[keitholivier]

Craig, I have been away from this forum for about 14 years. Back then, when people were converting manual lathes to cnc and wanted threading, they were all using Linux cnc/EMC. If Match 4 has an external motion controller then there is no reason it coudnt do what any of the others can do because its the same concept.

If I want to convert a universal mill to CNC I have several options. If I want features like rigid tapping, I will need to make sure they are supported. For general machining, just about anything will work. Given this would be a cast iron machine with oil lubricated ways, it could never be as fast as something running on linear guides (not if I wanted it to last). The whole concept is low volume production. If I was to reach 100 a year I will retire a millionaire... I just cant go out and spend $125k for a bare cnc vertical mill when I need to run those sort of volumes. And the vertical mill would not neccersarily make a more rigid setup for hobbing the gears. So right now I will use the electronic leadscrew concept adapted to the rotary table to just handle the hobbing specifically and pick a different solution for any other automation of the mill itself. Once I earn some money, I can go with a small minimill to machine the aluminum housings, it can have an ATC and run batch jobs overnight or at least largely unattended. I not contesting who was first with what, but Match was definitely not a "preferred solution" to threading on a lathe or rigid tapping when I was last active on this forum.

Hi,
I use an Ethernet SmoothStepper by Warp9TD, $195.00USD, as does Roger if I'm not mistaken. Artsoft, now actually called New Fangled Solutions, does not manufacture motion boards. There are a half dozen
credible manufacturers of Mach ready motion boards, not counting the swag of somewhat less credible Chinese motion board manufacturers. Artsoft has NEVER made hardware.

I disagree, Mach predates LinuxCNC. LinuxCNC grew out of EMC2 many years ago, and one of the EMC2 developers, Art Fennerty, branched out and wrote the parallel port driver for Windows which started Mach and hobby CNC. LinuxCNC came later. Given that LinuxCNC is quasi-realtime, it can be a feedback controller, whereas Mach requires certain work arounds to achieve the same result.
It is fair to say that LinuxCNC supports rigid tapping etc 'natively' whereas Mach uses both realtime motion control features or the feedback features of servos, or even more recently Ethercat, a
distributed motion control set up.

You may choose to disbelieve when I say that with AC servos and Mach4 you can achieve perfectly synchronised motion....but I achieve that daily, to the limit of the accuracy of my machine, say 0.01mm.
I rather doubt my machine would be considered accurate or rigid enough to make highly loaded gears such as you describe, but I certainly believe Mach is at least capable of the task.

That's nonsense, Mach predates Centroid by a decade or more.

Virtually nothing. The main thing you get with Industrial is the 'Red Carpet Treatment' from NFS. You also get parametric Gcode programming called MacroB. It has
no more axes, or motors, or is any faster or more accurate or anything else. MacroB is used industrially but it does nothing that regular Gcode cannot but has things
like conditionals ('If' and 'While' loops) in Gcode for example.

Mach4Hobby costs $200USD, one time purchase, that allows up to five separate machines to be licensed, and as many demo copies as you require.

Craig

[joeavaerage]

Hi,
it comes down to the two different strategies.

Because LinuxCNC is quasi-realtime two axes can be synchronized, if one slows the other will slow also.

Mach4 ( or UCCNC or PlanetCNC among others) it relies on the coordination between two axes that is implied by Gcode. Mach for instance could not determine
that one axis has slowed and thereby slow another axis in sympathy. Mach4 is not a feedback solution in that sense. What Mach can and happiliy does is generate
coordinated movement between two axes, and provided both axes behave then the motion is identical to the LinuxCNC motion.

Presumably you will build your machine or axes or whatever such that if you command a 20thou cut, it will cut 20thou, not 19 or 21 but 20 and not slow
one iota when doing it. This is just good machine design, and no matter the control solution you'll need a good machine. It that circumstance, what I have previuosly
called 'torque authority' then either Mach4 OR LinuxCNC are equivalent. If your machine lacks 'torque authority' I doubt even LinuxCNC will save it.

In this sense, if you ask the manufacturer of the ESS 'does the ESS support rigid tapping' he would say no, because the traditional interpretation is that one axis is slaved to another,
however if the machine has 'torque authority' then two axes move in coordinated fashion, and that the ESS (and countless others) do, day in and day out. In this manner I have done rigid tapping
with my machine and my servo driven spindle. The spindle becomes a C axis and it is coordinated with the Z axis...ergo rigid tapping.

Either way, its your money and your choice.

The short answer to the question you posed at the start of this thread was' Is the Centroid Acorn capable of gear hobbing'.

The answer is:
1) If you interpret that gear hobbing requires one axis slaved to another, then no, the Centroid Acorn cannot do that. The Centroid Oak may be able to. Galil certainly. LinuxCNC certainly.
2) If you machine has 'torque authority' on all axes then any controller (Centroid Acorn for example) that can coordinate two axes in the manner of Gcode will work.

