[vinair]

Another Brio faced product from Honda http://www.motorbeam.com/2015/01/car...dia-late-2016/ Beat it!!

Now to my question, how do common platforms work? Understand if its a body on ladder design, where most of the underpinnings would remain the same and just the body design changes. But when it comes to a monocoque construction, wonder how does a platform concept work as the body itself lends to the basic skeletal of the overall design and tinkering it is as good as going for a new design, any thoughts on the same?

[Mr.Boss]

"Common platform" isn't something dealing with the body or the floor. It is a common term referring each and every part that is used, right from the electrical & electronic parts, seats, engine, power train, under body (chassis) parts, trims, door locks, etc. In simple, using common parts across the models.

PS: Even in case of BIW / floor, few panels / zone are made common (best example is engine bay, strut mount towers, spare wheel area, crumple zone, etc)

[DerAlte]

"Common platform" refers to a master BoM (Bill of Materials) of the assemblies (e.g. engine), sub-assemblies (e.g. drive train, dashboard etc.) and components (body, chassis, fuel tank, seats etc.) that go into a vehicle. They contain references to locations in drawings which show how an assembly / sub-assembly / component is connected / mounted at it's location (also indicates bolts, nuts, washers, lock nuts, lock washers etc. needed to mount - this helps the assembly line station to stock these and instruct the worker).

Based on the variant (corresponds to the publicly known model name, and possibly suffix like Classic / Magna / Sport etc.) designed on a platform, each row in the BoM indicates a specific Part Code (absent if that variant doesn't use it) that is to be used. Some are common, some are variant specific. The basis is a Platform Name, not the chassis / engine / drivetrain, since
a. a variant, e.g. a compact SUV, may have a slightly longer chassis
b. engine may be user selectable (mounting points remaining same)
c. gearbox may vary (manual, autobox, 4x4 etc.)
d. some components / sub-assemblies may be country specific
e. some trim levels may have components not present in lower trims
f. (not seen so far in India) number of doors may be different, e.g. 2 / 4 door sedan, or 3 or 5 door hatchback
and so on and so forth!

As far as Ladder Frame or Monocoque chassis is concerned, both are amenable to be used in the Platform concept, i.e. they can be made to accept different components / assemblies / sub-assemblies in a particular mounting position. "Chassis" is just another sub-assembly indicated in the BoM. Engineering division of a car manufacturer, and enthusiasts, relate better to use of either, but that is completely from a engineering (on-road behaviour) viewpoint. From manufacturing viewpoint they are just "chassis". Of course, engineering div. never specifies LF AND monocoque as possible variants - it is engineering philosophy to use only either in a vehicle platform.

"Platform name" doesn't really mean anything to an end user, i.e. person buying the car. It is a scheme relevant only to the engineering division and the factory, and completely focused on making manufacturing of vehicles efficient. Unfortunately Marketing, facing a severe shortage of buzz words in a crowded market, resorts to telling the public the Platform Name seemingly as a differentiator in their public dissemination nowadays.

[GTO]

Here's a great discussion on Tata's modular platform : link.

[dark.knight]

As others have already pointed out, platform sharing is a loosely used term which isn't as relevant to the buyer as it is for the factory.

In operations management a simpler term exists called 'parts sharing' which is what this actually is. The benefit of parts sharing is purely restricted to production, where the supply chain can be much more efficient & quicker whilst using a lot less space if the same spare parts can be used in multiple products (in this case an automobile). Costs of inventory management & research-development also drastically reduces because they don't have to tweak anything to fit into another product. This was supposed to be the next big thing in profit maximization, but hold on its not that simple.

For starters, its common knowledge that sharing parts makes things a whole lot easier. Common knowledge to the consumers as well who would assume much more reasonable pricing or express their irritation that an expensive vehicle has parts sharing with another vehicle 2 segments lower. The company would also have to deal with massive part recalls if found defective since it is used in many models. QC would have to be much more cautious. Similar platforms also risk becoming drab or repetitive and age much faster irrespective of design, the general consumer psychology is in terming somethings as new when they can't be seen often enough or label them old if they're too commonplace. Brands shouldn't really jump on this bandwagon too soon, it takes away a bit of what TQM brought to the table.

[GTO]

Platform sharing is here to stay.

As long as the parts are competent, no one is going to complain. For instance, the BMW 5 Series, 7 Series & Rolls Royce Ghost essentially share the same 'platform'. Each is an excellent car in its own right.

On the other hand, the Brio <-> Mobilio are poor examples of sharing. Those budget interiors & quality might be acceptable in a 5 lakh Brio, but certainly not in a 10 lakh Mobilio. The Mobilio's falling sales indicate that the market agrees with this. Maruti handled the platform / sharing better with the Swift & Ertiga...right from tweaking the face of the Ertiga to differentiate it from its hatchback sibling, and offering more powerful petrol / diesel engines.