Mach Settings

[ltcjr71]

I'm interested to hear what everyone has there Mach 3 Settings at. I did a search and see some old posts. Seems like it would all be figured out by now.

My machine is a turnkey mill, which I have been fiddling with to get it right. Everything is better, but seems like I could get better results. What makes me think this? Glad you asked. I have a cnc4pc speed controller for my VFD and when I went to tune it, I noticed it was already turned all the way up. The instructions also mentioned a setting way lower in mach 3. So something must be different on my machine config. No way would cnc4pc create something that is maxed from the start.

What made this all come to light, was that I had x axis moves that faulted all the time. This cost me a ton of money. Finally, Tommy and I went over the configs and changed SOMETHING to 10 from 15. Problem gone, but everything was out of wack. Basically Spindle speeds were messed up and didn't reflect proper speeds. I had to set all the pulleys again and that still does make sense to me.

Here are my config settings, please post yours. Any helpful comments as well could go a long way. Does anybody know a way to get faster/reliable rapid speeds? I can't get more than 130 ipm. Sounds fast until you have code generated for high speed machining.

Base Machine:
HP Compaq DX2300
Pentium 4 3ghz with 512 ram
Windows XP SP2

Mach Settings

General Config
Kernel 45,000
Spindle setup (motor control) PWM Base Freq 9, min PWD 1%

Motor Tuning
Axis Steps Per Vel Accel Step
X & Y 20,000 130.02 10 10
Z 20,000 90 10 10
Spindle 20,000 112.5 30 10


Thanks much.

[sdfoiler]

Did you ever set the pulley speed in the config/spindle pulleys section of Mach? It took me forever to figure that out - since I never use any other gear speeds other than High/3, I never set anything thinking it wouldn't matter. However, even if you only use the high, you still have to set the pulley speed (3650 or whatever your motor is) so mach knows what is max. Once I did that, everything worked great with the cnc4pc card and I could use the recommended values and adjust with the pot on the cnc4pc card.

Try that and see what happens. From my understanding, the Step Pulse in the motor tuning (probably what you changed) is what the CNC4PC card uses to convert the step pulses to proper voltage - the higher the number, the higher the voltage -at least to a limit. If that is what was changed, I could see your spindle going crazy if it was setup properly then that number was adjusted.

As for rapids - I've had plenty of issues, so I now run mine at 80, 80, and 60 (x,y,z). It was the only way to not fault out. Granted, I'm going to upgrade to bigger motors to at least get me up to the 120 range, but I've learned to live with the slower rapids just to have the reliability.

[ltcjr71]

I did set all my gears in the pulleys, so I can change them and still be showing the correct spped. I did it in the oposite order though. The spindle was tuned to the numbers I mentioned, then I setup the pulleys. Are you saying that I should of set my pulleys first then the spindle tuning? Would you mind sharing your pulley and motor tuning settings?

[Runner4404spd]

you should be able to consistently run at 120 imp and not lose position. i added the fault detection circuitry to my geckos so when i faults everything e stops like it should. make sure your ways are good and broken in. i spent about 24 hrs running all three axis back and forth from the max to the min and back at rapid speed. as this went on about 4-6 hours i stopped everything, checked screws and adjusted the gibbs. i finally got the point where i'm satisfies with the machine and i was cutting an aluminum intake top today, with 1/2" 2 flute aluminum end mill at 4500 rpm .5 depth of cut and .125" woc and running at 80 ipm. i tried pushing faster but the machine is not heavy enough for that and sent alot of vibration through the machine, so i backed off.

anyway there is no reason to settle for poor performance, just need to find out where the problem lies and fix it.

[sdfoiler]

you should be able to consistently run at 120 imp and not lose position. i added the fault detection circuitry to my geckos so when i faults everything e stops like it should.

anyway there is no reason to settle for poor performance, just need to find out where the problem lies and fix it.

Although I do agree with this, I could never get above 90ipm on rapids without the geckos faulting on either the x or y. And yes, now I'm monitoring them and estopping when a fault occurs because of all the ruined material. I burned out a motor on the x axis early on because the gibbs were too tight. The problem with alot of this is most is done by "feel". When someone enters this arena with little knowledge of how things work (me), it's really hard to explain how to adjust them so they are tight but not too tight.

Long story short, I now have a year of cnc-ing under my belt, and have learned quite a bit. And am now in the process of upping the size of the x/y motors so I can reliably hit at least 100ipm. I have probably 70lbs of fixtures on my table all the time, so I'm sure that's some of the reason I need the extra oomph. My problem is the parts I make take around 12-16 hours of machining for one part, so I can't afford to have a fault in the middle of the part. I have to be on the safe side of reliability instead of speed (which I'm fine with).

As for the settings in Mach - I just have one pulley set at 3450 (I never change the speeds). The spindle motor tuning is then set to the standard settings cnc4pc recommended (off the top of my head I think it's 1000 steps per, max velocity (2700), 450 accel and 3 for a step pulse. Then I just adjusted the pot to get 10v from the analog voltage going to the vfd. Yes, I believe you should set your spindle pulley speeds first, then adjust the motor tuning and pot to match.

Hopefully in the next week or so, I'll be up in the 100-120ipm range rapids, even though I'll still be cutting around 15-30ipm with a spindle speed of 3400. Everything is a learning experience - but over time, things start to make much more sense.

[ksanalytical]

This is slightly off topic, but the CNC4PC speed control board (I assume M6) has been mentioned twice now with regard to spindle speed control with the VFD. Is the turnkey package from IH (with their VFD) still a manual speed control system? Or do they incorporate an integrated speed control like the CNC4PC. Just trying to decide if I need to get the M6 on order and IH isn't answering the phone at the moment.

Ken

[Cruiser]

M6 = ?
m3 = sp on cw
M4 = sp on ccw
M5 = sp stop
Sxxx = rpm per gear selected in hz output, 10hz to 120hz
gear selection = rpm range & torque amplification

[ltcjr71]

After three years with the mill, I am finally able to trust my machine a little more. I received my mill with the step set to 15 and that was causing faults all the time.

Over the last 3 days of my vacation, I have been doing some upgrades to help improve the mill.

First, my x belt was stretched since coolant likes to eat it and the plastic covers are junk. I made nice .100" aluminum ones, sealed them on and followed that with a rubber cover over the entire essembly. This solved the problem of coolant coming in through the shaft and in to the encoder. If you have colland in the lines, that is probably where its coming from. I also noticed that the slot that was suppose to have a o-ring, didn't.

One thing to also mention was that the bearing that presses in to the front plate was waaaay to tight. So tight that it was causing to bind. Fixed that too.

Oiled the machine to the hill and made some chips. Since I changed the step setting, I have been able to hit 120 rapids on my x and y. I set the z to 90, just so I don't have to worry.

After all that work, I am seeing better performance. I was cutting 6061 at 65ipm and didn't even flinch. It was a baby cut of .15, but better than before.

As for the Mach settings, I was hoping to see some numbers. Anybody care to post there motor tuning and now pulley settings?

[ksanalytical]

Cruiser,

Sorry, should have been "C6" as in the motor speed control. I hear that this is not necessary on the turnkey mills though... Your attempt at an answer to my erroneous question is appreciated in any case.

Ken