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Old 9th June 2010, 15:21   #1
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Smile Automotive Manufacturing - An Overview

This forum being one which is frequented most by Car enthusiasts and containing loads of info on cars, I felt, maybe I should try to contribute in a little way by starting a thread on the Car Manufacturing process. (In ways there is a lot of similarities with the Commercial Vehicle Manufacturing process as well as the Two Wheeler manufacturing process and I'll try to have some insights to be given on them too.
@FellowBHPians: Anyone with knowledge on the Manufacturing process, please contribute to make this thread rich!
@Mods: In case there is a thread already on the topic, please merge it (apologies if I would have missed finding one)

A car manufacturing process is one of the most interesting and technologically advanced. Probably one of the most advanced in terms of the use of technology as well as execution of complex logic. To appreciate the Manufacturing process one needs to know that an automobile comes together with 3000 - 4000 parts and a typical manufacturer churns out anywhere between 700 - 2000 vehicles (There are some though with a production capacity of about 250). The synchronization of the Auto Manufacturers with the Tier 1 Suppliers have to be spot on as delays or large quality rejects can cause a big dent to the production volumes (which would mean enthusiasts like us would need to wait more for our new cars). Lot of interesting production techniques are used in todays manufacturing and it has evolved a lot from the Mass Production system of Henry Ford and then the Japanese manufacturers (Toyota specifically) bringing in the Lean Production Concepts. Today it is one of the most agile and adaptive and the concepts of production methodologies are so strong that now we find most discrete manufacturing processes following Lean to even some IT companies... anyways.. not to digress too much from the "core" topic, let me try to talk about the life of a car inside the plant :-)

Press Shop : This is where the production process starts, with most of the Metal parts getting pressed out of Steel Sheets. The door panels, Roof, Bonnet, Boot Lid etc are typically pressed in to form the basic structure of the automobile. The pressing process is a multi-step process where the sheets are pressed into shape in stages.

Weld Shop : The Weld shop is typically the place where the automobile is born. The point of birth for most monoque design cars are where the Underbody takes shape from the Pressed parts. It can be the marriage of the Underbody front & rear or in some cases the the entire underbody can be a single pressed unit. In stages, the Side panels, the roof are then welded to the underbody and the automobile begins to take its shape. The welding process is typically Tungsten Inert Gas (TIG) welding, mostly done by Robots and is a treat to watch, wherin you have all these multi axis robotic arms work in unison and utmost precision.




Paint Shop : The output of the Weld Shop is called as a BIW or a Body In White. These are the cabs that enter into the Paint Shop. The painting process is one of the most complex and cleanest of process. The Paint booths for example have to be completely dust free. The various sub-process in the Paint Shop include
(a) Pre-treatment where the BIW is dipped into an electrolyte solution which would help in better paint deposition on the Metal.
(b) Sealant : Prior to the application of paint, the BIWs enter the sealant area where the sealant is applied.
(c) Paint Booths: The BIWs enter the paint booths, for the final painting process. This is typically an area where it is mostly robots again which do the job, or you would need highly skilled human workforce. A highly clean environment is maintained and access is limited and if at all, it has to be with wearing the right kind of overalls.
(d) Oven: The painted bodys are then passed through the oven where the final baking process of the Paint takes place.
(e) Wax Booths: Where application of a fine layer of wax takes place. This is sometimes skipped for some local market vehicles or the lower variants.
(f) Polishing : One of the most laborious processes and the most time consuming one as well. Each of the cars are polished to give the right shine and gleam. A simple rule of thumb, the longer and more elaborate the Polishing process, the better is the shine. So the costlier the car, the longer would have been the polishing done on it.



