Newbie - Help with Motors.

Discussion in 'General Electronics Chat' started by potman100, Aug 5, 2016.

  1. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    Hi

    Ok, I am a total newbie to electronics, but have been working in IT for 20 plus years and have been a keen programmer
    for most of that time.

    What I'm trying to Do !

    In my spare time, i sell used media Cds / Dvds online, I get lots that are scratched and need resurfacing, I bought a machine
    to do it, but it was quite expensive, and now I find I really need another but don't really want to spend another £1500 on one.

    So, the machine I bought it seems to me is quite basic, it has a motor that a round cd / dvd sized table is attached to and it
    spins, on the lid there are 2 round foam pads that when the lid is closed sit on top of the cd / dvd which has been placed label
    down on the table, it applies some polish to the cd / dvd and the table and the upper pads spin / rotate and polish the disc.

    So, I want to try and make a similar system, I noticed you could get just a driver board to control a DC motor, so I purchased a
    cheap one from ebay and a 12v 5 amp PSU to run it, and with the help of Youtube I used an old hard drive motor and have it
    all working without blowing myself up. What I have come to realise is that the Hard Drive motor is under powered for the polishing
    process, and stalls the motor easily.

    So, I have been looking in to buying a better motor and this is were I'm getting confused,

    I think I need to get a motor that has high torque ?

    As I am new to this my soldering skills are very poor, so I wanted to use a Arduino, with a driver shield to do the control.

    What would be best, a 12v or 24v motor ?

    There seems to be quite a lot of driver shields on Ebay, any recommendations ?

    I hope this is clear for you, just give me a shout if not and I can clarify any part that is unclear.

    Thanks for any help or ideas you are able to provide.

    Regards

    Darren
     
  2. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    I have no experience of this product, but what does the £1500 version do that this £20 one doesn't?
    http://www.ebay.co.uk/itm/Procare-P...325080?hash=item2c8d213658:g:-rwAAOSwfcVUI8uv

    Check out what speed your existing one runs at. It doesn't matter what voltage the motor is as long as it will produce the correct speed with enough power to do the job.

    Surely an arduino is way OTT for this job - are you trying to use a stepper motor to do this? As far as I can see a simple DC motor (where you just connect it to a power supply) and a switch is all you need. Such motors generally run fairly fast so you will likely need one that comes with a gearbox. This will reduce the speed and increase the available torque.
     
  3. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    Hi Albert

    Thanks for your reply, the one you pointed out in your link, just scratches the disk even more, the one I have
    take 30 seconds to remove a lot of scratches, it's more of a professional re-surfacer made to to do a lot of
    disks very quickly, here a link

    http://totaldiscrepair.co.uk/machines/vmi-hybrid-2/

    I want to use the Arduino, so I can add an LCD, and would want to add some sensors and look at automating loading
    of Media for cleaning ect.

    I was thinking of this motor

    http://www.ebay.co.uk/itm/sourcingm...135af9c&pid=100005&rk=5&rkt=6&sd=282033416006

    I was just unsure about the Voltages.

    Regards

    Darren
     
  4. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    The voltage of the motor doesn't really matter as long as it has enough torque to do the job at the right speed. There is no way we can tell how much torque you will need - it depends on the speed and the friction with whatever is against the surface of the disc.
    Are you going to use the consumables from the VMI machine? It looks like you will need some kind of pump judging by the tubing inside it. I think it will take a herculean effort to produce a DIY version of that machine.
     
  5. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    I've have looked into the consumables and as a starting point I was going to use the VMI ones, but look
    for a cheaper solution in the long run.

    The VMI has 2 bottles installed in it, one is polish and the other is water, looking at the cycle it adds polish to the
    disk at the start and runs for 20 out of 30 seconds and then adds water to clean the polish away, so I think there
    are 2 pumps.

    I have wanted to have a play about with Arduino platform for a while, and after looking at the programming side that is no problem
    and I'm not to bad with making things, its just the electronics side of it I need to understand.

    I'm not in a rush to got it done, so I was just going to get one job done at a time, starting with the spinning platform. and after researching
    around the net, there does not seem to be a problem with getting the Modular Hardware to do almost anything.
     
  6. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,951
    387
    Probably a good way to go would be to get the speed the VMI machine uses and some idea of the pressure applied by the pads, then you can get a motor/gearbox which gives the right speed. If the motor is not powerful enough then that won't do at all but if the motor is way too powerful it will work just fine - maybe draw more current but that's the only drawback.

    There are pumps intended for car windscreen washers that will do the job nicely and as you say there are modules to do anything you can imagine and some things you can't!
     
    potman100 likes this.
  7. Tonyr1084

    Active Member

    Sep 24, 2015
    535
    86
    I have some practical experience with polishing equipment. I worked as a "Micro-Section Technician" for several years. Everyone wanted to know how I polished my samples so highly. Of course I had access to thousands of dollars worth of equipment, but the simplest trick to my final polish was simple dish washing soap.

    Add a drop or two of dish washing soap to your rinse water AFTER you've completed the polishing phase. It'll make the surface a lot cleaner and smoother. The soap liberates the remaining polish from the pad and as that polish evacuates (heaviest particles first) the remaining finer grains do the rest.

    I polished a piece of "Nytronic 60" to a mirror finish just for fun. One of the other techs grabbed it and admired how well it was polished. So he rubbed it on his shirt to give it a finer polish. Stupid fool - he scratched the hell out of the surface. I had to go back two steps (diamond compound) to remove the damage he caused by his soft cotton shirt. Then my 0.05 gamma alumina polish. Under the microscope you could still detect scratches, but when I used the sample and some soap to clean the polishing pad the scratches were gone.
     
  8. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    Hi Tony,

    Thanks for the info, the VMI Hybrid I use at the moment just takes normal water for the final rinse, and whilst it does leave a very clean surface, to the human eye anyway, I would image if you looked at it under a microscope this would not be the case.

    The Hybrid pads suffer with polish build up over time and once it dries it causes scratching to the disk, it is recommended that you wash them under warn water each day, but the down side to this is it seems to cause the top layer of the pad to lift slightly, also causing minor swirl scratches on the disk. By adding the washing up liquid this would clean the pad and remove the unused polish on the pads.

    Just for you info these are the pads that are supplied in the consumables kit :

    http://totaldiscrepair.co.uk/wp-content/uploads/2014/12/vmi-hybrid-cons-new-800px.jpg

    I will give this a try.

    Regards

    Darren
     
    Last edited: Aug 6, 2016
  9. Tonyr1084

    Active Member

    Sep 24, 2015
    535
    86
    Expect to experiment with the amount of dish washing soap you add. Depending on your reservoir, the mix will vary. And the added benefit - you're not removing them and compromising them.
     
  10. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    They are removable, in the picture I linked above the bottle's are used as the reservoir.
     
  11. Tonyr1084

    Active Member

    Sep 24, 2015
    535
    86
    Your thread is on motors. I have a bunch of motors I've scrapped out of printers. You can get them for free on CraigsList. I get them on KSL.com (local news organization that runs a web site classified for buying and selling stuff. Free stuff too.)
     
  12. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    Nice, I will have a look.
     
  13. Tonyr1084

    Active Member

    Sep 24, 2015
    535
    86
    Seems to me the biggest motor I've found in desktop printers is the motor that drives the ink cartridge back and forth. Powerful and fast, and runs anywhere from 12 to 18 volts usually. IF I remember correctly.
     
  14. potman100

    Thread Starter New Member

    Aug 5, 2016
    7
    0
    I have an old printer, I'll whip the motor out and have a play with it.
     
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