Some progress today, managed to cast the table.
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Printable View
Some progress today, managed to cast the table.
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Good to see that you are still at it.
Some progress:
It started to look a bit like a mill:
Attachment 26698
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.
Attachment 26694
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.
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After several rounds of scraping, it is flat to about 0.02 - 0.03 mm
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Y axis and saddle installed:
Attachment 26691
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.
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More progress, rails installed, steppers installed on temp 3D printed mounts, temporary head and spindle.
First axis movements (Y axis not working):
https://www.youtube.com/watch?v=rAVX...ature=youtu.be
Attachment 26993
Next steps:
Alignment, use mill to mill better mounts, mill permanent head BT30, servos, way covers.
Does anyone have any experience with the cheap AC servo's on aliexpress? In particular the 60ST-M01930? Not found much on these.
Has anyone bought way covers from aliexpress? I was thinking about getting some "Armoured bellow cover"?
Nick
Ive looked at the servos, Ill be getting some once we get this house buying marlarky done.
Congrats, commented on your video.
Where you located Nick.? Says E yorks.? Anywhere near Goole.Quote:
Originally Posted by Nick
I've got some 400W waiting to go on a machine which are exactly the same drives and motors just lower power. So if you want to have a play with them on the bench your welcome to come over. For the money, they can't be beaten.
Edit: Actually just had thought.? They could actually be 600w I had set of 400w and 600w but fitted one set to a machine and I think they where the 400w. I'll Check when I get back to work on Monday.
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
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 controllerQuote:
Originally Posted by Nick
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.
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.Quote:
Originally Posted by Nick
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.
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.
Attachment 27310
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?
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.
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 . . :whistle::hysterical:Quote:
Originally Posted by Nick