Injection molding process parameters of common plastics
Time：2021-01-21 15:25:48 / Popularity： / Source：
One, high density polyethylene (HDPE)
| Barrel temperature feeding area |
30～50℃ (50℃) |
| Zone 1 |
160～250℃ (200℃) |
| Zone 2 |
200～300℃ (210℃) |
| Zone 3 |
220～300℃ (230℃) |
| Zone 4 |
220～300℃ (240℃) |
| Zone 5 |
220～300℃ (240℃) |
| Nozzle |
220～300℃ (240℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
220～280℃ |
| Barrel constant temperature |
220℃ |
| Mold temperature |
20～60℃ |
| Injection pressure |
has good flow properties, avoid using too high injection pressure 80～140MPa (800～1400bar); except for some thin-walled packaging containers, it can reach 180MPa (1800bar) |
| Holding pressure |
Degree of shrinkage is high, and it takes a long time to hold product. Dimensional accuracy is key factor, which is about 30% to 60% of injection pressure. |
| Back pressure |
5～20MPa (50～200bar); places where back pressure is too low may cause uneven product weight and dispersion. |
| Injection speed |
High injection speed is required for thin-walled packaging containers. Medium injection speed is often more suitable for other types of plastic products. |
| Screw speed |
High screw speed (line speed of 1.3m/s) is allowed, as long as plasticization process is completed before end of cooling time; torque requirement of screw is low. |
| Metering stroke |
0.5～4D (minimum to maximum); 4D metering stroke is very important to provide long enough residence time for melt. |
| Residual material |
2～8mm, depending on metering stroke and screw diameter. |
| Pre-drying |
No need; if storage conditions are not good, dry it at 80℃ for 1 hour. |
| Recovery rate |
100% recycling possible |
| Shrinkage rate |
1.2～2.5%; easy to twist; high shrinkage; no shrinkage after 24h (shrinkage after molding). |
| Gate system |
Point gate or multi-point gate; heated hot runner, insulated hot runner, inner pouring sleeve; relatively small cross-sectional area, enough for thin section products |
| Machine downtime |
No need to use other materials for special cleaning work; PE is resistant to temperature rise |
| Barrel equipment |
Standard screw, standard three-section screw; for packaging container products, mixing section and shear section have a special geometry (L: D = 25:1), straight-through nozzle, and check valve |
Two, polypropylene (PP)
| Barrel temperature Feeding area |
30～50℃ (50℃) |
| Zone 1 |
160～250℃ (200℃) |
| Zone 2 |
200～300℃ (220℃) |
| Zone 3 |
220～300℃ (240℃) |
| Zone 4 |
220～300℃ (240℃) |
| Zone 5 |
220～300℃ (240℃) |
| Nozzle |
220～300℃ (240℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
220～280℃ |
| Barrel constant temperature |
220℃ |
| Mold temperature |
20～70℃ |
| Injection pressure |
It has good flow properties, avoid using too high injection pressure of 80～140MPa (800～1400bar); except for some thin-walled packaging containers, it can reach 180MPa (1800bar) |
| Holding pressure |
Avoid product shrinkage, it takes a long time to hold product pressure (about 30% of cycle time); about 30% to 60% of injection pressure |
| Back pressure |
5～20MPa (50～200bar) |
| Injection speed |
High injection speed (with accumulator) is required for thin-walled packaging containers; medium injection speed is often more suitable for other types of plastic products |
| Screw speed |
High screw speed (line speed of 1.3m/s) is allowed, as long as plasticization process is completed before end of cooling time. |
| Metering stroke |
0.5～4D (minimum to maximum); 4D metering stroke is very important to provide long enough residence time for melt |
| Residual material |
2～8mm, depending on metering stroke and screw speed |
| Pre-drying |
No need; if storage conditions are not good, dry it at 80℃ for 1 hour. |
| Recovery rate |
100% recycling possible. |
| Shrinkage |
1.2～2.5%; high degree of shrinkage; no shrinkage after 24h (shrinkage after molding) |
| Gate system |
Point gate or multi-point gate; heated hot runner, insulated hot runner, inner pouring sleeve; gate position is at the thickest point of product, otherwise large shrinkage is likely to occur |
| Machine downtime |
No need to use other materials for special cleaning work; PP is resistant to temperature rise |
| Barrel equipment |
Standard screw, standard three-section screw; for packaging container products, mixing section and shear section have a special geometry (L: D = 25:1), straight-through nozzle, and check valve |
