[peteeng]

Hi Jack - Very nice build! Peter

[joeavaerage]

Hi Jack,
I agree with Peter, very good looking build. I can well imagine it would do aluminum very nicely.

It was my first build and certainly far from perfect.

That is very much the nature of designing and building your own. Like your first build my first mini-mill had a myriad of imperfections and yet I did good work with it
for eight years. I have eliminated many of the imperfections with my new machine, but almost inevitably made a whole bunch of new ones. 'Progress not perfection'.
My new mill is at least an order of magnitude more rigid, accurate, powerful and fast.

Amongst the things that I have learned is that some matters which you might think very important are not and other matters which you barely considered are.

Probably the most obvious to me is flood cooling.

I had it on my mini-mill, but it was poor conceived and I seemed to spend a lot of time cleaning up. My new mill is much better, but the coolant filtration system needs
a major rework. When it works the way its supposed to its a dream, beautifully clean cut parts and many tens of hours of tool life. When it doesn't, say it blocks up, then
first is that you wreck the tool and usually the job with it....unless you keep your eyes on it continually.

The plastic parts I'm making at the moment take 1.5 hrs over two operations. I've had to bring the boring operations forward in the sequence of operations so that I can
ensure the tool has no swarf wrapped around the shank of the tool and thereby wreck the boring op. I really need a ring of coolant nozzles around the tool with moderately
high pressure to keep pesky swarf/chips from building up. It's little details like that, that cause the most grief and yet those same little details when attended and allowed for,
have a 'night and day' difference to the finished parts.

Craig

[CallumRD]

Hi all, I'm back again with some more questions as I flesh out this project.

I almost have the frame finished so I'm looking into electronics more.

I'm looking for a control board recommendation for a new board for a simple 3 axis CNC mill. I've settled on Delta B3 servos, ideally the multi-turn absolute CA encoder versions, for the x, y, and z axes. These can be purchased with standard -L drives or etherCAT -E drives. I'm also running a servo with encoder for the spindle motor. I'll be using Mach4 to run everything. Ideally, I'd have a control board that supports the following features:

- rigid tapping (synchronized z and spindle using encoder outputs), mostly used with smaller taps (1/4"-20 / M6 and smaller)
- support for the B3's CA multi-turn absolute encoder for maintaining servo (and thus axis) positions through power on/off cycles
- connection to computer via ethernet or similar; I don't want to be using expansion cards

I haven't purchased the servo drives yet so I'm not locked into etherCAT or standard wiring configurations. Once I've found a control board that will work for me, I'll order the corresponding drives to work with it.

I appreciate any input anyone has on a control board for this build. My budget is not huge, but I'm willing to pay what's necessary to put together a robust, capable system. I just don't want to spend more than is necessary.

[peteeng]

Hi Callum - I'd look at a Dynomotion controller. It has its own thread here:

https://www.cnczone.com/forums/dynom...kflop-kanalog/ Peter

[joeavaerage]

Hi,
the real question is what CNC software do you want?

I use Mach4 and an Ethernet SmoothStepper and have done for nine years. I would avoid Mach3, all development ceased on it nine years ago, notwithstanding that it works, it is obsolete.

Other viable choices are UCCNC, LinuxCNC and Centroid Acorn.

Of these I believe LinuxCNC is the only one that offers direct support for rigid tapping, however I think all would accommodate multi-turn absolute encoders.

I use Delta B2 servos....so there is nothing unusual about Mach4 and encoders, but Mach4 (and UCCNC and Centroid) are not feedback controllers whereas LinuxCNC is.

There is nothing wrong with the Dynamotion board peteeng has recommended....but it is not tied to any CNC software.....and that is the choice you should make.

Craig

[CallumRD]

Hi,
the real question is what CNC software do you want?

I use Mach4 and an Ethernet SmoothStepper and have done for nine years. I would avoid Mach3, all development ceased on it nine years ago, notwithstanding that it works, it is obsolete.

Other viable choices are UCCNC, LinuxCNC and Centroid Acorn.

Of these I believe LinuxCNC is the only one that offers direct support for rigid tapping, however I think all would accommodate multi-turn absolute encoders.

I use Delta B2 servos....so there is nothing unusual about Mach4 and encoders, but Mach4 (and UCCNC and Centroid) are not feedback controllers whereas LinuxCNC is.

There is nothing wrong with the Dynamotion board peteeng has recommended....but it is not tied to any CNC software.....and that is the choice you should make.

Craig

Thanks for the response. I'll be using Mach4. I realize it's not a real-time feedback software layer, hence my questions about controllers that are capable of handling rigid tapping in some capacity.

- - - Updated - - -

Hi Callum - I'd look at a Dynomotion controller. It has its own thread here:

https://www.cnczone.com/forums/dynom...kflop-kanalog/ Peter

Thanks. I'll look into them.

[joeavaerage]

Hi,
if you are using Mach4 then you need a Mach4 compatible motion controller, of which there a a half dozen manufacturers with probably 20 models all up. As I stated earlier I use an Ethernet SmoothStepper,
and have good reason to believe it is the best of the bunch....but you must be aware I am partisan about that...so do your own work.

Mach4 is NOT natively capable of rigid tapping, as conventional rigid tapping requires feedback from the spindle to synchronize movement of the Z axis....and Mach4 (unassisted) is not capable of that.
You can induce Mach4 to rigid tap.....IF.....your spindle is position capable, ie a servo. You then use your spindle as a C axis, and program Gcode to synchronise the C axis and the Z axis. I have done it,
and it works fine. It does not rely on any special property of either the CNC software or the motion controller but rather that Gcode naturally interpolates and synchronises two (or more) axes in a move.
While I have done it I don't use it very much. Its an interesting novelty rather than a daily op.

I made my own breakout board. In particular I wanted (and you too no doubt) differential signaling to the servos to get full bandwidth. I also wanted an 'input centric' breakout board for which an MB3 ( a very good and capable
comercial breakout board by CNCRoom) does not quite match.

Craig