QUALITY CONTROL

AND INSPECTION

OF TYRESSAI ANJANEYA

CONTENTS• Structure of Tyres

• Manufacturing Processes Involved

• Inspection Processes• Pre-Production Inspection

• Materials Inspection

• Production Inspection

• Visual Inspection

• Weight and Measurement Inspection

• Final Inspection

• Parameters of Testing

• Machines Used

• ISO Standards

• References and Gallery

STRUCTURE OF A TYREDifferent parts of the Tyre are:

• Tread: The part of the tire in contact with the ground. It must provide traction, long wear and cut resistance. The tread depth and design vary based on site and application.

• Carcass: Contains the inflation medium. The greater its strength, the greater the pressure it can hold.

• Breakers (Belts): These are placed between the tread and carcass. They help to join these parts. They also distribute road shock to protect the carcass. In bias/belted and radial constructions, they control the diameter of the tire.

• Bead: Bundles of high tensile steel wire. They anchor the tire to the rim.

• Sidewalls: The protective rubber covers on the side of a tire.

• Inner liner: A specially formulated rubber compound inside the tire that minimizes permeation. It works with the rim and O-ring to contain the inflation medium in tubeless designs.

MANUFACTURING PROCESSES

Manufacturing Processes Involved:

• Compounding and mixing:

Compounding is the operation of bringing together all the ingredients required to mix a batch of rubber compound. Each component has a different mix of ingredients according to the properties required for that component.

Mixing is the process of applying mechanical work to the ingredients in order to blend them into a homogeneous substance. The mixing is done in three or four stages to incorporate the ingredients in the desired order.

The ideal compound at this point would have a highly uniform material dispersion; however in practice there is considerable non-uniformity to the dispersion

• Component Separation:

Components fall into three classes based on manufacturing process: calendaring, extrusion, and bead building. The extruder machine consists of a screw and barrel, screw driver, heaters, and a die.

The extruder applies two conditions pressure. The extruder screw also provides for additional mixing of the compound through the shearing action of the screw.

The calendar is a set of multiple large-diameter rolls that squeeze rubber compound into a thin sheet, usually of the order of 2 metres wide.

• Tire building:

Building is the process of assembling all the components onto a tire building drum.

Typical TBM operations include the first-stage operation, where inner liner, body plies, and sidewalls are wrapped around the drum, the beads are placed, and the assembly turned up over the bead. In the second stage operation the belt package and tread are applied and the green tire is inflated and shaped.

• Curing:

Curing is the process of applying pressure to the green tire in a mould in order to give it its final shape, and applying heat energy to stimulate the chemical reaction between the rubber and other materials.

• Final Finish:

After the tire has been cured, there are several additional operations. Tire measurement is a test where the tire is automatically mounted on wheel halves, inflated, run against a simulated road surface, and measured for force variation. Tire balance measurement is a test where the tire is automatically placed on wheel halves, rotated at a high speed and measured for imbalance.

Large commercial truck/bus tires, as well as some passenger and light truck tires, are inspected by X-ray or magnetic induction based inspection machines that can penetrate the rubber to analyze the steel cord structure.

In the final step, tires are inspected by human eyes for numerous visual defects such as incomplete mould fill, exposed cords, blisters, blemishes, and others.

TYRE INSPECTION PROCESSES

• Pre-Production Inspection:

As per SAE J 332, each machine to be used for composition and manufacturing of different tire types will be thoroughly inspected for any damage or defects and any other potential damaging factors detected.

The purpose of this inspection process is to verify that all of the equipment and devices to be used for tire production is in working order to ensure quality products.

Machines that show damage and/or defects should not be used for production to ensure that no production anomalies will take place as much as possible.

TYRE CODE

• Materials Inspection

All of the materials to be used for tire construction will be thoroughly inspected for any imperfections to avoid defective products the soonest it has been detected. The purpose of this inspection process is to ensure that all of the materials to be used are free from damage and/or defects.

Materials that show signs of damage or defects will be automatically rejected and will not be used throughout the entire production process.

• Production Inspection:

All of the materials that pass the inspection process will be then transferred to the assembly line where the entire tire manufacturing process is initiated. Throughout the duration of the manufacturing process, each material will undergo different departments before getting the final product.

These departments are:

• Mixing and Compounding – rubber materials to be used will be mixed with different agents to form a rubber compound to be used for tires.

• Calendar, Extrusion and Bead Building – all of the needed components for tire manufacturing will be prepared during this production queue to ensure all of the materials are complete prior to the next production process.

• Tire Assembly – after, all of the materials have been prepared and gathered, tire building will be performed and will be inspected on a regular basis until all of the components are properly coated.

• Curing – all of the tires that are halfway finished will undergo curing process where immense pressure will be applied in a mould in order to create the suitable shape of the tire. By using a machine to assist with the roundness, the success rate of curing items is above 80 percent.