Craig

[RCaffin]

Roger, I will be making gears that need to run at 120+hp sustained with input shaft speed of up to 5800rpm.

All this on a hobby machine?????

I believe that some commercial CNC machines have been converted to Mach3 or Mach4, but by people who really understood what they were doing. I can't see why that should not work fine, as in many ways even Mach3 has capabilities NOT found in slightly older large commercial machines. Older commercial CNCs often ran a subset of NIST g-code; some older ones even required a many k$ extra PCB to handle G2 and G3. The difference is that those older CNCs had controllers built with discrete TTL chips - lots of them, on big PCBs, while modern CNCs use GHz processors and very powerful FPGA accelerators. A world of difference!

The more modern Mach3 and Mach4 (and the Linux equivalents) are able to handle 6 axes or more, in full sync, because they are just software running on those GHz processors. Even so, they offload the time-critical stuff to external motion controllers (such as the ESS) which use FPGAs running and hundreds of Megahertz. However, while those old controllers cost a small fortune (complex limited volume PCBs), modern stuff like Mach3 &4 are just software, running on a stock desktop of laptop machine. Cost of reproduction is 0.1%.

IF I had to do that job, I would have to start with a physical machine large enough to handle the parts. The teeth are likely to be much larger than mine, so you should be able to buy suitable hobs. I would not hesitate to use Mach3, which is what I use today. Then I might run the gears together for a few hours with some polishing paste on the teeth. I don't mind cheating if it works! I might repeat the polishing after heat treatment too.

Splines: I chose to use taperlocks instead. Commercial ones (eg Fenner) are B I I I G, too big for my jobs, so I machined my own. But at that horsepower and shaft size you should be able to have a sales engineer sort you out. A good taperlock fitting, done up tightly, is not going to shift.

Cheers
Roger
PS: yes, I use an ESS, with the latest driver. It threads well.
PPS: to the best of my knowledge, Mach3 (under an earlier name) more or less started the transition.
PPPS: Chinese clones are crap. They can do G0 and G1, and sometimes G2 & G3. But the doco is (not).

[keitholivier]

Roger, Im not sure you would regard a 3500lb universal mil as a "hobby machine". They are routinely used for high precision prototype/toolmaking work. They are equipped for manual operation although they usually have power feed on all axis including the knee. Not the bolt on sort of power feed, this is all geared of the main spindle motor, ie the horizontal cutting axis.

All this on a hobby machine?????

I believe that some commercial CNC machines have been converted to Mach3 or Mach4, but by people who really understood what they were doing. I can't see why that should not work fine, as in many ways even Mach3 has capabilities NOT found in slightly older large commercial machines. Older commercial CNCs often ran a subset of NIST g-code; some older ones even required a many k$ extra PCB to handle G2 and G3. The difference is that those older CNCs had controllers built with discrete TTL chips - lots of them, on big PCBs, while modern CNCs use GHz processors and very powerful FPGA accelerators. A world of difference!

The more modern Mach3 and Mach4 (and the Linux equivalents) are able to handle 6 axes or more, in full sync, because they are just software running on those GHz processors. Even so, they offload the time-critical stuff to external motion controllers (such as the ESS) which use FPGAs running and hundreds of Megahertz. However, while those old controllers cost a small fortune (complex limited volume PCBs), modern stuff like Mach3 &4 are just software, running on a stock desktop of laptop machine. Cost of reproduction is 0.1%.

IF I had to do that job, I would have to start with a physical machine large enough to handle the parts. The teeth are likely to be much larger than mine, so you should be able to buy suitable hobs. I would not hesitate to use Mach3, which is what I use today. Then I might run the gears together for a few hours with some polishing paste on the teeth. I don't mind cheating if it works! I might repeat the polishing after heat treatment too.

Splines: I chose to use taperlocks instead. Commercial ones (eg Fenner) are B I I I G, too big for my jobs, so I machined my own. But at that horsepower and shaft size you should be able to have a sales engineer sort you out. A good taperlock fitting, done up tightly, is not going to shift.

Cheers
Roger
PS: yes, I use an ESS, with the latest driver. It threads well.
PPS: to the best of my knowledge, Mach3 (under an earlier name) more or less started the transition.
PPPS: Chinese clones are crap. They can do G0 and G1, and sometimes G2 & G3. But the doco is (not).

[RCaffin]

Roger, Im not sure you would regard a 3500lb universal mil as a "hobby machine".
Errr, welll, no
Unless I had more $$ than I have.

Mind you, I would not object to having one! As long as it was a CNC, not a manual. I am not a trained machinist you see.
Hum - a 'dead' 3,500 lb machine and a budget to refit with electronics and servos etc - could be fun.

