The process and Parameters of Tyre Manufacturing Engineering

1. CE 435 -- Intoduction to Polymers 1
Firestone Tires
Parag Patel
Joshua Pun
Cory Robinson

2. CE 435 -- Intoduction to Polymers 2
Outline
 Introduction
 Tire Production
 Overview of Tread Separation Problem
 Legal Matters
 Conclusion/Questions

3. CE 435 -- Intoduction to Polymers 3
Introduction
 Charles Goodyear 1800 – 1860
– 1821: Went into hardware business
– 1833: Started making rubber goods
– 1834: Failure in first rubber venture
– 1837: Eliminated some of the rubber defects
– 1838: Bought patent from partner
– 1844: Discovered Vulcanization

4. CE 435 -- Intoduction to Polymers 4
Tire Production
 Statistics:
Source: http://www.rubbernews.com/subscriber/charts/global.html
Tire Sales % of Total Tire Sales % of Total
(M illions $ ) Corp. Sales (M illions $ ) Corp. Sales
Bridgestone Corp.
Tokyo,Japan
M ichelin et Cie.
Clermont-Ferrand,France
Goodyear Tire & Rubber Co.
Akron,Ohio/USA
Continental A.G.
Hanover,Germany
Sumitomo Rubber Industries Ltd.
Kobe,Japan
Pirelli S.p.A.
Milan,Italy
Yokohama Rubber Co. Ltd.
Tokyo,Japan
2,408.20 70% 21
93.5 70%
2,725.20 40% 3005.8 49%
3,41
3.80 76% 3,750.00 75%
4,900.00 50% 4,334.00 58%
1
1
,51
5.60 85% 1
1
,31
1
.00 85%
1
3,500.00 92% 1
2,91
6.30 93%
1999 1998
Co./Headquarters
1
3,500.00 74% 1
2,634.80 74%

5. CE 435 -- Intoduction to Polymers 5
Raw Materials
 Fabric (steel, polyester, nylon, etc.)
 Rubber (synthetic, natural, or blends)
 Reinforcing Chemicals (silica, resins, etc.)
 Anti-Degradant (Ozonants, paraffin waxes)
 Adhesion Promoters (brass, cobalt salts)
 Curatives (cure accelerators, activators, sulfur)
 Processing Oils (Oils, Tackifiers, Softeners)

6. CE 435 -- Intoduction to Polymers 6
Processing & Production
 Mix Process Oils, Rubber, Reinforcers,
Accelerators, & Anti-Degradants
 Coatings
– Fabric
– Steel Belt
 Bead

7. CE 435 -- Intoduction to Polymers 7

8. CE 435 -- Intoduction to Polymers 8
Processing & Production (con’t)
 Components taken to tire machine for
assemble
– Inner liner
– Ply Fabric (two layers) – possible cause of
problem
– Apexes
– Chafer Strips
– Steel Belts
– Curing
– Inspection

9. CE 435 -- Intoduction to Polymers 9

10. CE 435 -- Intoduction to Polymers 10
Chemistry of Tires - Introduction
 Overview of Vulcanization Process
 Description of Brass-on-Wire
Adhesion
 2nd Major Issue in Faulty Firestone
Tires

11. CE 435 -- Intoduction to Polymers 11
Vulcanization
 Process by which rubber is chemically
crosslinked (e.g. disulfides)
 Makes material stronger, elastic, resistant
to solvents, and moderate heat/cold.
 Rubber is heated in the presence of sulfur
and accelerator.

12. CE 435 -- Intoduction to Polymers 12
Properties
Source: Mark, James E. Science and Technology of Rubber. Academic: San Diego, CA, 1994

13. CE 435 -- Intoduction to Polymers 13
Vulcanization (con’t)
 Heat with and without accelerators
– Without: 5 hrs @ 140 oC / 8 phr sulfur
– With: 1-3 min @ 140 oC / 0.5 phr sulfur
 Main Considerations:
– Size and type of object (thick walled -> longer curing time)
– Compound vulcanizabliity and flowability
– Type of vulcanization (mould vs. boiler)
– Maximum vulcanization temperature of material or system
– Removal of article from mould (higher temp, more difficult)

14. CE 435 -- Intoduction to Polymers 14
Mechanisms
Source: Mark, James E. Science and Technology of Rubber. Academic: San Diego, CA, 1994

15. CE 435 -- Intoduction to Polymers 15
Brass-on-Wire Adhesion
 Process by which brass (CuZn)
deposited on steel belts
 Important for proper metal/rubber
adhesion
 Care must be taken to prevent
oxidation of both brass and steel

16. CE 435 -- Intoduction to Polymers 16
Brass-on-Wire Adhesion
 Formation of Copper Sulfide Layer
 Rubber infiltration into porous CuS layer
 Prevent ZnS/FeS layers (not porous)

17. CE 435 -- Intoduction to Polymers 17
Faulty Tires
 Brass on Wire coatings must be strictly
monitored.
 Coated/Uncoated wire should be kept in
environmentally controlled conditions.
 Free from particulate matter.
 Employee accusations of improper
handling
– Poor quality control
– Used oxidized/improperly handled wire

18. CE 435 -- Intoduction to Polymers 18
Cause of Problem
 The Ford Motor Company
-size of the Ford Explorer
-recommended tire pressure too low
 Drivers of the Vehicles
-improper maintenance of tires
-wear and tear

19. CE 435 -- Intoduction to Polymers 19
Legal Matters
 Both Firestone and Ford are in an ongoing
battle with the public
 Bridgestone/Firestone Position
-taken the responsibility for faulty design
-initiated world wide recall
-offered free replacements
-still believe blame should not wholly be
on them

20. CE 435 -- Intoduction to Polymers 20
Legal Matters (con’t)
 Ford Motors Corporation’s Position
-stands by their design of Ford Explorers
-changed recommended tire pressure
 Plaintiff’s Position
-continue to file lawsuits
-boycott product manufactured by Ford
and Firestone

21. CE 435 -- Intoduction to Polymers 21
Conclusions & Q/A
 Firestone liability in poor quality
control & tread design
 Ford maintains 26 psi sufficient, but
has changed target to 30-35 psi.
 Questions