. .
Page 1 of 2 12 LastLast
  1. #1
    Hello everyone,

    Been out the picture for a while due to health reasons however I am now finally designing my CNC conversion for my VM32l.

    I have read loads of posts and spoken to various members - and from their excellent advice I have finally narrowed it down.

    The mill will be fitted with Ballscrews (2005 on Z / 1605 on X and 1605 / 2005 on the Y undecided still ) and driven directly (no reduction/ gearing )

    Power will be the custom Toroidal power supply - as in many of the forums.

    The Z already has a internal gas strut.


    I have 3x drivers already - (0~7A - 18-80V DM860H) DM860H - however I can sell or save these.


    After looking at low inductance I have the following shortlist for all 3x axis:


    This stepper with above drivers (0~7A - 18-80V DM860H)

    4 Wire- Inductance: 1.85 mH 20%(1KHz) - Holding Torque: 4Nm(566.4oz.in)


    or a Closed Loop Kit

    4 wire - Inductance: 1.8 mH 20%(1KHz) - Holding Torque: 3 Nm(424.92 oz.in) with 0~7A(0~5 RMS)+24~50VDC (Typical 36VDC) Driver

    or

    Closed Loop with separate Driver for the extra vdc

    4 wire - Inductance: 1.8 mH 20%(1KHz) - Holding Torque: 3 Nm(424.92 oz.in)

    0~8.5A(0~6 RMS) - 20~80VAC/30~110VDC (Typical 48/60VDC)

    I have tried to keep inductance below 2.0

    Any other suggestions are welcome including different motors for different axis and nema 34's etc; however re the torque curves, I see very little benefit and they have a higher MH (3 and upwards)


    BONUS QUESTION

    How much roughly do people pay re customs and VAT form BST for ballscrews - working on costings

    Many Thanks

    Mike

  2. #2
    I found that trying to get a decent torque rating with a good low inductance was nigh on imposible in the crappy uk. There's a lot of junk around!!!
    I'm using these 4nm (566oz) 3mh ind steppers in parallel with 60v psu on my Amat25lv and don't regret it so far.
    https://www.cnc4you.co.uk/Stepper-Mo...H401-03-Nema23
    Bit pricey this company though.

    I'd go with this closed loop myself. Wish I'd gone this route earlier.
    https://www.omc-stepperonline.com/cl...2CNema%2024%5D
    Now. It's 2.6mh but when compared with the one you linked that's 1.8mh
    https://www.omc-stepperonline.com/cl...1%2C1168.53%5D
    The torque curve looks the same for both once you get past 500rpm.
    So this 566oz in my view is just as good for speed but should give better acceleration as it's higher at the start of the chart.
    Get the AC driver and just stick a toroidalol it.


    However. I just looked at your very first standard stepper one
    https://www.omc-stepperonline.com/ne...m-4-wires.html


    If I wanted closed loop I'd go with the 566oz and if I wanted open loop I'd stick with the 495oz.
    I'd likely use AC drivers either way.
    Wish you'd linked these a couple of month ago


    My machine is slightly lighter than yours though but I can't see the table and carriage on yours being massively far off it.

  3. The Following User Says Thank You to dazp1976 For This Useful Post:


  4. #3
    Many thanks for the info -

    Would you have any recommendations for some good AC driver for open and closed loop setups ?

    Thanks

  5. #4
    If your going to go with Closed loop then your better going with 3 phase closed loop. The step angle is 1.2deg instead of 1.8deg so much smoother and the extra phase gives them a bit more torque higher up the speed curve. Only down side is they only come with 50Vdc Max drives unless you go upto Nema 34.

    I've fitted loads of these and this company is good to deal with.

    https://www.aliexpress.com/item/3303...61cf761f3tsKRK

    RE Vat then it's dependant on the amount declared on the customs paper work (and there in lies a clue to getting it down) usualy there is no import duty other than a rip off fee of around 15- 20 the shipping agent charges for paper work.
    Last edited by JAZZCNC; 25-05-2020 at 06:58 PM.
    -use common sense, if you lack it, there is no software to help that.

