
PET 1. Temperature setting: nozzle 280~295℃, front section 270~275℃, middle section 265~275℃, rear section 250~270℃; screw speed 50~100rpm, mold temperature 30~85℃, mold temperature of amorphous type is below 70℃, and back pressure is 5-15kg.
2. Use a desiccant dryer, barrel temperature is 240~280℃, injection pressure is 500~1400℃, injection molding temperature is 260~280℃, drying temperature is 120~140℃, and required time is 2~5 hours.
PI 1. Density 1.16~1.64g/cc, deformation temperature 278~380℃.
2. Burning point 388℃, glass transition point 250℃, fast curing speed, resin temperature 410℃, mold temperature 200℃, injection pressure 800kg/cm², normal injection speed, normal molding time, pre-drying 200℃, 6 hours required, molding shrinkage rate 1.6%, glass fiber reinforcement 40, fluidity 75.
PMMA  1. This material is characterized by strong toughness and poor material flow, so it is suitable for low temperature molding. Speed should be slow, so that temperature inside tube can not rise.
2. Runner and nozzle hole should be enlarged when designing mold.
3. Acrylic molding is technical processing and molding. A clean room must be opened to isolate dust during operation, funnel should be clean, mold should be light, and white gloves should be worn to keep it clean.
4. General type: material tube temperature 180~240℃, injection pressure 750~2400kg/cm², mold temperature 40~70℃, drying temperature 70~75℃ (below 0.1~0.2%), 4 hours required, shrinkage rate 0.4 ~0.8.
5. Heat-resistant type: material tube temperature 220~260℃, injection pressure 750~2400kg/cm², mold temperature 40~70℃, drying temperature 70~75℃ (below 0.1~0.2%), 4 hours required, shrinkage rate 1.1~1.2.
6. Drying temperature is 80℃, it takes 3~4 hours, temperature of material pipe is 200~220℃ for the first stage; 190~220℃ for second stage; 170~200℃ for third stage; 150 for fourth stage ~180℃; mold surface temperature is 20~90℃.
7. Temperature setting: nozzle 185~215℃, front section 190~200℃, middle section 175~190℃, rear section 170~190℃; screw speed 80~200rpm, mold temperature 30~80℃, use high pressure injection pressure, hold pressure for 2~3 minutes, back pressure 150~400kg/cm².
8. Density is 1.14~1.20g/cc, deformation temperature is 76~116℃, and molding shrinkage rate is 0.2~0.8%.
9. Coefficient of linear expansion is 0.00005~0.00009/℃, and heat distortion temperature is 68~99℃ (74~107℃).
POM 1. Pay attention to temperature management during molding. POM material should not stay in glue cylinder for too long, otherwise it will be easy to overfire and yellow.
2. Melted gas is very dense, contact points of nozzle and flange are the most likely to corrode, so a good material should be used.
3. Heating temperature 190~220℃, mold temperature 80~120℃, material tube temperature 170~225℃, ejection temperature 190~210℃, injection pressure 800~1500kg/cm², holding pressure depends on the wall of plastic part, and minimum operating temperature is 180℃.
4. Use a hot air dryer, drying temperature is 100~120℃, it takes 1~4 hours, temperature of material pipe is 190~215℃ in the first section; 195~215℃ in second section; 180~205℃ in third section; 150~180℃ in fourth section; and 60~120℃ in mold surface temperature.
5. Temperature setting: nozzle 185~215℃, front section 190~200℃, middle section 175~190℃, rear section 170~190℃; screw speed 80~200rpm, mold temperature 30~80℃, injection molding 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/℃.
PP 1. PP material will start to deteriorate from around 280℃, so heating temperature should be below 270℃. Its molecular orientation is very strong. When molding at low temperature, it is easy to warp and twist due to molecular orientation, so care should be taken.
2. A high-pressure forming machine must be used for high-pressure forming.
3. Retract and tilt may enlarge. Runners and gates must be designed in accordance with fluidity. Pay attention to control of material temperature and mold degree.
4. Molding shrinkage rate is about 0.35%, heating temperature is 180~300℃, mold temperature is 20~80℃, barrel temperature is 220~270℃, ejection temperature is 210~280℃, injection pressure is 400~1000kg/cm², and minimum operating temperature is 200℃.
5. Gate design must pay attention to adhesion of molded product. Design of molded product must prevent dents and deformation. Forming shrinkage is about 0.8~1.5%.
6. Use hot air to dry. Drying temperature is 60~90℃, it takes 1 hour, and temperature of barrel is 240~250℃ for the first stage; 190~250℃ for second stage; 170~230℃ for third stage; 150~210℃ for fourth stage; and 20~60℃ in mold surface temperature.
7. Temperature setting: 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℃, 30~70% holding pressure, 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%, heat distortion temperature 57~63℃ (96~110℃).
PPS 1. Density 1.34~1.40g/cc, deformation temperature 110~265℃, molding shrinkage rate 0.4~1.4%.
2. Barrel temperature is 290~360℃, injection pressure is 500~1400kg/cm², mold temperature is 120~150℃, and injection molding temperature is 300~370℃.
3. Burning point is 288℃, glass transition point is 90℃, curing speed is fast, resin temperature is 320℃, mold temperature is 150℃, injection pressure is 600kg/cm², injection speed is fast, molding time is short, the pre-drying is 140℃, it takes 3 hours, molding shrinkage rate is 1.6%, and glass fiber reinforced 100.
4. Use hot air dryer, drying temperature 130~150℃, it takes 2~3 hours.
5. Use a desiccant dryer, drying temperature is 120~140℃, and it takes 2~4 hours.
PS 1. Easy to shape.
