IAF Test Form

Name:Jack Matatula

Test Date:12/30/2014

Administered by:Elaine Pascoe

Method utilized to administer the test: Interview E-mail Other______

IAF Code: 14 ISO 9001

IAF Test Revision: 1`

Level: Level 1 Level 2 Level 3

Test Score: 100%

Question
Auditing and leading the audit team. / Answer / Correct / Partially Correct
(Indicate% deducted) / Wrong / Remarks (if applicable)
5.2
1. How do you review the scope and applicability of exclusions for the Rubber and Plastic business? / Where exclusions are made, claims of conformity to this International Standard are not acceptable unless these exclusions are limited to requirements within clause 7, and such exclusions do not affect the organization's ability, or responsibility, to provide product that meets customer and applicable statutory and regulatory requirements".
For rubber and plastic product business, check whether the process include design and development, verification, validation. / x
2. Can you explain in general the processes in Rubber and Plastic business? / Rubber process
The manufacturing of rubber products involves six principal processing steps (mixing, milling, extrusion, calendering, curing, and grinding), with ancillary steps in between. Initially, the raw rubber (natural or synthetic) is mixed with several additives which are chosen based upon the desired properties of the final product. The mixed rubber is often milled and transferred to an extruder where it can be combined with other rubbers. Many rubber products contain synthetic fabric or fibers for strengthening purposes. These fibers are typically coated with mixed rubber using a calender. The extruded rubber and rubber coated materials are then assembled into a final shape and cured. Among the steps in the tire assembly process, described in more detail below, are bead building; cementing and marking; cutting and cooling; tire building; and green tire spraying. It is during the curing process that the rubber vulcanizes (crosslinks), producing the characteristic properties of finished rubber. Once the final product is cured, it is often ground to remove rough surfaces and/or to achieve symmetry.
Mixing consists of taking the raw rubber and mixing it with several chemical additives. These additives consist of accelerators (to initiate the vulcanization process), zinc oxides (to assist in accelerating vulcanization), retarders (to prevent premature vulcanization), antioxidants (to prevents aging), softeners (to facilitate processing of the rubber), carbon black or other fillers (to serve as reinforcing / strengthening agents), and inorganic or organic sulfur compounds (to serve as vulcanizing agents).
Mixing typically is performed in an internal batch mixer. The internal mixer contains two rotors which shear the rubber mix against the wall of the vessel. Internal mixing is performed at elevated temperatures up to approximately 330oF.
Once mixed, the rubber is discharged from the mixer and processed into slab rubber or pellets.
Rubber mixing typically occurs in two or more stages wherein the rubber is returned to the mixer and remixed with additional chemicals. The initial stage results in non-productive compounds, and the final stage results in productive compounds. It should also be noted that various rubber compounds produced at a particular facility can be exported to other facilities for use there.
Non-productive compounds consist of the raw rubber, process oils, reinforcing materials such as carbon black and / or silica and the antioxidant / antiozonant protection system. These materials are mixed at temperatures around 330oF. The final, “productive,” stage involves mixing the rubber from the last non-productive stage with the activators, accelerators and sulfur curing agents. This stage is mixed at
a lower temperature (around 230oF) because the rubber compound will now scorch and cure at elevated temperatures.
Plastic Process
The production of plastics can be roughly divided into four categories:
a)Acquiring the raw material or monomer.
b)Synthesizing the basic polymer.
c)Compounding the polymer into a material that can be used for fabrication.
d)Molding or shaping the plastic into its final form.
Raw Materials
Historically, resins derived from vegetable matter were used to produce most plastics. This included such materials as cellulose (from cotton), furfural (from oat hulls), oils (from seeds) and various starch derivatives. Today, most plastics are produced from petrochemicals which are widely available and tend to be cheaper than other raw materials. However, the global supply of oil is exhaustible, so researchers are investigating other sources of raw materials, such as coal gasification.
Synthesis of the Polymer
The first step in plastic manufacturing is polymerization. The two basic methods by which polymerization can occur are addition and condensation reactions. These can occur in the gaseous, liquid and occasionally solid phase. Sometimes the polymer synthesis can take place at the interface of two immiscible liquids in which the monomers are dissolved.
Additives
Chemical additives can be used in the production of plastics to achieve certain characteristics. These additives include:
  • antioxidants to protect the polymer from degradation by ozone or oxygen
  • ultraviolet stabilizers to protect against weathering
  • plasticizers to increase the polymer’s flexibility
  • lubricants to reduce friction problems
