The automobile industry is more or less a conglomeration of different types of engineering industries. The sub-assemblies and parts are manufactured through various engineering process like forge shop, heat treatment shop, pickling plant, degreasing plant, machine shops, press shops, assembly shops, welding plants, engine testing beds, carpentry, electroplating and paint shops, upholstery etc.
The various components are either manufactured at the plant or outsourced and brought to one assembly line. In the assembly line various parts are assembled while the production line moves so that at the end of the line the completed product is received.
There are different methods of forming metals into particular shapes like press forging, machine forging and extrusion. The extrusion process involves forcing the metal through a die by means of a ram. Forging and pressing are usually applied to steel, brass, copper, aluminium, magnesium, zinc and alloys of those.
Machining which involves cutting of metals in various ways, includes the operations of boring, drilling, gear cutting, grinding, milling, planning and turning.
Major Process Areas
Metal castings are produced in a foundry. Cylinder heads, cylinder block and crankcase are usually cast using sand casting technique in a foundry. These days the engines are made out of aluminium alloy rather than cast iron and there have been rapid changes in technology.
The principal sections of a foundry are the pattern shop, the foundry proper and the fettling shop.
Pattern Shop: In this shop are made the wooden patterns which are used to shape the sand moulds with which the metal is poured. Use of varnishes and methylated spirits may also be found here. These patterns are made to exact dimensions and often are of great value. Use of water for fire fighting may cause the pattern to swell and become disturbed, thus making it useless.
Foundry Shop: This may be sand or a die foundry. In the sand foundry, molten steel, iron brass, copper and aluminium or magnesium alloys as the case may be, is poured into a mould of sand which has already been shaped by a wooden pattern. In the die foundry, a molten alloy is injected, usually under pressure, into a metal mould. The alloys have a low melting point.
Fetting Shop: Here the unwanted plugs of metal (called runners and risers) formed in the pouring process are trimmed off the castings by means of a band saw, a grinding machine or a hand file. Fine machining is done in the machine shop. The risks in these shops vary with the metal being used.
Machine Shop: Crankshafts, cylinder blocks, cylinder heads and other components are received at the factory as raw castings from other manufacturing sites and external suppliers. Drilling, grinding and milling operations are carried out with the utmost precision to ensure a perfect finish. These days most of the production lines and machining centres are almost fully automated. Most of the machinery is fully encapsulated, ensuring the highest standards of safety and cleanliness. Refrigeration system are used for cooling the cutting fluids and other media. The debris is handled separately and fluids are recovered.
Press Shop: Various body parts and components are used in the manufacture of an automobile. Once of the processes involved is press shops where huge hydraulic presses are used for generating various components. The raw material used is high-quality steel plate hot galvanised in a large majority of cases. Depending on the body component, these steel plates vary in thickness and in their dimensions. Steel mills supply most of these steel plates as huge coils weighing several tonnes. The coils are unravelled and cut up into slabs. Then they are drawn, bent and stamped fully automatically in several steps to provide the right shape with the right contours.
Body Shop: In a series of individual steps the Body Shop assembles the plates and panels pressed to shape in the Press Shop to form the body-in-white, initially building the front section, rear section and floor pan subsequently welded together to form the complete floor assembly. In subsequent steps the side panels, roof, doors, front and rear lids round off and complete the entire body of the vehicle. In modern automobile plants, Industrial robots do 95 per cent of the work in the Body Shop in a fully automatic process, applying a high standard of know-how in technology, precise joining as well as spot welding, soldering, bolting and bonding processes for automobile bodies with utmost precision down to the last millimetre. Highly qualified and motivated associates consistently monitor the quality of the welding spots, the accuracy of the entire body, as well as the quality of surfaces. To verify the results of the work done, they apply the most advanced ultrasound facilities as well as conventional "hammer and chisel" methods monitoring the quality of the welding spots. With this latter method, the experienced associate taps the welding spots lightly with a hammer to determine their strength and stability. Laser technology is used additionally, above all to maintain the exact dimensions of the body with utmost precision. Consistently maintaining and servicing all the facilities and production systems, specialists ensure an absolutely smooth and flawless production process, the bodies made with such supreme precision being subsequently transferred to the Paint Shop and Assembly Area.
