blow moulding by alok kumar. blow moulding a process to produce hollow products like bottles,...

40
BLOW MOULDING BY ALOK KUMAR

Upload: kenneth-davidson

Post on 30-Dec-2015

226 views

Category:

Documents


7 download

TRANSCRIPT

Page 1: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

BLOW MOULDING BLOW MOULDING

BY

ALOK KUMAR

Page 2: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

BLOW MOULDING

          A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics.

 Advantages

Moulding extremely irregular (reentrant) curves

Low stresses in the product

Possibility of variable wall thickiness

Use of polymers with high chemical resistance

Favourable processing costs

         Required pressure levels of 25 to 150 psi and with some resins 200 to 300 psi. But Injection Moulding requires 2000 to 30,000 psi and hence development of high internal stresses.

Page 3: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Materials Used

Small parts, under 5 litres,

Polyolefines (LDPE,HDPE,PP )

polyvinyl Chloride (PVC)

      Polyacrylonitrile (PAN)

      Polystyrene (PS)

      Styrene Acrylonitrile (SAN)

      Polyester (Saturated , PET)

 Large parts, over 5 litres including technical parts,

  Poly olefines (HDPE / PP)

      Polycarbonate (PC)

      Polyacetal (POM)

      Polyamides (PA)

Polyvinylidene Fluoride (PVDF)

Page 4: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

TYPES OF BLOW MOULDING

1.     Extrusion Blow Moulding (EBM) which pricipally uses an unsupported parison (75% usages)

2.     Injection Blow Moulding (IBM) which principally uses a preform supported by a metal core pin (25% usages).

3.    Stretch Blow Moulding either EBM or IBM to obtain bioriented products.

 

Page 5: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Extrusion Blow Moulding

Extruding a parison and Blowing the same.

Machinery

  1.     An Extruder

  2.     A die head and

 3.     A Blow Mould

 Process

Melting the Plastics in an Extruder.

     Forming the parison (A hot plastics tube).

     Clamping the two mould halves around the parison and keeping closed. 

     Inflating the parison inside the Blow (female) mould.

Cooling of the expanded parison

Opening the mould and ejecting the product.

Page 6: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 7: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Advantages

High rate of production.

       Low tooling costs.

        Incorporation of blown handle ware.

        A wide selection of machine manufacturers.

 Disadvantages

Higher Scrap Rate.

Use of recycled scrap.

Limited wall thickness control.

 

Page 8: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 9: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Few Points

The die head can have one or more openings and hence one or more parison can be extruded.

         The size and weight of the product dictates whether an accumulator is required or not.

-         Usually a blow pin is located opposite the pinched end of the tube and compressed air inflates the parison.

         The compressed air can enter through (1) the extrusion die mandrel or (2) through a blow pin or (3) through blowing

needles that pierce the parison.

       The wall distribution and thickness of the blown part are controlled by parison programming, the blow ratio and part configuration.

         The mold clamping can be hydraulic and/or toggle.

         For cooling Co2 systems, air chillers can be used.

Page 10: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Parison Programming

 By Electronic Parison Programming. (Orifice modulation method) in which the die is fitted with hydraulic positioner that allows positioning of the inside die diameter during parison drop. The OD to ID relationship of the tapered die orifice opening is versed in a programmed manner to increase or decrease the parison wall thickness.

 Parison Swell

  After leasing the die, the melt – which has been under shear pressure – undergoes relaxation that causes cross-sectional deformation or swell which is called as parison swell.

Page 11: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Average parison swell for few commodity plastics

 

Plastics Swell, present

  HDPE (Phillips) 15 - 40

  HDPE (zeigler) 25 - 65

  LDPE 30 - 65

  PVC (rigid) 30 - 35

PS 10 - 20 PC 5 - 10

Page 12: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Pinch-Off

  The pinch-off is the very critical part in a Extrusion Blow Mould where the parison is squeezed and welded together requiring good thermal conductivity for rapid cooling and good toughness to ensure long production runs.

 

Types

1. Double angle pinch-off with 45 angles and 0.010 in

land.

2.   Double angle shallow pinch-off with 15 angles and 0.010 in land.

3.   Pinch-off with a dam.

 

Page 13: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Parison Blowing

Air is used to blow the parison tube against the mold walls. It does 3 functions

 -         It expands the parison against the mould.

 -         Exerts pressure on the expanded parison to product surface details.

 -         Aids in cooling the blown parison.

 

Page 14: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

EXTRUSION BLOW MOULDING

I.     CONTINUOUS EXTRUSION

II.     INTERMITTENT EXTRUSION

Page 15: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

I. CONTINUOUS EXTRUSION

The extruder will be in operation continuously and parison will be produced continuously.

• Horizontal rotary wheel

• Vertical rotary wheel

• Shuttle continuous extrusion

Page 16: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 17: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 18: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

HORIZONTAL ROTARY WHEEL

        Uses continuously extruded parisons 

        The moulds are mounted and indexed to the extrusion head where the moulds pickup the parison and transfer it to a second station for the introduction of a pin to blow the bottle.

         Multiple moulds are mounted on a large wheel and one extruder and one parison feeds the moulds.

