Home Made 4th Axis with Harmonic Drive Unit! - Page 3


Page 3 of 3 FirstFirst 123
Results 25 to 36 of 36

Thread: Home Made 4th Axis with Harmonic Drive Unit!

  1. #25
    Gold Member
    Join Date
    May 2005
    Location
    USA
    Posts
    3262
    Downloads
    0
    Uploads
    0

    Default

    Hi WidgetMaster;

    Thanks for the inspiration. I'm a working stiff at the moment and often take inspiration from your posts even if finding the time to work on some projects is a bit stressed.

    I will keep this thread in mind (hopefullly as I'm past 40) when out and about looking for deals for parts and such.

    The only thing I see missing is the ability to clamp the fixture plate to the housing. Was this avoided for a reason or do you think it is a bad idea overall?



    Dave



  2. #26
    Registered leberen's Avatar
    Join Date
    May 2006
    Location
    USA
    Posts
    106
    Downloads
    0
    Uploads
    0

    Default

    Simply amazing,

    the scale of your a axis (4th) is amazing, very nice work for that HUGE motor. My Maxnc 4th axis is 50% complete, your instructions have shown me that it can become complete soon! Thankyou for your writeup.



  3. #27
    Registered
    Join Date
    May 2003
    Location
    USA
    Posts
    550
    Downloads
    0
    Uploads
    0

    Default

    Nice work Widgetmaster.. an appropriate name there..

    Is there a bearing between the harmonic drive and the work holder or is the drive bearing holding all together?

    Also would you think an iron angle plate would work as the basis fo rthe support base?

    nice job..



  4. #28
    Gold Member widgitmaster's Avatar
    Join Date
    Jun 2005
    Location
    USA
    Posts
    3344
    Downloads
    0
    Uploads
    0

    Cool

    Quote Originally Posted by fyffe555
    Nice work Widgetmaster.. an appropriate name there..

    Is there a bearing between the harmonic drive and the work holder or is the drive bearing holding all together?

    Also would you think an iron angle plate would work as the basis fo rthe support base?

    nice job..

    Thanks!

    This particular Harmonic Drive had a massive hub on the end, so I used it to support the faceplate!

    An iron angle will work, its just easier to make things out of aluminum! Steel is tough and wears out my cutters!!

    Thanks again
    Eric



  5. #29
    Registered
    Join Date
    May 2005
    Location
    USA
    Posts
    219
    Downloads
    0
    Uploads
    0

    Default rotary axis mounted

    Hi! It's been almost a year but I finally installed the harmonic drive 4th axis that Widitmaster made. It fits perfectly on the tooling plate that I got off of ebay. I still have to figure out how to connect up the 5-phase stepper motor with the 5-phase driver. I guess I could always just replace the stepper motor with a regular one. Then I'll have to figure out what to make with the 4th axis and how to generate the g-code.

    Attached Thumbnails Attached Thumbnails Home Made 4th Axis with Harmonic Drive Unit!-img_0469-jpg  


  6. #30
    Registered
    Join Date
    Jun 2005
    Location
    USA
    Posts
    233
    Downloads
    0
    Uploads
    0

    Default

    It's just a thought, but...

    As someone who doesn't have enough hands-on experience, it would be interesting to know if there is any measurable taper to the "L" sides. The outside edges should be dead square, but I wonder if the inside might be a bit tapered caused by bit deflection, or the large bit you used was strong enough not to deflect in a measurable way.

    If you wanted an additional bit of angular accuracy, could you not take one minute fly cutter pass on the inside of the "L" bracket, only where the motor flange makes contact? It wouldn't be without risk, because the fly cutter might want to whack or nick the nice radius you made, so the fly cutter would need to be tested to see if it swings into anything.

    It looks good, congratulation.



  7. #31
    Registered
    Join Date
    Jan 2007
    Location
    USA
    Posts
    634
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by juzwuz View Post
    I guess I could always just replace the stepper motor with a regular one.
    I would strongly recommend against that as it will probably destroy the unit instantly. There are gearheads that are built as separate units from the motor, but as far as I know, from what the factory rep has told me anyway, that the 5-phase steppers are built onto them as a unit and because of the way they are assembled attempting to separate them can ruin them instantly or at best throw off the alignment, which is EXTREMELY critical. People apparently send units back to the factory asking for for re-alignment, but it is usually cheaper to just buy new units if that has happened - so they can be trashed real fast pulling them apart.