Three, polystyrene (PS)
| Barrel temperature Feeding area |
30～50℃ (50℃) |
| Zone 1 |
160～250℃ (200℃) |
| Zone 2 |
200～300℃ (210℃) |
| Zone 3 |
220～300℃ (230℃) |
| Zone 4 |
220～300℃ (230℃) |
| Zone 5 |
220～300℃ (230℃) |
| Nozzle |
220～300℃ (230℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
220～280℃ |
| Barrel constant temperature |
220℃ |
| Mold temperature |
15～50℃ |
| Injection pressure |
It has good flow properties, avoid using too high injection pressure of 80～140MPa (800～1400bar) |
| Holding pressure |
30%～60% of injection pressure; relatively short holding time |
| Back pressure |
5～10MPa (50～100bar); where back pressure is too low, bubbles are easy to produce in melt (product has gray and black lines) |
| Injection speed |
Generally faster, multi-stage injection is based on shape of product; for thin-walled packaging containers, it should be as fast as possible, and use accumulators when necessary |
| Screw speed |
High screw speed (maximum linear speed is 1.3m/s) is allowed; but in order to achieve good results, plasticizing process should be as slow as cooling time |
| Metering stroke |
0.5～4D (minimum～maximum); 4D metering stroke is very important to provide enough residence time for melt |
| Residual material |
2～8mm, depending on metering stroke and screw speed |
| Pre-drying |
No need; if storage conditions are not good, dry it at 80℃ for 1 hour. |
| Recovery rate |
100% recycling possible |
| Shrinkage |
0.3%～0.6% |
| Gate system |
Point gate; heated hot runner, insulated hot runner, inner pouring sleeve; relatively small cross section is sufficient |
| Machine downtime |
No need to use other materials for special cleaning work; PS is resistant to temperature rise |
| Barrel equipment |
Standard screw, straight nozzle, check valve |
Four, polyvinyl chloride-unplasticized (PVC-U)
| Barrel temperature Feeding area |
30～50℃ (50℃) |
| Zone 1 |
140～160℃ (150℃) |
| Zone 2 |
165～180℃ (170℃) |
| Zone 3 |
180～210℃ (190℃) |
| Zone 4 |
180～210℃ (200℃) |
| Zone 5 |
180～210℃ (200℃) |
| Nozzle |
180～210℃ (200℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1.
| Melting temperature |
210～220℃ |
| Barrel constant temperature |
120℃ |
| Mold temperature |
30～60℃ |
| Injection pressure |
80～160MPa (800～1600bar) |
| Holding pressure |
Can not be set too high, 40～60% of injection pressure, based on mold and gate |
| Back pressure |
In view of its thermal sensitivity, correct setting of back pressure is very important; heat generated by friction of screw (turn off heat input control) is better than heat generated from barrel heating ring; back pressure does not exceed 30MPa (300bar) |
| Injection speed |
Do not set too high and be careful of shearing effect of material; where product is prone to denaturation or sharp edges, multi-level injection speed should absolutely be required. |
| Screw speed |
Use the lowest setting allowed, maximum speed is 0.2m/s; if necessary, delay plasticization to ensure that in the case of a long cooling time, metering operation can be completed before end of cooling time at low screw speeds; high torque and uniformity are required. |
| Metering stroke |
1.0～3.5D |
| Residual material |
Should be small: 1～5mm, depending on metering stroke and screw diameter; screw must be installed with barrel to ensure minimum fit |
| Pre-drying |
If storage conditions are not good, dry it at 70℃ for 1 hour. |
| Recovery rate |
Allows material to be recycled without thermal decomposition |
| Shrinkage |
0.5%～0.7% |
| Gate system |
Straight gate, chip gate or disc gate is better, point gate can also be used for small products; gate should have an arc transition towards product |
| Machine downtime |
Turn off heating, no back pressure plasticization, allow melt to flow for 2～3mm, then operate machine slowly like an extruder; repeat operation until barrel temperature drops to 160°C, then extrude remaining material and empty barrel |
| Barrel equipment |
Hard PVC screw; some need barrel with heating ring and cold air blowing device; screw head with or without screw groove, straight through nozzle |
Five, plasticized polyvinyl chloride (P-PVC)
| Barrel temperature Feeding area |
30～50℃ (50℃) |
| Zone 1 |
140～160℃ (150℃) |
| Zone 2 |
150～180℃ (165℃) |
| Zone 3 |
160～220℃ (180℃) |
| Zone 4 |
160～220℃ (190℃) |
| Zone 5 |
160～220℃ (190℃) |
| Nozzle |
160～220℃ (200℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1.
