Low cost drive for my mill #MILLS #MODS
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Hi John and everyone,
As you can see, I¡¯ve just added a brute (12nm @ 6amps) of a stepper motor to my mill. The question that I have is what is the easiest / cheapest way of providing a digital drive to it ? I have the stepper motor driver for it, ?all (!) I need is the clever stuff. What I going to do for the moment (because I have the bits in my box) is to use a XR8038 chip to provide a variable frequency, and an old Schnieder baby PLC (Zelio) ?to handle the logic. I would like to be able to handle, backlash , use an encoder or similar to move the mill by small but accurate amounts, have different speeds left and right, mill to a point and return, etc, etc. All nice to have but who¡¯s done what ? And how did it work. I suppose I could look at something PC based, I have a couple of old HP 7900 ultra slimline boxes that would work if they¡¯re fast enough.? So John D. And friends please what do you suggest ? Bob |
¿ªÔÆÌåÓýDo you have a DRO on your mill?? ?If you do you could whip up a couple of Arduino stepper drive controllers that just give you variable speed and use them as power feed controllers. ? If not then there are? few approaches. ?For sure you want to purchase some sort of Break Out Board so you can run your wiring once and then not have to change it.? For my CNC Router I went PMDX-125 and MACH3.? And immediately found I wanted a USB SmoothStepper for which the PMDX is already wired for. ? Without the DROs you really want some sort of display so you can move to positions.? I can't ever see using a CNC router manually.? It would be like trying to 3D print manually. ? But a mill starts out as something that can be worked with manually.? And so a PC with either MACH or LinuxCNC becomes the simplest. And MACH3 is really easy to set up if you have a parallel port.? LinuxCNC less so but it's possible.? With LinuxCNC and MESA you can either go with the 7i92H for about $89 and into any old Break Out Board ? or the 7i95 for $295.? ? A number of people swear by these ? It's ready to go but small screen and although the users claim support is good I don't have any knowledge of that.? A 3 axis system with DHL shipping arriving in about a week is about $300 Cdn plus any taxes that might be payable.? Connect to your stepper drivers and you are good to go.? ? The $295 US MESA solution still requires a PC.? But only one with Ethernet and I suspect even an older ?laptop would work with this running LinuxCNC.? Heck nowadays laptops are available for a few hundred dollars.? ?But for me in Canada with shipping I think total outlay would be closer to $500 Cdn. without the PC.? The down side is the steep learning curve for LinuxCNC.? The up side is there are lots of people using it.? ? Alternatively with MACH4 and an Ethernet Smooth Stepper or there are others now, my outlay would also approach $500.? You still need some sort of Break Out Board. ? Then there's this project from three years ago but he changed over to LinuxCNC from the BeagleBone MachineKit.? But I don't think he offers any for sale.? You'd have to build it all yourself. ? From his posting: This was my take which I used for 12 months before switching to Linuxcnc The cape connects directly to the BBB and the 2 other boards connect via a short 26 way cable ? ? ? ? What I'd like to build is something like the Chinese CNC controller but with that Ethernet connection to LinuxCNC.? Bt at $300 Cdn I'd spend more than that just building the first prototype. ?And unlike my ELS which I wanted for my Gingery Lathe so I could thread, I now have CNC on the mill and an ELS on a Southbend.? ? So needless to say I'm still thinking about all of this. ? Feel more confused? John ? ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Bob T
Sent: March-28-20 4:54 PM To: [email protected] Subject: [digitalhobbyist] Low cost drive for my mill ? Hi John and everyone, |