1 Processing of thermoplastic polymers Introduction Extrusion  Extruder  Processes  Tools and products  Elements of extrusion line Injection molding  The injection molding machine  Phases  Structure  Tools Hollow articles  Extrusion blow molding  Injection blow molding  Rotational molding Other technologies  Calendering  Thermoforming  Welding  Compression molding  Pretreatments, mixing  Mechanical fabrication

2 Introduction Shear rate in the different processing techniques  Compression molding( = 1-10 s -1 )  Calendering( = s -1 )  Extrusion( = s -1 )  Injection molding( = s -1 ) Large productivity, unique properties Processing: non-equilibrium processes  Shearing

3 Extrusion – extruder line, components Components: motor, gear, flexible coupling, feeder extruder feeder die caliber, cooling bath Pull-out assembly saw tipping tray

4 Extrusion – plasticating unit Flexible coupling Thrust assembly Feeder Barrel Vacuum hole Pressure regulator Thermocouple, pressure sensor screw Heating, cooling Gear

5 Extrusion – screw and other components Components: breaker plate, filter; die; sizing plate; cooling; pull-out assembly; extruder line Melt pumping zone Compression zone Solid transport zone

6 Extrusion - processes Screw characteristics Solid transport Pumping flow Drag flow Leakage flow

7 Extrusion – melting Melt, Rotating flow Screw flight Surface of barrel Melt film Melt/solid interface Solid

8 Extrusion – rate distribution, transport Drag flow Barrel surface Pressure flow Screw surface Open dischargeClosed discharge

9 Extrusion – flow rate, operational points Flow rate  Extruder  Tool

10 Extrusion – tool, product Melt Air Core Tool body Caliber Ironing zone Product: pipes, profiles, sheets, cable insulation, multilayer films, granules

11 Injection molding - machine Die headStandard extruder head Barrel Screw Feeder Tachometer drive Hydraulic motor Screw drive Thrust bearing Two hydraulic injection cylinders Heaters Non-return valve flow assembly Injection chamber

12 Injection molding - machine a) Closed valve b) Open valve Components: driving unit, feeding, barrel and screw, non-return valve

13 Injection molding – tool closing Solution: mechanical, hydraulic, hydro-mechanic Clamp ram Oil port return Product Oil port forward Moving platenStationary platen Tie rod Tool

14 Injection molding – tool closing Ejector pins Backing plates Spure bush Opening plain I Opening plain II

Injection molding cycle Clamping Plasticating unit moves to the mold Injection molding Holding pressure Cooling, plasticating Mold opens, ejection 15

Injection molding cycle 16

17 Injection molding - phases Plasticating, dose, melt quality JettingTurbulent flow melt Tool filling: free spring turbulentlaminar

18 Injection molding – phases, cooling

19 Injection molding – structure Cross section Direction of flow Skin Core

20 Injection molding – structure, properties Orientation – anisotropic properties

21 Injection molding – structure, properties Internal stresses

22 Hollow articles – extrusion blow Extruder Extruder tool Blowing tool Cutting edge Preform Blowing

23 Hollow articles – extrusion blowing Important question  Closing force  Waste  Calibration of neck  Welding lines  Stretching and swelling  Temperature distribution  Cooling  Surface quality

24 Hollow articles – extrusion blow molding Whiskey and PET bottles

Injection blow molding Production of PET bottles Multistep processing technology  Injection molding of preforms  Blowing the preform Reasons  Transportation of preform is economic  The blowing step is toghether with filling of the bottle. Blowing is above 100 °C (clean) 25

Injection blow molding Production of PET bottles Technology 26

27 Hollow articles – rotational molding Tool fillingCooling chamber Heated chamber Tool rotating motor Arm Door Air Air heating Ventilation Rail Tool Tool movement

Hollow articles – rotational molding 28

29 Hollow articles - calendering Extruder Two-roll mill F-calender Pull-out Cooled rolls Rolling Main steps: introduction of components; premixing, homogenization; melting, gelation; melt homogenization; feeding of calender; calendering, forming; pull-out, cooling; printing, treatment; rolling, storage

30 Hollow articles - themoforming Thermoforming  Cups (whipped cream)  Productivity Welding  Direct welding  Indirect welding Compression molding Pretreatment, mixing Mechanical fabrication Thick parts Thin corners and edges Products Sheet heating Fixing vacuum Insulation

Hollow articles - themoforming Production of yogurt cups 31

Hollow articles - themoforming 32