imperfect circles - Page 2


Page 2 of 6 FirstFirst 12345 ... LastLast
Results 21 to 40 of 118

Thread: imperfect circles

  1. #21
    Member coherent's Avatar
    Join Date
    Apr 2003
    Location
    Arizona, USA
    Posts
    540
    Downloads
    2
    Uploads
    0

    Default Re: imperfect circles

    Quote Originally Posted by ericclinedinst View Post

    Part of the issue is that the htd belts don't fully full the gt profile. Causing backlash each time there's a direction change.
    If that's the case then even having a HTD on one side of the X and a correct GT belt on the other could possibly cause issues? Don't know if it would be enough to cause racking/binding, but the room for error that could I'd imagine is very small considering the minimal tolerance of the rails/bearings



  2. #22
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by coherent View Post
    If that's the case then even having a HTD on one side of the X and a correct GT belt on the other could possibly cause issues? Don't know if it would be enough to cause racking/binding, but the room for error that could I'd imagine is very small considering the minimal tolerance of the rails/bearings
    Unmatched belts isn't an issue. I have all htd at the moment. Tuesday will be all GT.



  3. #23

    Default Re: imperfect circles

    Sorry I didn't reply sooner. I had to get some information from my engineers and run some tests.

    Regarding the drive design:
    • The drives are the same as what's in the other machines that we've sent out. The design has been tested at our facility for many hours with a dozen drive units and the backlash remained at a minimum under 0.005in. We also have over 100 drives in the field and haven't had a backlash issue with any of them except this set.
    • The original tolerances for some of the bearing pockets were specified 0.001-0.002in larger than they should have been for a press fit. As a result, some of the bearings ended up being a tight slip fit instead of a press fit. We determined 0.001-0.002in wouldn't have an impact in the drive operation. We tightened up the tolerances by 0.002" on the latest versions for a good press fit. Keith, are you saying that your bearing pockets had several thousandths of play in them?
    • I am curious about the spindle. We press the spindle and timing hub together and they shouldn't have pulled apart like that. Did you press it out?
    • The belt and hubs are matched for HTD.
    • HTD belts, hubs, and spindles were chosen after consideration of several factors. In addition, we did testing in house of several different belt profiles include GT2. We did not see a noticeable increase in backlash on the system in the HTD belts over the GT2 style belts during our testing.


    That said, we are going to be re-looking at the drives and making sure we get it right. We plan on testing some GT2 belts and hubs and re-testing for backlash. We also plan on looking at the whole design and figuring out where we can do better. Keith, I will contact you via email and get this resolved. I will post the results of the testing and any changes here.

    Fine Line Automation
    www.finelineautomation.com


  4. #24
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default Re: imperfect circles

    The drives are the same as what's in the other machines that we've sent out. The design has been tested at our facility for many hours with a dozen drive units and the backlash remained at a minimum under 0.005in. We also have over 100 drives in the field and haven't had a backlash issue with any of them except this set. - I dont doubt that. My problem is I didnt pay for your other customers machines. I paid for mine. Lets not focus on what you have done for others and instead focus on how to make mine right?


    The original tolerances for some of the bearing pockets were specified 0.001-0.002in larger than they should have been for a press fit. As a result, some of the bearings ended up being a tight slip fit instead of a press fit. We determined 0.001-0.002in wouldn't have an impact in the drive operation. We tightened up the tolerances by 0.002" on the latest versions for a good press fit. Keith, are you saying that your bearing pockets had several thousandths of play in them? -
    No. the bearings themselves have play in them.


    I am curious about the spindle. We press the spindle and timing hub together and they shouldn't have pulled apart like that. Did you press it out? - With my thumb.


    The belt and hubs are matched for HTD.
    HTD belts, hubs, and spindles were chosen after consideration of several factors. In addition, we did testing in house of several different belt profiles include GT2. We did not see a noticeable increase in backlash on the system in the HTD belts over the GT2 style belts during our testing. - this is simply if GT2 belts are better, then why not use them?



