[mamech]

hello

I am new to the world of LinuxCNC, and I have some questions about it.

1) I have read that LinuxCNC can interface 9 axis. Are these axis are simultaneous true axis? in other words, it can really control a 9 axis CNC machine (or 9 axis robot) which uses all its axis in the same time for complex motions?


2) There are LinuxCNC and Mach, what are the main adnvatages of LinuxCnc over Mach, beside its being opensource?

3) The most important question, what is the maturity of LinuxCnc in motion resolution and accuracy aspects compared to commercial Cnc controllers produced by siemens, beckhoff, fanuc, etc....

thank very much

[dharmic]

.

[samco]

it has 9 simultaneous axis in gcode (XYZABCUVW) You can map these any way you want. Linuxcnc has kinematics which allows you to convert joint to world mode. (so a 9 joint robot arm can be programmed in normal gcode.)

Linuxcnc is the motion controller running in realtime on the computer. This is 99% good. (sometimes it is an issue finding a computer that runs realtime well) This allows you to have control of the real time subsystem. (and doesn't require expensive external motion controllers)

it is linux - which can be scary to some people. It really shouldn't be - the linux os is as easy to use as windows.

It is stable and any bugs that would cause stability issues would be fixed pretty darn quick. Features on the other hand would require someone to come forward and take it on. (but anyone could because it is open source)

[OlfCNC]

I think you should install Linux first and if you can deal with it then you will be OK if not then use something else. I selected the "something else" option.

[Cromaglious]

Yes Linuxcnc is worth it. Tormach used it for the basis of thier Pathpilot. the main problem with linuxcnc in my mind is finding a machine with good enough realtime performance. Linuxcnc is really setup out of the box to use a parallel BOB or 2 or 3. That said you can use certain virtualized interfaces. via ethernet or a hardware bus (PCI, PCIExpress, cardbus, ISA, EISA, VESA) Linuxcnc does NOT like any of the USB interfaces, since by definition USB is not realtime.

That being said, there are other open source cnc programs. They just dont run on a computer. I'm talking about the Arduino, PIC, and other microcontrollers, which by definition are pretty much real time. Most of the problems with Arduino's is the 16Mhz clock. There are board out there that are running a version of Marlin/Sprinter (the defacto cnc softare for Arduino's) on 48Mhz and up boards. I'm running a laser cutter on a Arduino Mega 2560 with RAMPS 1.4 board, and building a 3040 engraver setup using the MKS board with THB6600 drivers (32V with 4.5A for the steppers and 50V for the brushed DC spindle with a PWM driver. I currently is running with a parallel BOB with the THB6600 drivers off a LinuxCNC 2.7 debian AMD Athlon box.

I'm going to the MKS board so I can have jobs copied to a SD card and popped into the MKS LCD SD Card reader or upload them via bluetooth to the SD card. So I don't have to tie up an entire desktop to drive it.

[mamech]

thanks for all . Really I was in need for information from more experienced people in this field.

That being said, there are other open source cnc programs. They just dont run on a computer. I'm talking about the Arduino, PIC, and other microcontrollers, which by definition are pretty much real time. Most of the problems with Arduino's is the 16Mhz clock. There are board out there that are running a version of Marlin/Sprinter (the defacto cnc softare for Arduino's) on 48Mhz and up boards. I'm running a laser cutter on a Arduino Mega 2560 with RAMPS 1.4 board, and building a 3040 engraver setup using the MKS board with THB6600 drivers (32V with 4.5A for the steppers and 50V for the brushed DC spindle with a PWM driver. I currently is running with a parallel BOB with the THB6600 drivers off a LinuxCNC 2.7 debian AMD Athlon box.

I'm going to the MKS board so I can have jobs copied to a SD card and popped into the MKS LCD SD Card reader or upload them via bluetooth to the SD card. So I don't have to tie up an entire desktop to drive it.

I know about marlin firmware, but is not it restricted to steppers only? I saw it used mainly in 3d printers, with softwares like pronterface and repetier that are dedicated to 3d printers.
Does marlin firmware support using Analog/Communication industrial servos?
What is the CNC software that you use for Desktop interface with arduino mega that has marlin firmware?

[Cromaglious]

thanks for all . Really I was in need for information from more experienced people in this field.



