ELEMENTARY STEPS SHAPING METHODS POST SHAPING DIE FORMING HANDLING OF PARTICULATE SOLIDS MOLDING & CASTING MELTING PRESSURISATION & PUMPING

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Clifford Mosley
5 years ago
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2 ELEMENTARY STEPS SHAPING METHODS POST SHAPING RAW MATERIALS RAW MATERIALS HANDLING OF PARTICULATE SOLIDS DIE FORMING MELTING MOLDING & CASTING PRESSURISATION & PUMPING SECONDARY SHAPING MIXING DEVOLATILLIZATION AND STRIPPING CALENDERING & COATING MOLD COATING

3 EXTRUSION PROCESS INJECTION PROCESS THERMOFROMING PROCESS COMPRESSION PROCESS

4 POLYMERIC MATERIALS 1 VERGIN POLYMERS (A FEW ADDITIVES ADDED) 2 POLYMER BLENDS (A FEW ADDITIVES AND COMPATIBILISER ADDED) 3 POLYMER COMPOUNDS (ADDITIVES AND FILLERS ADDED)

DIRECTION DIRECTION ADDITIVESING and FILLERS FILLERS AND REINFORCMENTS FILLERS OR EXTENDERS ARE NORMALLY ADDED TO INCREASED BULK VOLUME,HENCE REDUCE COST.

5 DIRECTION DIRECTION ADDITIVESING and FILLERS FILLERS AND REINFORCMENTS FILLERS OR EXTENDERS ARE NORMALLY ADDED TO INCREASED BULK VOLUME,HENCE REDUCE COST.THE REINFORCEMENTS ARE, ON THE OTHER HAND,INCORPERATED TO ENHANCE THE PROPERTIES, ESPECIALLY MECHANICAL ONES. EXAMPLE:CALCIUM CARBONATE,SILICA,CLAY,FIBER GLASS, WOOD FIBER,CARBON FIBER. Y Y X X X X Y Y > X FIBER REINFORCED Y Y = X PARTICULATE FILLER

6 DYES AND PIGMENT DYES ARE SOLUBLE COLORANT FOR POLYMER BUT THE PIGMENTS ARE INSOLUBLE ONE. SOME COLORANTS MAY ALSO ADVERSELY AFFECT ON POLYMER PROPERTIES. DYE ADDITIVE PIGMENT ADDITIVE

7 FLAME RETARDANTS FRAME RETARDANTS ARE USED TO INHIBITE/LOWER THE FLAME PROPAGATION RATE. THEY CAN BE DONE BY ABSORBING HEAR OR PRODUCEING LARGE AMOUNT OF INCOMBUSTIBLE GAS SUCH AS CO 2. EXAMPLE:ANTIMONY OXIDE,ORGANIC PHOSPHATES,HALOGENIC COMPOUNDS,ZINC BORATE. TABLE: UL-94 RATING FOR FLAME TEST UL-RATING V-0 V-1 V-2 SUMMARISED DESCRIBTION NO TEST SPECIMEN BURN LONGER THAN 10s. SAME AS V-0 BUT ALL SPECIMEN MUST EXTINGUISH IN 30s. SAME AS V-1 AND THERE IS A DRIP TO IGNITE DRY COTTON. TABLE: LIMITING OXYGEN INDEX(LOI)(ASTM D635-74) POLYMERS POM PP PE PET PS PC PEEK PTFE PHENOLIC RESIN LOI(%)

8 POLYMER PROCESSING And RHEOLOGY = MELT FLOW INDEXER (MFI) g OF EXTRUDATE 10 mins WEIGHT PISTON HEATED BARREL POLYMER MELT EXTRUDATE

9 POLYMER PROCESSING And RHEOLOGY APPLICATIONS DENSITY (g/ml) MFI (g/10mins) BLOW MOLDING MONOFILAMENT FILM INJECTION MOLDING WIRE & CABLE SOURCE:HDPE(EL-Lene TM ) FROM SCG CHEMICAL

10 APPLICATIONS DENSITY (g/ml) MFI (g/10mins) FLAT YARN & SHEET FILM INJECTION MOLDING SOURCE:PP(EL-Pro TM ) FROM SCG CHEMICAL APPLICATIONS DENSITY (g/ml) MFI * (g/10mins) OPTICAL DISK EXTRUSION LENSES CAMERA CASE(FIBER GLASS REINFORCED) CAMERA CASE(CARBON FIBER REINFORCED) * 300/ SOURCE:PC(Lupilon TM ) FROM TPPC(MITSUBISHI ENGINEERING PLASTICS)

