Dynomotion Forum

This mill has been sat in my workshop since before I bought the Denford Cyclone lathe, but it kept getting bumped down the roundtuit list, as other machines have taken priority. I think since this machine got rolled into place, a Denford Novamill has been and gone (bought as I needed to make tool holders for the Cyclone, and it happened to turn up at a reasonable price just as I was looking), my little 3040 based digitising machine has been built, and I've bought and retrofitted a Denford Triac mill.

However, as I do various repair work, something capable of handling big lumps of metal is needed, and I've got a plan for a replacement for my Denford Cyclone that will need a big mill to make, so this has finally reached the top of the Roundtuit list.
It's an old Matchmaker CNC conversion that was based on a Shizouka ST-N mill. Think a bit bigger than Bridgeport size, but far sturdier Japanese construction!
It originally left Matchmaker as a stepper driven machine, but at some point in it's history, it got retrofitted with a Heidenhain servo system. The previous owner bought it solely to get the Heidenhain system off it for spares for the Interacts that he ran (or at least that his son ran, as he personally thought they were rubbish!), so I bought the mill as it stands for a bit over scrap value.

Over the years I've had it, I have managed to repair the auto-lube system (needed a new filter, a couple corroded pipes replaced, along with a few blocked metering valves), and get new wiring in for the Summit "one arm bandit" toolchanger pneumatics, and the limit switches. The spindle motor has also been off to free-off the corroded and seized vari-speed system.

So as a few Dynomotion boards turned up yesterday, I thought I'd start a thread about the retrofit.

hello moray;

Nice project and good luck..

For reasons I won't go into right now, this is now the current priority project, as I need a bigger mill.

Servos are in the process of being ordered. Three 1.2kw 3000 RPM for the main axes (the originals were 1kw SEM DC brushed, and I've been advised 110frame 1.2KW will be a better match than 1KW 90 frame), and one 400W with 12:1 reduction gearbox for the knee.

I'm currently deciding on what board combination to use.

All the new servo drives can operate in either +/-10V or pulsed (Step/Dir, Quadrature, or CW/CCW).
VFD for the spindle needs 0-10V.
There is also a stepper motor to control the varispeed pulley for the spindle, which will need a step/dir output.

I'd like to add a glass scale to the knee for positioning (and to get indexing marks every 50mm to avoid having to move it all the way down to a home switch).
MPG for jogging.
SSO/FRO pots.

That puts requirements at-
5 encoder inputs
1 0-10V output (which could possibly be done via Modbus instead)
2 Analogue inputs
1 step/dir output
Then I either need 4 +/-10V outputs, or 4 step/dir outputs.
And I'd like to keep a step/dir available for a future A-axis.


I'm keen to avoid running the servos via +/-10V, to avoid tuning, however I'm also aware of the KFlops encoder and step/dir conflicts, so +/-10V may be the more practical option. (Tom, can I suggest a KFlop replacement that allows 8 encoders and 8 step/dirs? And Ethernet? )


I'm currently considering Kanalog, to get access to differential encoder inputs, and analogue inputs.
I can add one of my JP5 split out boards to get up to 4 differential step/dir outputs, at the sacrifice of 4 encoders inputs, which means a shortage of step/dir/encoder inputs/outputs, so two things would have to use +/-10V

The other option is a total custom board to maximise differential encoder/step/dirs, so I can run 5 encoder inputs, and get 6 step/dir outputs.
Then add a KNozz for the 0-10V output, and two analogue inputs.


At the moment, I'm considering just going for the Kanalog option for quickness, as I have all the bits needed on hand, however the custom board option is something I'd like for the next project..

I'm getting ready to start a conversion to an AN-S. Would you mind telling me which servos you ordered? I'm currently looking at my options and trying to decide what makes sense.

wrinkols wrote: ↑

Wed May 20, 2020 8:57 pm

I'm getting ready to start a conversion to an AN-S. Would you mind telling me which servos you ordered? I'm currently looking at my options and trying to decide what makes sense.

I've ordered Lichuan 1.2kw servos with matching A4 drives.
They sell on Aliexpress, however you can get a better deal through Alibaba.
I'm getting them for $250 per set, with 5m cables, and braking resistors

I've not got them yet, as I also ordered a 400W servo set with a 16:1 reduction gearbox for the knee, and the gearbox takes 15-20 days to custom make.

I've got no idea how they're going to perform, but their older drive is a pretty common drive, so I'm hoping the new drive will be better. The newer drive certainly gives plenty of control options.

I'm hoping I'll have them within the next couple of weeks, but I've got plenty other tasks to get done on the mill to keep me busy.

Time for some project/thread resurrection.

After the last post, I ended up buying a new CNC lathe so the urgency to get this functional dropped down the list, however having had to contract out a couple jobs, and turn down a few recently, I figure it's about time to get this working, and do something will all the bits that I keep moving around the workshop.

It's now got all main axis servos mounted (required new mounting adapters), and I've spent some spare time over the past week getting all the major bits mounted in the control cabinet - Starting at the top
Konnect + Kogna (standoffs are also mounted for an adapter plate to mount an Odriod H3+ that I have lying around, which should be ideal for this)
Row of breakout boards. Only a fraction of the terminals will actually be used, as some key connections are on different headers.
DIN rail for various terminals/PSUs
Three 1.2kw Lichuan servo drives for the main axes, and a 0.4kw that will eventually drive the knee (I still need to strip the drive from the knee, and work out how to mount the 0.4KW + reduction gearbox)
5KW 240 -> 380V VFD for the spindle, Sine filter for the spindle motor, 1.5KW 240 -> 380V VFD for the coolant pump (very much overkill, but it's cheaper than a new suds pump!), and a mains power stepper driver for the spindle vari-speed control.


I'm currently sat dithering over whether I need to add another length of DIN rail along the bottom for the 240V terminals/contactors, as I'm not sure the one row of DIN rail will be enough..

Looks like the cabinet is off to a clean start!

Not to state the obvious but it's easier to add the din rail now rather than later. Even if you don't end up filling them completely it will still make install and future service easier.

Keep up the good work.

The additional DIN rail has already been added.

I made up a preliminary list of all the 240V DIN rail mounted bits, and everything might have fitted on the other rails, provided I didn't need much room for low voltage bits (most should be wired direct to the breakout boards), but I figured keeping all the high voltage stuff low down would be a better option, rather than having high and low voltage on the same rail.

Yeah, one would rather not chance, 'riding the lightning,' just trying to troubleshoot a bit or relay!