| Melting temperature |
200～220℃ |
| Barrel constant temperature |
120℃ |
| Mold temperature |
30～50℃ |
| Injection pressure |
80～120MPa (800～1200bar) |
| Holding pressure |
30%～60% of injection pressure |
| Back pressure |
5～10MPa (50～100bar) |
| Injection speed |
In order to obtain a good surface quality, injection should not be too fast (if necessary, use multi-stage injection) |
| Screw speed |
Set middle screw speed, maximum reduced linear speed is 0.5m/s |
| Metering stroke |
1.0～3.5D |
| Residual material |
2～6mm, depending on metering stroke and screw diameter |
| Pre-drying |
No need; only if storage condition is not good, it can be dried at 70℃ for 1h. |
| Recovery rate |
Allows material to be recycled without thermal decomposition |
| Shrinkage |
1%～2.5% |
| Gate system |
Point gates can be used for small products; gate should have an arc transition toward product |
| Machine downtime |
Turn off heating, plasticizing without back pressure, and operate several extrusion cycles |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Six, nylon 6 (PA6)
| Barrel temperature Feeding area |
60～90℃ (70℃) |
| Zone 1 |
230～240℃ (240℃) |
| Zone 2 |
230～240℃ (240℃) |
| Zone 3 |
240～250℃ (250℃) |
| Zone 4 |
240～250℃ (250℃) |
| Zone 5 |
240～250℃ (250℃) |
| Nozzle |
230～240℃ (250℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
240～250℃ |
| Barrel constant temperature |
220℃ |
| Mold temperature |
60～100℃ |
| Injection pressure |
100～160MPa (1000～1600bar), if it is processing thin section and long runner products (such as wire tie), it needs to reach 180MPa (1800bar) |
| Holding pressure |
50% of injection pressure; because material condenses relatively quickly, a short dwell time is sufficient. Reducing holding pressure can reduce internal stress of product |
| Back pressure |
2～8MPa (20～80bar), need to be adjusted accurately, because too high back pressure will cause uneven plasticization |
| Injection speed |
It is recommended to use a relatively fast injection speed; mold has good air permeability, otherwise coking will easily occur on product |
| Screw speed |
Screw speed is high, and linear speed is 1m/s; however, it is better to set screw speed lower, as long as plasticization process can be completed before end of cooling time; lower screw torque is required |
| Metering stroke |
0.5～3.5D |
| Residual material |
2～6mm depends on metering stroke and screw diameter |
| Pre-drying |
Drying at 80℃ for 4h, except for feeding directly from filling container; nylon has water absorption, should be stored in a moisture-proof container and a closed hopper; water content exceeding 0.25% will cause molding changes |
| Recovery rate |
10% regrind can be added |
| Shrinkage |
0.7%～2.0%; or if 30% glass fiber is added, shrinkage rate is 0.3%～0.8%; if temperature provided exceeds 60℃, product should be gradually cooled; gradual cooling can reduce shrinkage after molding, that is, product exhibits better dimensional stability and small internal stress; steam method is recommended; nylon products can be checked for stress by molten flux |
| Gate system |
Point type, latent type, chip type and straight gate are all possible; it is recommended to use blind holes and sprue sockets to break cold material point; hot runners can be used; due to narrow processing temperature range of melt, hot runner should provide closed-loop temperature control |
| Machine downtime |
No need to clean with other materials; molten material remains in barrel for up to 20 minutes, after which thermal degradation is prone to occur. |
| Barrel equipment |
Standard screw, special geometric size has high plasticizing ability; non-return ring, straight nozzle; for reinforced material with glass fiber, high wear-resistant bimetal barrel is required |
Seven, nylon66 (PA66)
| Barrel temperature Feeding area |
60～90℃ (80℃) |
| Zone 1 |
260～290℃ (280℃) |
| Zone 2 |
260～290℃ (280℃) |
| Zone 3 |
80～290℃ (290℃) |
| Zone 4 |
280～290℃ (290℃) |
| Zone 5 |
280～290℃ (290℃) |
| Nozzle |
280～290℃ (290℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
Temperature of feeding zone and zone 1 directly affects feeding efficiency, increasing these temperatures can make feeding more even.