I know about marlin firmware, but is not it restricted to steppers only? I saw it used mainly in 3d printers, with softwares like pronterface and repetier that are dedicated to 3d printers.
Does marlin firmware support using Analog/Communication industrial servos?
What is the CNC software that you use for Desktop interface with arduino mega that has marlin firmware?

There is a new project out which takes step and direction and using a nano pro drives a encoded dc motor in a closed loop. Do for a 3 axis machine you'd actually have 4 arduinos.

[daniellyall]

there is a board you can get to turn a stepper into a closed loop stepper and it takes step and direction

[109jb]

There is a new project out which takes step and direction and using a nano pro drives a encoded dc motor in a closed loop. Do for a 3 axis machine you'd actually have 4 arduinos.

There are servo drives that have been doing that for ages. Gecko servo drives for one, but there are many other brands.

[109jb]

Marlin/Sprinter (the defacto cnc softare for Arduino's)

Maybe for 3D printers, but Marlin is not well suited at all for things like milling, or lathes, etc.

There is just too much in Marlin that either doesn't conform to RS274ngc standards, or is flat out missing to make it suitable for something like a milling machine. Sure it can be done by working around those deficiencies, but there are other AVR options that are much better. I looked at a tot of them and settled on GRBL because it is much better suited to a milling operation. Here is just a short list of some of the Marlin problems as applied to milling machine operation.

No spindle speed control
No coolant control,
G02/G03 can't do helical motion,
No work offsets (G54-G59)
No plane select
No tool length offset
......... and the list goes on

None of the microcontroller based motion controllers I am aware of support canned cycles or cutter radius compensation, so if you need those you are out of luck.

[109jb]

hello

I am new to the world of LinuxCNC, and I have some questions about it.

1) I have read that LinuxCNC can interface 9 axis. Are these axis are simultaneous true axis? in other words, it can really control a 9 axis CNC machine (or 9 axis robot) which uses all its axis in the same time for complex motions?


2) There are LinuxCNC and Mach, what are the main adnvatages of LinuxCnc over Mach, beside its being opensource?

3) The most important question, what is the maturity of LinuxCnc in motion resolution and accuracy aspects compared to commercial Cnc controllers produced by siemens, beckhoff, fanuc, etc....

thank very much

1 - Yes, LinuxCNC can control 9 axes simultaneously

2 - I tried Mach and wasn't all that impressed considering that LinuxCNC can do more for free
I believe it is limited to 6 axis control
It doesn't appear to have any kinematic engine, so can only be used on a machine with orthogonal axes. IE: No core XY, arm style robots, etc.
Mach 3 has many reported bugs that some have no solution for.

3 - The motion control resolution and accuracy should be every bit as good as a commercial controller on a properly set up machine.However, accuracy is more dependent on the machine than on the controller anyway. The controller can output commands to move 0.000001", but if the machine can't mechanically achieve this it doesn't matter.

There are many settings to tailor the motion accuracy to what you desire.For example, take a series of moves along line segments. Due to the fact that an axis drive can't have infinite acceleration it will have to slow down in corners. Think about driving a car around a corner, You can pretty precisely go around that corner at a slow speed, but as speed increases the corner gets more and more rounded off. Same thing with the machine. It is a trade off and your setting dictate the tradeoff. The more precisely you want to follow programmed paths, the slower the cycle time. You can set it up so that for every move the machine comes to a complete stop before performing the next one and therefore it would not round the corner.

[daniellyall]

what gecko board does closed loop on a stepper

[109jb]

what gecko board does closed loop on a stepper

I didn't say stepper driver. I said servo driver.

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[tommylight]

I am a hard core LinuxCnc user (and modifying it to my needs has become simple ) so i will not enter in a mach vs Lcnc battle (the war is still going on, and mach is loosing badly, especially with version 4 ), so here is my opinion:
use LinuxCnc and never look back !!! It will take some time to learn the complicated stuff ( like controlling a 9 axis machine with any number of inputs and outputs ), but you will thank us later.
As for simple stuff, you need about 10 minutes to have the machine running, if you have the hardware ready. Everything after that goes like: oh i can do this....i can add that.....i can modify this..........and a whole new world opens up. It is a wonderful world, if you do not want to be closed in a box......a black box......with no lights......or doors....or windows !!! Dang, i said "windows" !!!
Am going to a corner to be ashamed for a minute or two !

