Re: Names

>Then we had Fred smith pushing CAD/CAM, and even making a foolish statement
>that anyone making just one or two parts shouldnt be using CNC at all.
>He did get soundly shouted down on that statement!

For those of you who missed the little CNC discussion forum and
presentations, I was not pushing Vector at all (it was in the title, but not
the words). I merely showed when it is best to use CNC as opposed to manual
machining. Most of my discussion was about the $100,000 CNC lathe I watched
wreck itself & a statement to be safe when using CNC machines.

As far as being shouted down, this is what happens when a group of
fanatical CNCers get together and one amongst them commits the blasphemy of
saying that their official religion is not the only answer, especially in
public. ;-) I stand by my statement that the best way to machine a single
part is OFTEN and USUALLY by turning the cranks. As I pointed out in my
talk, there are indeed shapes and contours that can more efficiently be
machined with CNC. There are however those that are not best done that way.

For example, Drilling and Tapping a single hole. I guarantee that I can do
this faster on my Bridgeport than on any CNC machine. This is a quick,
efficient process, all the tools are ALWAYS placed near my work area, and
just reaching to push a button makes for a less efficient process.

Just so any anal retentives reading this will understand, the hole is
a 1/4-20, center drilled, and tap drilled with a #7 drill. The hole also
has a 45 degree chamfer on each side, put there with a 45 degree
countersink. The material is 1/2 aluminum. The hole location is +/- .020,
it has been pre spotted with a scribe, 1/2 inch from each side of the upper
left corner. Total time to make the part, including the time to decide that
the hole is needed, is about 1 1/2 to 2 minutes.

I don't care how smart you are, there is no getting around the fact that
this is more efficiently done by cranking handles. Furthermore, If I had to
put the same tapped hole in 10 identical parts, I would also say that I
could still do it more efficiently without CNC. (Total time would be about
20 seconds per part 4 1/2 to 5 minutes total for ten holes.) However, I
would be starting to sweat from playing material handling robot.

If you use the best tool for the job, you will utilize those cranks on your
lathe & mill when it makes sense to do so. You will also use CNC when it is
obvious that it will yield the best results. CNC will allow you to overcome
some lack of skill as a machininst, but it will not allow you to push a
button and make a part. You still need to plan your process, decide on
workholding techniques, set your tools, and have an understanding of the
cutting processes, feeds, and speeds.

Best Regards,

Fred Smith
IMService

imserv@...
Phone: 248-486-3600 or 800-386-1670
Fax:248-486-3698