A Question for You Air Only Guys
 

I needed to get a couple jobs done. The screws need to be replaced on the
Taig so I couldn't use its regular flood oil coolant setup until I fix it.
I used my smaller machine, rubbed a little Tap Magic on the work piece and
hit it with a blast of compressed air. When surfacing off the aluminum work
piece with a 1/4" end mill (largest that spindle will hold) it got pretty
hot, but it worked great when 3D carving with a 1/16 ball mill. I ran full
pressure off my compressor (125 PSI I think) and used a simple ball valve to
regulate flow somewhat, but I let it flow pretty heavily. So... how much
air do you guys use? Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be adding
an electric shut off valve to the air line to that cabinet, so my compressor
will shut off when I am done with a cut, but I was thinking if I could
consume less air and get a decent job I would add a flow and pressure
regulator too.

A Question for You Air Only Guys
 

On Sun, 18 Mar 2012 12:32:00 -0700, Bob La Londe wrote:

I needed to get a couple jobs done. The screws need to be replaced on
the Taig so I couldn't use its regular flood oil coolant setup until I
fix it. I used my smaller machine, rubbed a little Tap Magic on the work
piece and hit it with a blast of compressed air. When surfacing off the
aluminum work piece with a 1/4" end mill (largest that spindle will
hold) it got pretty hot, but it worked great when 3D carving with a 1/16
ball mill. I ran full pressure off my compressor (125 PSI I think) and
used a simple ball valve to regulate flow somewhat, but I let it flow
pretty heavily. So... how much air do you guys use? Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be
adding an electric shut off valve to the air line to that cabinet, so my
compressor will shut off when I am done with a cut, but I was thinking
if I could consume less air and get a decent job I would add a flow and
pressure regulator too.

Speaking naively, because I don't do this, either: a pressure regulator
may be the least necessary part. Just putting in a valve to let you
throttle back the airflow will "regulate" the flow to the extent that the
compressor is maintaining pressure. A regulator will let you keep the
flow steady, which means that you'll conserve air when the compressor
pressure is high (by not letting the flow increase at high pressure).

But I suspect that the two biggest things that will save air will be to
find the minimum flow necessary to keep things cool, followed by that
electric cut-off dingus that you're proposing.

Does anyone use augmenter tubes, to get more low-pressure flow from the
naturally low-flow, high pressure stream out of a nozzle?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

A Question for You Air Only Guys
 

"Tim Wescott" wrote in message
...
On Sun, 18 Mar 2012 12:32:00 -0700, Bob La Londe wrote:

I needed to get a couple jobs done. The screws need to be replaced on
the Taig so I couldn't use its regular flood oil coolant setup until I
fix it. I used my smaller machine, rubbed a little Tap Magic on the work
piece and hit it with a blast of compressed air. When surfacing off the
aluminum work piece with a 1/4" end mill (largest that spindle will
hold) it got pretty hot, but it worked great when 3D carving with a 1/16
ball mill. I ran full pressure off my compressor (125 PSI I think) and
used a simple ball valve to regulate flow somewhat, but I let it flow
pretty heavily. So... how much air do you guys use? Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be
adding an electric shut off valve to the air line to that cabinet, so my
compressor will shut off when I am done with a cut, but I was thinking
if I could consume less air and get a decent job I would add a flow and
pressure regulator too.

Speaking naively, because I don't do this, either: a pressure regulator
may be the least necessary part. Just putting in a valve to let you
throttle back the airflow will "regulate" the flow to the extent that the
compressor is maintaining pressure. A regulator will let you keep the
flow steady, which means that you'll conserve air when the compressor
pressure is high (by not letting the flow increase at high pressure).

But I suspect that the two biggest things that will save air will be to
find the minimum flow necessary to keep things cool, followed by that
electric cut-off dingus that you're proposing.

Does anyone use augmenter tubes, to get more low-pressure flow from the
naturally low-flow, high pressure stream out of a nozzle?

Augmenter tubes? Like an expansion chamber?

