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Selection of hot runner nozzles depending on mould mass and material fluidity
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Types of material |
Plastics
with good fluidity:
PP, PE, PS, SB |
Plastics
with medium fluidity:
ABS, SAN, TPE,
PA, PMMA, EVAC |
Plastics
with poor fluidity:
PC, POM, PPE, PPS,
PSU, PET, PBT |
| Nozzle type |
Injection mass [g] |
| D... - 1 |
30 |
10 |
5 |
| D... - 2 |
60 |
30 |
10 |
| D... - 3 |
200 |
100 |
40 |
| D... - 4 |
600 |
300 |
100 |
| D... - 5 |
1200 |
600 |
250 |
| D... - 6 |
2000 |
1000 |
400 |
General information:
- Each successive nozzle type number also indicates the injection mass [g] according to the table above.
- Addition of filling materials reduces plastic fluidity.
- Values of the injection mass given in the table are approximate values determined for maximum gate diameter. The exact injection mass value depends on the type of processed material, the ratio of flow length to mould wall thickness and other variables of plastic processing.
Selection of gate diameter
Selection of hot runner nozzles depending on type of material
- amorphous plastics: PS, SB, SAN, ABS, PVC, CA, PMMA, PC, PSU, PEI
- crystalline plastics: PE, PP, PA, PET, PBT, POM, PPS, PEEK
- quick solidifying crystalline plastics: PA, POM, PET, PBT, PEEK
- slow solidifying crystalline plastics: PP, PE
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- thermally stable plastics: PE, PP, PMMA, PC, PS
- thermolabile plastics: PVC, POM, PBT, PET, CA, PPA, PEEK
- plastics with tendency to string: PA, PP, PEHD, PET, PS, PC
- plastics with small resistance to cutting: PVC, CA, POM, EVAC
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- Nozzle with a needle tip is recommended for mouldings where the gate vestige is essential. It is recommended for frequent change of injected material colour. It also enables intensive cooling in the gate area. It is used for such plastics, as: PP, PE, PS, SAN, ABS, PMMA, CA, EVAC.
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- Nozzle with an open tip is recommended for mouldings where the gate vestige is not important. Injection into mould cavity or indirect injection. Recommended for processing amorphous plastics and slow solidifying crystalline plastics: PP, PE.
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- Nozzle with a needle tip in housing sleeve inserted in mould cavity or "cold channel" (indirect injection). Little gate vestige. It is used with quick solidifying crystalline plastics: PA, PBT, PEEK and amorphous plastics: PS, PMMA, PC, SB, ABS.
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- Nozzle with an open tip in housing sleeve inserted in mould cavity or “cold channel” (indirect injection). Visible gate vestige, high temperature of gate area. Used for quick solidifying crystalline plastics: PA, POM, PET and amorphous plastics.
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- Nozzle with plastic-isolated needle tip is recommended for all applications in which gate vestige is essential and for processing materials that have a tendency to string or drool. Good cooling in the gate area. Recommended for processing: PP, PE, PS, SAN, ABS.
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- Plastic insulated nozzle with an open tip. It is recommended for applications in which gate vestige is not important. Ideal for indirect injections ("cold channel"). Intensive cooling of gate area is possible. Recommended for amorphous plastics and slow solidifying crystalline plastics: PE and PP.
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- Nozzles with an open tip designed for technical mouldings in which gate vestige is not important. Recommended for processing recycled material because of its design that enables easy cleaning. Use decompression when processing materials that have tendency to string or drool. Used with amorphous and crystalline materials.
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- Nozzle with a needle tip (mini-torpedo) placed at the end of the nozzle. Easy change of colour. Used for amorphous and slow solidifying crystalline plastics.
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- Nozzle with a long injection needle placed inside the channel. The needle is heated by nozzle body and melted plastic heat. Very little gate vestige, easy change of colour and adjustable gate area temperature. Used with such plastics, as: PS, SAN, ABS, PP, PE.
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- Nozzle with an open tip inserted into mould cavity. Visible gate vestige. Used with amorphous and slow solidifying crystalline plastics.
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- Nozzle with a needle tip (mini-torpedo) placed at the end of the nozzle. The needle is heated by nozzle body and melted plastic heat. Used with quick solidifying crystalline plastics: PA, PBT, PEEK.
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- Nozzle with a long injection needle placed inside. The needle is heated by nozzle body and melted plastic heat. Quick change of plastic colour. No deposits of material. Used for: PS, SAN, ABS, PP, PE.
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- Nozzle with an open tip. Visible gate vestige. Injection into mould cavity or indirect injection. Used with quick solidifying crystalline plastics.
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Tips concerning nozzle selection
Application of nozzles with needle tips for plastics with small resistance to cutting, plastics containing organic dyes and plastics with anti-burn additives is not recommended.
When processing reinforced plastics or plastics with anti-burn additives use nozzles with special tips of KT type.
When choosing a nozzle always take into consideration:
- injection mass
- type of material
- change of colour (how often)
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- flow length
- type of filler if used
- desired gate vestige
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