Paint Shop: The first step in the Paintshop is to clean the vehicle bodies delivered by the Bodyshop. The next step is the process of hot-galvanising and phosphating serving to protect the body from corrosion and provide an adhesive surface for the layers to follow. Then the body is dipped into a bath of water and paint in the cathodic dipping process. In modern automobile plants instead of conventional spray painting, dip painting is used. In this process, the vehicle bodies being dipped into various baths for pre-treatment and rotated in the process, allowing the protective layers of paint to reach all hollow cavities in the body. The result is an absolutely consistent, all-round priming process guaranteeing exceptional rust proofing and adhesion of paint on the body. Subsequently robots spray a layer of protective coating on to the underfloor, in particular to protect the body from stonethrow. To improve the vehicle's acoustics, sound-insulating mats are fitted in place wherever appropriate and all seams, joints and connection points are sealed with plastic.
Today every automobile manufacturer, to stay in competition, introduces various models and different variants of the same model for the customer to choose from. Considering this huge range of variants, only a consistent and highly sophisticated computer system is able to handle the logistics required. The process of planning assembly operations starts right from the beginning in the development of a new vehicle, which then, during assembly, literally "grows" together according to the customer's specifications in hundreds of job processes precisely tailored to one another: from the roof lining to the headlights, from the instrument panel to the bumpers, from the rear-view mirror to the seats. Many other components such as the wiring harness, the seats or drive-train are initially pre-assembled out of individual components before arriving at the assembly line and being fitted in the vehicle just in time and just in sequence. Fitting the engine and chassis into the body of the vehicle is the absolute highlight in the vehicle assembly process, installation of the drive-train giving the fully equipped body its heart and soul. Once all the parts and components have been assembled, the new vehicle is filled with all the operating fluids required and properly tuned for the road, thus being prepared to set out for the first time under its own power. Final quality control checks are done prior to dispatch.
The principal sections of a foundry are the pattern shop, the foundry proper and the fettling shop.
Regulated storage with adequately spaced racks and avoiding wooden mezzanine floor will improve the risk. Separate and detached godowns for paints, varnishes, thinners, hazardous chemicals, etc. is a must. Such godowns should be designed to have more ventilation to eliminate possibilities of formation of dangerous concentration of air / vapour mixture inside the godown. The entire electrical installation should be of flame proof type.
Water should not normally be applied to a stop valve or a safety valve at which LPG is leaking, nor to the associated piping nearby; to do so may render the valve inoperative due to freezing. Utmost discretion must be exercised in the use of water on a fire involving LPG in liquid form since the effect is to increase the rate of vaporisation and intensify the fire. The application of a jet of water would raise a cloud of burning gas and liberate enormous heat.
Painting process generates considerable amount of flammable vapours. The electrical equipment for the painting areas and booths should be of flame proof type. Static electricity dissipation arrangements are critical. High degree of house keeping is essential. Proper grounding of electrical equipments is required. It is preferable that paint dipping, spraying and baking areas are segregated from other process areas. Ventilation ducts should be sprinklered. Heat and Smoke detection systems are suggested.
Though relatively less hazardous, the presence of cutting fluid and high temperature generation in tool tips ignition is possible if process is not properly controlled. High standard of house keeping in terms of removal of cutting debris and proper treatment of waste material is critical. Electrical installation should be of the totally enclosed type.
The information set out in this document constitutes a set of general guidelines and should not be construed or relied upon as specialist advice. Independent legal advice should always be sought. Therefore Risktechnik accepts no responsibility towards any person relying upon these Risk Management Guides nor any liability whatsoever for the accuracy of data supplied by another party or the consequences of reliance upon it.
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