A Question for You Air Only Guys
 

On Sun, 18 Mar 2012 14:59:56 -0500, Tim Wescott
wrote:

On Sun, 18 Mar 2012 12:32:00 -0700, Bob La Londe wrote:

I needed to get a couple jobs done. The screws need to be replaced on
the Taig so I couldn't use its regular flood oil coolant setup until I
fix it. I used my smaller machine, rubbed a little Tap Magic on the work
piece and hit it with a blast of compressed air. When surfacing off the
aluminum work piece with a 1/4" end mill (largest that spindle will
hold) it got pretty hot, but it worked great when 3D carving with a 1/16
ball mill. I ran full pressure off my compressor (125 PSI I think) and
used a simple ball valve to regulate flow somewhat, but I let it flow
pretty heavily. So... how much air do you guys use? Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be
adding an electric shut off valve to the air line to that cabinet, so my
compressor will shut off when I am done with a cut, but I was thinking
if I could consume less air and get a decent job I would add a flow and
pressure regulator too.

Speaking naively, because I don't do this, either: a pressure regulator
may be the least necessary part. Just putting in a valve to let you
throttle back the airflow will "regulate" the flow to the extent that the
compressor is maintaining pressure. A regulator will let you keep the
flow steady, which means that you'll conserve air when the compressor
pressure is high (by not letting the flow increase at high pressure).

But I suspect that the two biggest things that will save air will be to
find the minimum flow necessary to keep things cool, followed by that
electric cut-off dingus that you're proposing.

Does anyone use augmenter tubes, to get more low-pressure flow from the
naturally low-flow, high pressure stream out of a nozzle?
I use air nozzles that entrain air and they work well for blowing
chips and such. They work using the Coanda effect. Much more effective
than a regular air nozzle. quieter too.
Eric

A Question for You Air Only Guys
 

Bob La Londe wrote:

I needed to get a couple jobs done. The screws need to be replaced on the
Taig so I couldn't use its regular flood oil coolant setup until I fix it.
I used my smaller machine, rubbed a little Tap Magic on the work piece and
hit it with a blast of compressed air. When surfacing off the aluminum
work piece with a 1/4" end mill (largest that spindle will hold) it got
pretty
hot, but it worked great when 3D carving with a 1/16 ball mill. I ran
full pressure off my compressor (125 PSI I think) and used a simple ball
valve to
regulate flow somewhat, but I let it flow pretty heavily. So... how much
air do you guys use? Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be
adding an electric shut off valve to the air line to that cabinet, so my
compressor will shut off when I am done with a cut, but I was thinking if
I could consume less air and get a decent job I would add a flow and
pressure regulator too.
Air blast is probably the worst way to remove chips and cool
things. A really good nozzle can move the chips with less air
flow, but it is still inefficient. A jet of flood coolant takes
very little energy compared to a big air compressor.

Jon

A Question for You Air Only Guys
 

Jon Elson fired this volley in news:fICdnY1
:

A jet of flood coolant takes
very little energy compared to a big air compressor.



Indeed.

Additionally, it provides lubrication, and "spot cooling" at the specific
areas (cutting edges) where air cannot impinge because of the pressure
"buffers" that corners produce.

LLoyd

A Question for You Air Only Guys
 

"Gunner Asch" wrote in message
...
On Sun, 18 Mar 2012 16:13:22 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Jon Elson fired this volley in news:fICdnY1
:

A jet of flood coolant takes
very little energy compared to a big air compressor.



Indeed.

Additionally, it provides lubrication, and "spot cooling" at the specific
areas (cutting edges) where air cannot impinge because of the pressure
"buffers" that corners produce.

LLoyd

Well said!

Unfortunately, it does not answer the question(s) asked. For a variety of
reasons I need to keep that particular machine "dry" with just oil on the
ways and screws. While I appreciate the flood coolant may be superior in
almost everyway, and that water based flood coolant may be better than oil
in almost everyway, there are reasons that I want to keep this machine dry.
The taig runs oil flood. The Hurco will run Kool Mist (water based) 77.
This machine runs dry or with just a contact surface lubricant rub. No
mist. No flood. Air is ok though. Air alone actually worked pretty good,
and air with a very very very light rub of Tap Magic worked almost
perfectly.

