Z-axis gone bananas

Have you overridden the axis limits to get yourself operational? If not, try that button on UCCNC...

Is your Z limit switch faulty?

Power down the machine and manually turn the Z axis lead screw? Try toggling the limit switch and see if the flag is triggered in UCCNC.

Just some quick thoughts...

Doug

I don't know what to say, Doug. I just came in the workshop with a mind to try your suggestions, so I fired the computer up, loaded UCCNC, powered the Clockwork Orange, took a deep breath and clicked the Home All button while jumping the mouse to the Stop button just in case. The machine then simply homed the three axis as if nothing had happened.

I don't know what happened much less why it happened, this is rather annoying as I like to know what goes wrong so I can devise preventive measures at least.

So thank you very much for your concern, but as you see your suggestions fell into a barrel with no bottom, so to speak. It apparently cured itself, the Clockwork Orange just needed a nice sleepy night to let the hangover go, I suppose.

:huh:

O.k., well in a sense that's reassuring but I agree, it's better to diagnose the problem rather than leave it to chance for it to happen again and potentially ruin a toolpath.

Doug

Whatever the cause of all this, I'm going to connect the Clockwork Orange to an UPS as I believe that weather events may cause variation to the power supply, possibly leading to disturbance of the machine electronics. I've already witnessed some very sporadic glitches that I have no other explanation for.

I do not know whether this is true or not as I have no monitoring equipment, but two wise precautions are better than none.

Whatever the cause of all this, I'm going to connect the Clockwork Orange to an UPS as I believe that weather events may cause variation to the power supply, possibly leading to disturbance of the machine electronics. I've already witnessed some very sporadic glitches that I have no other explanation for.

I do not know whether this is true or not as I have no monitoring equipment, but two wise precautions are better than none.

Hi.

You have experienced similar issues to me. When I was cutting my guitar neck recently, I experienced two glitches. The first just caused the machine to stop and software to crash. I put this down to a local current spike on the downstairs electrical ring main caused by my wife turning on the grill to make cheese on toast for the kids' lunch! :ohmy: Then later on during cutting of the lower side of my guitar neck, another glitch occurred. This caused the Z axis to 'lose' many steps and ended up cutting about 12 mm instead of 1.2 mm! Thankfully I hit the emergency stop before any real damage was done. This, I believe was due to her turning on a 900 Watt microwave oven to heat up food for the kids' evening meal. :ohmy:

I also came to the conclusion that some sort of current and/or voltage regulated power supply would be a good idea, then I saw that regulated laboratory bench power supplies up to 30 V cost about £250-£400. I'm not even sure that this is the correct thing. Uninterruptible power supplies (UPS) are much more costly but if you find something suitable less than £250, please post up details.

http://uk.rs-online.com/web/c/test-measurement/bench-power-and-power-measurement/bench-power-supplies/

I work as an Operations Engineer at a nuclear power station and national grid system frequency is one parameter we have constantly on display and I can tell you that we have observed much greater variation and more frequent and longer lasting excursions above or below the contractual control range of 49.8 to 50.2 Hz in the last few years. We surmise that this is due to the unpredictability of all the newly commissioned renewable energy generation (particularly wind power) on the grid. For example, a couple of days ago the frequency dipped sharply below 49.8 Hz due to Heysham Stage 2 Unit 7 trip at 12:12 hrs. However, I doubt that small scale national grid disturbances will affect equipment locally. Grid system frequency variations cause machinery (particularly prime movers such as gas circulators or feedwater pumps) to speed up and slow down enough to affect primary control parameters which is annoying when you're trying to optimise the unit to provide a steady power output at an appropriate margin to the limits.

Regards.

Doug

Hi,
since the power supply provided by Stepcraft is a switching power supply the AC frequency sould not matter at all.
If a burden of approx. 1000W leads to a power loss you should get your own supply circuit from the fuse box to the Stepcraft or just switch to a less burdend circuit.