| Melting temperature |
270～290℃ |
| Barrel constant temperature |
240℃ |
| Mold temperature |
60～100℃ |
| Injection pressure |
100～160MPa (1000～1600bar), if it is processing thin section and long runner products (such as wire tie), it needs to reach 180MPa (1800bar) |
| Holding pressure |
50% of injection pressure; because material condenses relatively quickly, a short dwell time is sufficient. Reducing holding pressure can reduce internal stress of product |
| Back pressure |
2～8MPa (20～80bar), need to be adjusted accurately, because too high back pressure will cause uneven plasticization, injection speed is recommended to be relatively fast; if mold has good air permeability, otherwise product will be prone to coking |
| Screw speed |
High screw speed, linear speed is 1m/s; however, it is best to set screw speed lower, as long as plasticization process can be completed before end of cooling time; the required screw torque is low. |
| Metering stroke |
(0.5～3.5) D |
| Residual material |
2～6mm depends on metering stroke and screw diameter |
| Pre-drying |
Drying at 80℃ for 4h, except for feeding directly from filling container; nylon is water-absorbent, should be stored in a moisture-proof container and a closed hopper; water content exceeding 0.25% will cause molding changes. |
| Recovery rate |
10% recycled material can be added |
| Shrinkage |
0.7% to 2.0%, or if add 30% of glass fiber, 0.4% to 0.7%; if provided temperature exceeds 60℃, product should be gradually cooled; gradual cooling can reduce shrinkage after molding, that is, product exhibits better dimensional stability and small internal stress; steam method is recommended; nylon products can be checked for stress through molten flux |
| Gate system |
Point type, latent type, chip type and straight gate are all possible; it is recommended to use blind holes and sprue sockets to break cold sprue; hot runner can be used; due to narrow processing temperature range of melt, hot runner should provide closed-loop temperature control |
| Machine downtime |
No need to clean with other materials; molten material remains in barrel for up to 20 minutes, after which thermal degradation is likely to occur |
| Barrel equipment |
Standard screw, special geometric size has strong plasticizing ability; non-return ring, straight-through nozzle; for reinforced materials with glass fiber, high wear-resistant bimetal barrel is required |
Eight, polybutylene terephthalate (PBT)
| Barrel temperature Feeding area |
50～70℃ (70℃) |
| Zone 1 |
230～250℃ (240℃) |
| Zone 2 |
240～260℃ (250℃) |
| Zone 3 |
250～260℃ (260℃) |
| Zone 4 |
250～260℃ (260℃) |
| Zone 5 |
250～260℃ (260℃) |
| Nozzle |
250～260℃ (260℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
250～260℃, narrow molding range; easy to condense below 240℃, thermal degradation above 270℃ |
| Barrel constant temperature |
210℃ |
| Mold temperature |
60～80℃ |
| Injection pressure |
100～140MPa (1000～1400bar) |
| Holding pressure |
50%～60% of injection pressure |
| Back pressure |
5～10MPa (50～100bar) to avoid frictional heat |
| Injection speed |
Because of high solidification rate and crystallization rate, high speed is required; to avoid cooling and condensation of melt during injection process; it is important to maintain good air permeability in mold, otherwise entrapped air will easily cause coking at the end of runner |
| Screw speed |
Maximum screw speed is equivalent to linear speed of 0.5m/s |
| Metering stroke |
(0.5～3.5) D, because melt is very sensitive to overheating and remaining time in barrel is too long; remaining time should not exceed 5min. |
| Residual material |
2～5mm, depending on metering stroke and screw diameter |
| Pre-drying |
Dry for 4h at 120℃ |
| Recovery rate |
If flame retardant is mixed, no more than 10% recycled material is allowed, provided that it has been pre-dried and there is no thermal degradation; materials without flame retardant can be added 20% recycled material |
| Shrinkage |
Much depends on mold temperature, the higher mold temperature, the greater shrinkage; shrinkage rate is 1.4% to 2.0%, or 30% glass fiber is added to make shrinkage rate to 0.4% to 0.6% |
| Gate system |
Glass fiber reinforced materials avoid use of central direct gates and point gates; position of gate should ensure that mold cavity is evenly filled; there is a hot runner at gate, and temperature must be closed-loop controlled |
| Machine downtime |