Something totally different is better is a good answer sometimes, but not in
this particular case.

A Question for You Air Only Guys
 

"Bob La Londe" wrote in message
...
I needed to get a couple jobs done. The screws need to be replaced
on the Taig so I couldn't use its regular flood oil coolant setup
until I fix it. I used my smaller machine, rubbed a little Tap Magic
on the work piece and hit it with a blast of compressed air. When
surfacing off the aluminum work piece with a 1/4" end mill (largest
that spindle will hold) it got pretty hot, but it worked great when
3D carving with a 1/16 ball mill. I ran full pressure off my
compressor (125 PSI I think) and used a simple ball valve to regulate
flow somewhat, but I let it flow pretty heavily. So... how much air
do you guys use? Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be
adding an electric shut off valve to the air line to that cabinet,
so my compressor will shut off when I am done with a cut, but I was
thinking if I could consume less air and get a decent job I would
add a flow and pressure regulator too.

I just brush on a little bit of MSC cutting oil for steel or kerosine
for aluminum. There is a noticeable but not serious difference between
completely dry and lightly oiled, but no additional benefit from more
oil as long as I run at HSS recommended cutting speeds.
http://en.wikipedia.org/wiki/Speeds_and_feeds
Those are for dry cutting.

The older $3 Enco end mills dull quickly unless run slower. Otherwise
I haven't had heat problems on mild steel, 303, drill rod and graded
bolt shanks.

Sometimes the super-duper tapping fluids give a better finish. I use
them very sparingly to avoid the fumes.

jsw

A Question for You Air Only Guys
 

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
Jon Elson fired this volley in news:fICdnY1
:

A jet of flood coolant takes
very little energy compared to a big air compressor.



Indeed.

Additionally, it provides lubrication, and "spot cooling" at the specific
areas (cutting edges) where air cannot impinge because of the pressure
"buffers" that corners produce.

LLoyd

Depending on the material being cut conduction can play a major factor as
well. I discovered the same affect in reverse when trying to weld aluminum
thicker than 1/4 inch. I had to preheat and weld short stretches in order
to get it to weld properly.

While the micro spot of impact at the edge of the cutter may not be directly
impacted by air cooling flow it most certainly will not build heat as much
and conduct it up the tool and into the spindle to the same degree if both
the work piece and the tool are being cooled.

Anyway, This machine will remain dry one way or another for the foreseeable
future. If you have some thoughts on doing that I would be more than glad
to hear them. Your insights are always educational.

Bob

A Question for You Air Only Guys
 

"Bob La Londe" fired this volley in news:BlM9r.9099
:

If you have some thoughts on doing that I would be more than glad
to hear them.

Bob,
The only things I can recommend are to use fairly large-diameter piping
and high pressure, ending in multiple small lamilar-flow jets that will
increase the velocity, let you direct the flow close to the heating zone,
and provide significant expansion cooling as they work.

The added velocity will also give you better chip clearance, and drive
you out of the shop with noise -- so wear ear-gear.

LLoyd

A Question for You Air Only Guys
 

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Bob La Londe" fired this volley in news:BlM9r.9099
:

If you have some thoughts on doing that I would be more than glad
to hear them.

Bob,
The only things I can recommend are to use fairly large-diameter piping
and high pressure, ending in multiple small lamilar-flow jets that will
increase the velocity, let you direct the flow close to the heating zone,
and provide significant expansion cooling as they work.

The added velocity will also give you better chip clearance, and drive
you out of the shop with noise -- so wear ear-gear.

Thanks Lloyd. That particular machine is inside an MDF cabinet which helps
a lot for sound deadening. You have to raise your voice to have a
conversation right next to it, but 15 feet away you can have an almost
normal conversation even with the shop doors closed. It could probably be
better, but I put lexan doors on the front rather than more MDF. Currently
the air is just a 1/4" piece of copper tube fed by a 3/8 air line with a
valve in between. It worked pretty good, but consumed prodigious amounts of
air. I am looking at various air volume increaser jets etc. The compressor
on the other side of the room is louder than the noise from the cabinet.

A Question for You Air Only Guys
 

"Bob La Londe" fired this volley in news:yyN9r.4410
:

I am looking at various air volume increaser jets etc.