2. When ejecting from mold, pay attention to cracking of bowl, select a suitable mold opening and closing mechanism.
3. If molded product is likely to crack, pay attention to design of molded product. In special circumstances, use a retreat tilt of more than 1°, and pay attention to mold not to have a recessed part.
4. Molding shrinkage rate is about 0.45%, heating temperature of general type is 160~310℃, mold temperature is 40~70℃; heating temperature of impact resistant type is 180~310℃, and mold temperature is 40~70℃.
5. Use a hot air dryer, drying temperature is 60~80℃, it takes 1~2 hours, material tube temperature is 180~260℃, the first stage is 220~240℃; second stage is 210~240℃; third stage is 180~230℃; fourth stage is 150~180℃; mold surface temperature is 10~70℃. It takes 2 hours.
6. Temperature setting: nozzle 190~225℃, front section 180~225℃, middle section 160~220℃, rear 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 transition temperature 85~110℃, load bending temperature 68~105℃ (50~95℃), conductivity coefficient 0.0003cal.cm.s .sm/℃, density 1.03~1.05g/cm³, tensile strength 350~550kgf/cm², stretch rate 1.2~3.6%, coefficient of elasticity 22000~32000 kgf/cm², impact strength 1.9~2.4kgf.cm/cm, Rockwell hardness M60~84, transparent, water absorption 0~0.03%.
PSF 1. Use a desiccant dryer, heating temperature 340~400℃, mold temperature 160~200℃, drying temperature 80~160℃, drying time 3~4 hours.
2. Density is 1.24~1.30g/cc, deformation temperature is 164~190℃, and molding shrinkage rate is 0.15~0.9%.
3. Glass transition point 189℃, fast curing speed, resin temperature 350℃, mold temperature 130℃, injection pressure 900kg/cm², normal injection speed, normal molding time, glass fiber reinforcement 30, fluidity 45.
4. Material pipe temperature 330~360℃, nozzle 330℃, first section 330℃, second section 320℃, third section 290℃, mold temperature 95~100℃, injection pressure 700~1000kg/cm², molding shrinkage The rate is 0.7%.
PTFE 1. Heating temperature is 260~340℃, mold temperature is 100~160℃.
2. Glass transition temperature is 19℃, copper foil tear strength is 7.1 lb/in, the Z-axis thermal expansion coefficient of sheet is 73ppm/℃, dimensional stability is 0.8%, and ease of manufacture is 25%.
3. Tg is very low and it is too soft at room temperature.
PU or PUR 1. Use a desiccant dryer at a drying temperature of 90℃, which takes 1 to 4 hours, and a mold temperature of 80 to 100℃.
2. Material tube temperature 180~240℃, density 1.14g/cm², shrinkage rate 0.6~0.8%, water absorption rate 0.02%, material tube selection small~medium, melt gauge pressure 60~80kg/cm², compression ratio 2.2~ 2.5:1, L/D ratio is 18-20.
PVAC Heating temperature is 120~200℃, and mold temperature is 20~55℃.
PVC 1. Temperature in pipe should be 170-190℃ for heating, high temperature heating above 200℃ should be avoided, and mold temperature should be 50-60℃.
2. Residence time of plastic should be short. Use the slowest rotation feeding method to prevent temperature in tube from rising, and use slow injection method to allow gas to be discharged from mold body. Vent hole of mold should be large, screw needs to be electroplated, no anti-reverse device is necessary, nozzle hole should be enlarged, and shot must be shot to the end each time, so that no stagnant material is contained in pipe. When operation is stopped, temperature must be slowly lowered, and operation will continue to promote injection of all internal stagnant materials when defective product is finished.
3. Control of material temperature is more important, and it is better to use a screw molding machine.
4. Gate and runner design should make it have a smaller flow resistance.
5. Mold must be treated with corrosion-resistant surface.
6. Heating temperature is 149~213℃, mold temperature is 50~70℃, material pipe temperature is 165~185℃, ejection temperature is 175~195℃, injection pressure is 1000~2800kg/cm², and minimum operating temperature is 165℃.
7. Use a hot air dryer, temperature of material tube is 150~190℃, it takes 1~4 hours, and drying is 80~100℃. Temperature of material tube is 180~200℃ for the first stage; 180~200℃ for second stage ; third stage is 160~180℃; fourth stage is 140~160℃; mold surface temperature is 20~600℃.
8. Temperature setting: nozzle 185℃, front section 180℃, middle section 175℃, rear section 165℃; screw speed 60rpm; mold temperature 25~70℃.
9. Density 1.1~1.6g/cc, deformation temperature 55~100℃, molding shrinkage rate 0.1~0.5, 1~5%, linear expansion coefficient 0.00005~0.000185/℃, molding shrinkage rate 0.1~0.5%, heat distortion temperature 57 ~74℃ (82℃).
PVDC Heating temperature 150~200℃, mold temperature 50~70℃.
SAN Heating temperature is 170~290℃, mold temperature is 40~80℃.
TPU 1. It must be fully dried before processing, and moisture content is preferably below 0.03.
2. Processing of recycled materials shall not exceed 25% of the total amount.
3. BS/PVC can be added during processing to change fluidity or physical properties of TPU, but it should not exceed 15% of the total.
4. Pp/LDPE can be used to clean material tube during color change processing.
5. Shrinkage rate is about 0.3-0.8%. Increasing gate diameter of mold, increasing holding time and injection pressure, and reducing mold temperature can all reduce shrinkage of molded product during injection.
 
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