Turn off heating system and operate machine like an extruder until no plastic is extruded; restart machine after production is interrupted, extrude melt until there are no bubbles |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Nine, polyethylene terephthalate (PET)
| Barrel temperature Feeding area |
50～70℃ (70℃) |
| Zone 1 |
240～260℃ (250℃) |
| Zone 2 |
240～260℃ (250℃) |
| Zone 3 |
250～290℃ (270℃) |
| Zone 4 |
250～290℃ (270℃) |
| Zone 5 |
250～290℃ (270℃) |
| Nozzle |
250～290℃ (270℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
270～280℃ |
| Barrel constant temperature |
220℃ |
| Mold temperature |
120～140℃ |
| Injection pressure |
Thin section products can reach 160MPa (1600bar) |
| Holding pressure |
About 50% to 70% of injection pressure to avoid wall shrinkage; select holding time as needed; too long holding time is easy to cause internal stress, especially for amorphous resins, which will reduce impact resistance of product |
| Back pressure |
5～10MPa (50～100bar) to avoid frictional heat |
| Injection speed |
Because of high solidification rate and crystallization rate, high speed is required; to avoid cooling and condensation of melt during injection process; it is important to maintain good air permeability in mold, otherwise entrapped air will easily cause coking at the end of runner |
| Screw speed |
Maximum screw speed is equivalent to linear speed of 0.5m/s |
| Metering stroke |
(0.5～3.5) D, because melt is very sensitive to overheating and remaining time in barrel is too long; remaining time should not exceed 5min |
| Residual material |
2～5mm, depending on metering stroke and screw diameter |
| Pre-drying |
Dry for 4h at 120℃. |
| Recovery rate |
Up to 20% recycled material can be added, provided that recycled material must be well pre-dried without thermal degradation; no stretching, bending, and impact strength are same as new material |
| Shrinkage |
It varies greatly, depending on resin, section thickness, mold temperature and holding pressure: shrinkage rate is 1.2% to 2.0%, or 30% glass fiber reinforced material is added to make shrinkage rate of 0.4% to 0.6% |
| Gate system |
Any common system gate can be used; there is a hot runner at gate, and temperature must be closed-loop controlled |
| Machine downtime |
Turn off heating system, and operate machine like an extruder until no plastic is extruded; if other thermoplastic materials are replaced at material port, it is recommended to clean with PE or PP |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Ten, polycarbonate (PC)
| Barrel temperature Feeding area |
70～90℃ (80℃) |
| Zone 1 |
230～270℃ (250℃) |
| Zone 2 |
260～310℃ (270℃) |
| Zone 3 |
280～310℃ (290℃) |
| Zone 4 |
290～320℃ (290℃) |
| Zone 5 |
290～320℃ (290℃) |
| Nozzle |
300～320℃ (290℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
280～310℃ |
| Barrel constant temperature |
220℃ |
| Mold temperature |
80～110℃ |
| Injection pressure |
Depends on flow length and section thickness: thin-walled products need fast injection; if good surface quality is required, use multi-stage slow injection |
| Screw speed |
Maximum linear speed is 0.6m/s; plasticizing time corresponds to cooling time; screw needs a large torque |
| Metering stroke |
0.5～3.5）D |
| Residual material |
2～6mm, depending on metering stroke and screw diameter |
| Pre-drying |
Drying at 120℃ for 3h; keeping moisture content below 0.02% will make mechanical properties better |
| Recovery rate |
Up to 20% recycled material can be added; higher proportion of recycled material will maintain heat resistance, but mechanical properties will decrease. |
| Shrinkage |
0.6%～0.8%, if it is glass reinforced type, 0.2%～0.4% |
| Gate system |
Gate diameter should be at least equal to 60% to 70% of maximum wall thickness of product, but gate diameter should be at least 1.2mm (inclination of gate is 3 to 5°, or product with good surface quality needs 2°); Point gates can be used for even smaller products |
| Machine downtime |
If production is interrupted, operate machine like an extruder until there is no plastic extrusion and temperature drops to about 200°C: clean barrel, use high-viscosity PE, pull screw out of hot barrel and use a wire brush to remove remaining material |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Eleven, acrylonitrile-butadiene-styrene copolymer (ABS)
| Barrel temperature Feeding area |
40～60℃ (50℃) |
| Zone 1 |
160～180℃ (180℃) |
| Zone 2 |
180～230℃ (210℃) |
| Zone 3 |
210～260℃ (240℃) |
| Zone 4 |
210～260℃ (240℃) |
| Zone 5 |
210～260℃ (240℃) |
| Nozzle |
210～260℃ (240℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1.
