I would like to CNC vertical mill some 2024-T3 aluminum parts from
stock approximately 12"X12"X2". The parts are about 6"X6"x2" and have
a general profile tolerance of +/-.001. The parts will require full 3
axis machining.

What are my basic options for a fairly affordable CNC but one that has
decent enough speed and rigidity to make these parts in an
average/reasonable amount of time? For instance I would be happy if I
could make them in half the time that say a $50,000 used Haas or Fadal
VMC could make them in. The machine would only run about 10 hours a
week so it doesn't need to be too hell-for-stout.

A small machining center? A retrofit/conversion? A benchtop? Import
vs domestic? Other options?

I would like to keep the price down under about $7k if possible. Am I
dreaming?

Thanks folks.

Joe

On 2 Feb 2005 23:05:27 -0800, wrote:

I would like to CNC vertical mill some 2024-T3 aluminum parts from
stock approximately 12"X12"X2". The parts are about 6"X6"x2" and have
a general profile tolerance of +/-.001. The parts will require full 3
axis machining.

What are my basic options for a fairly affordable CNC but one that has
decent enough speed and rigidity to make these parts in an
average/reasonable amount of time? For instance I would be happy if I
could make them in half the time that say a $50,000 used Haas or Fadal
VMC could make them in. The machine would only run about 10 hours a
week so it doesn't need to be too hell-for-stout.

A small machining center? A retrofit/conversion? A benchtop? Import
vs domestic? Other options?

I would like to keep the price down under about $7k if possible. Am I
dreaming?

Thanks folks.

Joe



+/-.001, 3 axis profiling, $7k, half the machining time of a machine
costing 7x ???
Not gonna happen.

Your main issue is that I don't think you'll find a machine fast enough for
+/-.001" on 3 axis in your price range. Your cutting AL, but I also don't
think you'll find anything rigid enough in your price range to hold .001".

If you want fast feed, that also means faster spindles. Fast spindles means
hotter cutters and you'll want flood coolant and that generally means an
enclosure. Enclosure cost more money. So do the pumps, tanks... for the
coolant.

You don't want to pay $50k for a machine but want better than that level of
performance. Regardless of your opinion on Fadals, Haas' etc, you really
*do* get something for your money spent.

Decide which of your parameters you'll sacrifice (tolerance, speed, price).
--
Skuke
Reverse the domain name to send email

= For instance I would be happy if I
could make them in half the time that say a $50,000 used Haas or Fadal
VMC could make them in.

think you mean twice the time

The machine would only run about 10 hours a
week so it doesn't need to be too hell-for-stout.

A small machining center? A retrofit/conversion? A benchtop? Import
vs domestic? Other options?


Look for bridgeport rigid ram cnc , 7k all day, I prefer heidenhain, but
the very late BOSS [with a crt for instance] are ok from what I hear,
the the bridgeport factory pc controls seem to get mixed reviews.

get as new as you can afford.

buy nothing prior to about 1985, preferably 1990

if this is a money making proposition, don't be afraid to borrow money,
those HAAS toolroom mils start around 20, so a 4 year lease is something
in the 4 hundreds a month, do the math.

Dreaming. A new VMC with those specs will cost $30K-$40K. You might find
something used for 2/3 that price. Don't bother with benchtop stuff
unless you're certain you'll never be running larger parts. Consider
adding an automatic tool changer to your features list.

Profiling requires servos and a decent (i.e. modern vintage) controller
that can run all 3 axes simultaneously with look-ahead. Beware of
low-cost older machines with decent iron but have stepper drives or a
controller box Marconi would recognize.

We bought a couple of these VMCs last year, and they've worked out well
in terms of reliability and throughput:

http://www.atrump.com/toolroom/Maximill/MAXIP1.htm

wrote:
I would like to CNC vertical mill some 2024-T3 aluminum parts from
stock approximately 12"X12"X2". The parts are about 6"X6"x2" and have
a general profile tolerance of +/-.001. The parts will require full 3
axis machining.

What are my basic options for a fairly affordable CNC but one that has
decent enough speed and rigidity to make these parts in an
average/reasonable amount of time? For instance I would be happy if I
could make them in half the time that say a $50,000 used Haas or Fadal
VMC could make them in. The machine would only run about 10 hours a
week so it doesn't need to be too hell-for-stout.

