Re: [Emc-users] Face Milling

[Gene Heskett]

On Thursday 21 May 2020 21:46:50 John Dammeyer wrote:

> So I popped over to a friends to borrow a carbide 3 cutter face mill. 
> Alas the MORSE Taper draw bar fitting wouldn't work with my R8 to MT3
> adaptor.  But the more rounded cutters gave me the idea to use my
> green wheel on the carbide brazed cutter I was usingin the mid size
> fly cutter holder.
>
> No difference really other than the cast aluminium tended to melt onto
> the tip more easily.  I had clamped a failed casting into a large
> vise.
>
> Having seen my friends fly cutter bits (modified carbide inserts) I
> started thinking about the amount the 1/4" shank cutter protruded.  I
> found a 5/16" HSS tool bit and touched up the tip.  Then screwed it in
> place.  Ultimately I ended up using a set screw (long story) but all I
> can say is Wow!
>
> http://www.autoartisans.com/mill/TestFlycut_1.jpg
>
> http://www.autoartisans.com/mill/TestFlycut_2.jpg
>
> Silky smooth.   No light past a straight edge laid across it.  With my
> eyes closed dragging fingernail across it I can't feel the pass
> transitions.  Milling done by moving X axis.  Last pass was 0.003"
> DOC, 390 RPM, 2.1 IPM.  About 2"diameter fly cutter.  Overlap about
> 0.2" between passes.
>
> So I suspect the 1/4" tool bit vibrated like heck as it grabbed and
> cut the work and that's what did much of the scratching on the
> retreating edge.
>
> John

More than likely the 1/4" tool was borderline dull, and flexing sideways, 
tipping its face.

I have also found, when doing alu, that an HSS bit can be made much 
sharper than carbide on the powered rouge waterstone I sharpen wood 
plane blades with giving a much smoother finishing cut than carbide 
inserts ever thought of.  Carbide inserts can be sharpened but take a 
huge toll on the rouge if not using a feather touch, taking a long time 
to get the mirror edge that HSS can be done to in just a few minutes.

But you absolutely must have active coolant flow, mist working better 
than a liquid dribble, to keep the air away from your just cut surface 
to reduce the alox formation behind the cutters passage, which in turn 
eats the edge off your tool as it comes back around on thenext 
revolution.  Its that quick if left dry, even with carbide as the alox 
from burning alu is harder than your carbide. That alox formation behind 
the cutting edge in less than a thousandth of a second is also the 
majority of the heat generated when cutting alu, far more than the 
friction of the cut, that heat is carried away by the chip being 
removed.  Alu, in the presence of the 21% airborn oxygen is a very 
active metal, keep it sealed with a mist directed at the back face of 
your cutting tool so its wetted and sealed as quickly as possible behind 
the edge of your cutting tools passage.

So I do roughing passes with carbide, but finishing passes with HSS.

Another alu cooling method might be done by boxing the machine up in an 
air tight enclosure, and flooding the enclosure with dry nitrogen.

That of course has its problems with operator safety, and doesn't work as 
well for steel though, due to nitrogen embrittlement and the flooding 
gas costs lots more. I probably should not have mentioned it except I've 
been around it since the '60's as its used to pressurize transmission 
lines on broadcast towers.  Dried air is cheaper, but 50 yo copper still 
looks brand new when nitrogen is used in it, and the connection failure 
rates are vanishingly smaller.
>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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Re: [Emc-users] Face Milling

[John Dammeyer]

So I popped over to a friends to borrow a carbide 3 cutter face mill.  Alas the 
MORSE Taper draw bar fitting wouldn't work with my R8 to MT3 adaptor.  But the 
more rounded cutters gave me the idea to use my green wheel on the carbide 
brazed cutter I was usingin the mid size fly cutter holder.  

No difference really other than the cast aluminium tended to melt onto the tip 
more easily.  I had clamped a failed casting into a large vise.

Having seen my friends fly cutter bits (modified carbide inserts) I started 
thinking about the amount the 1/4" shank cutter protruded.  I found a 5/16" HSS 
tool bit and touched up the tip.  Then screwed it in place.  Ultimately I ended 
up using a set screw (long story) but all I can say is Wow!

http://www.autoartisans.com/mill/TestFlycut_1.jpg

http://www.autoartisans.com/mill/TestFlycut_2.jpg

Silky smooth.   No light past a straight edge laid across it.  With my eyes 
closed dragging fingernail across it I can't feel the pass transitions.  
Milling done by moving X axis.  Last pass was 0.003" DOC, 390 RPM, 2.1 IPM.  
About 2"diameter fly cutter.  Overlap about 0.2" between passes.