 

Page 19: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

VERTICAL ROTARY WHEEL

        Uses continuously extruded parisons

        Uses one extruder with multiple moulds

        The moulds pick the parison and moves around the axes of the wheel to blow the container, cool it and discharge it.

        The continuously extruded parison run like a tube and not cut individually for moulds.

 

Page 20: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

3. SHUTTLE CONTINUOUS EXTRUSION

        The extruder and parison head are located in the center and the moulds are mounted

to each side.

         The moulds shuttle to the parison, pick off the parison and move back to their

original position.

         This method led to the development of calibrated neck finish otherwise known

as compression moulded neck finish.

Suitable for processing of PVC

 

Page 21: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

INTERMITTENT EXTRUSION

         Uses a reciprocating screw extruder similar in operation to injection moulding.

         The extruder melts and accumulates molten resin at the end of the barrel while the screw retracts to allow for this accumulation of plastic. The moulds are mounted on a platen that only opens and closes and discharges the bottle. The screw moves forward and forces the plastics through a manifold to several extrusion heads as described above to form parisons for various moulds. This method provides high speed production from a single machine. By placing the blow pin in the centre of the extrusion head bottleswith a calibrated neck finish are produced.

 

        This method is very suitable for polyolefins.

 

Page 22: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

INJECTION BLOW MOULDING

        Injecting a preform and Blowing the same.

Process Steps

      Hot melt in exact amounts is injected through an injection moulding machine nozzle into one or more preform cavities. Hot liquid is circulated through mould heating channels around the preform cavity and the required preform temperature is achieved.

      The two part mold opens and the core pin carries the hot plastic to the second stage blow mold station.

      Upon mold closing, air is introduced via the core pin and the platic blows out and contacts the mold cavity surface. 

     The product cools and the blow mould opens and the product is ejected.

Page 23: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 24: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 25: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Advantages

1.   Bottle necks of varying shapes, sizes and wall thickness can be precisely molded,Free

of flash. 

2.   The wall thick nesses of a hollow body can be predetermined exactly.

3.   There is no seam on the bottom.

4.  There is no regrind to contend with, other than that generated on state-up and rejected parts, because there is no neck on bottom trim. 

5. It can be used to blow mold almost any type of plastics that can be injection molded.  

Page 26: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Disadvantages

 

1.   High change-over costs from one part to another. This is caused by the large number of molds and core pins required.

 

2.    Size limitations on parts which can be made by blow molding.

 

3.    Tooling costs are almost double that of extrusion blow molding.

Page 27: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

STRETCH BLOW MOULDING

        Biaxial Orientation Blow Moulding.

        The container is stretched radially by the blow air and vertically by a mechanical stretch rod.

Advantages

-         Better Strength

-         Better Clarity

-         Increased Impact Strength

-         Improved gas and water vapour barrier

-         Reduced Creep

 

Page 28: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Materials used

 PET PAN

PVC PP

ABS ACETALS

PS

Machine Categories

 

(i)      In-line machines

(ii) Two-stage machines

Page 29: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

 Inline machines

 In this process an extruded or injection moulded parison passes through conditioning stations which bring it to the proper orientation temperature and then stretched and blown in a final stage blow mould.

 

Advantages

 1.    Heat history is minimized (important for heat-sensitive materials like PVC and PET )

 2.    The preform can be programmed for optimum material distribution when maintained under continuous control. 

Page 30: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Two-stage machines

 In this process the extruded or injection moulded preforms that have been cooled are conveyed through an oven which reheats them to the proper orientation-blow temperature.

 Advantages

1.    Minimized scrap production

2.    Improved thread finish

3.    Higher output rates

4.   The capability to stockpile preforms, eliminating dependency between preform and bottle machinery.

Page 31: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

TYPES OF STRETCH BLOW MOULDING

       Injection Stretch Blow Moulding.

       Extrusion Stretch Blow Moulding.

 

EXTRUSION STRETCH BLOW MOULDING

•         Suitable for processing of PVC, PET.

 Process 

        Extruding a parison.

        Converting the parison into a preform.

        Blowing and stretching the preform in the final blow mould. 

Page 32: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

.

  

EXTRUSION STRETCH BLOW MOULDING

Suitable for processing of PVC, PET.

 Process

• Extruding a parison

• Converting the parison into a preform.

• Blowing and stretching the preform in the final blow mould.

 

Page 33: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

EXTRUSION STRETCH BLOW MOULDING

Page 34: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

INJECTION STRETCH BLOW MOULDING 

Suitable for processing of PET

 

Process

        Injecting a preform.

        Reheating the preform if necessary.

        Blowing and stretching of the preform in the final blow mould.

Page 35: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

INJECTION STRETCH BLOW MOULDING

Page 36: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 37: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 38: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages
Page 39: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

Guide for Air Blowing Pressure

PLASTIC PRESSURE (Psi)

Acetal 100-150

  PMMA 50-80

  PC 70-150

  LDPE 20-60

  HDPE 60-100

  PP 75-100

PS 40-100

  PVC (rigid) 75-100

  ABS 50-150 

Page 40: BLOW MOULDING BY ALOK KUMAR. BLOW MOULDING A process to Produce Hollow Products like bottles, containers, jars and jerrycans from thermoplastics. Advantages

THANK YOU