Cheers
Roger

[joeavaerage]

Hi,
the only problem with manual machines is backlash. Backlash petty much screws CNC. A good machine operator always has strategies to defeat backlash, its part of being a machinist.
CNC on the other hand, making coordinated moves is pretty much buggered by backlash. Fitting ballscrews to large manual machines is sure not for the faint hearted!

Craig

[RCaffin]

Fitting ballscrews to large manual machines is sure not for the faint hearted!
Need a large overhead hoist at least?

Diameters up to 80 mm seem to be available. Up to 50 mm on ebay even! So I think it should be possible.

Cheers
Roger

[joeavaerage]

Hi,
its not so much the diameter of the screw, as you say they are available right up to 80mm-100mm. A machine like OP is talking about say a 36mm or a 40mm would be fine, maybe a 32mm at a pinch.
The problem is diameter of the ballnut. For a 40mm ACME screw and the original bronze nut might be 70mm in diameter whereas a ballnut is more like 100mm in diameter. This requires
significant re-work of the nut mount, and that gets worse if you have a cross yoke like on a Bridgeport. How do you hold two ballnuts which are already outsize at precisely 90 degrees to each
other? Of course in can be done...and is done.....but not for the faint hearted.

Craig

[wendtmk]

Hi,

I disagree, Mach predates LinuxCNC. LinuxCNC grew out of EMC2 many years ago, and one of the EMC2 developers, Art Fennerty, branched out and wrote the parallel port driver for Windows which started
Mach and hobby CNC. LinuxCNC came later. Given that LinuxCNC is quasi-realtime, it can be a feedback controller, whereas Mach requires certain work arounds to achieve the same result.
It is fair to say that LinuxCNC supports rigid tapping etc 'natively' whereas Mach uses both realtime motion control features or the feedback features of servos, or even more recently Ethercat, a
distributed motion control set up.
Craig

LinuxCNC did not grow out of EMC2. They are one and the same, but the name had to be changed from EMC2 to LinuxCNC due to a threatening letter from a company called EMC willing to take the EMC2 developers to court over a copyright infringement of the name, even though the company had nothing to do with any kind of CNC software or hardware. EMC started it all and was around long before Mach became a viable software, and Mach does not predate it.. LinuxCNC is EMC, just with a different name.

Mark

[joeavaerage]

Hi,
well I should consider myself corrected...thanks for that.

Now have you given any thought as to whether OP can use a Centroid Acorn to do gear hobbing? I think not for reasons that I have posted......but what do you think?

Craig

[wendtmk]

Hi,
well I should consider myself corrected...thanks for that.

Now have you given any thought as to whether OP can use a Centroid Acorn to do gear hobbing? I think not for reasons that I have posted......but what do you think?

Craig

I'm just reading along, willing to learn as I go, secure in the knowledge that I don't know everything. But willing to correct bad information about things I do know quite a bit about. Been using EMC/EMC2/LinuxCNC since the mid 90's.

Mark

[keitholivier]

Roger, Im not sure you would regard a 3500lb universal mil as a "hobby machine".
Errr, welll, no
Unless I had more $$ than I have.

Mind you, I would not object to having one! As long as it was a CNC, not a manual. I am not a trained machinist you see.
Hum - a 'dead' 3,500 lb machine and a budget to refit with electronics and servos etc - could be fun.

Cheers
Roger

Roger, see the picture of the universal mill with the horizontal milling arbor with the left hand support from the ram. Its not a great example, they have a cheap and tall swivel vice and the arbor is pretty long, it could have been shorter. If the steel block was clamped directly to the table with toe clamps the whole set up would be more rigid. But these are great machines for low volume accurate work. The one shown is about $20k to your door.

[keitholivier]

LinuxCNC did not grow out of EMC2. They are one and the same, but the name had to be changed from EMC2 to LinuxCNC due to a threatening letter from a company called EMC willing to take the EMC2 developers to court over a copyright infringement of the name, even though the company had nothing to do with any kind of CNC software or hardware. EMC started it all and was around long before Mach became a viable software, and Mach does not predate it.. LinuxCNC is EMC, just with a different name.

Mark

Mark, thanks for setting things straight. For years it was known that the position control on EMC was better than the competition, but today with external motion controllers the differences are smaller than ever. And the FPGA boards just get cheaper and cheaper.

When I started my work with National instruments an FPGA motion control board cost several thousand $, today the NI stuff is more expensive than ever but the competition is now selling very powerful FPGA boards for just a fraction of the price. I have just been looking at a 4 channel FPGA board to do analysis of torsional vibration data and I can get a plug and play 4 channel FPGA board with a 98Mhz clock speed for $400, including software to configure and run it, capture data and do analysis. All included in the $400.