So I suspect the 1/4" tool bit vibrated like heck as it grabbed and cut the 
work and that's what did much of the scratching on the retreating edge.  

John




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Re: [Emc-users] Face Milling

[John Dammeyer]

Good idea.  I'll have to try that.
John


> -Original Message-
> From: Jon Elson [mailto:el...@pico-systems.com]
> Sent: May-21-20 3:44 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Face Milling
> 
> On 05/21/2020 11:39 AM, John Dammeyer wrote:
> > This was a year ago but based on the latest fly cutting results I'm getting 
> > slight ridges so either the fly cutter isn't exactly turning a
> perfect horizontal arc or I need to tram again.
> > http://www.autoartisans.com/mill/TrammedVertical.jpg
> >
> >
> Tramming the head-spindle to the table surface is not what
> you want, especially on an older (worn) mill.
> What I do is have a program that mills a circular path on a
> piece of scrap.  Step down a little at a time until it cuts
> all the way around.  Then, move to the center, and put in
> the dial indicator and sweep the circle.
> This allows you to tram to the actual X-Y plane of motion of
> the machine, which may NOT be parallel to the surface of the
> table.  My 1938 Bridgeport cuts a kind of saddle shape that
> moves up and down a few thousandths of an inch over about a
> 7" sweep.  This way, I can tram the head to be as close to
> perpendicular to that as possible.
> 
> Jon
> 
> 
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Re: [Emc-users] Face Milling

[Stuart Stevenson]

Use a lathe face plate with 3 adjustable supports and an indicator in the
the center of the spindle, move the machine to dial in the face plate to
the machine motion. Then use a bar in the spindle to swing the indicator to
sweep the face plate. Same as Jon's procedure but without machining.

On Thu, May 21, 2020, 5:46 PM Jon Elson  wrote:

> On 05/21/2020 11:39 AM, John Dammeyer wrote:
> > This was a year ago but based on the latest fly cutting results I'm
> getting slight ridges so either the fly cutter isn't exactly turning a
> perfect horizontal arc or I need to tram again.
> > http://www.autoartisans.com/mill/TrammedVertical.jpg
> >
> >
> Tramming the head-spindle to the table surface is not what
> you want, especially on an older (worn) mill.
> What I do is have a program that mills a circular path on a
> piece of scrap.  Step down a little at a time until it cuts
> all the way around.  Then, move to the center, and put in
> the dial indicator and sweep the circle.
> This allows you to tram to the actual X-Y plane of motion of
> the machine, which may NOT be parallel to the surface of the
> table.  My 1938 Bridgeport cuts a kind of saddle shape that
> moves up and down a few thousandths of an inch over about a
> 7" sweep.  This way, I can tram the head to be as close to
> perpendicular to that as possible.
>
> Jon
>
>
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Re: [Emc-users] Face Milling

[Jon Elson]

On 05/21/2020 11:39 AM, John Dammeyer wrote:

This was a year ago but based on the latest fly cutting results I'm getting 
slight ridges so either the fly cutter isn't exactly turning a perfect 
horizontal arc or I need to tram again.
http://www.autoartisans.com/mill/TrammedVertical.jpg


Tramming the head-spindle to the table surface is not what 
you want, especially on an older (worn) mill.
What I do is have a program that mills a circular path on a 
piece of scrap.  Step down a little at a time until it cuts 
all the way around.  Then, move to the center, and put in 
the dial indicator and sweep the circle.
This allows you to tram to the actual X-Y plane of motion of 
the machine, which may NOT be parallel to the surface of the 
table.  My 1938 Bridgeport cuts a kind of saddle shape that 
moves up and down a few thousandths of an inch over about a 
7" sweep.  This way, I can tram the head to be as close to 
perpendicular to that as possible.