  5. #25
    Member
    Join Date
    Nov 2012
    Location
    usa
    Posts
    108
    Downloads
    0
    Uploads
    0

    Default Re: imperfect circles

    My $.02 regarding the rack and pinion assembly:

    --The eccentric function in my opinion just adds complexity and moving parts. The whole system could be made tighter and cheaper with just a pivot point and no eccentric feature.

    --The amount of engagement of the pinion to rack could be almost doubled which would give longer life to the aluminum pinion. I wonder if putting the racks on a 1/4" stand off would be a good idea?

    Ward

    This being said, I'm super happy with my Saturn and I'm making good parts.



  6. #26
    Community Moderator difalkner's Avatar
    Join Date
    Nov 2014
    Location
    United States
    Posts
    729
    Downloads
    0
    Uploads
    0

    Default Re: imperfect circles

    I would certainly love to see greater pinion contact and spacing out the rack wouldn't bother me at all, assuming I'm not giving up any rigidity. Just putting a 1/8" flat washer between the rack and frame is something I've thought about doing, may still do that but I'd want to make sure they were all the exact same thickness. I'd have to check the bolt length but there's probably enough thread to do 1/8" without any problem. Putting a full length strip between the rack and frame would be better but I don't have access to a surface grinder to ensure the strip is a constant thickness.

    David
    Romans 3:23
    CurlyWoodShop - www.etsy.com/shop/CurlyWoodShop
    David Falkner - www.youtube.com/user/difalkner
    difalkner - www.instagram.com/difalkner


  7. #27
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by difalkner View Post
    I would certainly love to see greater pinion contact and spacing out the rack wouldn't bother me at all, assuming I'm not giving up any rigidity. Just putting a 1/8" flat washer between the rack and frame is something I've thought about doing, may still do that but I'd want to make sure they were all the exact same thickness. I'd have to check the bolt length but there's probably enough thread to do 1/8" without any problem. Putting a full length strip between the rack and frame would be better but I don't have access to a surface grinder to ensure the strip is a constant thickness.
    Aircraft aluminum sheet is consistently thick. My only
    Concern would be dissimilar metals corrosion.



  8. #28
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by sybilsurf View Post
    My $.02 regarding the rack and pinion assembly:

    --The eccentric function in my opinion just adds complexity and moving parts. The whole system could be made tighter and cheaper with just a pivot point and no eccentric feature.

    --The amount of engagement of the pinion to rack could be almost doubled which would give longer life to the aluminum pinion. I wonder if putting the racks on a 1/4" stand off would be a good idea?

    Ward

    This being said, I'm super happy with my Saturn and I'm making good parts.
    I'm happy with the Saturn, as well. It's an awesome machine. The rails are smooth, the gantry is solid. I just need this backlash issue resolved post haste. I have customers that I don't don't want to lose. Luckily for me, their orders aren't needed in a rush, so I have time, though with every passing day, I have less and less. I guess the main issue for me is the lack of urgency I am experiencing with getting this resolved in a timely manner.



  9. #29
    Community Moderator difalkner's Avatar
    Join Date
    Nov 2014
    Location
    United States
    Posts
    729
    Downloads
    0
    Uploads
    0

    Default Re: imperfect circles

    Quote Originally Posted by kebuttke View Post
    Aircraft aluminum sheet is consistently thick. My only
    Concern would be dissimilar metals corrosion.
    After I posted that I found a piece of 1" wide 0.125" thick aluminum from Lowe's and measured it in several places. It is very consistent in thickness so I may pick up 3 pieces, they're only 36" long, and go ahead and space the Y-axis racks out. I'm not too concerned about any corrosion. One side is against the powder coated frame and the other against the rack but the bigger thing is our shop is climate controlled and in all the years I've never seen a piece of anything corrode in here.

    David
    Romans 3:23
    CurlyWoodShop - www.etsy.com/shop/CurlyWoodShop
    David Falkner - www.youtube.com/user/difalkner
    difalkner - www.instagram.com/difalkner


  10. #30

    Default Re: imperfect circles

    Thanks for the suggestions. Keep them coming.