11 EXTRUSION BASED PROCESSES PROFILE EXTRUSION CABLE COATING BLOWN FILM FLIM CASTING FIBER SPINNING

13 SCREW FEATURE FLOW MECHANISM ANALYSIS OF FLOW BASIC SCREW DESIGN

14 EXTRUDER MACHINE DOWN STREAM PROCESS OR DIE FORMING BASIC FEATURE OF SINGLE SCREW EXTRUSION PROCESS

15 SCREW PROFILE AND TERMED OR COMPRESSION D

16 BASIC VARIATION IN SCREW DESIGN NYLON SCREW POLYETHYLENE SCREW PVC SCREW

17 POLYMER PELLETS ELECTRICAL HEATER (HEATING BAND) HOPPER NOZZLE BARREL

18 POLYMER MELTING IN SCREW FLOW DIRECTION MELTED WELL MIXED UNMELTED

19 EXTRUDER and DIE CHARACTERISTICS

21 BLOW MOLDING DIE SLIT DIE(FISH TAIL)

22 ROD DIE EXTRUSION BASIC DIE DESIGN FLOW PATTERNS NOT NOT YES

23 DEAD SPOT: UNEVEN HEAT UNEVEN SHEAR HISTORY DEAD SPOT

24 LAMINAR FLOW CONVERGED STREAMLINE FLUID ELEMENT DISTORTED CONVERGING FLOW: FLOW ARE TENSILE AND SHEAR FORCE FLUID ELEMENT BECOME DISTORTED THE MELT IS STRETCHED AS IT NARROW DOWN TOWARD EXIT

25 PARALLEL FLOW (THROUGH CHANNEL) 2 CONVERGING FLOW (THROUGH TAPERED) 3 EXTENED FLOW (THROUGH DIE LAND)

26 DIE SWELL: IT IS THE EFECT IN WHICH THE POLYMER SWELLS AS IT LEAVE THE DIE. IT RESULTS FROM RECOVERY OF THE ELASTIC DEFORMATION AS THE EXTRUDATE LEAVES THE CONSTRAIN OF THE DIE CHANNEL AND BEFORE IT FREEZES. D swell D D EXTD DIE D DIE D EXTD ID < ID OF DIE OD > OD OF DIE ROD DIE PIPE DIE

27 PROFILE EXTRUSION IT IS THE DIRECT MANUFACTURE OF THE PRODCUT FROM THE EXTRUDER DIE. THE PRODUCT ARE CONTINOUS LENGTH WHOSE CROSS SECTIONAL PROFILE IS DETERMINED BY THE DIE SHAPE. FOR EAMPLE; PIPING WINDOW FRAMES HOSE etc.

28 DOWN STREAM PROCESS EXTRUDER MACHINE CUTTING TAKE-OFF SIZING

29 VACUUM SIZING:

31 TYPICAL DIES FOR EXTRUSION PROCESS

32 CAST FILM AND SHEET EXTRUSION

33 BLOWN FILM EXTRUSION(HDPE)

BLOWN FILM EXTRUSION(PP) PP IS TENSION THINNING IN THE MELT AND ALSO ITS CRYSTALISATION RATE DURING COOLING IS SLOW; THIS MAKES IT DIFFICULT TO USE AIR COOLING.

34 BLOWN FILM EXTRUSION(PP) PP IS TENSION THINNING IN THE MELT AND ALSO ITS CRYSTALISATION RATE DURING COOLING IS SLOW; THIS MAKES IT DIFFICULT TO USE AIR COOLING. COOLED WATER IS UESD TO QUENCH THE POLYMER MELT. IT IS THEN REHEATED TO THE TEMPERATURE AND BLOWN. THE PROCESS IS SIMILAR TO THOSE STRETCH BLOW MOLDING OF PET.

36 BLOWN FILM ANALYSIS: F h f P R f FREEZ-LINE h o L R o BLOW-UP RATIO; B R R R f o DRAW RATIO; D R v v f o

38 PROCESS ANALYSIS: FIBER SPINNING: DRAW RATIO: D R v v v o MATERIAL SPEED EMERGING FROM SPINNERET, v f THE FIBER SPEED AT THE TAKE-UP ROLL AND L THE DISTANCE BETWEEN SPENNERET AND TAKE-UP ROLL. o f

39 CABLE & WIRE COATING METAL WIRE POLYMER MELT

40 EXTRUSION BLOW MOLDING

41 E X T R U S I O N B L O W M O L D

44 INJECTION MOLDING PRODUCTS

46 INJECTION SYSTEMS TERMINOLOGY CLAMP UNIT MOLD BARREL HOPPER HYDRAULIC DRIVE INDUSTRIAL INJECTION MOLD MACHINE

47 RECIPROCATING SCREW INJECTION

49 TOGGLE CLAMPING MACHINE TOGGLE CLAMP MOVING PLATEN FIXED PLATEN

Chapter 15-2: Processing of Polymers

Chapter 15-2: Processing of Polymers ISSUES TO ADDRESS... Other issues in polymers What are the primary polymer processing methods? Chapter 15-1 Polymer Synthesis Reactions There are two types of polymerization