Automotive parts manufacturing - new and replacement

The production of car parts is one of the most important segments of the overall automotive industry. The contemporary approach to the mass production of cars and the worldwide spread of assembly lines – has a strong impact on the automotive industry. As result – most of the parts used in motor vehicle production lines are manufactured close to the assembly plants. It allows for decreasing the cost of transporting parts from the central storages of the car company (eg. parts for Audis and Skodas from Germany and/or the Czech Republic to the USA, or parts used to assemble Toyotas from Japan to the United Kingdom).

Auto parts manufacturing is spread across the world, usually close to the assembly/production lines. In addition, such diversification has a positive impact on the development of local industries and businesses in regions, where big automotive corporations build their assembly lines. 

Although the automotive parts production for the assembly of new cars is an important part of the whole industry, the manufacturing of spare parts is almost as significant. In other words: each car (or: almost everyone) in its life cycle requires parts exchange – bodywork, powertrain, or suspension. That well-known fact makes the demand for auto parts almost as big, as for the new elements that are mounted in new vehicles. 

What is an automotive parts manufacturing process and how the big idea of industry 4.0 and CNC machines revolutionized that?

What is a car part manufacturing process and what are the standards?

Automotive parts manufacturing is a technological process in which a company produces elements to install in vehicles – according to the specification of the client. In that case: automotive company.  

Such parts can differ according to technologies utilized in cars of different brands. That makes – in the nutshell – that most parts made for Mazdas are not compatible with Audis (and: vice versa). 

It is worth mentioning, the car parts production for many car brands is more "for the vehicles made by particular car concern”. Thanks to that approach and the compatibility of parts between a selection of cars and car lines parts from Volkswagen will fit into other cars from the VAG group (Skoda, Audi, Seat, etc.). Parts from Peugeot can be used in other cars from the PSA group (eg. Citroën or contemporary Opel, since was obtained by said concern). 

From the perspective of an automotive manufacturer – it is a form of cost optimization. The same part can be used in a vast variety of applications, hence the cost of development can be divided among more models. It is a really rare situation, when some parts are compatible between cars from other concerns, except in singular situations like cooperation between big car companies (eg. "triples”: Toyota Aygo, Peugeot 107, and Citroën C1 from the early 2000s). 

It means all car parts made for a particular car (new, to be mounted in an assembly line, OEMs, substitutes) should be made according to the particular specification. Sadly, it is not always a rule. To answer such a problem European Union created the DVO Directive (The Block Exemption Regulation) that – to some extent – regulates the market of car parts in the Old Continent. 

That regulation divides 3 types of car parts:

• original, sometimes called OEM (original equipment), made for the car brand for use in the assembly line, 
• substitutes, identical in parameters as the OEM but produced in different factories/machining shops, 
• other parts.

In Poland, more popular is the older classification, which helps to "order” types of parts by their quality and compliance with the specification. It eases the selection of parts in shops, especially from the perspective of a detailed user. Thus, in Poland we can find categorization that includes letters like:

• O and Q are OEM parts, produced according to the specification of the car company; usually manufactured with installation in a new car in mind or usage in authorized services, 
• P, are parts of close to or similar quality to the OEM. They are usually produced with concern specification in mind and represent similar or almost identical quality production. Their can be called ”(very) good alternative”, 
• Z, called sometimes "cheaper alternatives”, that remain compatible dimension-vise but are not made with specification in mind. Usually, that means – these are poor-quality parts. But sometimes these components represent higher-than-OEM quality (eg. kevlar-coated clutch disc or forged engine pistons) and are used in motorsport or for tuning purposes.

The second and third categories are usually called "aftermarket parts”. Looking at these categorizations we can tell the whole process can be complicated – not only from the perspective of manufacturing but also: from the law. 

It is worth mentioning, that the part build quality often does not influence the compatibility with a particular model, thus: the ability to mount it in such.

What types of parts do the automotive industry need?

The list of car parts, manufactured for the automotive industry in machine shops all over the world is long. Worth mentioning – most of these parts are commonly used alongside many lines of cars for many concerns (also: the same parts can be used in internal combustion cars, hybrids, and electrical). 