Engine Shop and TransAxle: There would be no point talking about the Automotive Production without talking about the Heart of the Vehicle, i.e. the Engine and along with it the TransAxle. The reason I brought it in here after the Paint Shop Processes is because the birth of the Engine for a car, typically happens when the Vehicle is in the paint shop. The birth or identity of an engine is given when the Engine Block gets machined and the the EIN (Engine Identification Number) is punched into the Engine Block. The assembly process of the Engine is again precision controlled with various stages of machining the Pistons, fitment of the Piston rings and then lowering the assembly into the Engine Block. Finally the Engine Head comes and then the engine undergoes a series of tests. One of the most significant being the Leak Test and pressure tests. The engines are then "pre-run" in some cases before getting mated to the TransAxle. The TransAxle, consisting of the Gear Box assembly is typically made ready and made available at the marriage point. The Sequence of production of the Engine closely follows the Production of the Vehicle Body and that of the TransAxle closely follows the sequence of engine production.




Trim/Final Fitment This is the last and final stop for the automobile in the production process. When out of it, the vehicle is roadworthy with all its parts working in unison providing locomotion!!!
This part of the production process is where most of the fitment is actually done by human hands. The complicity lies in making the right parts available in the right sequence of production at the fitment area. (Right Place, Right Time, and Right Sequence is the key to it all). Most of the components of the car like the windshields, trims, Steering Column, electronics and the engine - vehicle marriage happens here. Finally after the wheels come in, the vehicle becomes capable of moving by its own power. Before getting dispatched out of production, the Vehicle undergoes stringent quality tests as well as the various important component information of the vehicle is captured and stored into the production databases. Following the drive test, the vehicle reaches the yard from where they are dispatched to the dealership and finally to waiting customers



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Old 9th June 2010, 16:43   #2
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Ri - nice bit of detail, Which plant have you used as an example? Do you have the rights for the snaps (or rather are they OK for posting?)

Prior to the Trim / final fitment would be the stage where the various rubber parts / fluids of the engine bay are installed, though possibly you may have considered them as part of this stage itself.

Nice Initiative, Quite informative.
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Old 9th June 2010, 16:59   #3
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Two similar threads (of quite a few more) :

New Car development : An insider perspective - From drawing board to customer

PICS : Ford's Chennai Factory. Detailed report on the making of Figos, Fiestas...

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Old 9th June 2010, 17:18   #4
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Nice info on car manufacturing. Also how body on ladder chassis body is made would also be nice.
But what bothers me is how the test drivers may drive our future cars.
Yeah yeah,better to test driven by someone else than to have a faulty machine but still...
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Old 9th June 2010, 18:05   #5
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Great info on manufacturing.

The 2 plants that I can see are-
  • BMW's spatanburg, North Carolina plant which produces the X5, X6 and now the 2011 X3.
  • The same plant used to manufacture the first gen Z4, which is now produced in Germany.
  • The last plant looks to be of TH!NK EV in Norway.
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Old 9th June 2010, 18:37   #6
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Quote:
Originally Posted by @ri View Post
The welding process is typically Tungsten Inert Gas (TIG) welding, mostly done by Robots and is a treat to watch, wherin you have all these multi axis robotic arms work in unison and utmost precision.
I guess that it is spot welding and not TIG/MIG.

Also the process covered here is just the assembly (which is a good start in itself). However, there are a lot of other things that get manufactured and then get assembled into sub assemblies. A typical process flow would be casting/forging/drawing etc, followed by machining and then sub-assembly.

The machine shop for the engine components and gear box components in itself can be an amazing sight to watch
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Old 10th June 2010, 08:40   #7
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Quote:
Originally Posted by srh View Post
I guess that it is spot welding and not TIG/MIG.

Also the process covered here is just the assembly (which is a good start in itself). However, there are a lot of other things that get manufactured and then get assembled into sub assemblies. A typical process flow would be casting/forging/drawing etc, followed by machining and then sub-assembly.

The machine shop for the engine components and gear box components in itself can be an amazing sight to watch
Yes you are right, it is spot welding, but it also is TIG (Tungsten being the element used) in some places, there are other means as well.

Quote:
Originally Posted by sidindica View Post
Great info on manufacturing.