    Ward, on the latest version of the rack and pinion we removed the eccentric bearing and replaced it with a double bearing setup and a shaft collar. This setup still allows the collar to remove axial play while providing more contact area between the bearing and the shaft.

    We are will definitely look into moving the rack out further with a shim. I am also looking at a few solutions for the pinion engagement.

    Fine Line Automation
    www.finelineautomation.com


  11. #31
    Member
    Join Date
    Mar 2012
    Location
    USA
    Posts
    103
    Downloads
    0
    Uploads
    0

    Default Re: imperfect circles

    Quote Originally Posted by FineLineAuto View Post
    Thanks for the suggestions. Keep them coming.

    Ward, on the latest version of the rack and pinion we removed the eccentric bearing and replaced it with a double bearing setup and a shaft collar. This setup still allows the collar to remove axial play while providing more contact area between the bearing and the shaft.

    We are will definitely look into moving the rack out further with a shim. I am also looking at a few solutions for the pinion engagement.
    Nate,

    Are these modifications being made available to machines already purchased at no charge?



  12. #32
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default Re: imperfect circles

    So i got the CNCRP drives in and on tonight. the backlash is down to .005 in the X. I am certain i can reduce it another .001 or so. I have yet to verify Y, but will do that tomorrow. from what i have seen, and my coworker, another A&P with years of experience, has seen of the comparison between what i had and what i now have, something is wrong with the drives i recieved with my machine. also, the proof is in the pudding as far as the eccentric bushings go. they work. they are smooth and didnt need improvement. I am still happy with the machine. However, at this time, with the drives i recieved as they were, i cannot recommend nates drives to run the saturn. there is too much work that needs to be done to them yet. i hope he can get it figured out and make a quality drive setup of his own design. or, sell a proven design. people WILL buy quality.



  13. #33

    Default Re: imperfect circles

    Quote Originally Posted by beltramidave View Post
    Nate,

    Are these modifications being made available to machines already purchased at no charge?
    Short answer is yes.

    Quote Originally Posted by kebuttke View Post
    So i got the CNCRP drives in and on tonight. the backlash is down to .005 in the X. I am certain i can reduce it another .001 or so. I have yet to verify Y, but will do that tomorrow. from what i have seen, and my coworker, another A&P with years of experience, has seen of the comparison between what i had and what i now have, something is wrong with the drives i recieved with my machine. also, the proof is in the pudding as far as the eccentric bushings go. they work. they are smooth and didnt need improvement. I am still happy with the machine. However, at this time, with the drives i recieved as they were, i cannot recommend nates drives to run the saturn. there is too much work that needs to be done to them yet. i hope he can get it figured out and make a quality drive setup of his own design. or, sell a proven design. people WILL buy quality.
    Keith, we'll get it fixed. Going through some testing right now. It's going to take about a week or 2 but we'll be sure to get it right. I'll contact you via email to work out the drive return.

    Fine Line Automation
    www.finelineautomation.com


  14. #34
    Member
    Join Date
    Jun 2010
    Location
    Australia
    Posts
    4252
    Downloads
    4
    Uploads
    0

    Default Re: imperfect circles

    I have not seen that sort of circle before. Most curious.
    At a guess, I would say you have both backlash in the drive AND flex in the system.
    Fixing that ... hum.
    Cheers
    Roger



  15. #35
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by RCaffin View Post
    I have not seen that sort of circle before. Most curious.
    At a guess, I would say you have both backlash in the drive AND flex in the system.
    Fixing that ... hum.
    Cheers
    Roger
    No flex. Just backlash. It's fixed.



  16. #36
    Registered
    Join Date
    May 2012
    Location
    USA
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by RCaffin View Post
    I have not seen that sort of circle before. Most curious.
    At a guess, I would say you have both backlash in the drive AND flex in the system.
    Fixing that ... hum.
    Cheers
    Roger

    Getting rid of the atrociously poorly toleranced fineline automation pinion drives in favor of the real deal cncrouterparts ones fixed the issue! Like the saying goes "Don't be fooled by cheap imitations."



