Cincinnati Millacron X axis slide

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28 Oct 2012 03:48 #25908 by LAIR82
Hey Jorge,

Yes that is correct, you will need to have the machine hydraulics on in order to move the X axis. The brake on the axis is hydraulicly released/spring applied. I believe I used the x axis enable out signal in ladder to fire the solenoid for the brake that way if the servo drive is not powered up the brake will always be applied. Not to sure but you probably need to be in the 650psi range on your machine to hold the entire slide with no power from the servo drive. Our machine will actually creep up a little bit when the hydraulics are cold the brake is released and the drive is unhooked. And it will fall quickly with those same conditions with the hydraulics off and the brake off.

Your machine may have a pressure reducing valve on the backside of the x slide unit to regulate the pressure to that cylinder. The 10cc we just got done with does not have that valve it is solely based off of system pressure(that's why it would creep in the mornings with the brake released and servo off). Pretty much all the bigger machines have that valve to adjust the pressure more precisely.
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28 Oct 2012 07:34 #25915 by jlviloria
Thanks for your answer,


on Monday we will activate our hydraulic system. I've only seen that has a solenoid, not regulate the pressure.

unfortunately I could not see the machine working never. to get an idea of how it worked.

friend I have another problem.

Now I have movement in both axes,

Today cautiously move my X axis achieved by removing the brake slowly and taking a piece of wood down.

but I worry that the variable:

MAX_ACCELERATION: 300,

I'm not sure that value. and not really not getting to an exact value.

In my case my Z axis moving 5000mm/min

0mm to 150mm away, when it reaches 150mm feels "blow" when it reaches the required position.

feels the blow in both directions, but more when going from 0 to 150mm
when going from 150-0 does feel little.

lubricate well, no obstruction, the shaft can move it by hand,

I think that may be the acceleration, or it may be that I have not reached the correct PID?

the blow is when the motor stops. not express it in English, sorry


Thanks for all your time, and your help

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03 Nov 2012 07:10 #26217 by jlviloria
RICK,

regards

a lubrication system is also through a compressed air operated pump?

the ladder diagram I can serve my?

Thank you.

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04 Nov 2012 04:05 #26244 by andypugh

MAX_ACCELERATION: 300,
I'm not sure that value. and not really not getting to an exact value.
In my case my Z axis moving 5000mm/min


300mm/s^2 doesn't seem like a very high acceleration. But you can try reducing the number to see if it makes things smoother.

Maybe the problem is the brake applying when it probably shouldn't?

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05 Nov 2012 20:10 #26272 by LAIR82
I do not understand what system you are talking about for your lathe? Is it the way lube system for the machine?

If it is the way lube system, then yes I controlled mine through the ladder.
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05 Nov 2012 20:33 #26274 by jlviloria
Thanks for your answer,

if the lube system.

mine has a pump that works with compressed air. I imagine must send a control signal to a solenoid to miss air through it and pull the plunger pump. is equal to yours.

your ladder is also adapted to mine?

mine must activate by sending pulses to work well.

I hope you understand me, excuse my English.

Jorge Viloria

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05 Nov 2012 20:58 #26276 by BigJohnT
My CHNC has a similar oiler that requires the air on for a few seconds and air off for a time. I do this in ladder when the machine is in motion.

John

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05 Nov 2012 21:00 #26277 by jlviloria
Andy, thanks for your response.


The problem I have now is that if you gain more acceleration, the movement does me good. no longer strikes,

but tried to set the PID of the servomotors. If I increase the acceleration of error peaks increase in the acceleration and deceleration.

not if it is another problem but I can not increase my P to more than 5 because it begins to oscillate. Peter told me that a low P is for adjustment.

Try D, but has been in vain. right now, I'm trying to I.

But the truth I'm lost.

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05 Nov 2012 21:21 - 05 Nov 2012 21:22 #26278 by andypugh

but tried to set the PID of the servomotors. If I increase the acceleration of error peaks increase in the acceleration and deceleration.

Which "error"
Discussion in another thread has us wondering if tuning PID on pid.M.error rather than axis.N.f-error might be better.
The way that f-error is calculated means that it will always have a higher value at higher speeds.

I can not increase my P to more than 5 because it begins to oscillate. Peter told me that a low P is for adjustment.
Try D, but has been in vain. right now, I'm trying to I.


Igain is used to get the last bit of steady-state error out. It won't make the machine any faster.

if a Pgain of 5 is as high as you can go, perhaps that is the right value? How does the machine move with a Pgain of 5?
The actual value of Pgain depends on a number of factors. If the PID input and feedback are mm and the PID output scales directly to volts then 5 does seem very low
(10V output with 2mm position error).
However, if PID command and feedback are encoder counts and PID output scales so that 1 = full power then 5 seems rather high.

What units are your PID input in, and what units are the PID output in?

Most importantly of all, does the machine move right? How does it compare to similar machines on Youtube?
Last edit: 05 Nov 2012 21:22 by andypugh.

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05 Nov 2012 21:47 - 05 Nov 2012 21:49 #26279 by jlviloria
Andy.

the machine moves well, although I have not managed to move 10000mm/min. I've only come to 7000mm/min. when 7000mm/min move faster than I get a warning in the "servodrivers".

The truth does not quite understand the translation.

the problem is that obviously when minus the max_acceleration the movement acceleration and deceleration slows. increase when moving fast acceleration in the acceleration deceleration but f-error causes very high peak in the acceleration and deceleration.

I do not understand that the input and output units of the PID?

work in programming of CNC machines, and moves well when I apply more acceleration. but the problem of peak-error f are what make me doubtful if I go on track

in the image pidnew-h acceleration 600
in the image pidnew-f acceleration 800
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Last edit: 05 Nov 2012 21:49 by jlviloria.

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