A small machining center? A retrofit/conversion? A benchtop? Import
vs domestic? Other options?

I would like to keep the price down under about $7k if possible. Am I
dreaming?

Thanks folks.

Joe

Look at: http://www.mckeanmachinery.com/inven...?TheKey=MT7562
as an example of used machines. Keep looking, they are everywhere!


wrote in message
ups.com...
I would like to CNC vertical mill some 2024-T3 aluminum parts from
stock approximately 12"X12"X2". The parts are about 6"X6"x2" and have
a general profile tolerance of +/-.001. The parts will require full 3
axis machining.

What are my basic options for a fairly affordable CNC but one that has
decent enough speed and rigidity to make these parts in an
average/reasonable amount of time? For instance I would be happy if I
could make them in half the time that say a $50,000 used Haas or Fadal
VMC could make them in. The machine would only run about 10 hours a
week so it doesn't need to be too hell-for-stout.

A small machining center? A retrofit/conversion? A benchtop? Import
vs domestic? Other options?

I would like to keep the price down under about $7k if possible. Am I
dreaming?

Thanks folks.

Joe

Wasn't there a big lawsuit over Bridgeport's home-grown CNC controller?
They were using customers for R&D, and a lot of them weren't too happy
about it.

yourname wrote:

Look for bridgeport rigid ram cnc , 7k all day, I prefer heidenhain, but
the very late BOSS [with a crt for instance] are ok from what I hear,
the the bridgeport factory pc controls seem to get mixed reviews.

Good info, thanks all.

Yaa, I meant *twice* the machining time of the 50k machines

I would be fine with a used machine but don't want something that will
require a lot of maintenance costs of course.

Does the ALLIANT CNC VERTICAL MILL W/ANILAM CRUSADER M EQUIPPED WITH:
9" X 42" fit the bill as far as ability to hold this tolerance and also
the run time?

I might be pursuaded to go with an enclosed machining center for a
little more money since it may work better down the road. What are my
price options for the smaller units and also for the less expensive
(I'm assuming import) units? Used prices but not for worn out stuff.
What are the top places to watch for these as they become available?

Thanks again guys.

Joe

On 3 Feb 2005 09:42:59 -0800, wrote:

Good info, thanks all.

Yaa, I meant *twice* the machining time of the 50k machines

I would be fine with a used machine but don't want something that will
require a lot of maintenance costs of course.

Does the ALLIANT CNC VERTICAL MILL W/ANILAM CRUSADER M EQUIPPED WITH:
9" X 42" fit the bill as far as ability to hold this tolerance and also
the run time?

I might be pursuaded to go with an enclosed machining center for a
little more money since it may work better down the road. What are my
price options for the smaller units and also for the less expensive
(I'm assuming import) units? Used prices but not for worn out stuff.
What are the top places to watch for these as they become available?

Thanks again guys.

Joe



I've programmed and run several Alliant w/ Anilam Crusader (circa 1985-90)
as well as well as later Fadals (1993+) and Bridgeport EZ Track (1998). Did
R&D, as well a 3 axis Aluminum molds. Neither of the knee mills could hold
+/-.001 without a lot of work and very careful setups. You needed to
consider ALL aspects of the problem if you really wanted to hold your
required tolerances. The Fadal could hold .001" on 3 axis w/o *too* much
trouble.

I'm sure you could find a used 3 axis knee mill in the $7k range, but that
machine would probably have been "ridden hard and put away wet." It won't
hold the tolerance you request (without a lot of extra work, and then only
just maybe).

Spend more money and you'll be happier in the long run. JMHO. Also, please
consider if you *really* need +/-.001" Are you making matched dies?
....duh, I guess not if they're aluminum. But my point is that .001" is
pretty tight to hold day in, day out with any kind of efficient speed.
--
Skuke
Reverse the domain name to send email

"skuke" wrote in message
. ..
On 3 Feb 2005 09:42:59 -0800, wrote:
Spend more money and you'll be happier in the long run. JMHO. Also,
please
consider if you *really* need +/-.001"

That was what I was wondering. I would recommend to the OP to find out how
the 3d contour will be measured, and go from there...

