View Single Post
      08-20-2012, 09:12 PM   #64
Lieutenant General
swamp2's Avatar

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

iTrader: (1)

Originally Posted by bruce.augenstein@comcast. View Post
Agree with most of this, assuming when you say "microns", you mean a whole bunch of them. Tolerances smaller than a micron in the automotive world? Forget it. You're dreaming.
Sorry, wrong.

Here is a quote from Addison D. Cole, CEO of Adcole Corporation an inspection machine company, about how improved engine tolerances are greening engines,

"In the last 25 years, crankshaft roundness tolerances have been reduced from eight microns to three microns. The green cars of the future will have high performance, small engines with very low emissions. Consequently, the production tolerances will continue to tighten..."
Originally Posted by bruce.augenstein@comcast. View Post
Here's a list of tolerances I found on the 'net for an S52 engine:
.00x mm is in fact x microns...

Also the S52 was now developed what, well over a decade ago? That's a long time from the perspective of precision, tolerances and robotics! The S65 surely has a variety of single digit micron tolerances.

Originally Posted by bruce.augenstein@comcast. View Post
I am not aware of BMW (or anyone else) using an automated process to custom fit individual pistons to individual cylinders. Are you? Seriously, if you know of such an automated process, I'd like to know about it too.
No factual/first hand knowledge of this but given the level of inspection this would not be too difficult at all. Watch the video posted below. The piston for each cylinder is placed in a specific holding fixture and robotic mover.

Originally Posted by bruce.augenstein@comcast. View Post
I am assuming that you will cling to your belief that today's automated tolerances have made any advantage of hand-building moot.
I would not go so far as to say there is no advantage for any part of the process. Specifically there likely is some actually implemented hand process that is better than some (albeit poorly implemented) machine process. I will say again that whatever is done by hand can be done better by machine (engine assembly or the like). Certainly anything where the human is in the loop will require machines in the loop to contribute to the process (specifically inspection machines). You just don't throw a nice Mitutoyo micrometer on any modern crankshaft to measure its roundness (let alone its diameter...).

Originally Posted by bruce.augenstein@comcast. View Post
If that's the case, then why would anybody do that unless volumes were very low.

Don't say marketing please. You think marketing dictates build techniques at MB? Don't be silly.

If not marketing or finance, then why?
You know the answer, it is ALL driven by volume and cost and their relation. Its very simple.