Kira VTC 30 - Page 4


Page 4 of 7 FirstFirst 1234567 LastLast
Results 61 to 80 of 131

Thread: Kira VTC 30

  1. #61
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Not quite.
    Close. Ball bearing, not a bearing set.

    Sent from my SM-T813 using Tapatalk



  2. #62
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Oh lol. Then I understand



  3. #63
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    I opened up the end away from the servo motor today. I didn't have time to find a bearing ball to do as you described underthetire, but I did measure on the flange and had a look at the bearing on this end. It looks like it's floating because this bearing is a regular NTN 6004Z only secured with a clip. I will measure it properly with a ball later but it looks like it's moving a bit. The bearing was also wet with rust water on this end so this will be replaced as well. If I'm lucky I can get away without replacing the whole screw.

    Edit: and yes this part of the machine will get a proper cleanup now! It looks nasty





    Attached Thumbnails Attached Thumbnails Kira VTC 30-kira_christmas-3-jpg   Kira VTC 30-kira_christmas-4-jpg   Kira VTC 30-kira_christmas-9-jpg   Kira VTC 30-kira_christmas-10-jpg  

    Kira VTC 30-kira_christmas-11-jpg   Kira VTC 30-kira_christmas-16-jpg  


  4. #64
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    At least that bearing is cheap. The other side will cost a few bucks. Rusty water is never good leaking out a bearing!
    Btw, I usually buy all my thrust bearings from all world machinery in Illinois, much cheaper usually than typical bearing houses, and they stock almost all of them.

    Oh, and another tip, if I see lots of water like that, check the way cover seals, usually means they are leaking bad. In some cases I've packed the bearings with marine wheel bearing grease. Not the best for high accuracy, however sure beats having them fail quickly again. Some customers had no way covers left, and they would still last a year.


    Sent from my SM-T813 using Tapatalk



  5. #65
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Rust from that bearing was almost a relief tbh. I’d much rather replace that bearing and the thrust bearing than the ballscrew itself so I really hope it’s just the bearings. The ballscrew was looking good with a nice oil film on it and same with the linear rails so I hope they are ok. The price of a ballscrew of this dimension is about what a whole machine is worth in working condition from what I could find out online..

    I think I won’t be using flood coolant tbh and now I have opened the drains in the tray below there. It was accumulating water earlier since all drain holes where closed. The water level was below the ballscrew so that’s a good thing, I read a lot about flood coolant for hobby use and for my use I think a mist system will be better. Sometimes the machine will prolly sit for 1-2weeks without use and I can’t deal with replacing 50-100liters every couple of months either. It’s just to much hassle for my limited use. With a misting system I will have way less waste to take care off.



  6. #66
    Registered
    Join Date
    Dec 2011
    Location
    Canada
    Posts
    161
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Nice build thread!

    I strongly encourage you to use flood coolant, mine is in my dad's shop and sits there unused for a couple weeks (sometimes more) too.
    Put a small motor with a helix or a small water pump and a timer to keep the coolant moving frome time to time and you'll be fine. Worst thing is when the coolant forms a skin on the top of the tank, as long as it keeps moving everything's fine.

    Flood coolant and proper tooling are key for dealing with aluminum, POM and soft materials! I might be wrong, but if you live in the UK check out APT tools, very nice carbide endmills at a really good price!

    Happy holidays, Aleix.



  7. #67
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Great to hear second opinion about this. How often do you have to swap it out and what do you do with all the oil leaking into the coolant tank? I have room that is only 10m2 without ventilation so smelly coolant will be noticed easy..



  8. #68
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    I decided to take down the other side today and have a look at that bearing. It is no doubt that the sound is comming from this one when I tested with the covers off moving at rapid speeds. The bearing also looks horrible before disasembly. Lots of rust and debris on the outside.

    I started by removing the servo and feeling the play with my hands. It was huge. Prolly 1-2mm and I could clearly hear and feel the play by hand. It's even possible to see in this video I made of me testing it. This play didn't show since the servo is connected directly without anything taking up the play in this direction. No doubt that the bearings are worn/damaged.