Regards,

Robin

On Thu, 3 Feb 2005 15:58:18 -0800, skuke wrote:

On 3 Feb 2005 09:42:59 -0800, wrote:

Good info, thanks all.

Yaa, I meant *twice* the machining time of the 50k machines

I would be fine with a used machine but don't want something that will
require a lot of maintenance costs of course.

Does the ALLIANT CNC VERTICAL MILL W/ANILAM CRUSADER M EQUIPPED WITH:
9" X 42" fit the bill as far as ability to hold this tolerance and also
the run time?

I might be pursuaded to go with an enclosed machining center for a
little more money since it may work better down the road. What are my
price options for the smaller units and also for the less expensive
(I'm assuming import) units? Used prices but not for worn out stuff.
What are the top places to watch for these as they become available?

Thanks again guys.

Joe



I've programmed and run several Alliant w/ Anilam Crusader (circa 1985-90)
as well as well as later Fadals (1993+) and Bridgeport EZ Track (1998). Did
R&D, as well a 3 axis Aluminum molds. Neither of the knee mills could hold
+/-.001 without a lot of work and very careful setups. You needed to
consider ALL aspects of the problem if you really wanted to hold your
required tolerances. The Fadal could hold .001" on 3 axis w/o *too* much
trouble.

I'm sure you could find a used 3 axis knee mill in the $7k range, but that
machine would probably have been "ridden hard and put away wet." It won't
hold the tolerance you request (without a lot of extra work, and then only
just maybe).

Spend more money and you'll be happier in the long run. JMHO. Also, please
consider if you *really* need +/-.001" Are you making matched dies?
...duh, I guess not if they're aluminum. But my point is that .001" is
pretty tight to hold day in, day out with any kind of efficient speed.
I have a Wells Index CNC knee mill. The mill itself weighs 6000 lbs.
So it's bigger than your typical bridgeport type knee mill which weigh
about a ton. The control on the mill failed a few years ago and I
bought a new control from AJAX. Even though about 20 years old and
plenty used the machine is quite accurate. So holding .0005" location
when boring holes is a breeze. I can get closer by changing the
program to compensate for position error because the machine repeats
to .0002". So an older machine can be checked for error in both
positioning, flatness, and squareness and if good enough then it might
fill the bill. I bought my Index mill mainly for complex shapes, not
for production. My next mill will be enclosed, the Index is not. Being
enclosed will keep the chips and coolant in the machine and allow
higher speeds and feeds without throwing chips and coolant all over
the place.
ERS

On Thu, 03 Feb 2005 16:19:33 -0800, Eric R Snow wrote:


But my point is that .001" is
pretty tight to hold day in, day out with any kind of efficient speed.

I have a Wells Index CNC knee mill. The mill itself weighs 6000 lbs.
So it's bigger than your typical bridgeport type knee mill which weigh
about a ton. The control on the mill failed a few years ago and I
bought a new control from AJAX. Even though about 20 years old and
plenty used the machine is quite accurate. So holding .0005" location
when boring holes is a breeze. I can get closer by changing the
program to compensate for position error because the machine repeats
to .0002". So an older machine can be checked for error in both
positioning, flatness, and squareness and if good enough then it might
fill the bill. I bought my Index mill mainly for complex shapes, not
for production. My next mill will be enclosed, the Index is not. Being
enclosed will keep the chips and coolant in the machine and allow
higher speeds and feeds without throwing chips and coolant all over
the place.
ERS


I agree with you that one can program out (minimize) positional errors by
approaching from the same direction to eliminate back lash issues, center
drill, drill... With all due respect, true hole position is much easier to
hold and measure than the 3 axis contouring the original poster wanted.

My experience with the knee mills (and even the Fadal to a much lesser
extent) is that to interpolate a round circle is pretty gosh darn difficult.
You wind up with some "egg" shaped hole with dwell marks at the axis' when
the ball screw must actually come to a complete stop for a moment to turn
the other direction.

Please try it: Interpolate a ~3-4" circle in a rigid piece of aluminum with
a good rigid endmill of your choice. Take a few finish passes. Then,
without removing the part from the vise (to eliminate other problems like
stress/tension relief), measure TIR with a test indicator. I'm pretty sure
you'll have at least .001" TIR.

