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
EXTRUSION PROCESS INJECTION PROCESS THERMOFROMING PROCESS COMPRESSION PROCESS
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.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
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
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(%) 15 17 17 21 18 24-26 35 90 35
POLYMER PROCESSING And RHEOLOGY = MELT FLOW INDEXER (MFI) g OF EXTRUDATE 10 mins WEIGHT PISTON HEATED BARREL POLYMER MELT EXTRUDATE
POLYMER PROCESSING And RHEOLOGY APPLICATIONS DENSITY (g/ml) MFI (g/10mins) BLOW MOLDING 0.956-0.966 0.03-0.70 MONOFILAMENT 0.954-0.957 0.80-1.00 FILM 0.954-0.956 0.04-0.15 INJECTION MOLDING 0.958-0.967 4.00-18.00 WIRE & CABLE 0.952 0.13 SOURCE:HDPE(EL-Lene TM ) FROM SCG CHEMICAL
APPLICATIONS DENSITY (g/ml) MFI (g/10mins) FLAT YARN & SHEET 0.910 2.4 3.5 FILM 0.910 10.0 INJECTION MOLDING 0.910 3.5 43.0 SOURCE:PP(EL-Pro TM ) FROM SCG CHEMICAL APPLICATIONS DENSITY (g/ml) MFI * (g/10mins) OPTICAL DISK 1.20 63.0 EXTRUSION 1.20 5.3 LENSES 1.20 5.3-8.0 CAMERA CASE(FIBER GLASS REINFORCED) CAMERA CASE(CARBON FIBER REINFORCED) * 300/1.2 1.44 6.9 1.24 7.0 SOURCE:PC(Lupilon TM ) FROM TPPC(MITSUBISHI ENGINEERING PLASTICS)
EXTRUSION BASED PROCESSES PROFILE EXTRUSION CABLE COATING BLOWN FILM FLIM CASTING FIBER SPINNING
SCREW FEATURE FLOW MECHANISM ANALYSIS OF FLOW BASIC SCREW DESIGN
EXTRUDER MACHINE DOWN STREAM PROCESS OR DIE FORMING BASIC FEATURE OF SINGLE SCREW EXTRUSION PROCESS
SCREW PROFILE AND TERMED OR COMPRESSION D
BASIC VARIATION IN SCREW DESIGN NYLON SCREW POLYETHYLENE SCREW PVC SCREW
POLYMER PELLETS ELECTRICAL HEATER (HEATING BAND) HOPPER NOZZLE BARREL
POLYMER MELTING IN SCREW FLOW DIRECTION MELTED WELL MIXED UNMELTED
EXTRUDER and DIE CHARACTERISTICS
BLOW MOLDING DIE SLIT DIE(FISH TAIL)
ROD DIE EXTRUSION BASIC DIE DESIGN FLOW PATTERNS NOT NOT YES
DEAD SPOT: UNEVEN HEAT UNEVEN SHEAR HISTORY DEAD SPOT
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
1 2 3 1 PARALLEL FLOW (THROUGH CHANNEL) 2 CONVERGING FLOW (THROUGH TAPERED) 3 EXTENED FLOW (THROUGH DIE LAND)
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
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.
DOWN STREAM PROCESS EXTRUDER MACHINE CUTTING TAKE-OFF SIZING
VACUUM SIZING:
TYPICAL DIES FOR EXTRUSION PROCESS
CAST FILM AND SHEET EXTRUSION
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. 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.
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
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
CABLE & WIRE COATING METAL WIRE POLYMER MELT
EXTRUSION BLOW MOLDING
E X T R U S I O N B L O W M O L D
INJECTION MOLDING PRODUCTS
INJECTION SYSTEMS TERMINOLOGY CLAMP UNIT MOLD BARREL HOPPER HYDRAULIC DRIVE INDUSTRIAL INJECTION MOLD MACHINE
RECIPROCATING SCREW INJECTION
TOGGLE CLAMPING MACHINE TOGGLE CLAMP MOVING PLATEN FIXED PLATEN