New Machine Build AMAT25LV Basically another PM25 clone :)


Results 1 to 8 of 8

Thread: AMAT25LV Basically another PM25 clone :)

  1. #1
    Member
    Join Date
    Jan 2018
    Location
    United Kingdom
    Posts
    197
    Downloads
    0
    Uploads
    0

    Default AMAT25LV Basically another PM25 clone :)

    Finally made a start.
    Enclosure built except for the doors.
    PC, control box, steppers all tested.
    Machine is torn down ready for parts to be made on the X2.
    Going with double nut 1605 all round using AC bearings X,Y and thrust on Z.
    Could prob do with a 2005 on the Z tbf.

    I've been working on the oil system first while it's in bits. Took out the ball oilers and have threaded their holes to M8x1.0. Have some 4mm push-fit swivel elbows for those and some smaller thread size ones the same for the screws.
    Think I'll have to do the Y axis motion before I fit any tubing etc so I don't damage any fittings while the saddle is being tossed around.

    The stock design on the Y axis is crap. Table nowhere near centred and it's nut position means it can't go all the way back to the column. To get truly more than 165mm it needs a head spacer and then the table hanging off the front at least 50mm.
    Not a fan of that.

    The way I'm planning to go about things is to clean up the underside of the saddle and fit the nut further forwards.
    Z bellows are being removed and replaced with the roller cover mod attached to the head and the saddle so it moves with both.
    When this is all complete the saddle will go all the way back thus achieving a true 185mm with an overhang on the dovetails around 30mm in either direction.

    I'll get there eventually and I'll put a pic or 2 up soon.
    Enclosure doors will be the last job.

    Starting off basic.Steppers running off 36v & 60v.
    Using 1600oz/in Z and 425oz/in on the X,Y with Mach3 controlling.

    Similar Threads:


  2. #2
    Member
    Join Date
    Jan 2018
    Location
    United Kingdom
    Posts
    197
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    It's very slow going.
    Nearly there with the Z Had a complete change due to the crap ballnut.
    My Z nut mount is made of 2 parts bolted together on top of each other. 2 single ballnuts are bolted either end. Tin foil is used as a spacer between the 2 nut mounts to spread the ballnuts to eliminate lash. It's a ballache of a design but looks like it will work.
    A couple of niggles need changing before I put a motor on.

    Almost done with the Y. I've opted to ditch the 425's and get some 1100oz instead.
    Reason being is I've put tin foil between the spacer and sleeve on the double nuts to spread them and minimise backlash. It's a little bit tight but spins and getting the AC bearings right is hit and miss.

    I just managed to get a test done on the Y axis and got a 0.025mm baclash reading (0.00098") I think that'll do.
    I really don't want to use the compensation in Mach if I can help it.
    Rapid moves had a stall at 2500mm/min so I'll leave it at 2000mm.
    It's pretty tight where bearings/nuts are concerned so It'll either go well or eat itself!!

    Been let down on material atm so I can't start on my X yet




  3. #3
    Member
    Join Date
    Mar 2017
    Posts
    18
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    That sure looks like a PM25 to me!

    To me, it seems like something is off if you need 1200 oz in motors on the X and Y and are only getting 100 IPM (2500mm as you noted). On my PM25, I have double nut ballscrews and I was using 400 oz in steppers and got more than double that speed easy. It also seems off if you are getting under .001" of backlash which means sticktion isn't really causing trouble.

    I would love to see some pictures if you have them!



  4. #4
    Member
    Join Date
    Jan 2018
    Location
    United Kingdom
    Posts
    197
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    Quote Originally Posted by shooter123456 View Post
    That sure looks like a PM25 to me!

    To me, it seems like something is off if you need 1200 oz in motors on the X and Y and are only getting 100 IPM (2500mm as you noted). On my PM25, I have double nut ballscrews and I was using 400 oz in steppers and got more than double that speed easy. It also seems off if you are getting under .001" of backlash which means sticktion isn't really causing trouble.
    I would love to see some pictures if you have them!
    I'll sort a couple of images later.
    I think I have the gib a bit tight for 1 and my ballscrew does have a bite in places as a result of my packing the spacer to eliminate as much lash as poss. Hence going with the bigger motor. (60V supplies).
    Pushing the carriage back and forth by hand without anything attached does show up a tight spot towards the front end of the ways.
    That is where I had the stall so a fiddle with the gib will be in order. Lapping/scraping is beyond me so hopefully it'll be better in time.

    I set the gib tightish to start with as the carriage had a wobble when overhanging the front end 30mm and above. Once the ballscrew etc were all fitted up it stopped doing it.

    I could in fact remove 1 piece of foil packer (0.03mm thick) and that will smooth out the ballnuts. But then the backlash will go up to around 0.05mm (0.0019").
    I would rather sacrifice some speed over increased lash and keep it at half that figure.