So I think trying to hold 3 axis timing on a cheaper, less rigid machine
will be all but impossible.

....just based on my experiences. ...your results may differ.
--
Skuke
Reverse the domain name to send email

skuke wrote in
:



Spend more money and you'll be happier in the long run. JMHO. Also,
please consider if you *really* need +/-.001" Are you making matched
dies? ...duh, I guess not if they're aluminum. But my point is that
.001" is pretty tight to hold day in, day out with any kind of
efficient speed.

Try holding +/- 0.001 mm (1 micron) all day, day in, day out. 0.001" is
like having a ballfield to play in by comparison.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

Tim Killian wrote:

Wasn't there a big lawsuit over Bridgeport's home-grown CNC controller?
They were using customers for R&D, and a lot of them weren't too happy
about it.

Nothing wrong with using customers for R & D, at least according to
microsoft.
jk

Ok, let's put it another way.... what small enclosed VMCs are available
and what do they usually run used (for one that hasn't been beat to
death)? I figure if there is a machining center with a toolchanger and
everything it will probably do what I'm after. I don't need to hold
..001" on the whole part but definitely need to for certain areas of it.

JOe

wrote in message
oups.com...
Ok, let's put it another way.... what small enclosed VMCs are available
and what do they usually run used (for one that hasn't been beat to
death)? I figure if there is a machining center with a toolchanger and
everything it will probably do what I'm after. I don't need to hold
.001" on the whole part but definitely need to for certain areas of it.

You need to identity what you need at this point. After reading this group
for several years, and selling tools for several years, knowing what you
*need* is paramount.

If you spend $7K on a machine that cannot do what you want it to, you have
wasted that money, and the time required to buy (and perhaps sell) that
machine.

So... Be specific...

Regards,

Robin

"jk" wrote in message
...

Nothing wrong with using customers for R & D, at least according to
microsoft.

Is it research if they aren't interested in the results?

Regards,

Robin

On Fri, 04 Feb 2005 00:54:57 GMT, Anthony wrote:



Try holding +/- 0.001 mm (1 micron) all day, day in, day out. 0.001" is
like having a ballfield to play in by comparison.



Doh! The OP would have just spent his entire budget (and then some) on
temperature controlled coolant and enviromental controlled shop and
inspection!
--
Skuke
Reverse the domain name to send email

On 3 Feb 2005 18:19:18 -0800, wrote:

Ok, let's put it another way.... what small enclosed VMCs are available
and what do they usually run used (for one that hasn't been beat to
death)? I figure if there is a machining center with a toolchanger and
everything it will probably do what I'm after. I don't need to hold
.001" on the whole part but definitely need to for certain areas of it.

JOe


You need a 6"-12" cube work envelope? Look at some of the newer Haas and
Fadal "tool room" mills. Haas even has a new line called the Office
Mill(?). I'm not sure that has enough power and space for your needs, but
check it out.

I think you basically need to stay away from knee mills if you *really* need
..001" on any significant parts of your job. Yeah, you could do it, but it's
just way more work. Look into bed mills with or without enclosures. Maybe
a Milltronics, Hurco or Prototrak (bed mill version). Even with the last
three mills, look for a head/quill design that will be sufficiently rigid
for your needs. I don't know the prices for any of the above, but they are
all well over $25k new.

Maybe you should just job out the contouring part you can't currently do??
--
Skuke
Reverse the domain name to send email

skuke wrote in news:gp8g5i8m5jmu$.1kacz6ey0d9hw.dlg@
40tude.net:




Doh! The OP would have just spent his entire budget (and then some) on
temperature controlled coolant and enviromental controlled shop and
inspection!

Hehe...and that doesn't include the automatic temperature adjustment for
the machine tool either.

I will agree, a knee mill type situation for the OP is not going to hold
his tolerances. The OP would be better off with a used, but good
condition bed mill.
OP: check out some used Mazak mills, ought to be fairly reasonable in
price, and they are good machines.



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

On Thu, 03 Feb 2005 17:32:51 -0800, jk wrote:

Tim Killian wrote:

Wasn't there a big lawsuit over Bridgeport's home-grown CNC controller?
They were using customers for R&D, and a lot of them weren't too happy
about it.

