541,075 active members*
2,735 visitors online*
Register for free
Login
IndustryArena Forum > MetalWorking Machines > Benchtop Machines > LMS 5500 (SX2.7) Conversion
Results 1 to 17 of 17
  1. #1
    Registered
    Join Date
    Jul 2010
    Posts
    16

    LMS 5500 (SX2.7) Conversion

    Almost done here - it's moving and cutting! Still working on a few things to make it perfect. Quite a process.

    Using PoKeys57CNC along with Clearpath servos, Mach4 control, makes for a very compact install - everything fits in the machine body except the 75V power supply.






    Had some significant fitment issues with the HeavyMetalCNC kit - apparently they changed the castings on the mills since it was designed. Did some of it on the machine itself while it was partially assembled (facing and eyeballed milling with a drill turning the ballscrew) and had to shop out 2 operations.

    https://imgur.com/a/VGRrmky


    • Top of Y ballscrew mount had to be trimmed to avoid clamping the chip shield solid
    • Z motor mount holes didn't line up - epoxied original holes on the mill and redrilled + helicoiled
    • X ballnut/mount wouldn't fit in the slot under the table - had a local shop mill off the corner
    • At this point I could actually use the machine somewhat to modify it's own parts
    • X spacer block needed to be taken down 2mm
    • X spacer block then wouldn't fit over the ballnut either - milled the 2 radiused corners
    • X motor mount needed new bolt slots since motor/ballscrew were misaligned by 3mm with the originals at their lowest point - had the shop make new slots and then I decked it down so the top was aligned with the spacer





    Currently working on spindle control. Instead of using a simple 5V signal, on the buttons, the front panel board has some kind of digital signal going across them. I'm assuming this is to avoid accidental activation due to electrical noise, unless they're just making it a PITA to interface on purpose. LMS sells interface boards for their SX2 based mills, but not for the SX2.7 - going to have to make my own.

    Reverse engineered the front panel board.


    First thought was I could just connect 5V to the buttons to activate them - nope. The 1k resistor is a pull up for some kind of digital signal, didn't feel like pulling out the logic analyzer and decoding it. The buttons did activate when putting a diode across the leads so an optocoupler would work.

    I couldn't figure out how to get the 57CNC board to activate it's optocoupled outputs in the right sequence and pulse them to simulate button presses though. The OC outputs aren't accessible from PoBlocks where I could do it. - Decided to lay out my own board, hopefully I'll be able to sell a couple of these for others that want a standard interface to the spindle.

    On the plus side, the speed control is a simple 0-5V interface, and there's a 1k resistor on the board isolating the output from the potentiometer - easily overridden by a signal injected there.

    Designed and laid out my own control board and currently waiting on production, I'll probably write the microcontroller code this weekend. It takes a standard spindle forward and spindle reverse input and translates it to simulated button presses. Also overrides the manual control knob with the speed signal while those inputs are active.



    The board solders to the back of the original with slots in it to make contact where needed. It adds a new control header that accepts spindle fwd/spindle rev and a 0-10v speed signal that is divided to 0-5v and buffered so it can override the potentiometer output. Nice and compact.

    I'll have 3 boards and only need 1 if anyone else has the same mill. Can do larger runs too.




    Next project / first CNC project - power drawbar. You got a peek at the air cylinders in the first pics.



    I have g-code for the first piece ready to go as soon as I get a few pieces of tooling I ordered, and my tool height setter. Need to get some practice with aligning my setups though - it's too wide on the Y axis for my mill! The bottom plate toolpath just barely fits. Haven't even gotten the mill fully set up and I'm already outgrowing it .

  2. #2

    Re: LMS 5500 (SX2.7) Conversion

    That's nice work! Cool!

    What are you looking at for drawbar pressure? Both with your Bellevilles and cylinders?

  3. #3
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    The 4" Parker LP cylinders I picked up have a pull force of 2062lbs each at the 175psi of my compressor, so I'm going to target around 3500lbs for the Bellevilles so it has some room for error. The current plan is to make the connecting bar from aluminum, but I can always go to steel if it bends.

  4. #4

    Join Date
    Aug 2020
    Posts
    21

    Re: LMS 5500 (SX2.7) Conversion

    Cool build, I've never seen someone build their electronics into the column!

    I ran a quick simulation of your connecting bar. At 4000lbs of force, a connecting bar as you have modeled (assumed dimensions of 6" length, 1.25" wide, 0.75" thick) will experience stresses that are close to 2 times the yield strength of 6061. If I were you, I'd skip making the bar out of aluminum unless you make it thicker and wider.

  5. #5
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    Good to know, thanks!! It was actually 7" on center for the bolts and 1.5x0.5, so even weaker. I have a waterjet as well, so 1/2" steel plate it is.

    What software are you using to simulate? I think there's a way to do it in Fusion, but I haven't figured it out yet.

