"jim" wrote in his blissful ignorance
On Sun, 24 Nov 2013 18:22:26 -0600, jim
wrote:
wrote:

On Sun, 24 Nov 2013 17:08:14 -0600, jim

wrote:

How many have you modeled in CAD and then manufactured
to within tenth of the designed part?

You still make no sense. Are you saying that precision machining
doesn't require the same level of modeling that sloppier work does?
Really?

First of all most of the examples of precision that have
been given involve no 3d modeling at all. And the rest
appear to be at best 2d modeling (e.g.. a lathe profile).


I'm saying that any CAD system can produce geometry that
is far more accurate than any manufacturing process. If a 3d
computer model has dimensions that are different than what you
like them to be, it is because of the input the software was
given, not because the software is sloppy.


http://www.mmsonline.com/articles/ge...icron-accuracy
"The axis position feedback system uses a 0.5-nanometer scale to
reliably track axis motion commands programmable in steps as small as
10 nanometers."

I've watched a large aspherical Germanium infrared camera lens being
diamond-turned to a mirror-like submicron finish on a CNC lathe.
http://media.defenceindustrydaily.co... Mosul_lg.jpg

All you demonstrate is that YOU don't know how to do this.

jsw