Epoxy granite vertical mill build log

[Nick]

Jazz thank you for your post, this makes a lot of sense, you've reassured me re the servos. I've decided on using the analog interface with Linux CNC, mesa 7i92 and 7i77 with the controller closing the outer loop. I might need some help with the tuning. I've bought 600w for the X and Y, I have also committed to the BT30 spindle with a 1.8 kw servo.



Waiting for the servo for the spindle, pneumatic cylinder and mesa cards.

Made a start on the pneumatics, I've gone with a "mist cooling" system using the water filter approach I found on the here, works well.

Got a lot of time consuming jobs done, filled the spindle head with epoxy granite, got the y-axis movement working. Made a few chips with jogging.

Next major problem is protecting the ways from chips, I've seen several designs. Would anyone be interested on collaborating on a way cover design?

I've seen a few designs:

Chris DePrisco made some with sheet metal: https://www.youtube.com/watch?v=3GSEayp8Ioo
This looks very labour intensive

This looks less labour intensive and less skilled, could potentially 3D print the sides: https://www.youtube.com/watch?v=G2DJ8RQy4D4

This project (which is a bigger, much more polished version of mine) uses way covers from aliexpress (I found a link and I think they cost about £400), this could be emulated by putting sheet metal on cheaper bellow way covers: https://www.youtube.com/watch?v=nTC5gWVmt0o

Then the simplest option is using rubber or a fixed cover with acrylic. Thoughts on this?

[JAZZCNC]

Don't overthink the way covers they don't need to have scissor mechanisms. Just let them slide so push-pull each other in and out. Many industrial machines use this method and it works fine, the Fadal machine I have here just uses the push-pull method. Your welcome to look at or copy these covers which are off the machine.

I'll take some pictures for you to see how they are made up.

I've decided on using the analog interface with Linux CNC, mesa 7i92 and 7i77 with the controller closing the outer loop. I might need some help with the tuning..

Do you have any experience of Linux CNC.? If not then get ready for a massive learning curve because with servos and closed-loop it's a different ballgame to Steppers. I'm very experienced with lots of controllers and I'm struggling big time with Linux CNC. Luckily I've got a Linux Guru in my camp working on it, hey Clive S . .

[Nick]

I'll take some pictures for you to see how they are made up.

That would be great. I've put some rubber sheeting in for the moment.

Do you have any experience of Linux CNC.? If not then get ready for a massive learning curve because with servos and closed-loop it's a different ballgame to Steppers. I'm very experienced with lots of controllers and I'm struggling big time with Linux CNC. Luckily I've got a Linux Guru in my camp working on it, hey Clive S . .

Nope, It's been a massive learning cure. Very slow progress, hours of scanning the Linux CNC forum. You get stuck on silly things like setting up the home switches for what seems like hours. I gave up with stepconf and pcnconf wizard and just played around with the "hal" and "ini" files. I have however got Linux CNC working with steppers via a computer parallel port.



I have made my first chips and broken my first end mill on the servo mount for the X-axis. There were lots of issues milling this the X-axis pulley keep slipping. It looks a bit rough, I left 0.5mm of axial so I had to file it down, no finish pass but I think it will be functional. Waiting for a new belt to try it out.



5mm 2 flute end mill: RPM: 8000-10000 WOC 1mm, DOC 4mm, chip load per tooth around 0.04mm, feed 600mm/min
8mm 2 flute: RPM 8000-10000, WOC 1.6mm, DOC 8mm, chip load 0.05?, feed around 1m/min

I have got the china servo motors (analog) working with Linux CNC on the desk, closing the loop in control, it wasn't too painful to figure out. The mesa 7i77 card is really nicely made, nice manual, lots of IO.

If anyone is interested I will write a tutorial on getting the china servos working with Linux CNC, it might help with small things like I got stuck for a a good few hours before I realised I needed to set Pn146 to 0 on the servo.

Very brief video of first'ish chips

https://www.youtube.com/watch?v=WzXHVFuu-qo

[JAZZCNC]

I have got the china servo motors (analog) working with Linux CNC on the desk, closing the loop in control, it wasn't too painful to figure out. The mesa 7i77 card is really nicely made, nice manual, lots of IO.

If anyone is interested I will write a tutorial on getting the china servos working with Linux CNC, it might help with small things like I got stuck for a a good few hours before I realised I needed to set Pn146 to 0 on the servo.

Very brief video of first'ish chips

Bloody hell not joking when said video was brief I blinked and was done. . .


Regards Linux and Servo's how's the following error, have you checked it in hal scope.? . . . We are struggling (well not me but my guru) with the Step/dir to get full speed without throwing a following error.

[JAZZCNC]

Hi Nick,

Here's those way covers I was talking about, pictures didn't do it justice so a little video shows it better. Hope it helps

[Nick]

Hi Nick,

Here's those way covers I was talking about, pictures didn't do it justice so a little video shows it better. Hope it helps

Ah thank you very much, I see what you mean now, those look great, really simple design, just sheet metal and a few welds. I will give making some a go.

Following error wise. What speed are you aiming for? How have you found tuning the internal PI loops? I'm struggling to tune the servos. I'm just about at less than 10 microns f-error now on the X and Y, I am cheating slightly acceleration dropped a bit, speed reduced to 1500mm/m. I think my main issue is the servo speed and torque loops aren't tuned. The error got a lot better when I put in the inertia load into Pn257 after I ran the Fn018 mode to get the inertia ratio. I'm using gain adjustment mode 1 (Pn258) and then adjusting the "rigid grade selection" until I get oscillations / vibration. I found the linuxCNC tune very sensitive to FF1

I haven't worked out how to properly tune the internal PI's because I can't work out how to bring linuxCNC into open loop and then command a specific speed in LinuxCNC. I am thinking about using the internal speed command function and toggling this with push buttons. Say set it to 250, -250rpm and then I will be able to jog it back and fourth while looking at the HAL scope.

[Clive S]

I haven't worked out how to properly tune the internal PI's because I can't work out how to bring linuxCNC into open loop and then command a specific speed in LinuxCNC. I am thinking about using the internal speed command function and toggling this with push buttons. Say set it to 250, -250rpm and then I will be able to jog it back and fourth while looking at the HAL scope.

Nick. What mode are you using ie position or torque etc. Have you seen or read this:-

https://forum.linuxcnc.org/10-advanc...etailed-how-to

I am in the same boat as you and struggling with a following error when using closed loop. Changing closed to open loop is just one change in the hal file.
This is also my first time with halscope