Hi,
since the power supply provided by Stepcraft is a switching power supply the AC frequency sould not matter at all.
If a burden of approx. 1000W leads to a power loss you should get your own supply circuit from the fuse box to the Stepcraft or just switch to a less burdend circuit.

I already stated that variations in the AC grid frequency are unlikely to cause this and in my case I stated that it was due to high consumer appliances sharing the same ring main circuit being switched on.

The additional information I gave on causes of grid frequency imbalance was for general interest only.

In my case, I will simply ensure that no high current demand consumers are turned on while I am running a toolpath.

Doug

Doug wrote:

In my case, I will simply ensure that no high current demand consumers are turned on while I am running a toolpath.

In other words "Send the wife and kids out for the day whilst I play in the workshop"!!! B)

Doug wrote:

In my case, I will simply ensure that no high current demand consumers are turned on while I am running a toolpath.

In other words "Send the wife and kids out for the day whilst I play in the workshop"!!! B)

Oh yes! You got it.

That translates to a Tuesday or Thursday for me 😉

Doug

Doug, please do a simple test: try looking at yourself in a mirror at night with the lights out. If you see yourself it means you need a career change.

On the other hand, if you can't see yourself in the mirror with the lights on, then it means you're a fookin' vampire and need killin' !!!

Hi guys! Still on this subject, occasionally "something" causes the machine to find new coordinates somewhere and go off on a different path than what is in the G-Code. Look at the photos for an instance, that L-cut on the lower right was absolutely not intended and also absolutely not in the G-code!

Normally I detect when this happens by a nerve shattering loud noise coming from the machine !!!

It just happens! It can go on any x, y or z direction or more than one in combination. The part I'm machining right now has had a holding stub destroyed by a cutter doing a wild run so I already know these last 3-4 hours work are going to Walhalla!

As another consequence, when the machine meets some resistance actual movement will lag compared to the programmed toolpath and timings, so after one of these seizures I have to stop everything and have the machine homed and back to zeros, and surprise, surprise, there are differences!

So after all what can I do to avoid this? It's all very weird as I saw no apparent brown out, I don't have anything else connected other than the vacuum cleaner making it's usual whine with no variation, so what's causing this?

Or is it something else entirely? sticking my hand under the machine in the control board area I feel the metal box around is warm to the touch, not hot, just warm. Can the boards be sensitive to heat? Room temperature is 24ºC...

I would be very suspicious of the Windows operating system myself - there are so many hidden operations lurking, just waiting to screw a real time operation and perhaps even corrupting UCCNC.

I use a dedicated cheapo 2nd hand Dell running XP Prof, and went through shutting down everything that didn't screw up UCCNC operation.

Certainly shut down any and all scheduled tasks and disconnect from the internet and close down any virus checking software. That was very tedious, but (touch wood) I don't think I've ever had an unscheduled operation in a couple of years.

Peter.

Or is it something else entirely? sticking my hand under the machine in the control board area I feel the metal box around is warm to the touch, not hot, just warm. Can the boards be sensitive to heat? Room temperature is 24ºC...

Never heard from anyone who has a problem with that but can remember that one user added some heat-sinks to the drivers and one added a fan...
However they did not have any problem with too high temeprature.

Thank you both for your concern. Doc, I'm not saying it's overheating, I'm not using any thermometer, I notice the area is warmer but really not warm enough (subjectively) to be a concern. I might measure the temperature difference between stopped/working but indeed that doesn't seem to be the problem, and as you have no history of this occurring then it's not a problem 🙂

Peter, now that's a bigger concern. These glitches are very sporadic and consequences unpredictable but normally catastrophic due to some corollary of Murphy's Law. Consequences include at times digging in the Whiteboard, forcing work to be thrown away, ruining the cutter, throwing axes out of tune, etc.

If the cause were physical it would be a matter of changing this or that, but software generated glitches are rather outside my control.

I have an old laptop on a shelf, if it still works I could use it dedicated to running off grid UCCNC and little else. OpSys is W.Vista. Wish me luck!