Some related data for injection molding
Time：2023-01-03 08:40:04 / Popularity： / Source：
Injection molding machine screw barrel troubleshooting table
Due to complexity of injection molding machine processing, various small problems are often encountered in production process. Although these problems are not serious, they always trouble production efficiency of factory and affect economic benefits. Therefore, I compiled a summary of problems related to screw of injection molding machine and conventional methods for solving problems, as shown in following table:
| Symptom | Part of reason for screw barrel | Solution |
| No injection | Screw breakage | Replace screw with a new one |
| Hopper frame "bridge" | Bring down bridge | |
| Temperature of feeding section of barrel is too high | Reset temperature of feed section to ensure smooth operation of water line | |
| Crushed material volume is too large | Re-crushing raw materials, changing design of feeding port of material tube (drawing grooves on inner wall, making eccentric milling slope), deepening depth of screw groove | |
| Product is yellow with black spots | Screw barrel wear | Replace corresponding screw or barrel according to wear condition |
| Screw assembly has a dead angle | Replace corresponding special screw or three small pieces | |
| Screw is carbonized by raw material | Use screw material with better corrosion resistance | |
| Nozzle hole is too small | Re-drill nozzle hole | |
| Screw compression ratio is too large | Replace corresponding compression ratio screw | |
| Screw temperature is too high | Cooling deep hole in screw core | |
| Poor product plasticization | Raw material cannot be fully melted in screw | Increase temperature of barrel and use a separate screw |
| Uneven product color mixing | Screw mixing effect is not good | Use high mixing screw |
| Injection end point is unstable | Left and right movable gap of apron is too large | Replace apron with a small movable gap |
| Apron and meson do not cooperate well | Replace rings and mesons with good outer diameter and end face verticality | |
| Gap between the apron and the barrel is too large | Replace corresponding wear parts | |
| Contact point between material tube and flange is easy to leak glue | Two ends of material tube and flange are not tightly attached | Overhaul inner and outer seam lengths of two workpieces |
| End face of flange is not perpendicular to outer seam | Overhaul verticality of inner and outer seams, end faces of two workpieces | |
| Insufficient tensile strength of screw or barrel | Use grade 12.9 screws, use tempered material tube, outer diameter of material tube | |
| It is difficult for screw to retreat | Temperature of feeding section is too high; broken material is too large; shell pressure setting is too large; setting of feeding section of barrel is unreasonable; gap between screw barrel and barrel is too small | Set reasonable parameters; re-shred smaller raw materials; replace screw barrel with a new one if gap is too large; design a reasonable feed port |
| Product has air bubbles | Back pressure is too low; compression ratio is too small; injection speed is too slow and mold temperature is not high; | Set reasonable process parameters and choose a screw with a larger compression ratio |
| There is abnormal noise in screw | Material tube is not assembled in place; size of material port of barrel is too small; diameter of screw shank is too small; straightness of screw is not good; design of screw discharge is not smooth enough; debris falls into barrel | Check size of each gear; reinstall; remove foreign matter; use three small pieces with smooth discharge structure when producing raw materials with poor fluidity |