| Barrel constant temperature |
220℃ |
| Mold temperature |
40～80℃ |
| Injection pressure |
100～150MPa (1000～1500bar) |
| Holding pressure |
Holding time is relatively short, 30% to 60% of injection pressure |
| Melting temperature |
220～250℃ |
| Back pressure |
5～15MPa (50～150bar); if back pressure is too low, air entrapped in melt will cause coking (there are gray and black lines in product) |
| Injection speed |
It is best to use graded injection: from slow to fast; injection speed is required to achieve good surface gloss, minimum fusion seam and high strength of fusion seam; ventilation tunnel needs to be opened at the junction of front runner |
| Screw speed |
Maximum screw speed is equivalent to linear speed of 0.6m/s, but it is better to set screw speed lower, as long as plasticization process can be completed before end of cooling time |
| Metering stroke |
(0.5～4) D |
| Residual material |
2～8mm, depending on metering stroke and screw diameter |
| Pre-drying |
In some cases, ABS can be fed directly from raw material bag without pre-drying, otherwise it will be dried at 80℃ for 3 hours; wet particles will cause cracks, scratches or bubbles in product |
| Recovery rate |
30% of recycled material can be added, provided that material has not been thermally degraded before |
| Shrinkage |
0.4%～0.7% |
| Gate system |
Point gates and hot runners can be used; minimum wall thickness should not be less than 0.7mm, because ABS has poor fluidity |
| Machine downtime |
No need to clean with other materials |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Twelve, acrylonitrile-butadiene-styrene copolymer/polycarbonate (ABS/PC)
| Barrel temperature Feeding area |
50～70℃ (70℃) |
| Zone 1 |
230～250℃ (250℃) |
| Zone 2 |
250～260℃ (260℃) |
| Zone 3 |
250～270℃ (265℃) |
| Zone 4 |
250～270℃ (265℃) |
| Zone 5 |
250～270℃ (265℃) |
| Nozzle |
250～270℃ (270℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
260～270℃ |
| Barrel constant temperature |
200℃ |
| Mold temperature |
70～90℃ |
| Injection pressure |
80～150MPa (800～1500bar) |
| Holding pressure |
40%-50% of injection pressure to avoid wall shrinkage of product; in order to minimize internal stress of product, holding pressure should be set as low as possible |
| Back pressure |
As long as 5～10MPa (50～100bar), avoid frictional heat |
| Injection speed |
Medium injection speed, to minimize friction heat; multi-stage injection; for some products, it is recommended to use slow to fast |
| Screw speed |
Maximum screw speed is converted to a linear speed of 4.0m/s |
| Metering stroke |
1.0～3.0) D, because melt is very sensitive to overheating and too long remaining time in barrel; remaining time should not exceed 6min, residence time in hot runner should be as small as possible |
| Residual material |
2～5mm, depending on metering stroke and screw diameter |
| Pre-drying |
Dry for 4h at 80℃ |
| Recovery rate |
20% of recycled material can be added, as long as material has not been thermally degraded and has been properly pre-dried; it is better if it is a product with low strength requirements |
| Shrinkage |
Almost isotropic, 0.5%～0.7%; for glass fiber reinforced type, 0.2%～0.4% |
| Gate system |
Any kind of ordinary gate can be used; there is a hot runner at the gate, and temperature must be closed-loop controlled |
| Machine downtime |
Turn off heating and operate machine to clean barrel like an extruder |
| Barrel equipment |
Standard screw diameter is 50mm; for large diameter screws, low compression and short metering section geometry are used; non-return ring, straight nozzle |
Thirteen, styrene-acrylonitrile copolymer (SAN)
| Barrel temperature Feeding area |
30～50℃ (50℃) |
| Zone 1 |
160～180℃ (180℃) |
| Zone 2 |
180～230℃ (210℃) |
| Zone 3 |
210～260℃ (240℃) |
| Zone 4 |
220～260℃ (240℃) |
| Zone 5 |
220～260℃ (240℃) |
| Nozzle |
220～260℃ (240℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1.
