oldtech
Full Member
Posts: 222
Machine: Power Route
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Post by oldtech on Jul 3, 2020 20:05:39 GMT
Background: I have converted my Power Route to run Linuxcnc. I'll add observations here as I explore Linuxcnc.
Complexity: Linuxcnc is more complex than GRBL, but it's complexity is somewhat layered, and I've been able to navigate it fairly easily. And of course this complexity adds a lot to what you can do. It is also a Linux based system so there are differences just due to the OS. However, I'm running Linux Mint which looks and feels a lot like Windows.
Graphics: Linuxcnc's graphics are not anti-aliased unlike most graphics on windows. However, this has the advantage of not hiding detail on cutting paths even though it is less pleasing to the eye.
Limits: Linuxcnc's soft and hard limits just work. You cannot jog outside of the limits. And if you execute a command in MDI that attempts to go outside of the limits you get errors, but you have not lost steps that require you to re-home. Likewise for running a program: only in this case you get a dialog saying that the program violates the limit and what limit. This was one of biggest frustrations with GRBL. GRBL's behavior reminded me the CP/M operating system in the 80s that would do what ever you typed even if it was not what you wanted - like writing a file to the end of tape with no errors but no file written either.
E-Stop: In GRBL for the Power Route, the E-Stop button is wired to simply cut off power. In linuxcnc, E-Stop is a built in function that stops the machine but does not kill the machine. All your settings are still there. So after hitting E-Stop you can start the program again without having to home or setup coordinates again. And you can put relays into the E-Stop circuit to control the power to aux equipment such as a shop vac or pump. A properly wired E-Stop will keep the hardware E-Stop and the software button on the screen in sink. Likewise for the power button. [So now I need to properly wire up both a power and E-Stop button  .] |
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Post by Bruce on Jul 5, 2020 2:40:34 GMT
Thanks for the update. What is the official Linuxcnc website?
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Post by btreichel on Jul 5, 2020 23:18:15 GMT
cp/m, did you really have to remind me?
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oldtech
Full Member
Posts: 222
Machine: Power Route
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Post by oldtech on Jul 6, 2020 0:06:05 GMT
Thanks for the update. What is the official Linuxcnc website?
Note that this installs both linuxcnc and linux mint with one installation. You will have to use the command line but nothing fancy - you can just copy and paste the commands.
The default GUI for linuxcnc is 'axis', but I'm now using 'probe basic' a more touch enabled modern UI somewhat similar to mach.
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oldtech
Full Member
Posts: 222
Machine: Power Route
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Post by oldtech on Jul 6, 2020 0:25:45 GMT
The scale factors for the calibrating the axes were surprisingly good (thanks Derek). I got 100.30 steps for the x-axis and y-axis and 200.15 steps for the z-axis.
I also measured the homing repeatability and it looks like repeatability is within 0.01mm (that's also the limit of my dial instrument).
Sigh: It looks like I need a more accurate dial instrument. Any suggestions? I currently have a Clockwise DIBR-0105.
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oldtech
Full Member
Posts: 222
Machine: Power Route
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Post by oldtech on Jul 26, 2020 19:08:31 GMT
One of the things that linuxcnc is designed to allow is multiple configurations. This morning I tried it out by creating a vertical milling configuration for my Power Route.
This configuration uses the extended z clearance plate that I created some months ago. Since the extended z clearance is higher than the gantry clearance (~5 inches), it would be easy to crash the gantry into a workpiece that is being milled using the extended z clearance.
So this configuration sets the home position to 500mm on Y with a travel limit of 80mm. Now the machine will not move outside of that area (500mm < y <580mm) so the danger of crashing the gantry into a workpiece is minimized.
Now I can safely mill a part as high as 170 mm while being clamped in a milling vice.
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hans
Full Member
Posts: 151
Machine: Other
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Post by hans on Aug 12, 2020 2:37:23 GMT
The scale factors for the calibrating the axes were surprisingly good (thanks Derek). I got 100.30 steps for the x-axis and y-axis and 200.15 steps for the z-axis. I also measured the homing repeatability and it looks like repeatability is within 0.01mm (that's also the limit of my dial instrument). Sigh: It looks like I need a more accurate dial instrument. Any suggestions? I currently have a Clockwise DIBR-0105. With a stepper motor and lead screw driven axis, and if we assume that no steps are lost and that the lead screw is accurate, then when moving with no "load," how can scale calibration not be "surprisingly good?" And the same question for rack and pinion systems, as long as the tooth count is accurate and the teeth are properly uniform. (With the rack and pinion, I can understand "jitter" if the teeth on the pinion are not uniformly spaced, but scale calibration just requires counting the teeth properly. (Same for the rack.)) I'm NOT meaning to argue with you at all, but I was surprised when building my Carve King and, later, my Mega V and found that a calibration step was expected. As an aside, when I did preform the calibrations I decided that I should use the movement of my router base to calibrate my measuring tools rather that the other way around. |
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