Ruby Casting (verneuli flame fusion)

Discussion in 'General foundry chat' started by Zapins, Apr 21, 2021.

  1. It all seems pretty complex at first but is worth the extra effort to learn: steppers have two windings that have to be sequenced in a particular pattern to make the motor spin backwards or forwards. They have good torque and run to zero speed at full torque too. So instead of a DC motor's two wires you typically have four wires for a stepper as they have two separate windings. These get fed DC power by a driver board that can operate the two windings in the right sequence to make it go forwards or backwards. The controller board is connected to the driver board and it generates a constant stream of pulses at the rate set by the speed control knob and has a wire to signal forward or reverse direction as well.
     
    Melterskelter likes this.
  2. Zapins

    Zapins Gold

    So if I understand correctly the setup is simple. A controller tells the driver board what speed to go at and the driver board send the electricity to the motor. No need for a computer or programming or other devices?

    Just plug and play?

    Do I just adjust the knob to change speed? Is torque the same at low speeds as at high speeds? If I'm setting it at 0.16 rpm will it turn the lead screw?

    Are there other numbers that need to match up in order to be compatible?

    Are all the parts you linked compatible if I bought them?
     
  3. Yes the controller has a knob for speed control and buttons for stop/start and direction of rotation. There's no programming needed, just connect the corresponding wires from the controller to the driver board and from the driver to the stepper motor and then connect power. Those Ebay boards I linked to have markings on the terminals but there should be instructions too. The maximum torque is constant regardless of speed, in fact when powered up and not rotating the shaft should be hard to turn, up to the maximum torque of the stepper motor.
     
    Last edited: Jun 19, 2021
  4. Zapins

    Zapins Gold

    Hmm ok. Interesting. How hard would it be to dial in 0.16 rpm though? Might be difficult to turn it on so slowly?

    What about these ball screws? https://www.amazon.com/gp/aw/d/B07DQK2YFN/ref=cm_cr_arp_mb_bdcrb_top?ie=UTF8

    Looks like they would be machinable if needed so I could cut threads off for gears if necessary but I don't know how many threads per inch (or cm) there are. Looks like not many which means the motors would need to turn even slower than 0.16 rpm to get them to turn at the right speed.
     
  5. Melterskelter

    Melterskelter Gold Banner Member

    To add to Mark's line of suggestions, learning to control stepper motors with Arduino is not that difficult and can open up a powerful "tool set." I have done some work with Arduino and have found it fascinating and useful.

    Denis
     
    Last edited: Jun 18, 2021
  6. I can't be certain but I think the 1605 ballscrew indicates a 16mm diameter by 5mm pitch screw so you'd be getting a minimum increment of 5/400 of a mm or 0.0125 mm per step (about a half thou/step). To get 0.16 RPM that would be 400 steps per rev times RPM, so 400 x 0.16 = 64 steps per minute to get 0.16 rpm, so you'd have to adjust the speed of the controller board to be a bit faster than one pulse per second. Also never remove the nut from the ball screw as the balls will fall out of their complex spiral paths and you'll never get it back together again.

    Denis is right in that there's plenty of existing samples of Arduino software that can be modified to do anything more complex than driving a screw up and down and the effort learning it is repaid.

    Edit: corrected the math.
     
    Last edited: Jun 19, 2021
  7. Zapins

    Zapins Gold

    I bought one stepper motor and the speed controller and driver that you linked. Will use it for the 10 rpm motor part or the tapper that dumps powder in. I'll get used to it and see how easy it is to configure. Then future projects can use it if its easy.

    As for the main platform motor I'm not sure if I can get the stepper to rotate so slowly with a smooth rotation. Seems other posts online had vibration issues when doing super slow rates. I think a smooth descent is very important. Might be worth just investing in traditional gears and motors for that platform.
     
  8. Melterskelter

    Melterskelter Gold Banner Member

    There are various tricks to get steppers to rotate slowly and smoothly---half stepping and microstepping strategies are used. Not to mention the possibility of using traditional gear or timing belt drives to also reduce shaft rotation over and above that obtained by adjusting step frequency. I am sure you have heard of folks doing it wrong. But GeckoDrive is a good resource for info on their drives, applications, and motors. I have been happy with the products I have purchased from them.

    https://www.geckodrive.com/

    Denis
     
  9. Good luck with the stepper system, I hope I picked the right parts combination, they are very handy systems and eliminate a lot of gears etc..