  8. #32
    Registered
    Join Date
    May 2010
    Location
    Australia
    Posts
    90
    Downloads
    0
    Uploads
    0

    Default Re: Home Made 4th Axis with Harmonic Drive Unit!

    Seems like making it properly also means it's going to cost a fair amount. In fact it looks like the Chinese 4th axis knock off are going for a similar price to just the Harmonic gear itself in this build.

    The question is, would it be worth spending a bit extra and getting everything done properly or is the Chinese unit good enough? This is obviously in the metal section so perhaps the Chinese isn't even in the same league as this home brew but just wondering about others' opinions.

    I think for me at the moment, I can probably get away with just working with aluminium at the most so I don't need a fully fledged metalworking monster.



  9. #33
    Registered D.L's Avatar
    Join Date
    Jan 2009
    Location
    Australia
    Posts
    265
    Downloads
    1
    Uploads
    0

    Default Re: Home Made 4th Axis with Harmonic Drive Unit!

    Don't change the motor, I understand the 5 wire to be the same as 6 wire with a shared centre tap for two of the inputs.
    It should be reconfigurable to use it as 4 wire, just as a 6 wire can be used as a 4 wire by ignoring 2 of the inputs which removes the centre taps and connects the coils in series.
    Surely this has been discussed elsewhere in the past 20 years in cnczone?

    General engineering and sub contract work in Victoria, Australia.


  10. #34
    Registered
    Join Date
    Dec 2015
    Posts
    117
    Downloads
    0
    Uploads
    0

    Default Re: Home Made 4th Axis with Harmonic Drive Unit!

    First off, this thread is more than a decade old. So why resurrect this sucker and not start a new one?

    Second off, you get what you pay for. There are genuine Harmonic Drive servo mount gear heads (planetary drives not harmonic) that have less than 3 arc minutes of backlash are available used on eBay for less than $200. I bought one and it's like new, not a mark on it. and I paid $195 shipped. 3 arc minutes at a 4 inch radius represents around .0035" of backlash. Maybe I got lucky with my unit (i've only ever owned one so I don't know) but I can only measure around .0015" of backlash at 4" radius, which is around 1.5 arc minutes. That's less backlash than both my X and Z axis, which both have around .002". So if I am to complain about backlash I would probably start there first.

    The HD gearhead is 33:1 ratio and good for 70 nm of torque. The stepper I am using is good for around 6nm at 6amps. I am running it lower than that though, only 3.5 amps. Given this, it would require around 150lbs of force to turn the axis at the maximum 4 inch radius and more than that the closer to the axial center. Once I max out the amperage that number will increase significantly.

    GIven all of that, I built a trunnion table (18" bed) using the parts outlined above as well as a host of other materials and bits for around $550. Yes there was machine time that I'm not counting, but it's a far superior table (or will be once's it's all squared up) than any of the Chinese units



  11. #35
    Registered
    Join Date
    Sep 2005
    Location
    Indonesia
    Posts
    944
    Downloads
    0
    Uploads
    0

    Default Re: Home Made 4th Axis with Harmonic Drive Unit!

    Do you guys know or have some experiences where to buy Chinese's harmonic drive ? Maybe a lot cheaper. Which product do you recommend? I saw on ebay there are lot of HD model or type.



  12. #36
    Registered
    Join Date
    Sep 2005
    Location
    Indonesia
    Posts
    944
    Downloads
    0
    Uploads
    0

    Default Re: Home Made 4th Axis with Harmonic Drive Unit!

    I found the one like on the link below, I did not see the one like yours, easy to install.

    https://www.aliexpress.com/store/gro...4b24ae2bXNuUof



Page 3 of 3 FirstFirst 123

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Home Made 4th Axis with Harmonic Drive Unit!
Home Made 4th Axis with Harmonic Drive Unit!