The 2 plants that I can see are-
  • BMW's spatanburg, North Carolina plant which produces the X5, X6 and now the 2011 X3.
  • The same plant used to manufacture the first gen Z4, which is now produced in Germany.
  • The last plant looks to be of TH!NK EV in Norway.
There are a few pics from the GM Thailand plant as well.


Thanks Rehaan for the links!

Quote:
Originally Posted by ACM View Post
Ri - nice bit of detail, Which plant have you used as an example? Do you have the rights for the snaps (or rather are they OK for posting?)

Prior to the Trim / final fitment would be the stage where the various rubber parts / fluids of the engine bay are installed, though possibly you may have considered them as part of this stage itself.

Nice Initiative, Quite informative.
@ACM, I have been a bit lucky to have seen the production processes of quite a few plants. So it is more of a generalized approach that I am talking of. The snaps are ok for posting I guess as they are easily available on the net.
There are many more finer nuances to manufacturing, as a first cut I tried to piece in the Overview of it. Will try to post a detailed process at each stage as well as the manufacturing methods used, lean , mass production etc. These concepts in itself are pretty interesting

@DicKy: Absolutely, a ladder on chassis as well as an insight to commercial vehicle manufacturing would follow. Two wheelers, I do not know the process in detail, but yes, one indian manufacturer has one of the "most" automated and "cleanest" plants I have seen ever! Better than even some of the big auto manufacturers.
Testdrives of the cars... well... I wish I had not seen them . But yes, you can say the cars are tested!!!!

Last edited by @ri : 10th June 2010 at 08:46.
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Old 10th June 2010, 09:48   #8
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Typical Flow diagram of a Monocoque Design
Automotive Manufacturing - An Overview-monoque.jpg

Typical Flow diagram of a Ladder on Chassis Design
Automotive Manufacturing - An Overview-ladderonchassis.jpg
In some cases, the Axle is mounted with the engine together on to the chassis.

Last edited by @ri : 10th June 2010 at 09:49.
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Old 8th April 2014, 08:43   #9
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Default Re: Automotive Manufacturing - An Overview

Toyota's future manufacturing plans see humans replacing robots.

Toyota’s next step forward is counter-intuitive in an age of automation: Humans are taking the place of machines in plants across Japan so workers can develop new skills and figure out ways to improve production lines and the car-building process.

Quote:
We need to become more solid and get back to basics, to sharpen our manual skills and further develop them
http://www.autonews.com/article/2014...placing-robots
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Old 8th April 2014, 09:13   #10
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Quote:
Originally Posted by volkman10 View Post
Toyota's future manufacturing plans see humans replacing robots.
Infact this is one of the main design philosophy for Honda as well, 'Man maximum, machine minimum'.
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Old 8th April 2014, 09:28   #11
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Some additional points:
1) Press Shop: This provides parts and assemblies to the weld shop. The car bosy is the costliest sub system. Various sizes of press machines are used starting from as low as 50T to 1500T (T=Tonnage). Operations like blanking, forming, drawing, piercing, flanging etc are done in these machines.
Material handiling plays an important role in this shops.

2) Weld Shop: More than 80% of the welding is RSW. (resistance spot welds). Rest are divided into laser welding, CO2 welding, MIG welding, Plug welding etc. Spot welds are favoured as they are cost effective, fast and provide the weld shop a clean atmosphere unlike CO2 or MIG welding.

Now a days the trend is to use hybrid materials, like aluminium, composites etc with the usual steel. This calls for alternate solutions, namely mechanical fastening (nut/bolts/rivets) or bonding (3M ScotWeld etc).

I am in the car industry, being associated with companies in India, also in Japan and Italy. Will be glad to add some points time and time again to my beloved forum. The fly in the oinment being my time crunch.

this forum has given me so much information over these years. Also a very nice thread. Kudos to the thread starter.

Some intersesting points:
# The doors which are bolted to the car body before painting are again taken down after painting process. This is to facilate the assembly of car interior parts. also doors are parallely assembled with the glazing (glass), trims, electricals etc.
Only in the final assembly they are re-assembled to the car body. The adjustment to the doors for gaps & flushness are done by playing with the hinge mountings.