Jon


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Re: [Emc-users] Face Milling

[Stuart Stevenson]

If you are getting mismatch from one pass to another your spindle is not
perpendicular to the plane of motion you have the workpiece clamped to. The
only other thing I can think of is if are cutting with the Y axis and
indexing the X axis for the passes across the workpiece. If the table
extends far past the Y axis ways you will have table droop because of
weight transfer. You cannot avoid it unless you have outriggers to support
the table.
Heh, on a knee mill if you use the X axis to cut and index the Y axis you
will end up with a convex surface you just faced.

hth
Stuart

On Thu, May 21, 2020, 11:42 AM John Dammeyer  wrote:

> This was a year ago but based on the latest fly cutting results I'm
> getting slight ridges so either the fly cutter isn't exactly turning a
> perfect horizontal arc or I need to tram again.
> http://www.autoartisans.com/mill/TrammedVertical.jpg
>
> Or it's something to do with the backlash.
>
> John
>
>
> > -Original Message-
> > From: Jon Elson [mailto:el...@pico-systems.com]
> > Sent: May-21-20 9:25 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Face Milling
> >
> > On 05/20/2020 11:56 PM, John Dammeyer wrote:
> > >
> > > Anyone used one of these?
> > > https://www.aliexpress.com/item/4000890081459.html
> > >
> > >
> > Years ago, we had CNC meetings at Roland Friestad's shop
> > near Galesburg, IL.  He made CNC retrofits to sell to tech
> > schools, and apparently made some of his own tooling.  I
> > found a bunch of very similar
> > small face mills with R-8 taper, and I think we bought all
> > he had. I'm still using them for this type
> > of face milling work.  The bigger the face mill, the more
> > accurately you need to have your machine trammed.
> >
> > Jon
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
>
> ___
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Re: [Emc-users] Face Milling

[Gene Heskett]

On Thursday 21 May 2020 12:07:42 John Dammeyer wrote:

> It's fairly robust.  Like a Grizzly G3616.
> http://www.autoartisans.com/mill/Mill_CNC
>
I almost bought one of those off the showroom floor at Lycoming Mall up 
in PA when grizzly had a facility there, but couldn't figure out how to 
get it home 350 miles to WV with my 99 GMC half ton surviving the trip, 
Too tall for a cargo van from uhaul, and IIRC its about 8k lbs.  
Trucking would have added to the price, a lot I thought.  Sigh.

> But it's got a poor excuse for an ACME feed not on the X axis with
> about 0.024" backlash.

Yikes!

> Climb milling in the X direction with slow RPM 
> and a large cutter causes the table to shake.  So once the spindle
> speed control system is in place the whole thing is coming apart for a
> ball screw retrofit.  And belt guards and covers etc.
>
> So with the current backlash it may not be robust enough for round
> cutters.
>
> John
>
> > -Original Message-
> > From: dave engvall [mailto:dengv...@charter.net]
> > Sent: May-21-20 7:04 AM
> > To: emc-users@lists.sourceforge.net
> > Subject: Re: [Emc-users] Face Milling
> >
> > Round inserts are nice if you have the power and stiffness to use
> > them. Only in desperation would I use a fly cutter simple because of
> > the unbalanced load.
> > Because of their radius the round inserts will give a nice finish.
> > Have fun.
> >
> > Dave
> >
> > On 5/20/20 9:56 PM, John Dammeyer wrote:
> > > I've been surfacing a casting that is larger than my machine
> > > envelope.   Not only that although pattern was 5/8" thick MDF the
> >
> > casting ended up with thicker and thinner parts.   With it shimmed
> > and moving clamps around I managed to flatten the bottom and then
> > clamp it down and surface the top.  But it took a long time.
> >
> > > I found LinuxCNC easy enough to use for this.  Just kept resetting
> > > x or y home and restarting the G_code.
> > >
> > > Anyone used one of these?
> > > https://www.aliexpress.com/item/4000890081459.html
> > >
> > > Or with the round carbide inserts
> > > https://www.aliexpress.com/item/32952847637.html
> > >
> > > Alternatively since I use the Tormach Tooling at a much higher
> > > price there is this flycutter.
> > > https://tormach.com/tts-superfly-cutter-kit-33031.html
> > >
> > > John
> > >
> > >
> > >
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> ___
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Face Milling

[John Dammeyer]

This was a year ago but based on the latest fly cutting results I'm getting 
slight ridges so either the fly cutter isn't exactly turning a perfect 
horizontal arc or I need to tram again.  
http://www.autoartisans.com/mill/TrammedVertical.jpg

Or it's something to do with the backlash.

