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Preform Design
Good Preform Design = Good Bottles
• Preform has to be designed for each bottle
type. The main requirement is called the bi
orientation ratio
• Bi orientation means 2 dimensions : Diameter
and length
• Preform thickness
• Preform cone design
Preform Design
Bi Orientation ratio
The bi orientation ratio has to be calculated for
each Preform/Bottle association.
Bi-orientations means 2 orientations, the first
orientation is the result between the bottle
length divided by the preform length. (TL)
The second orientation is the result between the
bottle diameter divided by the preform diameter
(TØ)
Preform Design
Bi Orientation ratio
- CSD, petaloid base, IV 0,82
τØ = 4 τL = 2.9
- CSD, champagne base, IV 0.82
τØ = 4 τL = 2.2
- NCB, water base, IV 0.76
τØ = 4 τL = 3.2
- Heatset, IV 0.80
τØ = 3.6 τL = 2.8
Preform Design
Preform thickness plays
an important role on
the final bottle wall
thickness
Preform wall thickness
vary from 2 to 3.5mm
for standard preform
Preform Design
A correct cone preform
design (height), has a
direct wall thickness
influence in the bottle
shoulder
Blowing Process
1. Preform feeding
2. Preform heating
3. From oven to wheel
4. Pre blowing
5. Blowing
6. Bottle out
Blower Overview
17
12 11
16
1
7
9
8
15
2
3
1
14
10 6
5
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Preform loading system
Preform hopper
Preform steep belt conv.
Preform roller sorter
Preform feed rail
Infeed starwheel
In-line heating system
Heating chain
Heating units
Transfer starwheels
Blowing wheel
Blowing unit
Air conveyor
Control unit
Control cabinet
Water supply
Air supply
Oven Process
Role is to heat preforms to blow bottles.
For that, certain numbers of individual
ovens are available usually number of
blowing station correspond with number of
oven units
eg : SBO 12 = 12 blowing Stations for 12
oven units
Oven Zones
Each individual oven unit has usually 8 to
10 zones
Last blower generation are equipped
with progressive pitch which has lot
benefit for lightweithing; difficult
bottle type.
Oven Zones
The oven below is equipped with 12
oven units; in the first 5 oven units
lamps could be turn on or off
individually.
In the last oven units the lamps
could be turns on or off and in
addition the lamps can be regulated
from 0 to 100%
Oven lamps
Preforms are heated by Infra Red
lamps, the warm air has to be
removed with air flow otherwise
the preform skin is burned
which gives milky bottles
Oven Zones
Heating zones from 1 to 10 has is
own heating preform area. These
zones are very important for
establish a bottle process
Blowing Process
Exaust after a thermal
process
Deformation axia and radial in the same time by
streching and preblowing around 7 bars
Blowing at 40
bars
Preform is positionned in
mold
Blowing Process
Stretching
Cylinder
Solenoid valves
Stretch rod
Nozzle Cylinder
Nozzle
Compensation
Shell mold
Base Mold
Blowing Process
•
•
Point 0 point 10 ?
Blowing Chart flow
Thermal stabilisation
with molds contact
Blowing 40 bars
Point 10 end of the axial and
pre blowing deformation
Point 0 start point of the axial
and radial deformation
PET Bi Orientation
Amorph material
1st orientation
2nd orientation
Bi oriented material