# The first part to go in the car body in the final assembly are the harness group(bundles of wires)

# The windshield in a modern car is glued to the car body, previous cars had the windscreens mounted with the help of rubber beadings (like M800). The advantage of gluing is that the windscreen now provides stuctural rigidity / torsional stiffness to the car body.

# Front fenders is preffered to be bolted to the car body. This is becuase of serviceability issue. As they are more prone to damage in normal traffic, it is beneficial to be bolted so that they can be easily replaced or repaired. Only in some handful cars they are welded (like the old Ford Ikon).

Last edited by mobike008 : 8th April 2014 at 10:39. Reason: Back to Back posts. Please avoid in future
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Old 8th April 2014, 10:20   #12
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Very informative thread. Request other members to chip in and make aware the rest of us, keen to know about the entire birth process of the machines we so much love.

BTW, what about hand crafted automobiles? Do they follow an entire different process?

Regards

Himanshu

Last edited by bhardwhu : 8th April 2014 at 10:21.
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Old 8th April 2014, 12:25   #13
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Quote:
Originally Posted by sarathlal View Post
Infact this is one of the main design philosophy for Honda as well, 'Man maximum, machine minimum'.
I think the design philosophy has nothing to do with the manufacturing process. What Honda means by 'Man maximum, machine minimum' is that they want to focus their car designs to maximize the space available for human occupants rather than the components of the car itself. In other words, out of the total space occupied by the car dimensions, the maximum space should be available to the user and not for the machine. Their Jazz is a classic example where, even though it was a hatch, it had acres of space compared to its competitors.
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Old 8th April 2014, 14:21   #14
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Regarding hand built cars:

Hand built cars are usually batch produced. Meaning, all the parts come to one location and they complete the vehicle. In a mass produced vehicle, it is a line process, the vehicle goes to centers for assembly.

The most expensive tooling cost (stamping / press dies) always belongs to the body shell or the BIW group.
The rest processes, mainly casting, machining, forging etc are less expensive even if the production numbers are not high.
So if the numbers are not high, it is not desirable to have a stamped part in a vehicle. for example in Buses, we do not find stamped parts. All the steel parts will be made in a press brake machine.

Now the follwoing is purely my view, a human cannot replicate the finnese and accuarcy of a machine. So companies which sells low volume cars usually will have a shoddy fit and finish. Read Morgan Aero. Unless you spend millions acheiving good fit and finish. Read Pagani Huayra. Some other intelligent companies might refrain themselves from processes which justifies huge production numbers and will produce cars with alternate manufacturing processes. For example they might use FRP ('Vette), composites etc.

Also low volume car makers employ techology from other companies, especially in power train and suspension components. For the rest they will brand themselves as a emotionally driven company with craftmanships and other jargons to inflate the retail price. In no way a Morgan Aero will be better than , say, a Nissan 370Z.

Another case: The whole picture.
Case in example, Carbon Fiber vs Steel :
If we excluded material cost, then in this case carbon fiber is actually cheaper to make then steel if we have a very small numbers of cars required. Mostly the bigger CFRP parts are usually made by hand and then put in an Autoclave for curing. Smaller and simple parts might be made by Resin transfer Mould (RTM) process.
Adding material costs slighlty offsets the benefits of the CFRP cost. But if you compare with the performance per kg aspect, then CFRP wins hands down.

In the end, a manufacturer will see the whole picture and then decide if it wants to produce hand built or mass produced cars. Most of the low volume sports cars now a days have CFRP bodies. Example Aventador, La Ferrari, P1, all the Paganis (Pagani's themselves are specialist of CFRP) etc.

Last edited by Valkyrie : 8th April 2014 at 14:25. Reason: Value addition
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Old 8th April 2014, 14:38   #15
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Default Re: Automotive Manufacturing - An Overview

Another excellent thread that shows the materials used in the manufacturing of cars: link (How cars are made from Materials)



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