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NickJ

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  • Birthday 01/19/1984

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  1. I am greatly impressed by your perseverance and those subframe bolts are a thing of beauty!
  2. As per previous post (and my partner's disgust) I have successfully carved the official OSCNC test pattern: This brought forward many answers, firstly the original machine coordinate system puts Z+ as moving down, this is a right pain so needed a swap on both Y and Z axis direction to get everything happy. Also found the air blast works really well at scattering chip around the workshop, once things progress further i'll re-install the vacuum hoods. And not so fun, while cleaning out the X axis pulley housing I found cable ties holding the drive cable plug, uh-oh Seems this has had quite a crash at some stage, busting both plugs, replacement cost hurts but have a pair on the way, really don't need that shorting out. for now its carefully back together with additional zipties until parts arrive. And it turned even worse after that, in an effort to clean up the housing better I pulled the ballscrew out, turns out it should not have been pulled out in one piece, the smaller diameter is meant to go out the other side, this took most of Saturday morning to rectify, but everything is clean and back together. Belt is pretty standard AT-10, pic here for reference if needed.... And to finish on good news, walked the dog past Anton's house this morning for a catch up and he lent me this wee toy Beautiful Soviet era tachometer, this confirmed my speed was out by a factor of 1.2, after some digging, I found LinuxCNC is limiting max speed to 10,000rpm, so far I have no idea why, but have scaled back the output voltage to 8.33V@10,000rpm which when asking for 2500rpm gave 2500 on the dial, awesome
  3. Whats backlash? Spent the day digging further into the greasing issues, pretty sure its now getting everywhere, lots of black gunk spewing out onto the rails and its much, much quieter! still have quite a list to do before full operation, but yeah, could start smashing out cabinets if the will to CAD them existed.
  4. According to the spec sheet for the machine 18,000 rpm, one explanation i’ve been given is 12,000rpm full load and 18,000rpm at reduced capacity.
  5. Continuation of roadside sharns sounds like a good idea, i'll get in touch later this week.
  6. This is the nameplate: That aligns with our best guess of 2 pole. 4 pole would put everything out by a factor of two right?
  7. VFD - Settings confirmed as all wrong, but not terribly so, but with "better" numbers the external tach is now all wrong, while I didn't get my head around the external output settings that feed it, for now I'll let it be until I can get my hands on a hand held tach, unless someone has a fancypants way to work out the number of poles if its not on the nameplate? Currently set at 2 because thats what it was and it turns........ Managed to spin up all axes again and get each one to home on the limit switches, good learning here, setting home as zero throws errors cos it trips the switch, moving home position to a nominal offset cured that. Also found a few of the limit switches not quite in position, so fixed them too. All Green! If I was so keen, the controller would accept and run a program In reality this puts me servo tuning away from using the machine, in true procrastination form I dug into the pneumatics... Spilling the wires and tubes out from the head I set up a test manifold to find out which solenoids worked and which were NFG. Expected result, more bits dumped in the bin Thankfully I was left with 7 operational 5/2 solenoids, a few other shuttle valves and a mountain of various fittings &hose, these were set up on a manifold and re-installed to work the tool change on the main spindle. All of this^ is now this: Not being one to leave a chance to test, a quick switchboard was thrown together linking the above solenoids In what I can only amount to a miracle, I somehow managed to get the polarity of the air lines correct allowing removal and insertion of a tool holder first time, while it was only manual, it gives me hope that if I can sit down with the ladder logic side, I should get tool changing on the functional list (Of course its not this easy, there are many interlock switches to monitor making sure everything is correct ie tool correctly loaded before 10,000rpm etc) The tool change was also horrifically violent, must re-adjust the needle valves. So, limit switches, homing and tool change. Time to sculpt? No, theres still more distractions! Enter the auto-greaser.... I personally hate these things, experience tarred from older, mistreated farm machinery where blockages cause dry joints and days disappear in feeble attempts to unblock lines or work out which orifice plate goes to which port. But, when they work, life is pretty darn peachy. Using the valves assembled for the above air tests, I soon found the pump wasn't building pressure, a quick loosening of fittings and air purge had that raised to a healthy 200bar grease pressure (safety glasses on) Cracking the furthest distribution block I soon had grease pouring out then followed by a MDF/grease goo flowing from the linear rails and ball screws. While the flow is pretty uneven, i'll give it a few cycles a day in the hope everything will even out, worst case the lines can be swapped for nipples. Ok, so large phallic engravings now or what? Nope, in the adventure of chasing the grease lines I found the X axis drive cover was actually split and therefore working out the actual reduction ratio is possible. Cover off locates, well, more grease. Grabbing the nearest doggy bag the goo was disposed of and wiped up Fairly certain its just grease, the belt appears healthy but I might try locate a new one and replace it if the price is palatable. And yes, this whole post has been a tease, I never managed to run a program, having a go at tuning the servos I realised I have no idea how to run the internal oscilloscope, back to the school of YouTube then I promise to cut something worthy.