Injection Molding Material Shrinkage Rate and Density Quick Lookup Table
| Material | Nominal | Density | Shrinkage |
| g/cm3 | % | ||
| Polystyrene | PS | 1.05 | 0.3-0.6 |
| Polystyrene, medium. high impact | HI-PS | 1.05 | 0.5-0.6 |
| Polystyrene-acrylonitrile | SAN | 1.08 | 0.5-0.7 |
| Acrylonitrile-Butadiene-Styrene | ABS | 1.06 | 0.4-0.7 |
| Phenylene-Styrene-Acrylic Acid | ASA | 1.07 | 0.4-0.6 |
| Low-density polyethylene | LDPE | 0.954 | 1.5-4.0 |
| High-density polyethylene | HDPE | 0.92 | 1.5-3.6 |
| Polypropylene | PP | 0.915 | 1.0-2.5 |
| Polybenzene-GR | PPGR | 1.15 | 0.5-1.2 |
| Polymethylpentene | PMP | 0.83 | 1.5-3.0 |
| Soft PVC | PVC-soft | 1.38 | 1.0-2.5 |
| Rigid PVC | PVC-rigid | 1.38 | 0.1-0.6 |
| Polyvinylidene fluoride | PVDF | 1.2 | 3.0-6.0 |
| PTFE | PTFE | 2.12-2.17 | 3.5-6.0 |
| Polymethyl methacrylate (propylene) | PMMA | 1.18 | 0.1-0.8 |
| Polyoxymethylene (vinyl acetal) | POM | 1.42 | 1.8-3.5 |
| Polyphenylene oxide or polyphenylene oxide | PPO | 1.06 | 0.1-0.7 |
| Polyphenylene oxide-GR | PPO-GR | 1.27 | <0.7 |
| Cellulose acetate | CA | 1.27-1.3 | 0.5 |
| Cellulose acetate-butyrate | CAB | 1.17-1.22 | 0.5 |
| Cellulose Propionate | CP | 1.19-1.23 | 0.5 |
| Polycarbonate | PC | 1.2 | 0.4-0.8 |
| Polycarbonate-GR | PC-GR | 1.42 | 0.15-0.55 |
| Polyethylene terephthalate | PET | 1.37 | 0.2-2.0 |
| Polyethylene terephthalate-GR | PET-GR | 1.5-1.57 | 1.2-2.0 |
| Polybutylene terephthalate | PBT | 1.3 | 0.9-1.8 |
| Polybutylene terephthalate-GR | PBT-GR | 1.52-1.57 | 0.3-1.2 |
| Nylon 6 (Polyamide 6) | PA 6 | 1.14 | 0.8-1.5 |
| Nylon 6-GR | PA 6-GR | 1.36-1.65 | 0.3-1 |
| Nylon 6/6 | PA66 | 1.15 | 1.2-1.8 |
| Nylon 6/6-GR | PA66-GR | 1.20-1.65 | 0.5-1.5 |
| Nylon 11 | PA 11 | 1.03-1.05 | 0.5-1.5 |
| Nylon 12 | PA 12 | 1.01-1.04 | 0.5-1.5 |
| Polyether alum | PSO | 1.37 | 0.7 |
| Polyphenylene sulfide | PPS | 1.64 | 0.5-0.7 |
| Thermoplastic polyurethane | PUR | 1.2 | 0.9 |
| Phenolic Formaldehyde Resin GP | PF | 1.4 | 1.2 |
| Melamine formaldehyde GP | MF | 1.5 | 1.2-2 |
| Melamine phenol formaldehyde | MPF | 1.6 | 0.8-1.8 |
| Polyester resin | UP | 2.0-2.1 | 0.5-0.8 |
| Epoxy resin | EP | 1.9 | 0.2 |
Plastic unit conversion table
| Flexural, tensile, compressive strength and modulus | |||
| MPa | Psi | kg/cm2 | kg/m2 |
| 1 | 145 | 10.19 | 101945.15 |
| 6.9×10-3 | 1 | 0.0703 | 703.07 |
| 9.8×10-2 | 14.22 | 1 | 10000 |
| 9.8×10-6 | 1.422.×10-3 | 0.0001 | 1 |
| Impact strength | ||
| ft-lb/in | J/m | kg-cm/cm |
| 1 | 53.35 | 5.45 |
| 0.0187 | 1 | 0.102 |
| 0.183 | 9.803 | 1 |
| British | Metric | SI Metric |
| 1ft | =0.3048m | |
| 1 in | =2.54cm | =25.4mm |
| 1 thou | =0.0254mm | =25.4μm |
| 1 yd2 | =0.8361 m2 | |
| 1 ft2 | =0.0929 m2 | |
| 1 in2 | =6.4516 cm2 | =654.16 mm2 |
| 1 yd3 | =0.7645 m3 | |
| 1 ft3 | =0.0283 m3 | =28.317 dm3 |
| 1 in3 | =16.387 cm3 | |
| 1 gal | =4.5459 litres | =4.5459 dm3 |
| ℉ | =(1.8×℃)+32 | |
| 1 ton | =1.0160 tomes | |
| 1 lb | =0.4536 kg | |
| 1oz | =28.3495g | |
| 1 lbf | =0.457 kgf 4.4482 N | |
| 1 lbf/in2 | =0.0703kgf/cm2 | =6.8948kN/m2 |
| 1 lb/ft3 | =16.018 kg/m3 | |
| 1 lb/in3 | =27.68 g/cm3 | =27.68 Mg/m3 |
| 1 Btu | =251.996 cal | =1.0550 KJ |
| Metric | British | SI Metric |
| 1 m | =3.2808 ft | |
| 1 cm | =0.3937 in | |
| 1 mm | =0.03937 in | |
| 1 m2 | =1.1959 yd2 | |
| 1 m2 | =10.7639 ft2 | |
| 1 cm2 | =0.1550 in2 | |
| 1 m3 | =1.3079 yd3 | |
| 1 m3 | =35.3147 ft3 | |
| 1 cm3 | =0.061 in3 | |
| 1 liter | =0.2199 gal | =1 dm3 |
