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IndustryArena Forum > MetalWorking Machines > Benchtop Machines > Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.
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  1. #1
    Join Date
    Sep 2017
    Posts
    32

    Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    Hi,

    So I am starting my first CNC build on a LMS 3990 minimill. This seems like the proper place to start this thread. (wow there are a lot of subforums...)

    I have previously used this as a manual mill and hated it. horrible tappet type gibbs. poor ergonomics. so thats why i'm converting it to CNC. hopefully itll be useful then with better ball screws and stepper motion.

    I bit the bullet and bought the FusionCNC kit. I read someone's horror story hear of waiting over a year, but I sent them an email before I sent paypal and was happy I got an immediate response. Hopefully it works out...

    I have broken down the process from starting CAD to machined part and am finding there are lot of costs involved.... about $1800, not including CAM software and the mill. I'd like to know if some of the cheaper options are better or if its really worth going with ESS+Mach3+G540, etc.

    Is TinyG an option? The specs say its 2.5A limited. I'm looking to use 3.5A steppers. Is this really more for 2.5+ routers? whats 2.5+ really mean anyway? Im assuming mostly XY and Z is there to occasionally set height.

    I read thru another beginner build thread and LinuxCNC was advocated but I really don't know anything about Linux and all that Linux related talk is turning me off.

    I'm looking to machine aluminum billet and plates. no steel. delrin and polycarb, sure.

    Anyway, heres my break down: Prices are current on automationtechnologies website.

    Create CAD File: Solidworks I am mainly proficient in this anyway, I use it professionally as a ME.
    Create CAM instructions: HSMXpress Free -found this doing research, is this a no brainer since its free and works within SW?
    Post CAM Processer HSMXpress Free

    Computer - old laptop from Vista vintage.

    Ethernet-Parallel Port Ethernet Smooth Stepper $170.99 -I don't have an old PC, I have old laptops. Then again, buying a used PC+parallel port is probably cheaper than this. But I read there are good performance benefits using this?


    CNC Control Software Lic Mach 3 $149.00 -I'll try the free version first, but from here it seems im committed to it if I use a G540.


    Gecko + 48V/12.5A PSU Enclosure $549.95 -ok, it looks like I could probably save on NOT buying this bundle. How important is an enclosure for it all anyway? I think id rather machine my own enclosure actually. Is the 600W/12.5A PSU overkill? the 350W PSU is cheap at $35.

    Stepper Motors KL23H2100-35-4B w/ cable x3 $164.85 -I like the idea of not soldering myself, but John? said they don't put resistors in the connector for you.... that seemed lame.

    CNC Conversion Ballscrews CNC Fusion kit #5 $655.00 -so the only other option is the Turkish guy? is that a better option anyway?
    Helical Shaft Coupler 1/4-1/4 x3 $72.00 -do they throw in the couplers with their kits? doesn't read so, kinda lame to buy them separately.

    Little Machine Shop 3990. again, this sucks as a manual mill. the idea is to dump more money to make it useful. seems silly when I read it out like that....

    Is going down this somewhat expensive path worthwhile in the end? Thanks.

    Tyson

  2. #2
    Join Date
    Aug 2006
    Posts
    670

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    Everything seems fairly reasonable. There are certainly places you could cut costs if you wanted too though. Lots of people use the UC100 USB to parallel adapter (only $100) in place of the ethernet SS.

    The G540 is a rock solid platform. I've used one for over 8 years. I had 1 driver fail and Gecko replaced the whole unit free of charge well after the warranty was over. That said there are cheaper options as well if you don't need/want the 4th axis.

    I think you should probably come to terms with the fact that you'll be soldering at some point in this build, haha. It's not difficult but takes a bit of time to do. but on the plus side, you can make harnesses exactly the way you want them.

    Ballscrew kits are always overpriced I think, but then again I have the means to manufacture my own. If you're going thru the trouble of modeling it all up, why not just design your own and have the ballscrews machined to your specs? I know there are a few vendors on ebay that will do the end machining for you for very reasonable prices.

    And on the topic of modeling. HMSexpress is cool and all, but if you want to do 3d contouring at some point you might as well switch to fusion360 now. At least for the CAM side of it. Fusion includes the professional version of HSMworks in it for free.

    As for if it's worth it. Only you can answer that.

  3. #3
    Join Date
    Nov 2009
    Posts
    4415

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    The G540 should work fine with Mach or Linux. Though IMO Linux is much more difficult to get started.
    The MX series by Leadshine are very good too.
    I second the Fusion choice.
    A lazy man does it twice.

  4. #4
    Join Date
    Apr 2003
    Posts
    540

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    My first mill was a LMS and I went with a G540. I simply used the manual mill to make the motor/bearing mounts and bought the all parts and electronics where I could find the best price. I went with ebay/Chinese ball screws and nuts. I have a lathe so machined them myself. The whole build took longer but I learned more and overall the cost was less than half of what I would have paid for a kit and the fusion setup. If you have a lathe, you can machine your own screw ends to specs... if not some of the ebay sellers with cut/machine them to your specs for fairly reasonable. It all depends on how much time and effort you want to put into the build. I will say that if you want to simply get a kit, the fusion is a well liked kit. Unfortunately there aren't a lot of other options as far as bolt on screw kits go.
    Good luck!