  • pigments to give the plastic colour
  • flame retardants
  • antistatics
Plastics are often manufactured as composites. This is achieved by adding reinforcements such as glass or carbon fibers to the plastics, increasing their strength and stability. Plastic foam is a different type of composite which combines plastic and gas. An example of this can be seen in styrofoam cups which are made of foamed polystyrene.
Shaping and Finishing
Compression molding is one of the oldest methods used for converting polymers into useful materials. It uses pressure to force the plastic into a certain shape. One half of a two-piece mold is filled with plastic and then the two halves of the mold are brought together and the plastic is melted under high pressure as shown below:
A common method used for shaping plastics is extrusion. A device, called an extruder, forces softened plastic through a shaped die from which it may emerge in almost any form, including a circular rod or tube, and a wide, flat sheet. The driving force is supplied by a screw which provides constant pressure. All extrusion products have a regular cross section. A variation on this method is extrusion blow molding, in which a plastic tube produced by extrusion is sealed around a blowing tube and expanded to the shape of a mold with compressed air. This technique is illustrated below:
Injection molding involves one or more extruders which force melted plastic into a cold mold where it is allowed to set to the required shape. An adaptation of this method is injection blow molding which is used to make plastic pop bottles. A thick-walled plastic tube is initially injection-molded around a blowing stick and is then transferred to a blowing mold. The tube is reheated and expanded to the shape of the mold by passing air down the blowing stick. This method is shown below:
Other methods also exist for shaping and finishing plastics including calendering which produces plastic sheets and transfer molding, in which softened plastic is forced by a ram into a mold. / x
5.3
3. How do you assess the interaction of the quality management system with other normative documents, standard and other relevant standard? / I will check:
  • how organization implement and control other normative document and other standard that may applies to product and/or service, it can be as external document
  • application to the product and/or service
  • the evaluation of compliance to the product and/or service
/ x
5.4
4. Can you describe the general business management concept, practice and inter- relationship between policy, objective and result? / Objectives are the goals set out by an entity based on the policies that are already in existence. The strategies are the methods employed to carry out the objectives.
I will check the result whether they achieved, if the result meets the objective, it means what stated by organization in the policy achieved. / x
5.5
5. What are the manufacturing processes for tires? / Tire plants are traditionally divided into five departments that perform special operations. These usually act as independent factories within a factory. Large tire makers may set up independent factories on a single site, or cluster the factories locally across a region.
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. Internal mixers are often equipped with two counter-rotating rotors in a large housing that shear the rubber charge along with the additives. The mixing is done in three or four stages to incorporate the ingredients in the desired order. The shearing action generates considerable heat, so both rotors and housing are water-cooled to maintain a temperature low enough to assure that vulcanization does not begin.
After mixing the rubber charge is dropped into a chute and fed by an extruding screw into a roller die. Alternatively, the batch can be dropped onto an open rubber mill batchoff system. A mill consists of twin counter-rotating rolls, one serrated, that provide additional mechanical working to the rubber and produce a thick rubber sheet. The sheet is pulled off the rollers in the form of a strip. The strip is cooled, dusted with talc, and laid down into a pallet bin.
The ideal compound at this point would have a highly uniform material dispersion; however in practice there is considerable non-uniformity to the dispersion. This is due to several causes, including hot and cold spots in the mixer housing and rotors, excessive rotor clearance, rotor wear, and poorly circulating flow paths. As a result, there can be a little more carbon black here, and a little less there, along with a few clumps of carbon black elsewhere, that are not well mixed with the rubber or the additives.
Mixers are often controlled according to the power integration method, where the current flow to the mixer motor is measured, and the mixing terminated upon reaching a specified total amount of mix energy imparted to the batch.
Component preparation
Components fall into three classes based on manufacturing process - calendering, extrusion, and bead building.
The extruder machine consists of a screw and barrel, screw drive, heaters, and a die. The extruder applies two conditions to the compound: heat and pressure. The extruder screw also provides for additional mixing of the compound through the shearing action of the screw. The compound is pushed through a die, after which the extruded profile is vulcanized in a continuous oven, cooled to terminate the vulcanization process, and either rolled up on a spool or cut to length. Tire treads are often extruded with four components in a quadraplex extruder, one with four screws processing four different compounds, usually a base compound, core compound, tread compound, and wing compound. Extrusion is also used for sidewall profiles and inner liners.