You don't need volume (well... within limits), you need a combination of
high velocity and expansion from the feed line.

A high-velocity lamilar jet of air will carry a prodigious amount of
ambient air along with it, but most of the goal is to get it to impinge
directly in the cut zone, then do most of its expansion work there. If
the velocity isn't high enough, the expansion occurs before the stream
gets to the work.

LLoyd

A Question for You Air Only Guys
 

"Bob La Londe" wrote in
:

I needed to get a couple jobs done. The screws need to be replaced on
the Taig so I couldn't use its regular flood oil coolant setup until I
fix it. I used my smaller machine, rubbed a little Tap Magic on the
work piece and hit it with a blast of compressed air. When surfacing
off the aluminum work piece with a 1/4" end mill (largest that spindle
will hold) it got pretty hot, but it worked great when 3D carving with
a 1/16 ball mill. I ran full pressure off my compressor (125 PSI I
think) and used a simple ball valve to regulate flow somewhat, but I
let it flow pretty heavily. So... how much air do you guys use?
Pressure? CFM?

My compressor ran continuously when I was running the mill. I'll be
adding an electric shut off valve to the air line to that cabinet, so
my compressor will shut off when I am done with a cut, but I was
thinking if I could consume less air and get a decent job I would add
a flow and pressure regulator too.

You can get a lot more air flow with less CFM/PSI using the right nozzle:

http://www.silvent.com/www/live/prod...aspx?TreeID=48

Depending on the nozzle, they claim over 40% reduction in air "costs".
The bad news is that they still want 10 cfm at over 100 PSI.

Doug White

A Question for You Air Only Guys
 

On Mon, 19 Mar 2012 14:28:54 -0700, "Bob La Londe"
wrote:

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
.3.70...
"Bob La Londe" fired this volley in news:BlM9r.9099
:

If you have some thoughts on doing that I would be more than glad
to hear them.

Bob,
The only things I can recommend are to use fairly large-diameter piping
and high pressure, ending in multiple small lamilar-flow jets that will
increase the velocity, let you direct the flow close to the heating zone,
and provide significant expansion cooling as they work.

The added velocity will also give you better chip clearance, and drive
you out of the shop with noise -- so wear ear-gear.

Thanks Lloyd. That particular machine is inside an MDF cabinet which helps
a lot for sound deadening. You have to raise your voice to have a
conversation right next to it, but 15 feet away you can have an almost
normal conversation even with the shop doors closed. It could probably be
better, but I put lexan doors on the front rather than more MDF. Currently
the air is just a 1/4" piece of copper tube fed by a 3/8 air line with a
valve in between. It worked pretty good, but consumed prodigious amounts of
air. I am looking at various air volume increaser jets etc. The compressor
on the other side of the room is louder than the noise from the cabinet.


Greetings Bob,
I have air nozzles made by two different makers but they both work the
same. Air comes out of an annular groove at the base of a cone. No air
comes out of the center of the cone. The air does focus to a point
about 4 inches from the nozzle end. And both types of nozzles entrain
lots of air so they are really good for removing chips. I wonder how
well a pin point air blast close to the cutter along with a more
diffuse air blast from farther away would work? One thing I am
seriously considering is CO2 cooling. I've been reading some about
super critical CO2 cooling systems being tried on machine tools.
Apparently one of the advantages when cutting soft materials is that
the cold makes the chip brittle (or at least not so soft) and more
likely to break. The CO2 itself also acts as a cutting fluid.
Eric

A Question for You Air Only Guys
 

Wowwie.. 1/4" is a big leak and not particulary high velocity nor an
accurately aimed jet of cooling air.

If you terminate that 1/4" line with a threaded fitting, you can experiment
with various line/tubing fittings to make an adapter for a more suitable tip
which will enable you to direct a fine blast more effectively.

The cutting tool is already twirling around in air, so it's essentially
fanning itself.
The aluminum workpiece is sinking away heat from the tiny contact area being
cut.

So, I believe the most benefit that can be attained from an accurately aimed
blast of air, would be chip evacuation, and not so much a cooling method.

