On Tuesday 18 December 2018 20:51:43 Chris Albertson wrote:
On Tue, Dec 18, 2018 at 2:50 PM Gene Heskett <[email protected]>
wrote:
> On Tuesday 18 December 2018 12:57:07 Chris Albertson wrote:
> > Gene,
> >
> > You should learn to use CAM software.
>
> I've made several passes at learning one pkg or another, but after
> half an hour without making any real progress, I'm back to measuring
> and defining points and writing gcode by hand.
30 minutes is unrealistic.
No, whats unrealistic is that in 30 minutes I wasn't able to get 2 lines
to come together and be coupled so I could move the joint and begin to
approach what I wanted to with a realstic chance of actually getting the
trapezoid I was looking for. Doing that in gcode is extremely simple
because you can lay out the trapezoid in 3 or 4 minutes, its
automatically a straight line from point a to b, b to c, c to d, and d
to a, insert a small ramp down in the a to b run and stay there till
leaving the a again.. Check your measurements and do the tool_rad comp
in your code, but by using some weird air moves, it demanded 3x what the
docs say to even get it to load the code without yelling at me. G42,
once its working will automatically round the corners. Fiddling with the
lower run length gets me the trapezoid needed since I lay that stuff out
so one end is x.5750 and the other end is -.5750 so it automaticaly
symmetrical. I had lots more trouble getting lcnc to accept the g42 than
anything else. The time killer is fixing the typu's cause I can't see
near as well as I could with the cataracts, and instrumenting it to
verify I didn't forget to turn on the spindle while I'm doing motor
power off runs of nearly an hour each just to watch the backplot get
screwed because of a typu. If I run it all the way thru. Every such
mistake is of course another broken mill. It needs spindle rpm it
doesn't have when tops is 2500. For something like this 10k is more
usable and that would cut the execution time to 1/4 what it is now. 2500
just buries the tool in swarf.
I bought another z casting 3 or 4 years back, thinking of machining it to
clamp a 24k revs 1 horse motor in place of its gearbox and spindle, but
then I've not been able to find a truly concentric means of mounting a
1/8" collet and mill in its 1/4" spindle. I'll probably trip over
exactly what I need, someday, if I have sense enough left to recognize
it when I see it.
If I don't fall over first... So far I'm beating the odds, I've outlived
all the jerks I might have killed had it been legal at the time they
needed it. Most of that was 60 years ago. :) First wife's 1st husband. A
problem if there ever was one.
Takes about a week to learn to use
something like that. But it's been 4 days now to make a simle "D"
cut out. If yousave a few days on every parts the payback is quick.
Plus you be able to make very complex, lofted parts with compound
curves.
Loft is not a problem even on that toy, z is the fastest axis by a factor
of at least 2, and I can with the drive mods I've made, use the full
height of an 18" post. And with doubled bronze z nuts, backlash might be
2 thou. Ditto for the ball screws for xy as I've restuffed those nuts
with oversized balls.
> > As an exercise I tried this,
> > took about 6 minutes. Four steps Draw trapezoid, filet the
> > corners, select tool, generate g-code for tool path. The
> > trapezoid is parametric so I can change the length by editing one
> > number.
>
> I'm about halfway there, and should be able to switch it to a db9/15
> size by throwing a software switch. But I'm also up to around 310
> LOC now. With the CAM program unrolling all the loops, this code
> would be 100K+ of build it from scratch to fix a typu in the cam
> drawings.
