Thread: Desktop sized CNC
Some time ago I have built 1200x700mm machine and it was pretty clear what electronics, mechanics and other items to use. Now, some time has passed - I have decided to build small, desktop machine (approx 400x400mm). But facing challenge - what electronics to use. My pc's does not have parallel ports anymore - is there decent USB BOB, or should I use motion controller connected to BOB ? What BOB should I use, what motion controller should I use (if needed at all). I want to have reliable machine so I could cut wood, aluminium, etc.
Any input, advice would be much appreciated :)
Here is some pic's and video from my previous build:
You made a nice job of that machine but has well electronics I'd look at using different components to what you used last time. Things have changed in last few years and now the price of Ballscrews and Profiled linear rails have dropped massively so with in reach of DIY budgets.
Regards the Electrics then go with Digital drives not old analog type ie Not M542. Lead shine AM882 are a very good drives at ok money if bought from china. Thou for small machine you could use the slightly lesser spec Dm 556 with 50Vdc Max.
Regards the Motion control then Ethernet is the best. For a small machine that doesn't use slaved axis then IP-M from Cslabs is by far the best. This doesn't need a BOB and comes with spindle speed control. It's very high quality unit with plenty of 24V I/O.
Other alternative is ESS smooth stepper used with a BOB, extra Bobs can be used if more than 5 inputs are required. No speed control unless BOB comes with it and only 5v I/O so more prone to noise.
These are the only two Motion controllers I'll use. I don't ike USB it's too unreliable but If I had to choose then the only one's I'd use are the UC300 or Pokeys 56CNC.
Last edited by JAZZCNC; 11-01-2016 at 02:20 PM.
Thank You for your advices JAZZCNC. Much appreciated.
As for rails, I think to use MGN12 rails with MGN12H carriages for Z and X axis. For Y axis HGR15 with HGW15CA (or other type, depending on final design) carriages.
I have concerns if MGN12 with MGN12H will be enough for Z and X axis ? (even though I have seen those used in small cnc machines).
I really liked the CSMIO/IP-M 4-axis Ethernet Motion Controller, but in specs it shows that the spindle axis is not supported ?
I have ordered 800w water cooled spindle from aliexpress (the size was the buying factor - 158 mm fits nicely in my design) I expect this will be good enough for small aluminium works ? :)
As for stepper drives, I will go with DM556 (or if needed - AM882). But what about steppers ? What torque I would need? (I plan to use pulleys and make 2:1 gearing or just leave it 1:1). The size is important too - smaller steppers are better for my design :)
Do I need closed loop steppers and drivers ? (are they worth the money ? )
Nice job on the first machine above, for the new desktop machine:
Rails: 15mm (xy and z) you can machine pockets. If not 20mm.
Controller: Expensive but very nice investment.
Spindle: Time will tell.
Drivers: DM556 it is then.
Motors: The "go to" option for most is 3Nm, I wouldn't consider motor frame size personally but I understand why you do, even still for the cost it's cheap enough and better investment to go with the normal choice.
Closed loop: You decide, forum search is your friend.
Last edited by Lee Roberts; 11-01-2016 at 06:20 PM..Me
But if you can afford them then there are some advantages other than the closed Loop.? . . Three phase motors are much smoother and give more torque across the speed curve. They also handle resonance much better.
Thou I'm not sure about those Drives/motors has I've never used them and not all Closedloop are the same. You'll also need at least 2Nm, ideally 3nm.
thank you for your comments.
Lee: is there any other decent controllers (usb or eth) I should consider besides the JAZZCNC recommendation ?
I found these steppers: 57HS22 Leadshine, they are 2.2nm motors and has only 1.8 phase inductance. Anybody has experience with these steppers ?
Belts and pulleys: is it enough to have 6mm belt width or should I go for 10mm or 15mm ? (15mm width pulleys looks too big on desktop sized machine :) ).
I have found this Kickstarter project, they claiming that theirs machine can do aluminium. And they seems using MGN12 rails ? Is this means that it is enough to have MGN12 or their machine more like "toy" compared to more robust DIY machines ?
Last edited by TadasM; 12-01-2016 at 09:23 AM.
Hello again :)
Have not decided on controller... Found PoKeys57CNC very interesting.
Do some one have experience with PoStep60-256 + PoKeys57CNC ? Or should I better stick to Leadshine DM556 ?
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