| 1 cm3 | =0.0000353 ft3 | |
| ℃ | =((℉-32)×5)÷9 | |
| 1 tonne | =0.9842 ton | |
| 1 kg | =2.2046 lb | |
| 1g | =0.0353oz | |
| 1 kgf | =2.2046 lbf | =9.8066 N |
| 1 kgf/cm2 | =14.2233 lbf/in2 | =98.0665kN/m2 |
| 1 kg/m3 | =0.0624 lb/ft3 | |
| 1 g/cm3 | =0.0361 ib/in3 |
Injection Molding Temperature Guidelines
| Raw material name | Code name | Nozzle temperature | First stage temperature | Second stage temperature | Temperature of feeding section |
| Polystyrene | PS | 150-230℃ 330-445℉ |
165-230℃ 330-445℉ |
155-215℃ 310-420℉ |
145-200℃ 295-390℉ |
| Styrene_Acrylonitrile | SAN(AS) | 190-280℃ 380-540℉ |
150-230℃ 300-445℉ |
150-230℃ 300-445℉ |
150-230℃ 300-445℉ |
| Acylonitrile-Butadient-Styrene | ABS | 210-230℃ 410-446℉ |
220-230℃ 428-446℉ |
210-220℃ 410-428℉ |
200-210℃ 392-410℉ |
| Cellulose Acetate | CA | 160-225℃ 320-440℉ |
185-225℃ 365-440℉ |
175-210℃ 345-410℉ |
160-190℃ 320-375℉ |
| Cellulose Acetate Butyrate | CAB | 140-190℃ 285-375℉ |
160-190℃ 320-375℉ |
150-180℃ 300-355℉ |
140-170℃ 285-340℉ |
| Acrylic | PMMA | 200-250℃ 390-480℉ |
220-250℃ 430-485℉ |
210-240℃ 410-465℉ |
200-230℃ 390-445℉ |
| Polyphenylen oxide (Noryl) | PPO | 225-290℃ 440-555℉ |
245-290℃ 475-555℉ |
235-280℃ 455-540℉ |
225-270℃ 440-520℉ |
| Polycarbonate | PC | 250-320℃ 480-610℉ |
290-320℃ 555-610℉ |
270-300℃ 520-575℉ |
250-280℃ 480-540℉ |
| Polysulphone | PSF | 300-360℃ 575-680℉ |
320-360℃ 610-680℉ |
310-350℃ 590-660℉ |
300-340℃ 575-645℉ |
| Polyamide 6.6 (Polyamide A) | PA | 260-295℃ 500-565℉ |
270-295℃ 520-565℉ |
270-295℃ 520-565℉ |
270-295℃ 520-565℉ |
| Polyamide 6 (Polyamide B) | PA | 220-260℃ 430-500℉ |
230-260℃ 445-500℉ |
220-250℃ 430-485℉ |
220-240℃ 430-465℉ |
| Polyamide 12 | PA | 195-250℃ 385-480℉ |
200-250℃ 390-480℉ |
190-240℃ 380-465℉ |
190-240℃ 380-465℉ |
| Polyurethane (linear) (Polyamide C) |
PUR | 175-230℃ 345-445℉ |
200-235℃ 390-455℉ |
190-225℃ 375-440℉ |
180-215℃ 365-420℉ |
| Acetat resin | POM | 185-220℃ 365-430℉ |
185-215℃ 365-420℉ |
185-200℃ 365-390℉ |
185-200℃ 365-390℉ |
| Lin. Polyester | PETP | 230-290℃ 450-555℉ |
240-290℃ 465-555℉ |
230-280℃ 445-540℉ |
220-270℃ 430-520℉ |
| Polyethylene Soft | PE | 185-250℃ 360-480℉ |
210-250℃ 410-480℉ |
200-240℃ 390-465℉ |
190-230℃ 375-445℉ |
| Polyethylene Hard | PE | 190-300℃ 375-575℉ |
230-300℃ 445-575℉ |
220-290℃ 430-555℉ |
210-280℃ 410-540℉ |
| Polypropylene | PP | 230-300℃ 445-575℉ |
220-290℃ 430-555℉ |
210-270℃ 410-520℉ |
200-250℃ 390-480℉ |
| Polytetrafluor-ethylene (Hostaflon Teflon FEP) |
PCTFE FEP |
320-390℃ 610-735℉ |
340-370℃ 645-700℉ |
320-350℃ 610-660℉ |
300-330℃ 575-625℉ |
| Tefzel | ETFE | 325-350℃ 620-600℉ |
350-365℃ 600-690℉ |
305-355℃ 580-670℉ |
295-345℃ 565-655℉ |
| PVC Rigid | PVC Rigid | 145-180℃ 295-355℉ |
160-180℃ 320-355℉ |
150-170℃ 300-340℉ |
140-160℃ 285-320℉ |
| PVC Soft | PVC Soft | 140-200℃ 285-390℉ |
150-170℃ 300-340℉ |
140-160℃ 285-320℉ |
130-150℃ 265-300℉ |
| Polyphenylene sulfide |
PPS | 310-320℃ 590-608℉ |
310-320℃ 590-608℉ |
300-310℃ 572-590℉ |
290-300℃ 554-572℉ |
| Liquid Crystal Polymer | LCP | 290-310℃ 554-590℉ |
310-330℃ 590-626℉ |
300-320℃ 572-608℉ |
280-290℃ 536-554℉ |
| Polyethersulfone | PES | 330-370℃ 626-698℉ |
330-370℃ 626-698℉ |
310-350℃ 590-662℉ |
300-340℃ 572-644℉ |
| Polyamide-imide | PAI | 320-330℃ 608-626℉ |
340-360℃ 644-680℉ |
310-330℃ 590-626℉ |
290-300℃ 554-572℉ |
| Polyetherimide | PEI | 325-410℃ 617-770℉ |
320-405℃ 608-761℉ |
310-395℃ 590-743℉ |
310-330℃ 590-626℉ |
| Polyetheretherketone | PEEK | 360-400℃ 680-752℉ |
380-410℃ 716-770℉ |
370-400℃ 698-752℉ |
350-380℃ 662-716℉ |
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