    So started taking things apart. Lot's of rust. Managed to crack a umbraco hex while trying to take off the locknut :S Guess I will have to drill it out again but that problem is for later.. I can't see any way to preload the bearings either. It looks like the locknuts should be thightened so the inner races go against eachother and onto the ballscrew mating surface on the other side and the outer races are pressed together with the massive ring going on the outside of the bearing. I've asked Kira if they could help out with assembly instructions and I hope they can so I'm able to replace this in the correct order again.



    Inspection of the bearings show lots of rust deep in both the race and the balls. These are some of the worst I've seen. When ordering new bearings is there any reason to not choose the rubber sealed ones? This area has clearly been contaminated before and in both ends there are open bearings. I suspect that buying a pre greased sealed bearing for both ends would improve the wear resistance by a lot. I see that NSK has a sealed option for the TAC series bearings (tho 20TAC47B instead of 20TAC47A that I got but I can't figure out what that A/B is for other than "internal design").


    Attached Thumbnails Attached Thumbnails Kira VTC 30-img_0839-jpg   Kira VTC 30-img_0819-jpg   Kira VTC 30-img_0825-jpg   Kira VTC 30-img_0826-jpg  

    Kira VTC 30-img_0828-jpg   Kira VTC 30-img_0830-jpg   Kira VTC 30-img_0841-jpg   Kira VTC 30-img_0845-jpg  

    Last edited by m1n1m; 12-26-2017 at 02:35 AM.


  9. #69
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Good thing you took it apart, that much movement with the servo/coupling trying to hold it will destroy one of those expensive parts. Standard tac20 thrust bearings, so that's good. Should be just reverse for assembly. The bearings are ground for preload. The new universal grind bearings may take some fitting, as they tend to be about .0012" smaller in width. The end cap with the bolts may have to be modified for this. Not a big deal if you have access to a lathe. If you do need to make the "step" bigger, face both surfaces in the same setup so they remain parralel.

    Sent from my SM-T813 using Tapatalk



  10. #70
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Both surfaces? The big surface and the clamping surface for the bearing? Should there be a gap when it’s clamped down like they specify on some machines to ensure it’s clamping it down? I found the bearings online but my local suppliers said it was special parts and that I had to go to machine supplier. I think I will go with sealed bearings now also to be 100% sure it won’t fail quick again due to debris.

    edit: I measured roughly with a caliper now and the pocket is 33mm deep and the flange has 3.5mm recess to push the bearing surface. That should leave 29.5mm space and the bearings is 2x15mm so it should in theory leave 0.5mm gap once snug, I will however take out the bearing holder and wash it in my ultrasonic washer and measure again once it is cleaner. I started cleaning out the mess yesterday but there is so much that I have to use a couple of hours today also.

    Last edited by m1n1m; 12-27-2017 at 06:46 AM.


  11. #71
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    .5mm would be fine.
    If you find sealed thrust bearings, please post a pic!

    You can find tac 20 bearings on eBay pretty cheap.

    Sent from my SM-T813 using Tapatalk



  12. #72
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Quote Originally Posted by underthetire View Post
    .5mm would be fine.
    If you find sealed thrust bearings, please post a pic!

    You can find tac 20 bearings on eBay pretty cheap.

    Sent from my SM-T813 using Tapatalk
    must have read wrong earlier. It was 0.05mm :X time will tell but it should be enough as long as there is no backlash measured I suppose.

    I think all thrust bearings from NSK can be ordered with that. The code for sealed lowcfriction is “DDG” after the bearing dimmensions in NSK numbers. Will post pics when I get mine. Here is the eBay link. There is a 6900rpm limit from what I can tell but should be well within that as 20m/min rapid is approx 1667rpm on a 25x12 ballscrew if I calced correctly. For the other end I’m thinking stainless/ceramic sealed to be safe from rust.

    https://m.ebay.com/itm/NSK-20TAC47BD...wAAOSwtVxaK1NZ



  13. #73
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Interesting, I've probably done at least 100 sets of thrust bearings, and don't recall ever seeing a sealed thrust bearing from the factory. The other end use whatever, it doesn't do anything but keep the end of the ballscrew from whipping. Some lower end machines don't even have a bearing on that end.

