Probing question again...

[A_Camera]

Probing on an average DIY cnc at 4000mm is unrealistic.

No, it's not, but you have to think outside your box.

With teh amount of overrun you will tend to break things(probes).

That depends on the probe and the touch plate.

IF you are that far a way from teh object that you need to probe at 4000mm you need to rethink your process and rapid over to a closer position before beginning the probing process.

Sure, some times that is possible like for Z height, some times it is NOT possible, like for instance center finding of a decently large object.

Probing at 20-30 IPM is an average good probing speed that lessens the chance of a long overrun and damage to your device.

I don't know where you got that figure from, poor imagination perhaps? ...but even so, 500 - 700 mm/min which is 20-30in/min (let's keep the same units, otherwise you might confuse some people) is also too fast and generates far too muck overrun as well as can actually break your probe or cause damage, depending on your probe and touch plate.

NOW IF you have a high speed fast acting servos (High accel rates) then have at it at high speed probing. But most do not have that option.

Has really NOTHING to do with servos vs. steppers. Many stepper based machines have very high speed also, so there is really ABSOLUTELY no relation.

Most modern controllers have 3 probing options

Probe to point and trip then stop
Probe to point stop reverse an offset value then probe at a reduced FR ( Double Tap, Probing speed always teh same)
Probe to point reverse and trip on switch remaking (Probing speed always teh same)

...so what?

They have served teh CNC industry very well over the years.

(;-) TP[/quote]

[A_Camera]

First I do not consider a pin and a touch plate as a safe probing device for anything but slow probing. That setup has very little overrun capability and damage can occur when 2 rigid objects meet at speed. Now that setup CAN be very accurate BUT very unforgiving.

I guess you read everything literally...

"Touch plate" does not have to be something rigid and unforgiving. In fact, it must not be a fixed plate at all. Use your imagination... 4000mm/min does not have to be 4000mm/min all the time for everything... Like I said, think outside the box...

Yes, I know "real" machines use servo, but again, that has nothing to the with probing or probing speed, and once again, even stepper based machines can be very fast.

[ger21]

In fact, it must not be a fixed plate at all

There are thousands of people using fixed plates for probing, with no issues at all.

[Derek]

In fact, it must not be a fixed plate at all

There are thousands of people using fixed plates for probing, with no issues at all.

So people are hitting a solid pad with a solid tool at 157.5 ipm (4000 mm/min). Not doubting it just amazed. The potential for catastrophic damage far outweighs the time saved by probing a tool that fast in my book.

[ger21]

I didn't say 150ipm.

Maybe I took his comment out of context.
I generally use 15ipm. Which only takes a few seconds, after jogging down close to the plate.

[Derek]

Ok that makes more sense. I jog to just above the plate and then run the Z macro from there.

[ger21]

OK, thank you for the clarification. We will look into this asap.

Any updates on this?

[cncdrive]

Yes, we still working on it.
Could locate the cause for the problem and elliminated it for the UC300ETH only yet, just tested it and it seems to be working fine,
what is remaining is to make the same API changes for the other controllers and then the issue will be corrected.
This will take a bit more time, but not too long...

[Battwell]

I'm glad someone else saw the same as me
Let's get it all perfect

My motto : perfection is achievable
Look at me

[A_Camera]

With high speed steppers Fast and Quick to accelerate or stop are not normally used in the same sentence.

Fast accelleration has EVERYTHING to do with high speed probing . You cannot high speed probe beyond teh point where you can limit teh overun before it cause damage to teh probing device.

Derek on your probing Center of Space routine did you specify that they had to be effecient with time to complete ? Did we work out a solution so that it run in the shortest time possible based on your machine ??? They take advantage of rapids and probing. AND they could even be more efficeint with more code added to support extra features. BUT you can easily get to the point of no returns on teh investment of extra coding.

(;-) TP

Like I said, you have a bit of too narrow thinking...

I know how to probe fast without damage to the tool or the probe surface. I also know that steppers are slower than servo, never the less, even steppers can have high speed and there is absolutely no connection between steppers and servo in respect to high speed probing. Even if servos have faster accelerations/decelerations than steppers, they still overrun and would damage the probe or the surface which is probed unless the probe is MADE for high speed.

I think you are a bit confused by this subject, so please leave it.