[RCaffin]

The one shown is about $20k to your door.
Sigh. If only!
My door is Sydney, Australia.

Cheers
Roger
PS: what is the brand?

[joeavaerage]

Hi,

For years it was known that the position control on EMC was better than the competition

That is extremely questionable. A modern AC servo and matching drive have feedback that exceeds LinuxCNC/EMC2, remembering the servo drive is made to perfectly match the servo
by the same manufacturer something that LinuxCNC cannot match.

As for the control of an entire machine then LinuxCNC is favoured, but increasingly the leading manufacturers are going to distributed motion control like Ethercat which are in effect a 'whole
swarm of servos operating in concert'. It would appear that leading CNC manufacturers have determined that the synchronisation between two (or more) autonomous servos is sufficient for their machines.

Craig

[keitholivier]

The one shown is about $20k to your door.
Sigh. If only!
My door is Sydney, Australia.

Cheers
Roger
PS: what is the brand?

Knuth
KNUTH Werkzeugmaschinen - Qualität und Service weltweit (german)

[RCaffin]

Dear me. Knuth don't seem to be even registered in Oz. Oh well.

For years it was known that the position control on EMC was better than the competition,
Ah, but who was the competition?

I suspect that it did not include packages like Mach3. If you run Mach3 through an ESS to Gecko drivers, then the limiting factors are going to be the quality of the leadscrews. A Gecko driver will send the motor to position X, where X is specified to the resolution of the hardware (in my case 0.8 um). A Gecko stepper driver will take the indicated number of steps. A Gecko servo driver will run PID from the optical encoder on the motor to get the feedback from the motor to within an encoder line or two of what Mach3 says.

There has been a bit of a revolution in CNC controls and hardware over the last 10 years or so. There are powerful FPGAs etc in everything now, such that machines are now pushing the limits of accuracy of the ballscrews. Ground ballscrews and precision linear rails make the older ACME and dovetails seem antique. The SW on a PC is capable of extreme accuracy and total synchronisation between all axes - 6 on Mach3. But not everyone in the industry is aware of this - or maybe does not want to be aware of it. A lot of old machines are now effectively obsolete. Granted, they may be still able to do what the owners want from them, which is fine. But if you are buying a new machine, you can expect a whole lot more performance.

Cheers
Roger

[phomann]

Hi all,

I have a centroid Acorn controller along with the lathe software licence that I purchased for a client that ended up pulling out of the order.

I can offer it at a bit of a discount if anyone is interested.
PM me for more information.

Cheers

Peter.


Sent from my iPhone using Tapatalk Pro

[RCaffin]

It would appear that leading CNC manufacturers have determined that the synchronisation between two (or more) autonomous servos is sufficient for their machines.
Possibly so.
But then, I cannot even imagine a CNC machine which did not have full sync between all the axes! It just could not work.

I have looked at ethercat in the past. It seems to be a rather complex solution to a fairly simple problem, at least for a CNC.
It might, on the other hand, be rather useful for factory automation, like running operations down a conveyor line. I would not want to try to use Mach for that.
I did use an 80C52 running Basic with some optical sensors for that once.

Cheers
Roger

[joeavaerage]

Hi,

But then, I cannot even imagine a CNC machine which did not have full sync between all the axes! It just could not work.

But that is exactly what Mach and many other software solutions do. They command two axes go to some end point in some given time...and both axes independently go there.
In this case we are talking about servos which have feedback control (within themselves) and are thus extremely good at following the motion commands issued by Mach or whatever.
I mean for years we used steppers which were open loop, Mach told the stepper to go 100 steps to the right, and it went there.....no feedback involved or even required.

The advantage of Ethercat is you can have up to 100 nodes. Thus you could have not just one, but several CNC machines with interconnecting conveyors etc ALL controlled with one PC.
The nodes are daisy chained together, so no big bundles of wires, just ethernet cables between nodes. A number of the leading CNC manufacturers are using Ethercat, while others use Profibus
and yet others use CANOpen....the point being is that MOST of them are going to 'distributed motion control'...so there IS NO CENTRAL MOTION CONTROLLER anymore. Each node is responsible
for its own 'share' of the motion control task. This is the exact opposite of what OP is talking about, he is wanting some central controller to effectively slave one axis to another whereas the modern paradigm
is to instruct two independent axes to execute moves such that the two combined execute some coordinated move, but each axis does only its part and no more.

For many its hard to get your head around that 1) its even possible and 2) that its desireable.....but if its good enough for DMG Mori, Okuma....etc, its good enough for me.

I have a customer whom works for a long standing speciailist gear cutting company locally. They have manual machines and two new CNC machines for this task, and the CNC machines
are Ethercat. Gear cutting is their sole task and can only presume they would not have bought Ethercat unless it worked.

Craig