  5. #5
    Join Date
    Sep 2017
    Posts
    32

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    i havent heard from fusionCNC folks yet, its only been 10 days tho. i thought about making my own mounting plates but id like to get started sooner than later. when i make my CNC lathe ill definitely make my own mounting plates for that.

    so Fusion360, is there a way around the subscription price? i eventually want to do some 3D ball end profiling but not going to start off that way.

    i saw the UC100 adapter as well. UC100 USB motion controller works with Mach3, Mach4 and UCCNC | eBay but does ESS provide better performance? i was under the impression it adds to the performance of the Gecko.

  6. #6
    Join Date
    Aug 2006
    Posts
    670

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    Quote Originally Posted by tyson77 View Post
    i havent heard from fusionCNC folks yet, its only been 10 days tho. i thought about making my own mounting plates but id like to get started sooner than later. when i make my CNC lathe ill definitely make my own mounting plates for that.

    so Fusion360, is there a way around the subscription price? i eventually want to do some 3D ball end profiling but not going to start off that way.

    i saw the UC100 adapter as well. UC100 USB motion controller works with Mach3, Mach4 and UCCNC | eBay but does ESS provide better performance? i was under the impression it adds to the performance of the Gecko.
    yeah, you can sign up for fusion as a student/maker/educator and it's free for 3 years. And for now, free to renew after the 3 years as well.

    The UC100, from what I gather does almost the same thing as the SS, but you don't get the 2nd and 3rd parallel port pins available.

  7. #7
    Join Date
    Sep 2017
    Posts
    32

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    received my kit.


    FWIW i would not recommend buying anything thru CNCfusion. shoddy quality, total lack of communication after they took my money except for a shipping notice. i've only gotten to doing the Y axis and found the ball screw to be 1/2" too long for my casting. looking back i've read this is a common issue, the response is to grind away the casting or make your own spacer. 1/2 inch?! just make the goddam ball screw shorter since its a repeated issue.


    a common counter point is that this is a hobby kit for hobbyists, one should be prepared to make your own modifications. bull****. if its a repeated issue over years of different customers, then make a correction.


    the obvious solution is to create a simple spacer. this ought to just be given with every kit if you are going to estimate the ballscrew extra long. then i can cut it thinner as needed without having to make it myself.

    https://imgbox.com/uj0XL6t7.jpg


    lastly, this is the shoddy quality you get. what the hell, how do you pass this flycutting off as paid work?

    https://imgbox.com/kyGfWtbS.jpg

  8. #8
    Join Date
    Sep 2014
    Posts
    4

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    I agree the kit should come with a spacer to alleviate the issue with modifying the casting. I will say though, that additional 1/2" of travel has saved me more than once. I think you will appreciate the additional travel after you have it. One piece of advice for assembly, use red loctite on the two lock nuts on the right side of the table. They will come loose otherwise in my experience.

  9. #9
    Join Date
    Sep 2017
    Posts
    32

    Re: Starting a LMS 3990 CNC Conversion, new to CNC. Guide me please.

    an update.

    progress has been slow, but i finally put together the whole FusionCNC kit together on all 3 axis.

    i'm really, really not a fan of this kit. The Y axis i already ranted about, I had a 1/2" spacer made, and added a 3rd fastener to the base, under the lead screw hole for extra support. That now works fine, and yes i get 1/2" travel on each side so that will come in handy later i'm sure.

    X axis went on without any drama.

    now my current rant is the Z axis bracket. looks like there was an improvement made on the number and hole pattern you drill right into the Z column. I think its ridiculous to attempt to drill this by hand, in situ. I disassembled the whole column and drill and tapped it on another machine. I had to measure the hole pattern myself, why the hell dont they just give you the hole pattern??

    my biggest complaint on the Z axis is that it covers up the gib adjustment screws. these nut and setscrew gib adjusters are already the worst part of the Sieg X2 design, and they made it even worse by covering it and making it impossible to access. ugh...

    plus my Z travel is reduced about 1" because of the bracket. i just dont get the thought that was put into this.


    now i just need to wire it all up. i'll build my own electronics enclosure when im done. something a little different than what i've seen. Any advice on any useful indicator lights to put on the enclosure? E-stop status/buzzer? Fault? Can I custom configure the outputs from the gecko G540 in mach3 to indicate anything useful?


    btw, i just got back from a Solidworks 2018 intro, so CAMWorks is now included standard with 2018. is this any better or different than HSMworks?

  10. #10
    Join Date
    Sep 2017
    Posts
    32
    I thought I should add that now that I got my system running, if anyone buys the Ethernet smooth stepper, you really need to buy the MALE db25 to idc26 serial cable to connect to the g540. Every ESS kit comes with a FEMALE db25 cable, shown in product photos, it's useless. Or you'll need an old printer cable with male male connectors to make the two work.

    You can buy idc connector with male db25 directly f I'm warp9, they mention it briefly on their site. Or buy a snap on male ribbon connector.

    Annoying. But oddly overlooked.

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