The calender is a set of multiple large-diameter rolls that squeeze rubber compound into a thin sheet, usually of the order of 2 meters wide. Fabric calenders produce an upper and lower rubber sheet with a layer of fabric in between. Steel calenders do so with steel cords. Calenders are used to produce body plies and belts. A creel room is a facility that houses hundreds of fabric or wire spools that are fed into the calender. Calenders utilize downstream equipment for shearing and splicing calendered components.
Tire building
Tire building is the process of assembling all the components onto a tire building drum. Tire-building machines (TBM) can be manually operated or fully automatic. 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.
All components require splicing. Inner liner and body plies are spliced with a square-ended overlap. Tread and sidewall are joined with a skived splice, where the joining ends are bevel-cut. Belts are spliced end to end with no overlap. Splices that are too heavy or non-symmetrical will generate defects in force variation, balance, or bulge parameters. Splices that are too light or open can lead to visual defects and in some cases tire failure. The final product of the TBM process is called a green tire, where green refers to the uncured state.
Pirelli Tire developed a special process called MIRS that uses robots to position and rotate the building drums under stations that apply the various components, usually via extrusion and strip winding methods. This permits the equipment to build different tire sizes in consecutive operations without the need to change tooling or setups. This process is well suited to small volume production with frequent size changes.
The largest tire makers have internally developed automated tire-assembly machines in an effort to create competitive advantages in tire construction precision, high production yield, and reduced labor. Nevertheless there is a large base of machine builders who produce tire-building machines.
Curing
Curing is the process of applying pressure to the green tire in a mold in order to give it its final shape, and applying heat energy to stimulate the chemical reaction between the rubber and other materials. In this process the green tire is automatically transferred onto the lower mold bead seat, a rubber bladder is inserted into the green tire, and the mold closes while the bladder inflates. As the mold closes and is locked the bladder pressure increases so as to make the green tire flow into the mold, taking on the tread pattern and sidewall lettering engraved into the mold. The bladder is filled with a recirculating heat transfer medium, such as steam, hot water, or inert gas. Temperatures are in the area of 350 degrees Fahrenheit with pressures around 350 PSI. Passenger tires cure in approximately 15 minutes. At the end of cure the pressure is bled down, the mold opened, and the tire stripped out of the mold. The tire may be placed on a PCI, or post-cure inflator, that will hold the tire fully inflated while it cools. There are two generic curing press types, mechanical and hydraulic.
Mechanical presses hold the mold closed via toggle linkages, while hydraulic presses use hydraulic oil as the prime mover for machine motion, and lock the mold with a breech-lock mechanism.
Hydraulic presses have emerged as the most cost-effective because the press structure does not have to withstand the mold-opening pressure and can therefore be relatively lightweight. There are two generic mold types, two-piece molds and segmental molds.
Large off-road tires are often cured in ovens with cure times approaching 24 hours.
Final finish
After the tire has been cured, there are several additional operations. Tire uniformity 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 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 mold fill, exposed cords, blisters, blemishes, and others. / x
6. What is Force variation? / Force variation The tire tread and sidewall elements undergo deformation and recovery as they enter and exit the footprint. Since the rubber is elastomeric, it is compressed during this cycle. As the rubber deforms and recovers it imparts cyclical forces into the vehicle. These variations are collectively referred to as Tire Uniformity. Tire Uniformity is characterized by Radial Force Variation (RFV), Lateral Force Variation (LFV), and Tangential Force Variation. Radial and Lateral Force Variation is measured on a Force Variation Machine at the end of the manufacturing process. Tires outside the specified limits for RFV and LFV are rejected. In addition, Tire Uniformity Machines are used to measure geometric parameters including Radial Runout, Lateral Runout, and Sidewall Bulge in the tire factory at the end of the manufacturing process as a quality check. In the late 1990s Hunter Engineering introduced the GSP9700 Road Force balancer which is equipped with a load roller similar to the Force Variation Machine used at the factory to grade tire uniformity. This machine can find the best position for the tire on a given wheel so the over-all assembly is as round as possible. / x