Yes, there are usually some parts that are dedicated to one model (sometimes – even a trim of equipment level), but they are usually manufactured by specialized companies. Sometimes that can be related to a rare type of part or the technology, but it is not so common. 

Having that in mind, the contemporary automotive industry needs the following types of parts:

• powertrain parts – eg. elements of engines and gearboxes (blocks, heads, valves, pistons, crankshafts) and additional equipment (eg. pomps, gears, turbos, or compressors housings and internals),
• drivetrain parts – eg. overall suspension (shock absorbers, springs, wishbones, axle shafts, rollers, and shafts) or other parts (rims, tires, studs, etc.),
• parts of car frame and body – many types of profiles, sometimes bent, stringers, and body components, such as door parts
• brake parts – from pomps and reservoirs, through calipers and breaking pads, to brake discs or brake cables,
• a vast variety of electrical parts – microcomputers, drivers, sensors (parking, darkness, rain), or even complete powertrains for electric or hybrid cars with peripheries and battery packs
• lightning – external and internal, 
• upholstery elements for the interior – from car seats to other "soft” elements inside the car,
• glass parts (currently: safety glass),
• safety elements (seatbelts or their parts). 

That list, although pretty long, only scratched the surface of the category called "automotive parts”. With the development of technology and the overall automotive industry, we can see many companies focused on the production of only one type of parts for cars, eg. engine blocks or small powertrain elements (eg. turbo housings or rotors). 

Although there are potential risks related to such diversification of production, it is – at the same time – an opportunity to produce better quality parts by way of lower cost. Companies and shops specializing in – for example – CNC machining of steel, can easily change their production from big elements of engine blocks to small car parts. 

In addition, high specialization makes the production of car parts, according to the concern specification, easier, and an experienced team of CNC operators can easily change the type of production and remain flexible.

What types of materials are used in automobile parts production?

The automotive industry needs many types of components – that is why car parts production demands a vast variety of material types. 

With the evolution of the whole industry, concerns left wood for many alloys of steel, aluminum, and plastics. A stronger focus on safety and ecology caused the bigger popularization of electronics and rare Earth minerals. 

Contemporary automotive parts production needs plenty of materials such as:

• steel – a backbone of the automotive industry, a crucial alloy for the production of engines block, construction parts, and powertrains (although cast iron and aluminum are now more popular, steel remains a key material in the automotive industry), 
• aluminum – is used in a vast variety of applications, from engine blocks to small construction parts, 
• plastics – elements of the car body, reservoir, exterior, and interior, 
• glass – as for the "safety glass”, but also glass fiber for many applications, 
• silicon and a vast variety of semiconductors – without them contemporary cars would not look the same and in the most situation: won't even start, 
• rare Earth minerals and other precious metals – electromobility and ecology-oriented solutions are dependable on them (eg. palladium is used in catalytic converters and other filtering devices). 

Each of these materials requires different types of machining, but still, the biggest part of that mix belongs to traditional alloys (steel, aluminum) and plastics. Its production can differ but usually is based on machining. The automation of milling, turning, or sanding processes and the introduction of computerized numerical control (CNC) allowed for speed-up production of car parts. That lead to decreasing the cost of the single part and more precision in production (thus: fewer problems with unmatched parts).

New parts, replacement parts: what are the differences in production

The key matter in the production of car parts is their compatibility with a particular model(s) and the technical specification of the concern. The second one is important, especially in the European Union.

And does that mean every party "incompatible with the car concern specification” and classified as "Z” is always a "poor quality replacement part”? Not always. 

Of course – in the market, you'll find many brands that order production of parts below said quality standards. Then we can call them "poor quality replacements”. 

On the other hand – the "Z” specification also categorizes parts that exceed the quality of the concern specification. Forged parts for motorsport and tuning parts, reinforced wires, or safety cages – these elements are not in the spectrum of "original part specification”, and can fit the car but are not "as OEM”.  Such parts can be specialized and made with way higher quality in mind. 

Utilization of the highest quality materials, eg. from the block of forged metal, which itself is more expensive to prepare and requires more machine time than typical parts made of the cast, can lead to higher unit price, yet better performance, wear-resistant and in the nutshell: better than OEM quality. 

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