John


> -Original Message-
> From: Jon Elson [mailto:el...@pico-systems.com]
> Sent: May-21-20 9:25 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Face Milling
> 
> On 05/20/2020 11:56 PM, John Dammeyer wrote:
> >
> > Anyone used one of these?
> > https://www.aliexpress.com/item/4000890081459.html
> >
> >
> Years ago, we had CNC meetings at Roland Friestad's shop
> near Galesburg, IL.  He made CNC retrofits to sell to tech
> schools, and apparently made some of his own tooling.  I
> found a bunch of very similar
> small face mills with R-8 taper, and I think we bought all
> he had. I'm still using them for this type
> of face milling work.  The bigger the face mill, the more
> accurately you need to have your machine trammed.
> 
> Jon
> 
> 
> ___
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Re: [Emc-users] Face Milling

[Sam Sokolik]

one of the small ones... :)  Bigger ones do increase your work area ;)



On Thu, May 21, 2020 at 11:27 AM Jon Elson  wrote:

> On 05/20/2020 11:56 PM, John Dammeyer wrote:
> >
> > Anyone used one of these?
> > https://www.aliexpress.com/item/4000890081459.html
> >
> >
> Years ago, we had CNC meetings at Roland Friestad's shop
> near Galesburg, IL.  He made CNC retrofits to sell to tech
> schools, and apparently made some of his own tooling.  I
> found a bunch of very similar
> small face mills with R-8 taper, and I think we bought all
> he had. I'm still using them for this type
> of face milling work.  The bigger the face mill, the more
> accurately you need to have your machine trammed.
>
> Jon
>
>
> ___
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Re: [Emc-users] Face Milling

[Jon Elson]

On 05/20/2020 11:56 PM, John Dammeyer wrote:


Anyone used one of these?
https://www.aliexpress.com/item/4000890081459.html


Years ago, we had CNC meetings at Roland Friestad's shop 
near Galesburg, IL.  He made CNC retrofits to sell to tech 
schools, and apparently made some of his own tooling.  I 
found a bunch of very similar
small face mills with R-8 taper, and I think we bought all 
he had. I'm still using them for this type
of face milling work.  The bigger the face mill, the more 
accurately you need to have your machine trammed.


Jon


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Re: [Emc-users] Face Milling

[John Dammeyer]

Thanks.  That's a lot of inserts if you have a collision.
John


> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: May-21-20 9:03 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Face Milling
> 
> On Thu, 21 May 2020 at 16:55, John Dammeyer  wrote:
> >
> > How many cutting bits and what type and R8 or straight shaft or some other 
> > quick change?
> 
> Mine is a standard shell-mill mount, and I mount it on a BT30 adaptor.
> I think it has 8 inserts.
> 
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> � George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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Re: [Emc-users] Face Milling

[John Dammeyer]

It's fairly robust.  Like a Grizzly G3616. 
http://www.autoartisans.com/mill/Mill_CNC

But it's got a poor excuse for an ACME feed not on the X axis with about 0.024" 
backlash.  Climb milling in the X direction with slow RPM and a large cutter 
causes the table to shake.  So once the spindle speed control system is in 
place the whole thing is coming apart for a ball screw retrofit.  And belt 
guards and covers etc.

So with the current backlash it may not be robust enough for round cutters.

John


> -Original Message-
> From: dave engvall [mailto:dengv...@charter.net]
> Sent: May-21-20 7:04 AM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Face Milling
> 
> Round inserts are nice if you have the power and stiffness to use them.
> Only in desperation would I use a fly cutter simple because of the
> unbalanced load.
> Because of their radius the round inserts will give a nice finish.
> Have fun.
> 
> Dave
> 
> On 5/20/20 9:56 PM, John Dammeyer wrote:
> > I've been surfacing a casting that is larger than my machine envelope.   
> > Not only that although pattern was 5/8" thick MDF the
> casting ended up with thicker and thinner parts.   With it shimmed and moving 
> clamps around I managed to flatten the bottom and
> then clamp it down and surface the top.  But it took a long time.
> >
> > I found LinuxCNC easy enough to use for this.  Just kept resetting x or y 
> > home and restarting the G_code.
> >
> > Anyone used one of these?
> > https://www.aliexpress.com/item/4000890081459.html
> >
> > Or with the round carbide inserts
> > https://www.aliexpress.com/item/32952847637.html
> >
> > Alternatively since I use the Tormach Tooling at a much higher price there 
> > is this flycutter.
> > https://tormach.com/tts-superfly-cutter-kit-33031.html
> >
> > John
> >
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> 
> 
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Re: [Emc-users] Face Milling

[andy pugh]

On Thu, 21 May 2020 at 16:55, John Dammeyer  wrote:
>
> How many cutting bits and what type and R8 or straight shaft or some other 
> quick change?