  6. #5
    Quote Originally Posted by dazp1976 View Post
    So this 566oz in my view is just as good for speed but should give better acceleration as it's higher at the start of the chart.
    Don't be fooled by those Speed/torque charts, in my experience they are unrealistic bullshit, they mean nothing in real world use.!!
    -use common sense, if you lack it, there is no software to help that.

  7. #6
    Quote Originally Posted by JAZZCNC View Post
    If your going to go with Closed loop then your better going with 3 phase closed loop. The step angle is 1.2deg instead of 1.8deg so much smoother and the extra phase gives them a bit more torque higher up the speed curve. Only down side is they only come with 50Vdc Max drives unless you go upto Nema 34.

    I've fitted loads of these and this company is good to deal with.

    https://www.aliexpress.com/item/3303...61cf761f3tsKRK

    RE Vat then it's dependant on the amount declared on the customs paper work (and there in lies a clue to getting it down) usualy there is no import duty other than a rip off fee of around 15- 20 the shipping agent charges for paper work.
    Thanks Dean,

    They probably the best performance to cost ratio currently ? As still have the ballscrews to purchase so trying to get good performance as like everyone I have a budget

    This will be paired with UCCNC and a u300eth (bought already) - If I get these I may need help wiring hehe

    also would the 50Vdc make a massive difference compared to a 2 phase with 70-80Vdc driver

    thanks again

  8. #7
    Quote Originally Posted by Hulksmash View Post
    also would the 50Vdc make a massive difference compared to a 2 phase with 70-80Vdc driver
    Yes it will mostly make a difference to the speed but not by a massive amount, roughly 300rpm, these will give 1200rpm and the others will be 1500rpm.
    They are not exactly like a standard stepper system and the encoders come into play so can restrict the speeds.

    If I wanted to have excess power and plenty of speed along with AC drives then I'd fit these and sacrifice the smoothness 3phase offers as they are 2 phase.
    Nothing gets close to these for power in the Nema 24 range. Again I've fitted plenty.

    https://www.aliexpress.com/item/3279...16523421DXQOr7

    The wiring is easy enough just shout if you need help.
    -use common sense, if you lack it, there is no software to help that.

  9. #8
    Thanks again will go take a look

  10. #9
    Quote Originally Posted by JAZZCNC View Post
    Yes it will mostly make a difference to the speed but not by a massive amount, roughly 300rpm, these will give 1200rpm and the others will be 1500rpm.
    They are not exactly like a standard stepper system and the encoders come into play so can restrict the speeds.

    If I wanted to have excess power and plenty of speed along with AC drives then I'd fit these and sacrifice the smoothness 3phase offers as they are 2 phase.
    Nothing gets close to these for power in the Nema 24 range. Again I've fitted plenty.

    https://www.aliexpress.com/item/3279...16523421DXQOr7

    The wiring is easy enough just shout if you need help.
    Not fair!!!!!
    Just looked at buying 2 and it wants 90 shipping?????

  11. #10
    Quote Originally Posted by dazp1976 View Post
    Not fair!!!!!
    Just looked at buying 2 and it wants 90 shipping?????
    email them.
    -use common sense, if you lack it, there is no software to help that.

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. CONVERSION: Weiss VM32 Mill Conversion
    By picclock in forum Conversion Build Logs
    Replies: 18
    Last Post: 07-08-2019, 10:27 PM
  2. CONVERSION: Warco WM18 Mill Stepper motor advice
    By Gotty101 in forum Conversion Build Logs
    Replies: 7
    Last Post: 18-08-2018, 04:06 PM
  3. Stepper motor selection, lower inductance vs holding torque
    By smeg up in forum Stepper & Servo Motors
    Replies: 3
    Last Post: 20-01-2015, 01:43 AM
  4. Weiss WMD25LV mill
    By Bill K in forum Milling Machines, Builds & Conversions
    Replies: 4
    Last Post: 29-06-2014, 11:52 AM
  5. EXPERIENCE: corkcnc ... a short tale
    By purpose in forum Trading Experience & Feedback
    Replies: 0
    Last Post: 29-12-2013, 03:43 PM

Bookmarks

Posting Permissions

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