Epoxy granite vertical mill build log

[Chaz]

Good to see that you are still at it.

[Nick]

Some progress:

It started to look a bit like a mill:



Next step was to flatten the base casting so I could get the rails on. It was to big an area to scrape and the reference surface and base were to heavy to invert. So I blocked off two rail sized areas with wood and then used an angle grinder to lower the rest of the surface, a bit crude but worked well.



I then flipped my surface plate and lowered it onto the base. It wasn't that far off, you could see damage from the previous owners of the surface plate.



After several rounds of scraping, it is flat to about 0.02 - 0.03 mm



Y axis and saddle installed:



Next step is to flatten the Z-axis rails, im using the same process as with the base, flipping the surface plate, it's really slow going.

[Chaz]

Ive looked at the servos, Ill be getting some once we get this house buying marlarky done.

Congrats, commented on your video.

[Nick]

Chaz - First movements have been very rewarding, hoping the pace picks up now.

I'm near Hull about an hour from Goole, that's a very kind offer, it might be a while till I could get over. That's reassuring that you've got them to work. I'm having a hard time making sense of the Chinese-English hybrid manual. I would be using them in the "position mode" initially, have you had any issues with overshoot? Are you using "open collector input mode" or using the suggested "AM26LS31 similar line drive"? Or 0-10v? I found the below video, which was bit concerning having to play around with the internal PID settings...

https://www.youtube.com/watch?v=qYgnIKDoVPY

Nick

[JAZZCNC]

I'm having a hard time making sense of the Chinese-English hybrid manual. I would be using them in the "position mode" initially, have you had any issues with overshoot? Are you using "open collector input mode" or using the suggested "AM26LS31 similar line drive"? Or 0-10v? .

I've used both Analog and Differential inputs on these drives, both work ok but Analog does require more work with tuning if closing the loop back to the controller
If you're using a decent controller with Step & dir then you won't need to mess around with line drivers as it will provide differential outputs.

I found the below video, which was bit concerning having to play around with the internal PID settings...

Don't be concerned because it's quite normal to have to tweak the PID settings. Servos are tuned according to the load they have to move so it should be no surprise that some tweaking is needed as it's impossible for them to be tuned correctly at the factory or when sat on a bench.

To how much tweaking needed depends on many factors including Input Mode and how or where the loop is closed. If using full closed-loop back to the controller then affectively 2 Pids have to be dealt with. First, the motor needs to be tuned to the drive using the drives PID. Then the position loop for the Controller needs to be tuned using it's PID.

Don't be afraid of PID tuning it's not rocket science but does involve a bit of black magic to perfect. Mainly it's just tweaking few settings until it behaves how you'd like. Little patience is all that's needed.

Edit: Checked today and the motors are the 600W version.

[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