Mine is a standard shell-mill mount, and I mount it on a BT30 adaptor.
I think it has 8 inserts.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Face Milling

[John Dammeyer]

How many cutting bits and what type and R8 or straight shaft or some other 
quick change?
John


> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: May-21-20 1:22 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Face Milling
> 
> On Thu, 21 May 2020 at 05:59, John Dammeyer  wrote:
> 
> > https://www.aliexpress.com/item/4000890081459.html
> 
> I have a 100mm dia face mill that I use for facing off castings. I
> bought it used from eBay.
> 
> But my milling machine has an excess of torque and a dearth of speed.
> 
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> � George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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Re: [Emc-users] Linuxcnc servo problem

[Peter C. Wallace]

Just rebuilt master and it seems to be fixed (feedrate set to 0 by esc)



Peter Wallace
Mesa Electronics




I take that back, its still flakey

Peter Wallace
Mesa Electronics


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Re: [Emc-users] Linuxcnc servo problem

[Peter C. Wallace]

On Thu, 21 May 2020, Peter C. Wallace wrote:


Date: Thu, 21 May 2020 07:15:22 -0700 (PDT)
From: Peter C. Wallace 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] Linuxcnc servo problem

On Thu, 21 May 2020, Horv?th Csaba wrote:


Date: Thu, 21 May 2020 14:01:04 +0200
From: "[UTF-8] Horv?th Csaba" 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: [Emc-users] Linuxcnc servo problem

Hi,

I have the following problem:

Linuxcnc 2.9 pre xxx

MESA 7i90HD + 7i33 + 3 analog servo (ELMO ISP)

If I am running a code and I press ESC button to stop the execute, then 
after pressing the button, the axes move again for approx. 15-20 mm.


The enable signal is not removed from the servo drives, so in principle 
they should hold a position.


What could be the problem?



Regards, Csaba


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Yow! thats a fairly nasty bug...

I can duplicate it here with master but not with 2.8

Master: esc in axis results in a random move command
(I hade a large -z move!)

in 2.8 esc just stops motion (feedrate set to 0)
in master you get a random move and feedrate is unchanged


Peter Wallace
Mesa Electronics



Just rebuilt master and it seems to be fixed (feedrate set to 0 by esc)



Peter Wallace
Mesa Electronics


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Re: [Emc-users] Linuxcnc servo problem

[Peter C. Wallace]

On Thu, 21 May 2020, Horv?th Csaba wrote:


Date: Thu, 21 May 2020 14:01:04 +0200
From: "[UTF-8] Horv?th Csaba" 
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: [Emc-users] Linuxcnc servo problem

Hi,

I have the following problem:

Linuxcnc 2.9 pre xxx

MESA 7i90HD + 7i33 + 3 analog servo (ELMO ISP)

If I am running a code and I press ESC button to stop the execute, then after 
pressing the button, the axes move again for approx. 15-20 mm.


The enable signal is not removed from the servo drives, so in principle they 
should hold a position.


What could be the problem?



Regards, Csaba


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Yow! thats a fairly nasty bug...

I can duplicate it here with master but not with 2.8

Master: esc in axis results in a random move command
(I hade a large -z move!)

in 2.8 esc just stops motion (feedrate set to 0)
in master you get a random move and feedrate is unchanged


Peter Wallace
Mesa Electronics



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Re: [Emc-users] Face Milling

[dave engvall]

Round inserts are nice if you have the power and stiffness to use them. 
Only in desperation would I use a fly cutter simple because of the 
unbalanced load.

Because of their radius the round inserts will give a nice finish.
Have fun.

Dave

On 5/20/20 9:56 PM, John Dammeyer wrote:

I've been surfacing a casting that is larger than my machine envelope.   Not only 
that although pattern was 5/8" thick MDF the casting ended up with thicker and 
thinner parts.   With it shimmed and moving clamps around I managed to flatten the 
bottom and then clamp it down and surface the top.  But it took a long time.

I found LinuxCNC easy enough to use for this.  Just kept resetting x or y home 
and restarting the G_code.