The energy cost and wear of the air compressor would be significant with a
1/4" orifice/air blast.
Getting the hole size down into the decimal range under 1/16" would probably
be effective.. possibly two small blasts depending upon how the table
traverses, so that a path is also kept clear ahead of the cutting tool.

You can experiment with various tip shapes without needing to get too
technically involved into concentrating a pinpoint blast, which is basically
the opposite of most commercially available sprayer tips for various fluids.
Tiny tubing can be gotten from aerosol products that supply those extension
wands for squirting the stuff into confined areas.

A tiny orifice hole with a tapered hole behind it, to accept an adjustable
needle valve/screw may be all that's actually needed.
How deep the straight hole is (beyond the tip of the needle point) will
likely be the determining factor for the shape or concentration of the air
blast.. WAG.

Testing air streams ain't so easy, but some sawdust may be helpful to see
what's taking place.
You may find that 40-80 psi will be very effective with small orifice sizes.

A smear of cutting lubricant may still be effective, as long as it isn't
making the fine chips stick to the workpiece.

I'd suspect that recutting chips would be far more detrimental to
performance than heat generated by the cutting tool.. JMG - just my guess,
you'll be the best judge of that based upon what you can see.

--
WB
..........


"Bob La Londe" wrote in message
...
Currently the air is just a 1/4" piece of copper tube fed by a 3/8 air
line with a valve in between. It worked pretty good, but consumed
prodigious amounts of air. I am looking at various air volume increaser
jets etc. The compressor on the other side of the room is louder than the
noise from the cabinet.

A Question for You Air Only Guys
 

"Wild_Bill" wrote in message
...
Wowwie.. 1/4" is a big leak and not particulary high velocity nor an
accurately aimed jet of cooling air.

If you terminate that 1/4" line with a threaded fitting, you can
experiment with various line/tubing fittings to make an adapter for a more
suitable tip which will enable you to direct a fine blast more
effectively.

The cutting tool is already twirling around in air, so it's essentially
fanning itself.
The aluminum workpiece is sinking away heat from the tiny contact area
being cut.

So, I believe the most benefit that can be attained from an accurately
aimed blast of air, would be chip evacuation, and not so much a cooling
method.

The energy cost and wear of the air compressor would be significant with a
1/4" orifice/air blast.
Getting the hole size down into the decimal range under 1/16" would
probably be effective.. possibly two small blasts depending upon how the
table traverses, so that a path is also kept clear ahead of the cutting
tool.

You can experiment with various tip shapes without needing to get too
technically involved into concentrating a pinpoint blast, which is
basically the opposite of most commercially available sprayer tips for
various fluids.
Tiny tubing can be gotten from aerosol products that supply those
extension wands for squirting the stuff into confined areas.

A tiny orifice hole with a tapered hole behind it, to accept an adjustable
needle valve/screw may be all that's actually needed.
How deep the straight hole is (beyond the tip of the needle point) will
likely be the determining factor for the shape or concentration of the air
blast.. WAG.

Testing air streams ain't so easy, but some sawdust may be helpful to see
what's taking place.
You may find that 40-80 psi will be very effective with small orifice
sizes.

A smear of cutting lubricant may still be effective, as long as it isn't
making the fine chips stick to the workpiece.

I'd suspect that recutting chips would be far more detrimental to
performance than heat generated by the cutting tool.. JMG - just my guess,
you'll be the best judge of that based upon what you can see.


I was considering trying something as small as an athletic ball needle in my
experiments. The 1/4" tube was a quick and dirty method and it worked for
what I needed to do at the time.

A Question for You Air Only Guys
 

"Bob La Londe" wrote in message ...

Thanks Lloyd. That particular machine is inside an MDF cabinet which helps
a lot for sound deadening. You have to raise your voice to have a
conversation right next to it, but 15 feet away you can have an almost
normal conversation even with the shop doors closed. It could probably be
better, but I put lexan doors on the front rather than more MDF.

Broadcast station air booths, recording studio control rooms and such are typically glazed using 2 layers of lexan or plexiglas with dead air between...this arrangement blocks sound transmission remarkably well.