Re: Re: What do we want?

Ray Henry wrote:

> When I re read my comment and your response I had to try to make ammends.
> I was not intending to belittle the experience of anyone in these virtual
> parts. I know that there are many folk here who have years and years of
> standing up to mills and lathes. I should have said that "some" of us do
> not have enough experience cutting chips to feel confident about our
> machining decisions and would like to pass that task off to a computer
> program. Then we can blame the damn thing when trouble comes. BTW I'm not
> sure how well computer programs can substitute for experience.

I have heard people say before, that one should run a manual machine first, before
moving to CNC. I think that is good advice. There is a lot of feedback, or 'feel'
that you get for feed rates, and similar things, that you will never get from CNC.
Many of these feedbacks also have sounds associated with them, and you still
do get the sound feedback. I'm still getting up to speed on the different sorts
of things you have to be aware of, with CNC. One big one is to watch out
for slamming fixtures into the stopped tool while setting up. I have a small
pile of neatly snapped off end mills that I made this way, and it is starting to
get into significant $. I thought I had graduated beyond that, but did it again
a few nights ago. It also means re-tramming the machine whenever I do that.

One of the big advantages of CNC is that you don't have the tool idling on some
surface for 30 seconds while you figure out what is the next coordinate to move
to. This helps things look good, and also reduces tool wear.

Another advantage (at least if you have ballscrews) is being able to climb-mill
just about everything, which gives better finish and longer tool life.

And, of course, once you have CNC, ANY straight line, no matter what the
angle, is as easy as moving so far in X or Y on a manual machine. It changes
the way you design parts!

And, still, things go wrong from time to time. Like the time I forgot to
touch the tool down to the part after a tool change, and it drove a drill bit
through a part at 50 IPM. It actually made a half decent hole, until the drill
broke off. Sometimes, stuff happens so suddenly that you have no time to
respond and hit the E-stop.

Jon