Nothing wrong with using customers for R & D, at least according to
microsoft.
jk

Which demonstrates a critical differnence between the machine tool and
software industries.

--RC
"Sometimes history doesn't repeat itself. It just yells
'can't you remember anything I've told you?' and lets
fly with a club.
-- John W. Cambell Jr.

The control on the mill failed a few years ago and I
bought a new control from AJAX.

Which package did you go with? What size servos did you use i.e. inch-pound
torque? What did you end up spending on the retrofit?

On Thu, 3 Feb 2005 16:52:33 -0800, skuke wrote:

On Thu, 03 Feb 2005 16:19:33 -0800, Eric R Snow wrote:


But my point is that .001" is
pretty tight to hold day in, day out with any kind of efficient speed.

I have a Wells Index CNC knee mill. The mill itself weighs 6000 lbs.
So it's bigger than your typical bridgeport type knee mill which weigh
about a ton. The control on the mill failed a few years ago and I
bought a new control from AJAX. Even though about 20 years old and
plenty used the machine is quite accurate. So holding .0005" location
when boring holes is a breeze. I can get closer by changing the
program to compensate for position error because the machine repeats
to .0002". So an older machine can be checked for error in both
positioning, flatness, and squareness and if good enough then it might
fill the bill. I bought my Index mill mainly for complex shapes, not
for production. My next mill will be enclosed, the Index is not. Being
enclosed will keep the chips and coolant in the machine and allow
higher speeds and feeds without throwing chips and coolant all over
the place.
ERS


I agree with you that one can program out (minimize) positional errors by
approaching from the same direction to eliminate back lash issues, center
drill, drill... With all due respect, true hole position is much easier to
hold and measure than the 3 axis contouring the original poster wanted.

My experience with the knee mills (and even the Fadal to a much lesser
extent) is that to interpolate a round circle is pretty gosh darn difficult.
You wind up with some "egg" shaped hole with dwell marks at the axis' when
the ball screw must actually come to a complete stop for a moment to turn
the other direction.

Please try it: Interpolate a ~3-4" circle in a rigid piece of aluminum with
a good rigid endmill of your choice. Take a few finish passes. Then,
without removing the part from the vise (to eliminate other problems like
stress/tension relief), measure TIR with a test indicator. I'm pretty sure
you'll have at least .001" TIR.

So I think trying to hold 3 axis timing on a cheaper, less rigid machine
will be all but impossible.

...just based on my experiences. ...your results may differ.
My point was that lead screw error can be programmed out. The
backlash, once measured, is entered as a parameter in the control. One
of the first things I did after installing the new control was measure
backlash and enter it in. Unfortunately, there is some variance in
backlash over the length of the travel. But, the machine will
interpolate a hole that's .0006 out of round in the approximate center
of travel. Of course, you are right about a smaller machine maybe not
being able to hold tight tolerances. My knee mill is 3 times heavier
and aboutt 1.5 times as large as a bridgeport mill. So it is massive
enough to get good accuracy on heavier parts.
ERS

On Fri, 04 Feb 2005 08:08:13 -0500, wrote:


The control on the mill failed a few years ago and I
bought a new control from AJAX.

Which package did you go with? What size servos did you use i.e. inch-pound
torque? What did you end up spending on the retrofit?
I used the servos already on the machine. If you want, e-mail me and
I'll send you my phone number and I'll tell you all about it.
Eric

OP: check out some used Mazak mills, ought to be fairly reasonable in
price, and they are good machines.


I concur. I think the Mazaks are at least another level higher from the
machines I mentioned previously and should have no troubles with your
tolerance. Of course, the downside is $$$$
--
Skuke
Reverse the domain name to send email

On Fri, 4 Feb 2005 08:17:32 -0800, skuke wrote:


OP: check out some used Mazak mills, ought to be fairly reasonable in
price, and they are good machines.


I concur. I think the Mazaks are at least another level higher from the
machines I mentioned previously and should have no troubles with your
tolerance. Of course, the downside is $$$$

Or Mori-Seki.

Gunner



" We have all heard that a million monkeys banging on a million
typewriters will eventually reproduce the entire works of
Shakespeare...Thanks to AOL and WebTv, we know this is not possible."