Simulation of the B&B Glass

Forming Process using VOF

Presented by:

Ferrari Simone

Structural and Fluid Dynamic Simulation Department

R&D Bottero Group

STAR Global Conference 2016 Prague, 7–9 March 2016

Agenda

Cuneo – (Headquarter)

Trana

Vicenza

Treviso

Pesaro

Italy

France

St. Jeannet

Germany

Grevenbroich

Donauwörth

United Kingdom

Rochdale

Company Profile

Shanghai

Foshan

Bengbu

China

USA

Kernesville

Brasile

Diadema

Company Profile

Business and Products

Flat Glass Hollow Glass

Bottero Business and Products

Special trailers

COMETTO industries

Focus on Hollow Glass Division

Hollow Glass

Offers a complete range for glass forming from fore-hearths to lehr

Glass Conditioning

Gob Forming

Container Forming

Ware Handling

Container Forming

Glass Conditioning

Gob Forming

Focus on Hollow Glass Division

Bottero E-MOC

Blank and Mold Mechanism

Innovation in glass

industry

Top mounted

Parallel Molds motion

Retrofittable

IS mold compatible

360° Axial and Radial Cooling

3D multi link mechanism Optimization of mechanism nodes position and design refinement

Check for oscillation absence and for stresses in main parts

Product Development: Blow Side E-moc Example

CFD Application Case

Blank Mold DG 6-1/4”

Cooling pattern optimization on

customer blank

Physics

Continuum:

• Solid: Blank Molds

• Fluid: Cooling Duct

Input:

• Solid: Gob’s heat

flux

• Fluid: Inlet Air

Pressure

CFD Application Case

Blank Mold DG 6-1/4”

Cooling pattern optimization on

customer blank

Results:

• Solid: Temperature,

Heat flux…

• Fluid: Temperature,

Air Pressure,

velocity…

The Goal

A strong container

A light container

Compromise on wall thickness

Uniformity of glass distribution

What is a glass forming machine?

Machine gives a shape

Machine is a heat-exchanger

Which is the key-property of glass to control with T?

Glass Viscosity vs. T

Container Forming Processes

Press & Blow Blow & Blow

Step 1

Step 2

Star Global Conference

2014 - Vienna

Blow & Blow Process

The gob is guided into a blank mold. 1

Air is blown into the mold in order to form

the “Parison”. 2

The mold opens and the partially formed

container is released and inverted through

180 degrees.

3

The container is transferred to the blow

mold. 4

Air is injected to blow the container into

the final shape. 5

Finished container is cooled down. 6

Container Forming Cycle

CFD Simulation 3D

VOF Region

• 2 Phases: Glass and Air

• Conduction, Radiation and Air

Convection

• Gravity

Input:

Viscosity (T)

CHT Interface

Solid Region

• Mould

• Cast iron thermal properties

• Conduction, Radiation and Air

Convection

Step 1 Blank Side – Parison Forming

VOF and CHT Simulation:

• T Glass Gob = 1138°C

• Physical Material

Properties

• Total Time = 3,4 sec

(Machine Timing)

Equipment Thermal Images Volume Temperature Distribution

Steady State Simulation

Step 1 Blank Side – Parison Forming

Step 2 Blow Side – Bottle Forming

High viscosity glass phase:

1. Stretching by gravity

2. Air blown at pressure 3 bar

Step 2 Blow Side – Bottle Forming

Final Bottle Results

Thickness Profile

• Compromise between structural properties and bottle weight

• Parison forming is the key step

Simulation Measure

0.00 2.00 4.00

1

3

5

7

9

11

13

15

17

19

21

23

25

27

• Simulation is based on physical parameters in both thermal and dynamic properties.

Conclusions

• The VOF model handles glass viscosity from liquid (100 P) to solid (109 P) with high time-steps.

• The simulation inputs are the machine settings (e.g. cycle timing, molten glass T).

• Application cases:

- Parison design to reduce the trials on molds and on machines

- Effects of non-idealities on process variables

Next goal is the optimization of the entire forming process to reach faster production and lighter bottles.

CONCLUSIONS

Gob Forming video

Questions?