    I'll settle for 2000mm/min (80" ish) rapids it's still more than my small Sieg.
    With only max 3000rpm on the 25 I can't cut massively quick with a 6mm 3fl anyways.

    Last edited by dazp1976; 04-13-2019 at 09:52 AM.


  5. #5
    Member
    Join Date
    Apr 2009
    Location
    USA
    Posts
    33
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    I had some of these same experiences in my build. I used hybrid steppers if you haven’t done the purchasing yet.

    Much quieter and I’m able to wire in an alarm setup so it works well in that aspect.

    I do wish I had better ball screws.



  6. #6
    Member
    Join Date
    Jan 2018
    Location
    United Kingdom
    Posts
    197
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    Progress on enclosure. 45L coolant tank at bottom. Needs doors.
    AMAT25LV Basically another PM25 clone :)-p1030887-jpg
    PC near the roof. Monitor mount top right.AMAT25LV Basically another PM25 clone :)-p1030888-jpgY slot cut as much as I wanted to go. Made new anchor points for the nut mount on the shelf area in front of where it originally was. Table rear travel now brings it closer to the column (15mm away). Means less overhang at the front. Unfortunately the easiest way of running the oil for me was to have the manifold located to the front. High pressure metal push fittings used all round.AMAT25LV Basically another PM25 clone :)-p1030893-jpg
    Bearing block was made wider to enable extra anchor points to be added at the sides to make sure it could hold the motor weight. Uses the 2* 8mm holes and 4* extra 6mm holes. My Seig gives a crap finish half the time. Be glad when this is running.
    Twin nut mount made for the X axis and recess cut in the saddle for clearance of nut and oil fitting. Nut will still need cutting down at the top.
    AMAT25LV Basically another PM25 clone :)-p1030894-jpg
    Built up the nut mount quite long to cover the DFU as much as possible. This should prevent any chance of nuts wobbling. Total travel measured in as 204mm using only a 59mm saddle overhang at the front. This means I have left myself the option of adding a 10mm head spacer to give a comfortable max travel of 200mm. Had to take it apart a few times to cut bits down here and there.
    AMAT25LV Basically another PM25 clone :)-p1030895-jpg
    I've ended up using only a 1605 screw with a twin SFU nut setup. Feels pretty solid and I'll upgrade to 2005 if needed. Drag chains for oil & coolant lines.
    There is a car roller blind mechanism been made for it using 0.5mm nitrile sheeting. Isn't fitted as I keep breaking the plastic brackets when knocking into it.
    AMAT25LV Basically another PM25 clone :)-p1030896-jpg

    With the roller unit fitted it will give a safe distance of 180mm from spindle centre to nitrile cover without material rubbing on it. That's about the distance I was looking for so I can cut a true 180mm sized square with the Z still protected.

    Attached Thumbnails Attached Thumbnails AMAT25LV Basically another PM25 clone :)-p1030887-jpg   AMAT25LV Basically another PM25 clone :)-p1030888-jpg   AMAT25LV Basically another PM25 clone :)-p1030893-jpg   AMAT25LV Basically another PM25 clone :)-p1030894-jpg  

    AMAT25LV Basically another PM25 clone :)-p1030895-jpg   AMAT25LV Basically another PM25 clone :)-p1030896-jpg  
    Last edited by dazp1976; 04-28-2019 at 10:19 AM.


  7. #7
    Member
    Join Date
    Dec 2015
    Posts
    341
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    Very nice! Your enclosure is very similar, at least and size and shape, to the one I built for my G0704.



  8. #8
    Member
    Join Date
    Jan 2018
    Location
    United Kingdom
    Posts
    197
    Downloads
    0
    Uploads
    0

    Default Re: AMAT25LV Basically another PM25 clone :)

    Adjusted this Y axis ballscrew way too tight me thinks. Too much friction. It runs o.k. but is speed restricted which is a little disappointing (2200mm/min).

    Backlash is stable at 0.025mm (0.00098") and it's repeating within 0.01mm over 170mm distance after many test runs according to the dial.

    What I did notice is that if I hit the soft limit point at more than 1300mm/min it throws the axis out by 0.2mm each time. I'll have to watch hitting them.
    Don't know whether to take some of the packing out of the DFU nut to loosen it a little. It should increase speed but will give a backlash of 0.05mm (0.002") affecting accuracy.

    What to do? I really don't like the stop/start business of the Mach3 lash compensation so don't want to use it if I can help it.
    I may just leave it all as is and see if bearings etc eat themselves or not.
    Only have the stock 3000rpm max spindle speed available so probably can't cut much quicker than 1000mm/min anyway.



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

AMAT25LV Basically another PM25 clone :)

AMAT25LV Basically another PM25 clone :)