Thread: Wobblycogs CNC Mk2
I've been having a look at the control / motion side of the machine for the last week or so hence the lack of updates. I think I've now settled on a fairly uncontroversial set of components but I'd be grateful if someone more experienced could have a quick look over the shopping list...
- Steppers - 4 * Nema23 3.1Nm, CNC4YOU
- Drivers - 4* AM882, Zapp - Is there a reliable cheaper source?
- BOB - PMDX-126 Rev C - I plan on using the Rev B slave feature for the X-axis.
- Spindle Speed Control - PMDX-107 - Unlikely I'll set this up straight away but might as well get it now
- Step Generator - Ethernet SmoothStepper
- Software - Mach3 - Might wait till Mach4 as it looks like there won't be an upgrade option.
- Stepper Cable - 4 Core CY Cable 1.5mm^2
- Spindle - Spindle 2.2kW with VFD
- Computer - One of several spares kicking around the house, running Win XP probably.
- Power Supply - Currently planning a self build...
I plan on adding limit switches, water cooling pump, radiator, etc but I think this will get me started. I could do with a recommendation on cable for the spindle though
Most of the machine will be bolted together with M4 cap head screws, will this be strong enough? I settled on M4 rather than M5 to get additional threads in to the aluminium box section. My gut feel is that with the number of bolts I'm using either would be fine but I don't want to go buying a million M4's only to find they are the wrong size
Last edited by Wobblycogs; 18-09-2013 at 11:26 AM. Reason: forgot the power supply
Snap to most of that apart from the slaved x axis...oh and the spindle.
I saw this Aluminium 120mm Radiator for PC or CNC Cooling. G1/4" Fitting | eBay cute little radiator on eBay and was thinking of getting it as I might put a water cooling mount on my machine for my spindle to cool the bearing housing down as I can see it getting quite hot. I've got a spare 120mm 24V fan to mount to it and would "borrow" some tubing and fittings from work to connect it all up.
Yeah, that's the sort of thing I was thinking off. I'm going to mount the radiator, fan and a small pump on the gantry somewhere. I've got a load of computer bits and some fish keeping bits so I might just be able to bodge something together from bits I can find around the house. I've read a few places that the water cooled spindles can run for quite a while without cooling so I think that'll get me started.
Drivers are, as usual, cheaper from aliexpress:
New Leadshine AM882 Stepper Drive Stepping Motor Driver 80V 8.2A with Sensorless Detection #SM414 @SD-in Motor Driver from Industry & Business on Aliexpress.com
4 seems a bit excessive to me. You can maybe justify two for the slaved axis, but I doubt you'll see much benefit using them compared to DQ860MA on the other axes.
BOB/Spindle control/ESS/Mach3... well if you must.
The cable you've chosen for the stepper motors is fine and also good for the spindle, or you could instead use 4-core 1mm^2 for the spindle. I'd stick with the 1.5mm^2 for everything as it just makes estimating the length required easier.
For the sake of saving approx £20 per drive I think I'll probably just go for all AM882's, in the grand scheme of things I don't think it will make that much difference to the overall cost as I've now thrown caution to the wind and given up on my "cheap" route....
I'm with you on this Neil. My spreadsheet currently shows it's going to cost in the region of £3200 although I think there are some savings to be made on materials. A £40 (maybe £80) saving would be nice and I'm thankful for the suggestion but at the same time I have to weigh that up against the fact I'm very time poor and spending a little extra to walk a well trodden path feels like a reasonable investment.
It's basically the same reason I've chosen to go the Mach3/ESS route. I'm sure I could get LinuxCNC to work with a cheap BOB but the days of me being able to spend 40 hours a week in the shop are, sadly, a distant memory. I'm also interested in trying to write applications to directly control the machine and doing that via the ESS looks like it would be significantly easier than trying to do it through the parallel port and dealing with the exacting timing issues (this could be very naive of me though).
Neil, would you'd be interested in a combined purchase of the AM882's Jonathan linked to?
Hang fire with the ESS/PMDX?spindle control because I've just received the Csmio-IP-M Today form Zapp and so far it's looking like a fantastic bit of kit that I feel is going to change my view on ESS/PMDX preference.!! . . Esp has I can get from Gary @ Zapp without all the crap of buyng from US.
It's very very neat and you can see it's been design with industry in mind has it's all DIN rail mounted with good quality terminal connectors and it uses 24v inputs/outputs.
Comes with spindle control built in and it's giving a super stable accurate RPM straight from the box, no messing with de-bounce or any thing like that like you can have with cheap spindle boards. Two Relays on board for controlling For/Rev.
Loads of Digital Input's/outputs all 24V signals.
So far I've only hooked it up to some AM882 and 3Nm motors on the bench but I can tell from way motors sound and the speed and smoothness I'm getting from them it's giving super smooth pulses. You can always tell nice clean pulse's when the motors are turning slow or spinning very fast and these sound sweet.!!
I'll be throwing all this lot on a machine shortly but before that I'm going to hook it up to my machine so can give it a good thrashing and compare it to ESS and the Russian PLCM-E3P(which it's currently running) also the old USB-SS. Will probably throw a thread up when I've played more, Rest assured I'll do my best break it.! . Lol
Last edited by JAZZCNC; 18-09-2013 at 04:59 PM.
I saw you mention you'd got a Csmio on another thread. I have to admit it had me interested but I couldn't find much else about it so went with the standard setup.
It certainly sounds like a top quality solution. If it's as good as you think and comes in at roughly the same sort of price I'll be more than happy to switch over, I await your review with bated breath :)
I'm all ears.......
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