Anyone used one of these?
https://www.aliexpress.com/item/4000890081459.html

Or with the round carbide inserts
https://www.aliexpress.com/item/32952847637.html

Alternatively since I use the Tormach Tooling at a much higher price there is 
this flycutter.
https://tormach.com/tts-superfly-cutter-kit-33031.html

John




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Re: [Emc-users] Linuxcnc servo problem

[andy pugh]

On Thu, 21 May 2020 at 13:03, Horváth Csaba  wrote:

> If I am running a code and I press ESC button to stop the execute, then
> after pressing the button, the axes move again for approx. 15-20 mm.

You mean that the program does not stop immediately?

How long is this extra movement in terms of time?

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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[Emc-users] Linuxcnc servo problem

[Horváth Csaba]

Hi,

I have the following problem:

Linuxcnc 2.9 pre xxx

MESA 7i90HD + 7i33 + 3 analog servo (ELMO ISP)

If I am running a code and I press ESC button to stop the execute, then 
after pressing the button, the axes move again for approx. 15-20 mm.


The enable signal is not removed from the servo drives, so in principle 
they should hold a position.


What could be the problem?



Regards, Csaba


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[Gene Heskett]

On Thursday 21 May 2020 01:57:06 andrew beck wrote:

> hey peter
>
> I had a look and the unless there is a shorted out pin in the servo
> drive connector itself I think the wiring is all good.
>
> and I highly doubt the servo drive has problems all I did was connect
> the 24v back into the servo on pin which is how it has been running
> for the last ages.
>
> anyway how do you recommend commoning the grounds?
>
> it is as simple as connecting the field power 0v ground with a wire to
> the logic power 0v ground?
>
Yes, but how you do it can be very important.

In your control box, install a longer bolt, #6 or #8-32 to the chassis. 
4mm if metric.

Connect all grounds to this bolt, checking that they are not grounded at 
the far end.  By doing this, you are establishing a single point ground 
that is the zero volt reference for the whole system. Connect this bolt 
to the building static ground, the bare wire in most power cabling.

Connect the machines frame to this bolt.

Connect the - rails of all supplies to this bolt.

Connect the - terminals of all cards to this bolt.

Break the 3rd pin off the computers supply cable and connect the 
computers chassis to this bolt. Power the computer not from the wall, 
but from the same power feeding this box. 

Connect the shielding of all shielded cabling to this bolt. Do not 
connect the far end of this shielding to anything that is otherwise 
grounded.

By making sure these grounds are not connected anyplace else you are 
breaking any ground loops which can and will act as antennas to insert 
noise into your control signals.

By having this single point ground, a nearby lightning strike can inject 
a 100k volt pulse into the system ground as what would be called 
a "ground bounce",  but the system will not see it as noise nor be 
damaged, because everything is bouncing in unison.

Regardless of what that bolt does during the strike, the 5 volt supply 
remains at 5 volts to this bolt, and the 24 volt supply remains at 24 
volts to this bolt. 

And when the storm is done, your chances of having anything damaged is 
reduced to the vanishing point.

Stay well Andrew.

[...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Face Milling

[andy pugh]

On Thu, 21 May 2020 at 05:59, John Dammeyer  wrote:

> https://www.aliexpress.com/item/4000890081459.html

I have a 100mm dia face mill that I use for facing off castings. I
bought it used from eBay.

But my milling machine has an excess of torque and a dearth of speed.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly

[andrew beck]

hey peter

I had a look and the unless there is a shorted out pin in the servo drive
connector itself I think the wiring is all good.

and I highly doubt the servo drive has problems all I did was connect the
24v back into the servo on pin which is how it has been running for the
last ages.

anyway how do you recommend commoning the grounds?

it is as simple as connecting the field power 0v ground with a wire to the
logic power 0v ground?

regards

Andrew

On Thu, May 21, 2020 at 4:26 PM andrew beck 
wrote:

