New Build - 'Audit' CNC - Lathe Attachment

[Chaz]

post a report pls.

Do the spindle bench test measuring the voltage with nothing attached to the output.

Is there a spindle encoder and is the spindle really 7000 rpm?

Uwe

I was just on the way to do that, see post above.

Spindle Encoder, yes, but not wired in yet, so disabled.

No, its not 7000, I was messing about with different speeds to see if I could get it to change the behaviour. In my report now its been set to a correct speed for the current gearing.

The VFD is Mollom G75. Seems decent, low noise. The online manual is a bit different to what I have but can take some pics later showing the various bits.

Will do bench test later, thanks.

[suntravel]

so no spindle encoder, spindle set to 2040 rpm max and Acorn shows 7000 rpm, this is strange.

It is also not a good idea to unplung and plug something while it is running.

pls do the spindle bench test like described in the install manual.

Uwe

[suntravel]

I've managed to get the Tool Turret motor replaced with a 400W Servo as I have no way to easily drive the 110V 3 Phase AC motor on the existing setup. I am back to trying to code the ATC Macro. I tried the Wizard created Axis driven type, which should work, its only a Rachet and Pawl type setup but its not.

So I prefer to just code it myself. I can use similar code to what I used on the Emco 320 however I'd prefer something simpler.

We discovered that I cant do G91 incremental moves on a lathe and therefore Uwe suggested U V W etc for X Y Z, however I cant find anything that tells me how I can move an A Axis incrementally on a lathe.

Chat GPT offers this as a workaround which Ill try ...

"#100 = #5021 (current A axis position system variable)
G90
G1 A[#100 + 15.0] F100 (move 15° relative to current position)"

Of course #100 is used elsewhere for messaging but its more the point of the code ...

Do not trust Chat GPT

#5021 ist the current position from the first axis, if A is the third axis use #5023

G90 is a Diameter cutting cycle

A better source of information is the Centroid lathe manual.

#100-149 are user variables

better to start with #110 and up for own stuff since #100-110 are commonly used in macros.



Uwe

[Chaz]

so no spindle encoder, spindle set to 2040 rpm max and Acorn shows 7000 rpm, this is strange.

It is also not a good idea to unplung and plug something while it is running.

pls do the spindle bench test like described in the install manual.

Uwe

The 7000 was before I made the change to 2040 RPM. The report has 2040 RPM.

Ill do the bench test in a bit.

[Chaz]

I've managed to get the Tool Turret motor replaced with a 400W Servo as I have no way to easily drive the 110V 3 Phase AC motor on the existing setup. I am back to trying to code the ATC Macro. I tried the Wizard created Axis driven type, which should work, its only a Rachet and Pawl type setup but its not.

So I prefer to just code it myself. I can use similar code to what I used on the Emco 320 however I'd prefer something simpler.

We discovered that I cant do G91 incremental moves on a lathe and therefore Uwe suggested U V W etc for X Y Z, however I cant find anything that tells me how I can move an A Axis incrementally on a lathe.

Chat GPT offers this as a workaround which Ill try ...

"#100 = #5021 (current A axis position system variable)
G90
G1 A[#100 + 15.0] F100 (move 15° relative to current position)"

Of course #100 is used elsewhere for messaging but its more the point of the code ...

Do not trust Chat GPT

#5021 ist the current position from the first axis, if A is the third axis use #5023

G90 is a Diameter cutting cycle

A better source of information is the Centroid lathe manual.

#100-149 are user variables

better to start with #110 and up for own stuff since #100-110 are commonly used in macros.



Uwe

Well, it was a guide and mostly worked. But if you look at my final macro, I did it a bit differently. There doesnt seem to be an incremental way to drive the A axis, so had to be inventive with just resetting it to home after each calc. Takes a bit of time but it seems to work fairly reliably now.

Plus, my point of the post wasnt the variable numbers, it was more the method of calculating the moves and then keeping the A axis correct whilst it did them.

[Chaz]

So, bench test passes. See the new vid, something interesting. If the VFD is powered off, the input 0-10V is stable. I power it whilst M3 is already enabled but the VFD doesnt run (M3 command is issued whilst VFD is offline), but allows me to see the 0-50 HZ (once power is applied), you can hear the MPG click as I change speeds, perfect.



As soon as I then stop the spindle M3 command and click it again, it drops the voltage down and is all over the place. As an aside, connecting the drain wire to earth (as per their manual) lowers it down a bit more from around 16Hz at full request to 13Hz. It is as-if something in the VFD is pulling the 0-10V down. I dont know the brand, might be an issue with the VFD. I dont think its config / wiring but Ill check again. The reason I moved to this VFD is that all 3 Nflixin 9100 that I have all introduce noise which upsets my Servo Drives, this one doesnt.

Its got an AI2 input too which I might try but need to move the wires and do some reconfig on the VFD.

[suntravel]

It is no problem to move a rotary axis on a lathe incremental, but I would not use it for a turret.

I am not sure how the Centroid macro is working, but if I had to make one from scratch and the turret can rotate in both directions, I would home the turret on T0101.
Each position difference is 360/ number of positions

For example:
turret with 12 positions 360/12=30 so T0101 = 0 /T0202=30 / T0303=60 ...

Then I would calculate the shortest way from current to next called tool and decide if turning left or right is shorter/faster and let the turret turn to the absolute position of the called tool

Uwe

[Chaz]

It is no problem to move a rotary axis on a lathe incremental, but I would not use it for a turret.

I am not sure how the Centroid macro is working, but if I had to make one from scratch and the turret can rotate in both directions, I would home the turret on T0101.
Each position difference is 360/ number of positions

For example:
turret with 12 positions 360/12=30 so T0101 = 0 /T0202=30 / T0303=60 ...

Then I would calculate the shortest way from current to next called tool and decide if turning left or right is shorter/faster and let the turret turn to the absolute position of the called tool

Uwe

Thing is, I cant drive the standard 110V 3 phase motor that comes with the turret standard, so this works for me. How do you command A to move incrementally?

The turret on mine only does 1 direction. It effectively clicks past the location reverses then to lock. So in effect im doing the same, each tool is 45 apart ... see the maths in my macro.

[Chaz]

In terms of the spindle, one option is to try and use PWM / Pulse mode instead. Not ideal but might work. Unless someone can see anything wrong with the 0-10V setup that I'm trying to get working?

[suntravel]

What do you mean with Hz on a 0-10V DC output?

IMHO and from the several resends in your report I think you have noise problems from not proper grounding the shielded wiring.

If the voltage is ok in the bench test the VFD is making the problems.

If the voltage is only fluctuating some percentage use a snubber circuit on the 0-10V line.

Uwe