    I would have thought the smooth movement of the platform isn't that crucial: so long as the fused material on the end of the ruby boule moves down at the same rate the fused alumina builds up it should be hunky dory. Like Denis mentions, a stepper running in half step mode will be moving in fairly fine increments indeed, say a 400 steps per rev stepper doing half steps gives you 800 steps per rev 0ver a 5mm pitch ballscrew or a quarter of a thou per step. Add some tooth belt reduction drive robbed from a dead photocopier/printer and you'd be hard pressed to see the movement at slow step rates.
     
  10. Zapins

    Zapins Gold

    Bought all the things I need to finish the bulk of the project. I have some lead screws coming, a 50 rpm gear motor, 170:1 worm screw gear, speed controller, shaft and lots of bearings. I have one stepper motor for the rotation part. Should be here next week some time so I can start assembling the contraption. I'll need one more stepper motor to make the tapper for the powder dispenser and then will need to buy a hydrogen generator or two. Apparently 15 L/min is the amount specified in the patent, I found one that makes 10 L so maybe that will be enough. Or maybe I need two setups. They seem to chew up amperage though, 10 L is approx 30 amps. I'll probably need to hook it up to my 50 amp welder outlet to power it all provided I can find a 15L output generator.

    Got to say working on this project has upper my skills using my lathe. I've been getting better and better results the more I use it. I really need a steady rest though. My parts keep vibrating when I cut without support. The new live center on my tail stock helps a lot but some parts are just the wrong shape for it and need a steady for proper support. Its to the point that if I wasn't 1-2 parts away from finishing the ruby caster I'd pause and make myself a steady before continuing.
     
  11. Melterskelter

    Melterskelter Gold Banner Member

    This may seem crazy to you, but I have known of serviceable steadies made of plywood. Yup, a base clamped to bedways, an upright 3/4 ply with a hole. Fingers of hardwood screwed to the ply. Maybe get fancy and put slots in the fingers for better adjustability. But, If you really need one right now, don't assume that a quick and dirty one can't get you through a tight spot.The actual loads on a steady are not that great.

    Then make a "real" one later.

    Denis
     
  12. Zapins

    Zapins Gold

    I've got all the parts for it. Just need to sit down and make one. Only part I don't know how I'd make is the slide that clamps to the table. It needs a V groove cut into it so it can go over the lathe bed. I could half ass it and make it work tho.
     
  13. Melterskelter

    Melterskelter Gold Banner Member

    It is quite feasible to cut a v-groove using the lathe as a shaper.

    You can also mount a piece on the cross-slide and mount a milling cutter in the chuck. I'd go into more detail with you on this if you get serious about the idea.

    I am assuming you do not have a mill or surface grinder. Cuz, either would allow you to cut the groove pretty easily.

    Denis
     
  14. Zapins

    Zapins Gold

    Sure I'm interested. Whats the best way to do it?

    I need this one off piece but if its easy and relatively quick I wouldn't mind making gears that way too.
     
  15. BattyZ

    BattyZ Silver Banner Member

    Your build has perfect timing. I would really like a solid ruby ring for my joining-of-taxes-ceremony next June. I know this is far out but I always thought it would be cool...wait size diameter are you shooting for? I have a vertical machining center so if you need some simple things done or some 3d surfacing you just holler!
     
  16. Zapins

    Zapins Gold

    Haha. I'm unsure the diameter of the ruby boule that will form. I'd guess about finger thickness. For the steady the diameter might be anywhere from 7 to 11 inches across depending on what scrap I have on hand to build it.
     
  17. BattyZ

    BattyZ Silver Banner Member

    I will have to read more into the patent and terminology, but if you would like help to machine something let me know. 7 or 11 inches is well within my work envelope.
     
  18. Zapins

    Zapins Gold

    Thanks! I'll keep that in mind. I might need some help making the slider. The rest I think I can make but I might have a go with the shaper route.

    I need a bit of help wiring up this stepper to the speed controller I got. I am unsure what the markings signify, there are more wires than the normal power and ground wires on most other motors.

    20210622_195743.jpg 20210622_195802.jpg 20210622_195848.jpg 20210622_195822.jpg 20210622_195727.jpg Screenshot_20210622-194509_Chrome.jpg
     
  19. BattyZ

    BattyZ Silver Banner Member

    Could you provide links to these? The 4 wires from the stepper normally are A1A2B1B2, like others have said represent the 2 sets of windings. PUL is how many steps, DIR is what way, ENA needs to have 5V to put out signals.

    I readback, found the links. Muh bad team.
     
    Last edited: Jun 22, 2021
  20. Zapins

    Zapins Gold

    Yes.

    I found these but still confusing. My second board doesn't have outputs like that I think?

    20210622_203145.jpg 907d1ff729daebc567f4011ffec950ab.jpeg
     

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