> the 24v common is currently not connected to the frame ground.  It is
> floating.  well the meanwell powersupply has a ground terminal on the input
> side that is connected to machine ground.  but the output side is
> completely unconnected eg the 24 v and 0v are floating
>
> I will double check the wiring and check if there is a problem
>
>
> On Thu, May 21, 2020 at 4:22 PM Peter C. Wallace  wrote:
>
>> On Thu, 21 May 2020, andrew beck wrote:
>>
>> > Date: Thu, 21 May 2020 15:53:45 +1200
>> > From: andrew beck 
>> > Reply-To: "Enhanced Machine Controller (EMC)"
>> > 
>> > To: "Enhanced Machine Controller (EMC)" <
>> emc-users@lists.sourceforge.net>
>> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting suddenly
>> >
>> > hey PCW and andy
>> >
>> > I just checked the mpg with a multimeter.
>> >
>> > I had my brother jogging .005mm at a time to try and catch the encoder
>> > pulses.
>> >
>> > when measuring between the B and /B pulses I could measure 2.5 volts
>> when
>> > the encoder triggered.
>> >
>> > I could not measure any voltage at any time through the A and /A
>> channels.
>> >
>>
>> Broken wire or connecoto problem?
>>
>> > PCW how do I common the 5v and 24v grounds together on the 7i76?
>> >
>> > I saw this sheet here for the 7i76E that seems to show that the 7i76E
>> only
>> > needs 24v and makes its own 5v if you set the jumpers right.  (is the
>> 7i76
>> > also the same?)  that would make life really easy
>>
>> No its normally suggested to have the 7I76 use FPGA power
>>
>> >
>> > [image: image.png]
>> >
>> > If I do have to use a separate 5v powersupply eg 5i25 for now can I just
>> > connect a wire between 24v ground and a unused logic 0v ground pin on a
>> > step gen port or something?  Or should I do something more elegant
>> >
>> I would check to see if the 24V common is already connected to frame
>> ground
>> if it is you should be OK
>>
>> > regards
>> >
>> > Andrew
>> >
>> > On Thu, May 21, 2020 at 3:19 PM andrew beck 
>> > wrote:
>> >
>> >> hey peter I will check that now before I put the machine together
>> >> again without the encoder config to make parts again
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> On Thu, May 21, 2020 at 3:05 PM Peter C. Wallace 
>> wrote:
>> >>
>> >>> On Thu, 21 May 2020, andrew beck wrote:
>> >>>
>>  Date: Thu, 21 May 2020 14:05:02 +1200
>>  From: andrew beck 
>>  Reply-To: "Enhanced Machine Controller (EMC)"
>>  
>>  To: "Enhanced Machine Controller (EMC)" <
>> >>> emc-users@lists.sourceforge.net>
>>  Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
>> suddenly
>> 
>>  hey peter
>> 
>>  I am using a 5i25 and 7i76 combo.  and currently supplying power
>> from the
>>  5i25
>> 
>>  so I don't particularly want to make the computer ground the same as
>>  everything else lol.
>> 
>> >>>
>> >>> Except the the computer ground is frame ground and the common for the
>> >>> servo
>> >>> drive quadrature outputs should also be returned to frame ground
>> >>>
>>  it sounds like I need to connect a external 5v powersupply up to the
>> 7i76
>>  and change the jumpers around to suit.  and then connect up
>> everything
>>  again.
>> >>>
>> >>> That will not change anything ground related
>> 
>>  I have a 7i89 coming soon and I will wait until then to sort this
>> out I
>>  think.  I will just disconnect the encoder feedback for now and make
>> some
>>  parts.
>> 
>>  as my servo drives are tuned now.
>> 
>> 
>> 
>>  its a bit silly that it only just now failed though.  it was working
>>  perfectly yesterday.
>>  regards
>> 
>>  Andrew
>> >>>
>> >>> Do you have valid differential signals across the A /A and B /B pairs?
>> >>>
>> >>>   ( >2 V absolute across the pins, that is more positive than +2V or
>> more
>> >>> negative than -2V )
>> >>>
>> >>> Thats would be the most diagnostic test
>> >>>
>> >>>
>> >>> On Thu, May 21, 2020 at 1:46 PM Peter C. Wallace 
>> wrote:
>> >>>
>>  On Thu, 21 May 2020, andy pugh wrote:
>> 
>> > Date: Thu, 21 May 2020 02:33:16 +0100
>> > From: andy pugh 
>> > Reply-To: "Enhanced Machine Controller (EMC)"
>> > 
>> > To: "Enhanced Machine Controller (EMC)" <
>> >>> emc-users@lists.sourceforge.net
>> >
>> > Subject: Re: [Emc-users] mesa 7i76 spindle encoder not counting
>> >>> suddenly
>> >
>> > On Thu, 21 May 2020 at 02:22, andrew beck >