Gildemeister NEF 480 Retrofit

Now that the FU range is working I can’t start wo wonder if I could change between the two hydraulic clutches automatically.
This would give me the chance to use quite a wide range of spindle speeds:

Min Max
770 2240
550 1600
390 1120
275 800
192 560
137 400
96 280
69 200
44 140
35 100
25 71
17 50

The big question is how would I do it.
My first Idea was to write a python module that sees the gearnumber and the lower higher limit. Speed and feed override.

There are only two points where it needs to take action
Low gear and high limit
Then set speed and feed override to 0

Here comes the tricky bit, execute an Mcode to change gear and set the correct parameters for gearchange

Reset spindle und Feedoverride
Wait two seconds

Similar for high gear and low limit.

So the question is, can I interrupt running G-code to execute short Goode and resume?

Thanks Patrick

So the question is, can I interrupt running G-code to execute short Goode and resume?

No, you can not 'inject' gcode while in auto mode.

One way you may want to think about is to build the automatic gear selector into a remap of the S word (setting spindle speed).
 

I was kind of expecting that.

Remapping the S words is a good suggestion. There I can do even more eg if the spindle is not already running also change the manual gear.

The idea was also to increase the range for speed override and these fancy constant surface speed things. So the invested code would have been handy. But I am already quite happy with my machine as it is. And it is a longer project caus i need to change some wiring.

BUT I am completely ne to cnc lathes its my first one before that I only hand cranked.

If you are comfortable writing your own component you could try to get there by using feed inhibit, external offsets, feed and spindle overrides.

The basic challenge is that you will probably want to back the tool off before doing the gear change as I understand you need to run it backward and forward to get the gears to mesh. So you would need to use feed override to basically halt the program then use spindle override to stop the spindle and switch spindle direction through hal logic. To back off the tool you _might_ be able to use external offsets but I don't know if that works with feed override at zero as I have never used it.

But maybe somebody else has an idea for a simpler solution.

[edit]
Using the simulation configuration in /configs/sim/axis/external_offsets it is possible to move the tool by external offsets while having Feed Override at zero. So this could be an interesting option for you.

Many thanks for your Input. I am not able to write components yet just a bit of python and maybe ladder.

My Lathe has 24 gears in total, but I choose 12 pairs by hand (moving two leavers).
EG I chose the pair 800 / 500 then I have two clutches one will engage 800 U/ min and the other 500 U/min. These clutches can be controlled with a solenoids.

At the moment I use gearchange to scale the pwm output.
And control gearchange and the solenoids by mcode cause also when I change between the clutches I need to adjust gearchange.

The manual gear I can only change with the spindle stoped. I was thinking about making the gear change automatically but I don‘t thin this would improve the usability of the lathe.

I just was thinking about using the clutches to increase the usable range of spindle speeds.
I would like to stop the feed when changing the clutches cause I Would like to reduce power while doing and give the motor time to ramp to the correct speed. This should take one second or so and then continue feeding.

This is a quite new Idea which came yesterday after the vfd was working as expected an I realized the the two clutched gears now overlap quite a bit.

I could use two stages of gearchange one controlled by mcode with stopping the spindle to change gears.

And one completely automatically. When I find a way to stop feeding this can be done in ladder or python.

Can I Hijack Feedhold?

I think, that is the pin you want.

motion.feed-inhibit IN BIT

When this pin is TRUE, machine motion is inhibited for gcode commands.

If the machine is performing a spindle synchronized move when this pin goes TRUE, the spindle synchronized motion will finish, and any following moves will be inhibited (this is to prevent damage to the machine, the tool, or the work piece).

If the machine is in the middle of a (non-spindle synchronized) move when this pin goes TRUE, the machine will decelerate to a stop at the maximum allowed acceleration rate.

Motion resumes when this pin goes FALSE.

Note: feed-inhibit applies to gcode commands -- not jogs.