    Sent from my SM-T813 using Tapatalk



  14. #74
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Oh, and a little trick on the gap, sometimes it's really hard to put a feeler gauge in to check for an air gap on the cap on small machines. I cut strips of paper and bolt the flange on. If the paper pulls out without ripping, you have a gap. Also seen plasti-gauge used on hard to measure machines.

    Sent from my SM-T813 using Tapatalk



  15. #75
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    There is more info on the page linked below. I just found it by accident when reading about different NSK bearings that I could fit and figured why not try sealed. The only downside I see is if moisture get's trapped behind the seal but if it come past the seal in the first place it would have washed away the grease in the open bearings and ruined them also. I'm giving it a go atleast.

    NSK - Angular Contact Thrust Ball Bearings - Sealed ACTBB for Ball Screw Support


    Yesterday I started cleaning the tray and surroundings. I found a total of 9 drain holes and all where clogged even if I opened one of them a few weeks ago. The whole bottom was filled with oil/coolant/metal pieces so I had to dig it out. Nasty job but nobody else was going to do it :P I'm not done yet but the worst is removed. I'm using brake cleaner and a towel for now. Respraying everything with preservation oil just while I'm working on it so things don't rust until I get the lube system and axis running again. Will clean the rest in a few days as it's damn boring and time consuming so I have to spread it out :P This job took 3-4 hours before it looked like the picture to the right.


    The bearing holder for the ballscrew was full of oil/coolant and some corrosion on the surface that prolly have been on for way to long. There was corrosion in it but not a huge amount so maybe it was set in with oil or something at assembly. Now after I've set it in with 20% Phosphoric acid (ferrobet rust remover) solvent it has become almost grey of color but it was "shiny" inbetween all the rust before. I tried washing them some more in the ultrasonic cleaner but I couldn't get the grey color away. Now I've placed the parts in a bath of 7% vinegar for some hours but that color does not wash away. Instead rust is showing in the surface on the parts that isn't below the vinegar. Am I doing this completly wrong? Have I removed some sort of rust protection by my stupid choice of cleaning?


    Attached Thumbnails Attached Thumbnails Kira VTC 30-img_0851-jpg   Kira VTC 30-img_0856-jpg   Kira VTC 30-img_0860-jpg   Kira VTC 30-img_0863-jpg  

    Kira VTC 30-img_0865-jpg   Kira VTC 30-img_0869-jpg  


  16. #76
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Don't need to be pretty, just clean. I usually just wire wheel then hit them with a stone to remove high spots. I've seen worse, trust me.

    Sent from my SM-T813 using Tapatalk



  17. #77
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    As promised underthetire here is a picture of the sealed angular contact bearings I bought for the X axis. They finally arrived today after using 2.5 week from USA to Norway.



    So I didn't have the proper tool for the nut on the ballscrew and since my cnc was out of service I had to do some manual work. It was quick and dirty but it worked perfectly. It was the previous owner and my sins showing on the nut. I know I should not have done that but it was really stuck so I had to help it with gentle knocks :X. I measured the ballscrew with a dial gauge as I thightened up the nut and the bearing holder and rotated the ballscrew as I snugged it up. The dial gauge showed good numbers so I was a happy mechanic


    Since I cleaned up the ballscrew I noticed that it had some coloring on the center part of it. Most likely this is where the bearing has been sitting on the screw while the machine was out of service for 4-5 years. Does it matter? It doesn't come off with gentle rubbing with a paper towel so I figured it was best to not go to hard at it.


    When everything was back on I set the backlash comp to zero on both X and Y axis and tested. I found 0.04 to 0.05mm backlash on one spot on the X axis and if I set 45 (0.001mm pr unit) in backlash comp it was spot on after in that area. If I moved it some it could be 0.02-0.03 off again (to much) so I reduced backlash comp to 30 to find a middle ground. I guess the screw has some wear and it's not unexpected for a machine from 1991. The Y axis has the same thing really. It had 0.05 and when I set 50 backlash comp it was good in that area. Both axis are now showing no movement when I push the table by hand and I guess that's a good thing at least even if the screws most likely has some wear.

    Then it's video time again. I tested rapid 50% and rapid 100% on X/Y axis. Before I thought Y axis had normal sound during rapid but now it's noisy as f... compared the the X axis. I guess this also shows sign of a broken thrust bearing?