  17. #37
    Member coherent's Avatar
    Join Date
    Apr 2003
    Location
    Arizona, USA
    Posts
    540
    Downloads
    2
    Uploads
    0

    Default Re: imperfect circles

    Quote Originally Posted by beltramidave View Post
    Nate,

    Are these modifications being made available to machines already purchased at no charge?
    Quote Originally Posted by FineLineAuto View Post
    Short answer is yes.

    Keith, we'll get it fixed. Going through some testing right now. It's going to take about a week or 2 but we'll be sure to get it right. I'll contact you via email to work out the drive return.
    This is good to hear. In addition to the backlash issue, I (like David mentioned) was also considering spacers behind the rack or other options to increase pinion contact. I'm hoping the drive fix increases pinion contact so spacers aren't necessary.

    I'm assuming you (Nate) will contact those buyers affected and make arrangements to send them new pinion drives once the fixes are made and return the ones that came on the machine?
    Other than a few minor issues, overall I'm happy with the machine also. It's not completed yet so my testing to date is limited, but I'm close to getting it finished and it's use will be daily parts production so glad that what I am hearing is that I bought it from a company that stands behind it's product and fixes issues or parts that are sub standard.

    kebuttke: Did the CNCRP drives change the pinion contact?

    Thanks
    Marc

    Last edited by coherent; 03-01-2017 at 01:56 PM.


  18. #38
    Registered
    Join Date
    Dec 2016
    Location
    United States
    Posts
    49
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by coherent View Post
    This is good to hear. In addition to the backlash issue, I (like David mentioned) was also considering spacers behind the rack or other options to increase pinion contact. I'm hoping the drive fix increases pinion contact so spacers aren't necessary.

    I'm assuming you (Nate) will contact those buyers affected and make arrangements to send them new pinion drives once the fixes are made and return the ones that came on the machine?
    Other than a few minor issues, overall I'm happy with the machine also. It's not completed yet so my testing to date is limited, but I'm close to getting it finished and it's use will be daily parts production so glad that what I am hearing is that I bought it from a company that stands behind it's product and fixes issues or parts that are sub standard.

    kebuttke: Did the CNCRP drives changes the pinion contact?

    Thanks
    Marc
    Yes. I will take some picture as a comparison when I get home, but there isn't the off kilter wear on the pinion like there was before. Removing the axial play using the drives with bushings made for almost zero play in either the pivot or the pinion.



  19. #39

    Default Re: imperfect circles

    Quote Originally Posted by coherent View Post
    This is good to hear. In addition to the backlash issue, I (like David mentioned) was also considering spacers behind the rack or other options to increase pinion contact. I'm hoping the drive fix increases pinion contact so spacers aren't necessary.

    I'm assuming you (Nate) will contact those buyers affected and make arrangements to send them new pinion drives once the fixes are made and return the ones that came on the machine?
    Other than a few minor issues, overall I'm happy with the machine also. It's not completed yet so my testing to date is limited, but I'm close to getting it finished and it's use will be daily parts production so glad that what I am hearing is that I bought it from a company that stands behind it's product and fixes issues or parts that are sub standard.

    kebuttke: Did the CNCRP drives change the pinion contact?

    Thanks
    Marc
    Marc,

    Yes, I'll be contacting everyone once we finish the fixes and do the testing.

    Regards,

    Nate

    Fine Line Automation
    www.finelineautomation.com


  20. #40
    Registered
    Join Date
    May 2012
    Location
    USA
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by kebuttke View Post
    Yes. I will take some picture as a comparison when I get home, but there isn't the off kilter wear on the pinion like there was before. Removing the axial play using the drives with bushings made for almost zero play in either the pivot or the pinion.

    Should we start a pool to see how long it's going to take Nate to refund Keith's money and another one to see how long it'll take to get these bad drives recalled and replaced? Oh. And those rack spacers?



Page 2 of 6 FirstFirst 12345 ... LastLast

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

imperfect circles

imperfect circles