How to make a tyre:
Tyre Manufacturing Process flowchart.
Basic Ingredients To Make A Tyre
1 Radial tyre manufacturing starts with
many kinds of raw materials, pigments, chemicals,
some 30; different kinds of rubber, cord fabrics,
bead wire, etc. The process begins with the mixing
of basic rubbers with process oils, carbon black,
pigments,antioxidants,accelerators and other additives,
each of which contributes certain properties to
the compound.
These ingredients are mixed in giant blenders
called Banbury machines operating under tremendous
heat and pressure. They blend the many ingredients
together into a hot, black gummy compound that
will be milled again and again.
2 The cooled rubber takes several forms.
Most often it is processed into carefully identified
slabs that will be transported to breakdown mills.
These mills feed the rubber between massive pairs
of rollers, over and over, feeding, mixing and
blending to prepare the different compounds for
the feed mills, where they are slit into strips
and carried by conveyor belts to become sidewalls,
treads or other parts of the tire.
Still another kind of rubber coats the fabric
that will be used to make up the tire's body.
The fabrics come in huge rolls, and they are as
specialized and critical as the rubber blends.
Many kinds of fabrics are used: polyester,
rayon or nylon. Most of today's passenger
tires have polyester cord bodies.
3 Another component, shaped like a hoop,
is called a bead. It has high-tensile steel
wire forming its backbone, which will fit against
the vehicle's wheel rim. The strands are aligned
into a ribbon coated with rubber for adhesion,
then wound into loops that are then wrapped together
to secure them until they are assembled with the
rest of the tire.
Radial tires are built on one or two tire machines.
The tire starts with a double layer of synthetic
gum rubber called an innerliner that will
seal in air and make the tire tubeless.
4 Next come two layers of ply fabric,
the cords. Two strips called apexes
stiffen the area just above the bead. Next, a
pair of chafer strips is added, so called
because they resist chafing from the wheel rim
when mounted on a car.
The tire building machine pre-shapes radial
tires into a form very close to their final dimension
to make sure the many components are in proper
position before the tire goes into the mold.
5 Now the tire builder adds the steel
belts that resist punctures and hold the tread
firmly against the road. The tread is the
last part to go on the tire. After automatic rollers
press all the parts firmly together, the radial
tire, now called a green tire, is ready
for inspection and curing.
6 The curing press is where tires
get their final shape and tread pattern. Hot molds
like giant waffle irons shape and vulcanize
the tire. The molds are engraved with the tread
pattern, the sidewall markings of the manufacturer
and those required by law.
Tires are cured at over 300 degrees for 12
to 25 minutes, depending on their size. As
the press swings open, the tires are popped from
their molds onto a long conveyor that carries
them to final finish and inspection.
7 If anything is wrong with the tire -
if anything even seems to be wrong with the tire,
even the slightest blemish - it is rejected. Some
flaws are caught by an inspector's trained eyes
and hands; others are found by specialized machines.
Inspection doesn't stop at the surface.
Some tires are pulled from the production line
and X- rayed to detect any hidden weaknesses
or internal failures. In addition, quality control
engineers regularly cut apart randomly chosen
tires and study every detail of their construction
that affects performance, ride or safety.
8 This is how all the parts come together:
the tread and sidewall, supported by the body,
and held to the wheel by the rubber-coated steel
bead. But whatever the details, the basics are
fundamentally the same: steel, fabric, rubber,
and lots of work and care, design and engineering.
Basic Ingredients To Make A Tire
Fabric steel, nylon, aramid fiber, rayon,
fiberglass, or polyester (usually a combination,
e.g., polyester fabric in the body plies and steel
fabric in the belts and beads of most radial passenger
tires)
Rubber natural and synthetic (hundreds
of polymer types)
Reinforcing chemicals -- carbon black,
silica, resins
Anti-degradants -- antioxidants, ozonants,
paraffin waxes
Adhesion promoters -- cobalt salts, brass
on wire, resins on fabrics
Curatives -- cure accelerators, activators,
sulfur
Processing aids -- oils, tackifiers, peptizers,
softeners
A P195/75R14 all-season passenger tire, the
most popular size, weighs about 21 pounds and
has approximately:
5 lbs. of 30 different types of synthetic
rubber
4 lbs. of 8 types of natural rubber
5 lbs. of 8 types of carbon black
1 lbs. of steel cord for belts
1 lb. of polyester and nylon
1 lb. of steel bead wire
3 lbs. of 40 different kinds of chemicals,
waxes, oils, pigments, etc.
Typical percentages of the Synthetic Rubber and
Natural Rubber rubber mix in various types of tires:
Passenger Tire 55% 45%
Light Truck Tire 50% 50%
Race Tire 65% 35%
Off-highway Tire 20% 80%
(giant/earthmover)
|