[daniellyall]

linuxcnc Is good if you have one off the nice linuxcnc guys helping if you don't know it at all, it will be fine, but if you get one of the not nice's linuxcnc person's well it turns to crap fast.

have a look on there web site it has a list of what's good to go out of the box and it will be easy as to do 1 Hour and it will be running. if you don't you have to change stuff, I would advise hitting up samco or olfcnc they are on the nice list if you get one of the Ahole it will be very hard.

tommylight may be a nice one two most of the linuxcnc guys that post on cnczone are.

[G59]

However, accuracy is more dependent on the machine than on the controller anyway.

Hmmm, that's not true. You can have a really sloppy machine that is fitted with glass scales and be very accurate.

Just so happens my brothers hobby machine needed an upgrade. It's a three axis wood router.
I just installed the latest LinuxCNC version because everyone ragged on Mach3, but mostly because he wanted a change(bored).
My first impressions was how easy it was to install. They made great progress here compared to 10 yrs ago. Simple and fluid.
Using the stepconfig to setup the controller was also quite intuitive.

What I dislike about LinuxCNC is the GUI. Yes, I tried gmoccapy and the other ones it comes with and they are all just poorly laid out. This is where you see the difficulties with Linux compared to Mach3. Very hard to modify anything in the GUI. Even a background color change is difficult if not impossible.
I even tried following an online GUI tutorial and they lost me when they tell you to go to Glade and GTK etc...... blah, blah, blah ..................defininetely not like using QT or VisualC++.
So that is really my only complaint. GUI changes by the average Joe is NO.

[109jb]

Hmmm, that's not true. You can have a really sloppy machine that is fitted with glass scales and be very accurate.

Just so happens my brothers hobby machine needed an upgrade. It's a three axis wood router.
I just installed the latest LinuxCNC version because everyone ragged on Mach3, but mostly because he wanted a change(bored).
My first impressions was how easy it was to install. They made great progress here compared to 10 yrs ago. Simple and fluid.
Using the stepconfig to setup the controller was also quite intuitive.

What I dislike about LinuxCNC is the GUI. Yes, I tried gmoccapy and the other ones it comes with and they are all just poorly laid out. This is where you see the difficulties with Linux compared to Mach3. Very hard to modify anything in the GUI. Even a background color change is difficult if not impossible.
I even tried following an online GUI tutorial and they lost me when they tell you to go to Glade and GTK etc...... blah, blah, blah ..................defininetely not like using QT or VisualC++.
So that is really my only complaint. GUI changes by the average Joe is NO.

I'll have to disagree. While you may be able to improve accuracy by adding glass scales to a degree, adding glass scales to a sloppy machine will not make it a good machine. A machine that is sloppy will still be sloppy. Let's say you have a sloppy machine that chatters during a cut and gives a horrible finish due to slop in the machine. The controller will not be respond anywhere near fast enough to fix it whether it has glass scales or not. If there is enough slop and you have settings that are to restrictive, the controller may fault because it can't resolve a mismatch between the scale position and the programmed position.

As for GUI's,. I actually prefer the LinuxCNC Axis GUI over Mach 3. However I could really care less about the GUI as the most important consideration to me if if the controller is stable and does its job. A pretty face on a substandard application doesn't do anything for me.

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[G59]

A machine that is sloppy will still be sloppy.

.

I have to agree.

A pretty face on a substandard application doesn't do anything for me.

But a pretty face and brains to go with it, is supreme. LinuxCNC has the brains, now let's work on better and more intuitive GUI's. LinuxCNC would quickly overshadow all the other hobby controllers if they would include a quick and simple 'screen designer' with it. In my opinion, that's what's missing here.

[tommylight]

Time after time...............was an old song by ...i do not recal, but time after time i have to wonder: what on goods green earth makes the Mach3 GUI good looking ?????
For the life of me i will not comprehend how could anyone call that monstrosity "a nice GUI".
Or as Jeremy Clarkson would say:" I have seen better looking camels ...with gingivitis "
Then again, Mach3 has a face only a mother could love !
I am off.

[G59]

what on goods green earth makes the Mach3 GUI good looking ?????

No one here said it was so good looking. Almost everyone who has used Mach3, has dabbled with a screen designer or changed screensets or added buttons etc...etc.....

Personally Mach3, UCCNC, and LinuxCNC all have the same problem. Not one of them was specificaly designed for a specific machine. They are a bundled software that you can use to turn or mill or drill or run robots with. So right away, you won't be able to please everyone. Hence the want for easier customizable GUI creation.

Thats all I'm saying.