    Attached Thumbnails Attached Thumbnails Kira VTC 30-img_1015-jpg   Kira VTC 30-img_1016-jpg   Kira VTC 30-img_1017-jpg   Kira VTC 30-img_1019-jpg  

    Kira VTC 30-img_1029-jpg   Kira VTC 30-img_1022-jpg  


  18. #78
    Member
    Join Date
    Feb 2009
    Location
    usa
    Posts
    6028
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Love it when a plan comes together!
    Dont feel bad about the nut. A brass drift is commonly used for that. Even my Mori Seiki tech bullitens show a hammer and drift. Its concidered a wear item.

    Sent from my SM-T813 using Tapatalk



  19. #79
    Member
    Join Date
    Feb 2012
    Location
    United States
    Posts
    41
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Quote Originally Posted by m1n1m View Post
    As promised underthetire here is a picture of the sealed angular contact bearings I bought for the X axis. They finally arrived today after using 2.5 week from USA to Norway.



    So I didn't have the proper tool for the nut on the ballscrew and since my cnc was out of service I had to do some manual work. It was quick and dirty but it worked perfectly. It was the previous owner and my sins showing on the nut. I know I should not have done that but it was really stuck so I had to help it with gentle knocks :X. I measured the ballscrew with a dial gauge as I thightened up the nut and the bearing holder and rotated the ballscrew as I snugged it up. The dial gauge showed good numbers so I was a happy mechanic


    Since I cleaned up the ballscrew I noticed that it had some coloring on the center part of it. Most likely this is where the bearing has been sitting on the screw while the machine was out of service for 4-5 years. Does it matter? It doesn't come off with gentle rubbing with a paper towel so I figured it was best to not go to hard at it.


    When everything was back on I set the backlash comp to zero on both X and Y axis and tested. I found 0.04 to 0.05mm backlash on one spot on the X axis and if I set 45 (0.001mm pr unit) in backlash comp it was spot on after in that area. If I moved it some it could be 0.02-0.03 off again (to much) so I reduced backlash comp to 30 to find a middle ground. I guess the screw has some wear and it's not unexpected for a machine from 1991. The Y axis has the same thing really. It had 0.05 and when I set 50 backlash comp it was good in that area. Both axis are now showing no movement when I push the table by hand and I guess that's a good thing at least even if the screws most likely has some wear.

    Then it's video time again. I tested rapid 50% and rapid 100% on X/Y axis. Before I thought Y axis had normal sound during rapid but now it's noisy as f... compared the the X axis. I guess this also shows sign of a broken thrust bearing?
    Looks like everything is coming together. Good luck.

    Sent from my SM-T550 using Tapatalk



  20. #80
    Member
    Join Date
    Oct 2015
    Posts
    215
    Downloads
    0
    Uploads
    0

    Default Re: Kira VTC 30

    Thanks guys

    Today it was the boring cleaning day. To bad I forgot to take pictures before I cleaned the covers. They where NASTY and full of old way lube and chips. Some rust has also apeared in the surface and especially inside it. I washed them whith degreaser and water, dried them and put them infront of my 1000w heater fan in the cnc room so it could dry until tomorrow. Should I lube the covers with anything to prevent corrosion and make them glide better? I used layup oil on top of it now that the machine has been out of service but that made chips stick to it and not fall off like it would if it was dry.


    That way cover rubber looked like an easy replacement. Is that some generic size that I can find online? Tried looking on ebay and various cnc shops but I couldn't find anything but those that ran a service repairing the covers if I sent them in. Just thought that I could order some rubber, cut/drill it to fit and replace it myself. I've sent Dynatect a request as it looked like they could supply all the types out there but I didn't find this exact model in their parts list.


    Attached Thumbnails Attached Thumbnails Kira VTC 30-img_1035-jpg   Kira VTC 30-img_1038-jpg   Kira VTC 30-img_1039-jpg   Kira VTC 30-img_1042-jpg  

    Kira VTC 30-img_1043-jpg   Kira VTC 30-img_1040-jpg  


Page 4 of 7 FirstFirst 1234567 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

Kira VTC 30

Kira VTC 30