TYRES IN ASSEMBLY LINE

CURING

• Visual Inspection:

After the production process, all of the finished products will undergo a thorough inspection regarding the condition and overall quality and design of each tire. The purpose of this inspection process is to verify that all of the tires out of production show no signs of damage or defects to ensure product reliability and durability as per quality control standards.

It is important that each surface area of the tire on queue must be visually inspected and machine tested to ensure that no hidden damage is detected.

• Tread Depth – the surface area of each tire will be inspected thoroughly to ensure that there are no cracks, moulds or bubbles detected.

• X-RAY inspection – the internal parts of the tire will be inspected for any underlying defects that could take place during initial use to ensure that all of the tires are structurally sound and reliable right out of production.

• Weight and Measurement Inspection:

Each tire will be measured will deflated and once again once inflated to properly specify the gross and net weight of each tire according to its category.

• Tire Uniformity Analysis – tires under the same category will be measured and weighed according to its product specification to ensure durability, reliability and strict quality control standards.

• Tire balance – tires, regardless of type, will be attached to a machine that emulates the vehicle will be used in order to properly measure the specifications of each tire assembly. Tires that are out of balance will be checked for air pressure and overall build to ensure proper size and weight on all tires.

Items that fail the weight and measurement inspection protocol will be evaluated for alternative repairs and reconstruction (depending on the damage) to save overall production time if applicable. Items that are beyond repair will be automatically marked as “DEFECTIVE

• Final Inspection:

The purpose of this inspection process is to verify that all of the tires under the production process will undergo a series of performance and battery tests while maintaining a defect-free product at the end of the testing and inspection phase. The common tests involved for this inspection process are:

• Tire Balance and Performance Analysis – all of the tires will be placed on mechanisms to emulate the vehicle specified to check tire balance and if tires are structurally sound and round.

• Tire rotation analysis – each tire will be put into spinning action to evaluate and analyze the behaviour of the tire being inspected while in operation to properly assess the condition of the tire and its overall composition.

• High-Speed Test – all of the tires will be tested on a road-like area where tires will be tested under high speeds to check tire balance and roundness at high speeds of at least 70 miles per hour.

• Damage-Rate Inspection – tires that have finished the entire inspection process will be re-analyzed for any incomplete mould fill and will be checked for damages like blemishes, blisters, exposed cords and other post-production anomalies that have taken place.

PARAMETERS OF TESTING

• Outdoor

• Braking on a dry surface (also for motorcycles, trucks and buses) • Handling on a dry surface (also for motorcycles) • Handling on a wet surface• Braking on a wet surface ECE R 117 / EC 1222/2009 (also for trucks and buses) • Longitudinal aquaplaning• Lateral aquaplaning• Steady-state circular test on a wet surface (also for trucks and buses)

• Indoor

• Rolling resistance• Measurement of force and torque • Temperature (online measurement of the temperature inside the tyre, on the inner liner and at the tyre surface)

AQUAPLANING

• Aquaplaning or Hydroplaning by tyres of a road vehicle occurs when a layer of water builds between the wheels of the vehicle and the road surface, leading to a loss of traction that prevents the vehicle from responding to control inputs.

• Aquaplaning is different phenomenon from water on the roadway merely acting as a lubricant.

MACHINES USED

• Tire Component Profilometer

• Tire Colour Inspection Tire Length Inspection

• Tire Component Offline Profilometer Tire Component Profilometer

• Tire Piece Weight Inspection

• Tire Component Profilometer

STANDARDS

REFERENCES• http://www.intouch-quality.com/blog/tire-inspection-qc-china/

• http://www.issia.cnr.it/wp/?portfolio=ndt-quality-control-of-tyres

• http://www.micro-epsilon.com/download/products/cat--systems--rubber-tire--en.pdf

• https://www.iso.org/obp/ui/#iso:std:63769:en

• http://www.iso.org/iso/home/store/catalogue_tc/catalogue_tc_browse.htm?commid=47686

• http://optotechnik.zeiss.com/en/products/tire-testing-intact/intact-otr

• http://www.tuv-sud.com/industry/automotive-transportation/automotive-solutions/automotive-component-testing/tyre-testing#tab_1427765935891907481211

• http://www.dunlop.eu/dunlop_ie/what-makes-dunlop-different/tire-tests/

• http://www.michelinman.com/US/en/safe-driving/tire-safety/inspection.html

• https://www.researchgate.net/publication/258807136_Identification_and_quality_control_of_marks_on_tires_through_artificial_vision

GALLERY

An opened tire mould being cleaned. The deflated rubber bladder is on the central post

Structure of a Tyre

Inspection in process

Inspection in process

Tyre Balance Inspection