View Single Post
      08-25-2012, 05:40 AM   #106
swamp2
Lieutenant General
swamp2's Avatar
United_States
381
Rep
10,367
Posts

Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (1)

Good post. Let's continue.

Quote:
Originally Posted by BMRLVR View Post
The Video in Question was of pre-production S65 Engines (some of the first ever built). Production S65's are indeed assembly line built since the hand building that the video shows could not come close to keeping up with the volume required.
Correcto. And this MB engine in question here is running a substantially higher volume than the S65.

Quote:
Originally Posted by BMRLVR View Post
Like you mentioned, cost is key in this equation and it costs a lot to hand assemble engines. As for machines making perfect parts time after time, you are almost correct, but many times the first parts from a batch will be better than the last parts out of a batch simply because cutter heads and other parts wear and that is where your variance comes from. At some point a machine needs to be re-calibrated to make up for this wear. A machine is only as good as the preventative maintenance program of the company that owns it, and since cash is king, preventative maintenance is getting cut back everywhere. When a machine has to go down for maintenance, production is affected and so is profit. However, with proper maintenance and adequate QC machines are definitely able to make virtually exact parts one after the other, the maintenance and QC is the variable and like I said above that is up to the company. (This reminds me of a story of a friend of mine who worked at the GM assembly line in Oshawa, Ontario........ He told me that by the end of the production run of the Eighth generation Chevrolet Impala, the dies used to stamp the body panels were so worn that the rear windows barely even fitted the body any more and GM refused to spend the money to replace them since the car was going out of production soon. The solution was to use extra urethane to take up the added gap between the window and body and stick the molding over top of it. I know we are not talking about GM here, but where ever cash is king sometimes corners are cut, no manufacturer shy of Bugatti or Rolls Royce are free of this type of thing)
Almost completely agree with you here. There is however a key difference. Machining vs. stamping. One has very low consumable tooling costs (replaceable cutting blades) and they other has really high ones (replace an entire stamping tool). Also in the case of machining, in cases where tolerances are critical (pretty well all internal engine dimensions) statistical process control and 100% part inspection are used. Those things together can pretty much eliminate the effects of slow and steady wear on cutting tools. There is much less luxury for stamping dies. I suspect they can be tuned up a bit along the way at a relatively low cost, perhaps welded, ground and or polished. Either way there is a fundamental difference.

[quote=BMRLVR;12565885]Anyhow I can ramble on and on, but in the end I think we are both right, machines are simply amazing at mass production of identical parts, so much so that no human could ever hope to even come close to matching the volume yet keeping tolerances so close. At the same time a hand built engine is almost always going to have tolerances that that are tighter than the one produced by machines simply because there is more time and hands on involvement to allow this. [quote]

Still don't fully agree with this. It is a but subtle. There are certainly combinations of team, process and equipment which are better than others combination of team process and equipment. One might compare a really well funded OEM engine production team (company) like BMW Porsche or even Ferrari (the latter is probably not the best example because of low volume they will necessarily have a higher percentage of human involvement) with a somewhat crude back yard team of buddies building big block Chevy drag engines for their team. They latter may fully blueprint and may do everything by hand but their limitations in terms of their sourcing, machining and inspection accuracy will not allow them to match the OEM who is perhaps 99% automated. Just because one complete team takes one small step (or even an entire process) by hand does not immediately let you conclude they have actually improved something over another teams outcome. The devil is in the details.

Quote:
Originally Posted by BMRLVR View Post
One thing that should be noted though, no automobile assembly line that I have ever seen has been able to totally eliminate people from the equation, there are always some humans in there!
Absolutely. Humans are physically present in some places, always but their ingenuity is omnipresent. This video does not cover engine assembly but does show a large part of the assembly of a modern BMW 3er. A truly amazing video.

Quote:
Originally Posted by BMRLVR View Post
Finally, I don't know of a machine made that can feel a grinding or drag, or hear a particular noise like a trained craftsman can. There are some things that machines just don't have and that is the human touch.
Acoustic and ultrasonic inspection techniques have been widely used since the 1970's for the inspection of the wear and functional state of machinery! A very commonplace application for this is for the non-contact inspection of ball bearings. Again, it is mostly about volume and cost.

Perhaps an interesting and loosely related topic would be a short list of the the very common things that humans are much better at than machines...

Quote:
Originally Posted by BMRLVR View Post
If AMG engines are hand assembled like they claim, I think there is at least some value in that. They may not necessarily be better because of it, but as an engine builder myself I feel a connection to the fact that another person from my craft put it together with his hands even if it was from parts largely made by an automated machine with many high tech tools.
The personal allure or romance of the craftsmanship has been discussed earlier. It is something with a strong emotional content for some. However, it should not be allowed to interfere with the facts! Personally I get the same type and level of allure and amazement for the omnipresent nature of the feats of manufacturing engineering that go into the making of some pretty mundane objects, not to mention something with the complexity of a modern automobile...
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK |
| Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors |
| Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels |
| XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit |