Axis Scale not right. NEED HELP

Backlash- I increase the STEPGEN_MAXACCEL to 200 with the MAX_ACCELERATION being 100.

From this I have to guess that these figures were at least 100 and 50 previously?
As you are from the States also assume that the figures are in inches? That is huge for a nema 23 powered stepper machine.

Too high acceleration is another big cause of lost steps, especially where an axis changes direction 180 degrees and there is a sudden ramp down and ramp up.

Take them right down to 10 and 5 respectively.
Then set MAX_VELOCITY down to something which equates to 3 - 6 feet per minute

Hopefully your machine will run smoothly albeit slower than it did and you can then experiment with the figures to get optimum tuning.

Faster is not always better, never missing a beat and always producing an accurate work-piece is best.

regards[/quote]

Thanks for the advice. I'll check my BASE_PERIOD when I get home and see what its set at. I need to do some more research there anyway.

The original MAX_ACCELERATION and STEPGEN_MAXACCEL were 100 and 125 to begin with. That axis is being driven by roller chain so its easy to get going. But I can slow it down. I think right now its my max IPM is 1200 and that's just insane fast. I have it turned down in AXIS to 340 for max speeds haha.

I tried 1/4 stepping and it didnt do much other then make the motors very loud, but I can try 1/8 and see if the resonance is better. I understand what you mean about interpolated steps and the software so Ill see what I can do.

Also BigJohn Ill turn off the visual effects and see what happens. I thought it might have been the PC trying to hibernate but I have all those options turned off.

Just so were clear Im not cutting at that speed just zipping back and forth

My latency was 24800 not 44000 like I said before.

What is your BASE_PERIOD set to in your .ini file? Try setting it to at least 75000 to start with


My BASE_PERIOD is currently about 35000. Should I kick it up around 70000 and see how it goes? Im going to get out into the shop to do some work today and Im going to drop my micro stepping down to 1/8th raise the baseperiod and see how it goes.

Hi

I would.

You can then play with velocity and acceleration at a very conservative thread speed until you either hit errors or are happy with it.

Then you can try reducing the thread interval which will either remove the errors / make movement smoother or you could get a realtime error before this happens, so you need to reduce velocity / accel and try again.

Most people set their acceleration far too high and have far higher max velocity than they require too.
There tends to be a macho 'faster is better' ethos and they brag about their 2 miles per minute from their Nema 23 machines as if they had 50KW servos.

What you want is a machine that never loses steps and ruins work pieces.

Read the Integrators Manual section on the INI file and you will see the settings available and their uses.
I would set the max accel and velocity for jogs down to 2/3rds of your max.
There is nothing like a momentary button press, release and press again immediately with too high accel, to trigger a following error.

Good Luck

Most people set their acceleration far too high and have far higher max velocity than they require too.

What you want is a machine that never loses steps and ruins work pieces.

Good point and I believe very true.

And as ArcEye points out if you set your speeds realistically you can run a safer longer base period with less chance of the RTA error. Less errors, less scrap metal.

Rick G

Alright so heres what ive done and the results

Changes
-Raised my BASE_PERIOD 40000 from 37102. I didn't want to push too high and loose performance and since I was changing other things at the same time I didn't want to move to far with my changes
-Disabled all background animations (thanks Big_John)
-Changed from 1/16th step to 1/8th step
-Posted all my test code from the WINE install of Vcarve, or used proven correct code and handwritten code
-Lowered all my accerations down to about 30 in step config. This seems to be a good conservative number.

Results
I ran 2 45 minute long complex programs (raptor skeletons) in the air to see if the computer would hiccup during the run. Everything ran Great!

I was able to cut a full sheet of parts in MDF at 120 IPM and never saw anything that made me worry. With my old drivers the machine alway sounded stressed at 70ish. Im hoping to do some tests in the coming weeks and find out my limits on DOC and feeds

Also the machine just seems more solid now. I did some considerable changes over the last few weeks so Im sure thats a result of everything. But it just feels better now. Im sure you guys know what I mean.

I have some deeper questions about the STEPGEN and BASE PERIOD options but Ill ask them in a different post as I feel like more people could benefit from them that way rather then digging through a 3 page thread.

Thanks for everyone's help!

Hi, I'm sorry I haven't been following following this thread, I have similar problems where my gearing is different on on differing axes and can only run at low speeds of about 120 In/min whether on jog or under load and am aiming for 240 in/min so won't be dooing much until I have sorted the mechanics. I noticed you have a smaller drive on the Z axis and you may have to configure around this. I'm running Gecko 540s and I loose steps when running a drive fast, not hard, and it appears my steppers don't want to run anything over +- 800 rev per min. Just another angle for what its worth.

cheers Paul

Glad to hear you are getting it sorted out.

I loose steps when running a drive fast, not hard, and it appears my steppers don't want to run anything over +- 800 rev per min.

Yep, everyone running steppers needs to keep in mind the torque of steppers drops off very quickly after a certain rpm, different motors and different motor sizes vary but if you try to exceed that motor's max rpm you may be disappointed.

Rick G

Hi found this, might be of interest to anyone following this thread. www.geckodrive.com/ark-2/support.html

cheers paul

Sorry should have said it is a graph and discussion RPM and torque fall off.