| Melting temperature |
220～250℃ |
| Barrel constant temperature |
200℃ |
| Mold temperature |
40～80℃ |
| Injection pressure |
100～150MPa (1000～1500bar) |
| Holding pressure |
Holding time is relatively short, 30% to 60% of injection pressure |
| Back pressure |
5～15MPa (50～150bar), if back pressure is too low, air entrapped in melt will cause coking (gray and black lines in product) |
| Injection speed |
Use fast injection to obtain good surface gloss and color, minimum fusion seam and maximum fusion seam strength |
| Screw speed |
Maximum screw speed is equivalent to linear speed of 0.6m/s, but it is better to set screw speed lower, as long as plasticization process can be completed before end of cooling time; medium screw speed is required |
| Metering stroke |
0.5～4.0D |
| Residual material |
2～8mm, depending on metering stroke and screw diameter |
| Pre-drying |
Dry for 4 hours at 80℃; improper storage will increase water absorption; this will cause cracks, scratches or bubbles on the surface of product during molding process |
| Recovery rate |
30% of recycled material can be added, provided that material has not been thermally degraded; for high-quality products, only authentic raw materials |
| Shrinkage |
0.4%～0.7% |
| Gate system |
Generally, any gate system and hot runner can be used |
| Machine downtime |
No need to clean with other materials |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Fourteen, organic glass (PMMA)
| Barrel temperature Feeding area |
60～80℃ (70℃) |
| Zone 1 |
150～200℃ (190℃) |
| Zone 2 |
180～220℃ (210℃) |
| Zone 3 |
200～250℃ (230℃) |
| Zone 4 |
200～250℃ (230℃) |
| Zone 5 |
200～250℃ (230℃) |
| Nozzle |
200～250℃ (230℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1
| Melting temperature |
220～250℃ |
| Barrel constant temperature |
170°C |
| Mold temperature |
40～80℃ |
| Injection pressure |
High injection pressure is required due to poor fluidity |
| Holding pressure |
100～170MPa (1000～1700bar); For thick section products, high pressure holding pressure and long pressure holding time are required, such as lenses (40%～60% of injection pressure, 2～3min) |
| Back pressure |
Relatively high back pressure is required: 10～30MPa (100～300bar); insufficient back pressure can easily cause voids or gray-black markings in product |
| Injection speed |
Depends on section thickness and flow length: thick section products require a very low injection speed to achieve a suitable forward flow effect; multi-stage injection: from slow to fast speed, it is recommended to use near gate for good surface quality |
| Screw speed |
Carry out plasticizing and cooling as slowly as possible to adapt to cooling time: maximum linear velocity is 0.6m/s; screw torque is required to be high |
| Metering stroke |
0.5～3.5D |
| Residual material |
2～6mm, depending on metering stroke and screw diameter |
| Pre-drying |
It is absolutely necessary to dry at 80℃ for 4h, because water absorption rate is as high as 1% |
| Recovery rate |
Allowed, as long as material has been properly dried and pigments are added; products produced by adding recycled materials no longer have good optical quality |
| Shrinkage |
0.3%～0.7% |
| Gate system |
Due to poor resin fluidity, a large gate is required; for lenses, gate should be 0.5mm smaller than thickness of outer contour of lens; diameter of gate should be at least as large as thickness of product section; in order to obtain a good surface quality near gate, sharp edges should be avoided between gate and product; for effective pressure transmission over long distances, gate (cross section) should be short and round or square; do not use a wide or/thin gate cross section |
| Machine downtime |
No need to clean |
| Barrel equipment |
Standard screw, special geometric dimensions are required for optical parts; non-return ring, straight nozzle |
Fifteen, polyoxymethylene
| Barrel temperature Feeding area |
40～50℃ (50℃) |
| Zone 1 |
160～180℃ (180℃) |
| Zone 2 |
180～205℃ (190℃) |
| Zone 3 |
185～205℃ (200℃) |
| Zone 4 |
195～215℃ (205℃) |
| Zone 5 |
195～215℃ (205℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1.
| Melting temperature |
205～215℃ |
| Barrel constant temperature |
170℃ |
| Mold temperature |
40～120℃ |
| Injection pressure |
100-150MPa (1000-1500bar); for thick-walled products with a section thickness of 3-4mm, injection pressure is about 100MPa (1000bar), and for thin-walled products, it can be increased to 150MPa (1500bar) |
| Holding pressure |
Depends on product wall thickness and mold temperature; the longer holding pressure, the smaller shrinkage of parts; holding pressure should be 80-100MPa (800-1000bar), pressure in mold can be 60-70MPa (600-700bar); where precision molding is required, it is advantageous to maintain same level of injection pressure and holding pressure (no pressure drop).