  6. #6

    Join Date
    Aug 2020
    Posts
    21

    Re: LMS 5500 (SX2.7) Conversion

    Having a waterjet is game changing, that's awesome. I use Solidworks for all my modelling and simulation. I know fusion has simulation as well, but to be honest I can't stand doing any CAD design in fusion and so I've never tried it. Fusion CAM on the other hand I quite enjoy.

  7. #7
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    Watched a couple videos and I think I got the basics figured out.

    It doesn't actually seem that bad, the 1/2 aluminum bar is close, maybe I can go up to 3/4 and save some weight on the head instead of going to steel.

    I'm actually surprised my little 1/4 sliding piece isn't deforming, but the spacer thingy that came with the machine is. I'm sure it's hardened and not regular mild steel though.


  8. #8
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    5/8 actually looks good, and I can do it with the stock I already have. Remaining red spots shouldn't be an issue since the model isn't considering higher grade steel and that the cylinders are bolted instead of "welded" with tiny contact points.


  9. #9

    Re: LMS 5500 (SX2.7) Conversion

    I have about 3000 lbs on my drawbar and it’s been more than adequate for my G0704. I’ve never had any pullout issues since having gotten it all going.

  10. #10
    Member
    Join Date
    Dec 2017
    Posts
    26

    Re: LMS 5500 (SX2.7) Conversion

    I'm sorry to hear you had fitment problems with the kit. I know I talked to you about it a little bit when you were installing it.
    I'm trying to get another machine to check everything and make any revisions that need to be made.
    As I'm sure everyone has noticed, a lot of these machines are on backorder.
    Soon as I can get one in, we will get these things fixed, and I am glad to have someone point it out to me.

    Bruce
    http://www.heavymetalcnc.com

  11. #11
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    Quote Originally Posted by Heavymetalcnc View Post
    I'm sorry to hear you had fitment problems with the kit. I know I talked to you about it a little bit when you were installing it.
    I'm trying to get another machine to check everything and make any revisions that need to be made.
    As I'm sure everyone has noticed, a lot of these machines are on backorder.
    Soon as I can get one in, we will get these things fixed, and I am glad to have someone point it out to me.

    Bruce
    They definitely changed the castings, so I don't blame you guys. I just thought that you may have shipped me the wrong kit for a different machine at the time.





    As for the machine, I cut my first CNC part and managed to vibrate the spindle bearings loose. I thought I destroyed the bearings when the runout and chatter went wild, was just a loose locknut, but I actually destroyed the bearings disassembling to diagnose.


    Ended up reading a bunch about spindle bearings, and it's getting an angular contact upgrade now.

  12. #12
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    New angular contact bearings are in. NO detectable runout on a tenths indicator! All for $100 in bearings off ebay, going with factory ones would have cost about the same.



    (Lathe tool is in there because I ordered the wrong TTS drill arbor, flattening the bottom and using it at my Tool1 for tool heights.)

  13. #13
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    Ok, I'm dumb and pegged my indicator... Rechecked it and got .0004, still not bad.

  14. #14
    Registered
    Join Date
    Oct 2013
    Posts
    492

    Re: LMS 5500 (SX2.7) Conversion

    Well at least you're honest, often a rare commodity these days.

    Stuart
    "THE GRIZZ" photo album - https://goo.gl/photos/yLLp61jooprtYzFK7
    Youtube - https://www.youtube.com/channel/UCT2lq9obzEnlEu-M56ZzT_A

  15. #15

    Re: LMS 5500 (SX2.7) Conversion

    .0004" sounds pretty good, especially at that length. I'd be cool with that on my 0704 on the taper interior. It's been ages since I have checked it though, so I can't remember how good or bad it was.

  16. #16
    Registered
    Join Date
    Aug 2006
    Posts
    636

    Re: LMS 5500 (SX2.7) Conversion

    Also remember that if you're checking it like you are in the video, you're really measuring the compounded error of the spindle, collet, and tool holder. I suspect that if you were to measure directly on the spindle you'd get a different value. Could be more or less than your current measured runout.

  17. #17
    Registered
    Join Date
    Jul 2010
    Posts
    16

    Re: LMS 5500 (SX2.7) Conversion

    Spindle interface is finally done. Had to order a second revision of the board, taking another 2 weeks, after one of the part libraries I used had the wrong footprint for my microcontroller, and I didn't figure it out until it was time to solder it on. (Use SamacSys instead of SnapEDA if you do PCBs, never had a wrong pinout/footprint from one, but had 2 wrong ones from the other...).

    I can't find my STLink to program the chip right now, but tapping 3.3v on a probe to it's pins activates the related function on the spindle board, so I know it'll work.


Similar Threads

  1. Esa Tria 5500
    By niki2014 in forum Controller & Computer Solutions
    Replies: 1
    Last Post: 03-23-2015, 07:39 PM
  2. labvolt 5500 lathe-mastercam 9 post processor
    By jres in forum Benchtop Machines
    Replies: 1
    Last Post: 03-02-2011, 04:33 AM

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
  •