  8. Hmmm it just gets more interesting..... Had a good read of the VFD manual, Power Electronics SD50, from that I identified the most likely settings which were in need of a check up- Control input, remote operation, min/max speed, control input type etc etc. Well, before getting to the inputs it turns out the basic characteristics are all wrong, input voltage, motor power etc so quickly dragged them to range, then moving to the control side I found it was set to remote operation, local speed control, set speed 400Hz or ~8000rpm. A quick reassignment of inputs and she's all happiness, typing GCode into Linux activated the VFD and spun up to speed, even the tacho now reads a reasonable value when asked for 3000rpm, no doubt confirming parameters will get things inline. Its a pretty big win in the overall process, but mindful that there may be some more bad settings I shut down and tomorrow will dig through the entire VFD menu and confirm each and every setting, yuck.
  9. Is that a legit move to avoid cert? Turning the tops off and threading for an insert and cap is straight forward machining, not having a stub makes it a bit more palatable too.
  10. Watching with great interest, I had resigned to getting someone else to do it but this has swayed me back, fiddlesticks.
  11. WTF was I smoking and where did I leave it? Fired up the machine today and sure enough, same issue with axis creeping on the encoders, with multimeter in hand I started checking the obvious... 5V ground to system ground....30mV - Nope, not there. Utterly disappointed at this hypothesis being wrong I clutched at easy straws, 24VDC ground to system ground........ 30mV Control board ground to system ground....... 30mV OK, lets see how you like oscilloscope! Hmm, thats a pretty good square wave coming back from the encoder, for noise..... Almost as if the axis was moving............ The good old tape around the screw trick soon showed that yes, the axis is actually creeping, not just one, but all 3, last session I was sure to confirm nothing was moving, I have no idea how I missed this, but there you go, sane conclusion to that issue and even better, I have working encoder feedback! Next question then, why does the machine error out as soon as I try start it? first guess was the lack of limit switches, getting these wired up was quick and easy but gave a new error, active axis vibration, aha! I've seen this before, what PID values are in? It would seem that default PID values are P=50 I=0 & D=0, not sure I can do the best to explain here, these fancy values are what allow it to get to where it wants to be, in short with P set too high, the system will vibrate obnoxiously, dropping this to P=0.1 will have terrible response (more on tuning to come) but with stability. So dial in the change, hit the enable switch and everything behaved! Scrubbing up on g-code from many years ago I gave the machine a quick jog around and confirmed travel scaling is within tape measure precision, later on i'll dial this in better, the current plan is to just get things going. With movement in all three directions, I moved to the VFD, again, wiring had to be converted from sinking to sourcing but soon had the output reading correctly (to my understanding) Switching on power to the VFD I hit go at 1000rpm only to be greeted by the sound of a jet engine taking off! It would appear the go command gets through but the speed reference is not quite doing anything except shooting to the moon. I'm unsure if this is wiring based or VFD based but leaves the next move as going over the VFD wiring (again) and comparing that with the manual (again) which will then be confirmed with the VFD internal settings.
  12. You bloody ripper! My eyes lit up when you posted those pics on your build thread, all we needed was someone to see if shipping would work, thanks for doing the honours!
  13. Just twist the 5V wire to earth........ Haha, yeah thats terribly written, I think the 5V supply isn't grounded correctly which has left the 5V floating, well at least thats the simplest answer to what is observed.
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