Under same cycle time condition, if holding time is extended, molding weight will not increase, which means holding time is optimized; usually holding time is 30% of total cycle time; molding weight is only 95% of standard weight, because shrinkage rate is 2.3%: when molding weight reaches 100%, shrinkage rate is 1.85%; balanced and low shrinkage rate keeps product size stable |
| Back pressure |
5～10MPa (50～100bar) |
| Injection speed |
Medium injection speed; if injection speed is too slow and mold or melt temperature is too low, fine holes will often appear on the surface of product |
| Screw speed |
Screw speed is equivalent to linear speed of 0.7m/s: screw speed is set as long as plasticization process can be completed before end of cooling time; screw torque requirement is medium |
| Metering stroke |
(0.5～3.5) D |
| Residual material |
2～6mm, depending on metering stroke and screw diameter |
| Pre-drying |
No need; if material is damp, dry it at 100℃ for about 4h |
| Recovery rate |
General molding can use 100% return material, precision molding can add up to 20% return material |
| Shrinkage |
About 2% (1.8%～3.0%); contraction stops after 24h |
| Gate system |
Point gates can be used for small products with average wall thickness; cross section of gate should be 50% to 60% of the thickest section of product; it is better to inject against some obstacles (neutrons, barriers) in cavity; molding with hot runner mold is also a process method |
| Machine downtime |
Turn off heating system 5-10 minutes before end of production, set back pressure to zero, like an extruder to empty barrel; when replacing other resins, such as PA or PC, clean barrel with PE |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
Sixteen, acetate Fiber (CA)
| Barrel temperature Feeding area |
30～40℃ (40℃) |
| Zone 1 |
140～160℃ (150℃) |
| Zone 2 |
160～185℃ (170℃) |
| Zone 3 |
170～200℃ (180℃) |
| Zone 4 |
170～200℃ (180℃) |
| Zone 5 |
170～200℃ (180℃) |
| Nozzle |
170～200℃ (180℃) |
Temperature in brackets is recommended as basic setting value, stroke utilization rate is 35% and 65%, ratio of module flow length to wall thickness is 50:1 to 100:1.
| Melting temperature |
200～210℃; Color change of melt indicates that temperature of melt is too high; if temperature of melt is too low, surface gloss and transparency will be affected |
| Barrel constant temperature |
160℃ |
| Mold temperature |
40～80℃ |
| Injection pressure |
80～120MPa (800～1200bar) |
| Holding pressure |
40%～100% of injection pressure; pressure should not be too high to avoid internal stress; thick-walled products allow a longer holding time |
| Back pressure |
5～10MPa (50～100bar) |
| Injection speed |
Fast injection for thin-walled products; slow speed for thick-walled products |
| Screw speed |
Medium screw speed, equivalent linear speed is 0.6m/s |
| Metering stroke |
(1.0～3.5) D |
| Residual material |
3～8mm, depending on metering stroke and screw diameter |
| Pre-drying |
Dry for 3h at 70℃ |
| Recovery rate |
20% of recycled material can be added, provided that there is no thermal degradation and pre-drying |
| Shrinkage |
0.4%～0.7% (0.4% in direction of material flow, 0.6%～0.7% in direction of cross section of material flow) |
| Gate system |
Point type/latent type gate; avoid jet flow when using auxiliary neutron equipped with spring, otherwise surface defects will easily occur near gate |
| Machine downtime |
Turn off heating system, plasticize several times without back pressure and empty barrel like operating an extruder |
| Barrel equipment |
Standard screw, special geometry is required in some cases, non-return ring, straight nozzle |
Seventeen, polyphenylene ether (PPO)
| Barrel temperature Feeding area |
40～60℃ (50℃) |
| Zone 1 |
240～280℃ (250℃) |
| Zone 2 |
280～300℃ (280℃) |
| Zone 3 |
280～300℃ (280℃) |
| Zone 4 |
280～300℃ (280℃) |
| Zone 5 |
280～300℃ (280℃) |
| Nozzle |
280～300℃ (280℃) |
| Melting temperature |
270～290℃ |
| Barrel constant temperature |
200℃ |
| Mold temperature |
80～120℃ |
| Injection pressure |
100～140MPa (1000～1400bar) |
| Holding pressure |
40%～60% of injection pressure |
| Back pressure |
3～10MPa (30～100bar) |
| Injection speed |
Products with long runners need to be injected quickly; but in this case, ensure that mold has sufficient air permeability |
| Screw speed |
Medium screw speed, equivalent linear speed is 0.6m/s |
| Metering stroke |
(0.5～3.5)D |
| Residual material |
3～6mm, depending on metering stroke and screw diameter |
| Pre-drying |
Dry for 2h at 110℃ |
| Recovery rate |
Material can be recycled, as long as returned material does not undergo thermal degradation |
| Shrinkage |
0.8%～1.5% |
| Gate system |
Use point or latent gate for small products, otherwise use direct gate or wafer gate; hot runner can be used |
| Machine downtime |
Turn off heating system; under low screw back pressure, operate several metering cycles to empty barrel like operating an extruder |
| Barrel equipment |
Standard screw, non-return ring, straight nozzle |
