gecko tuning V3 IH cnc mill DIY

[Runner4404spd]

i'm wondering what you guys are using to tune in your geckos on the IH mill kits. i've played with a variety of settings and it doesn't seem right. i've checked the back lash twice since then and its spot on with .000/.0005 max after all the preload and adjustments. so i can definitely say my geckos are causing fits. i have the ramps and the top speed set according to what gene told me.

right now i'm thinking of writing a program with eithe rg2 or g3 arcs and then tuning on the fly. ultimately i guess i really don't know what i'm looking for in terms of good performance. right now everytime i try and cut a circle i get flats where one motor is changing direction. this leads me to believe that i don't have enough gain in the system. the cuts through the arc look good. when all said and done i expect to be able to cut a nearly perfect circle with no flats. i don't mind spending the hours required to tune it but i want some indication of what i should expect. also where have most of the gain and dampening adjustment knobs ended up? i start between 10 and 11 o'clock on both damp and gain but where do i stop?

[Cruiser]

Runner, I think what you want is in the general config > shuttle accel = .0001 or less if your sys will take it. this should help whith the direction changes. anyway it did on mine ! As for the tuning, you may be trying to get them too tight ! try this. Start with damp and gain backed off and key board handy so you can make jog with direction changes. then turn up gain till it gets smooth and then turn some damp on till it sounds like brakes applying when you change direction then back off till it is smooth and quiet. This should get you about as close to the critical damping as your going to get without the fancy scope. Don't try to adjust it too tight, and listen to it when you change directions. you only need to move it an inch or two then back and forth. Its the smooth drive and decel accel at direction change that is of interest. When it is just sitting it should be totally quiet. If any sound at all from motor, it should be minimal and very faint. When they accel and run full rapid it should run silky smooth. If your too tight it will have a bit of growl in it. "Listen and soon you'll be an expert too" a quote from Aaron !

[Runner4404spd]

my shuttle accel was set at 1. what e3xactly does the shuttle accel do? what should that number be? i will proceed with the gecko tuning this morning, but honestly after doing this twice already i'm about ready to tear the enclosure appart and hook up an osciliscope to double check them.

[SCzEngrgGroup]

i'm wondering what you guys are using to tune in your geckos on the IH mill kits. i've played with a variety of settings and it doesn't seem right. i've checked the back lash twice since then and its spot on with .000/.0005 max after all the preload and adjustments. so i can definitely say my geckos are causing fits. i have the ramps and the top speed set according to what gene told me.

right now i'm thinking of writing a program with eithe rg2 or g3 arcs and then tuning on the fly. ultimately i guess i really don't know what i'm looking for in terms of good performance. right now everytime i try and cut a circle i get flats where one motor is changing direction. this leads me to believe that i don't have enough gain in the system. the cuts through the arc look good. when all said and done i expect to be able to cut a nearly perfect circle with no flats. i don't mind spending the hours required to tune it but i want some indication of what i should expect. also where have most of the gain and dampening adjustment knobs ended up? i start between 10 and 11 o'clock on both damp and gain but where do i stop?

I fail to see how damping or gain can cause flat spots in your cuts. The Geckos will *always* drive to the commanded position, it's just a question of how hard they'll "push" to get there, and and hwo they'l react to counter-forces. You want gain as high as you can get it, without instability. If gain is too high, you'll have excessive noise, and perhaps over-shoot. Too much or too little damping will change how it approaches final position, and it's ability to hold that position.

I got all three of mine setup in about 10 minutes, entirely by ear. Start with both gain and damping at about 10 o'clock. Jog the axis back an forth at rapid speeds. Increase both gain an damping, and try again. At some point, you'll find the motors start growling when stopped, but still move nicely. At that point you're close on gain. When set properly, Geckos *will* growl periodically when stopped. About once every second or two seems to be the ideal setting. Now start doing some really heavy cuts, and very fast rapids, and you may find you sometimes lose position. If so, then reduce the damping, and try again. The best setting will have gain as high as possible (to make the axis really "stiff", and damping as low as possible (to make it very responsive). If the gain is too low, the axis will be too quiet when stopped, and will be prone to position loss. If too high, it will be maiking constant noise when stopped (and the motors will get hot). If the damping is too low, you'll get over-shoot, oscillation, or faulting when accelerating rapidly. If too high, response will be slow, and you won't be able to accelerate rapidly without faulting.

Doing this, I have my knee mill running almost 400 IPM rapids, and all three axes are nearly unstoppable - they'l break tools without losing position. The tuning is NOT difficult, and does not require an oscilloscope, just a good ear and some common sense. Remember - get gain as high as you can, then tune damping to get good stability.

Regards,
Ray L.

[Cruiser]

Runner, I don't know the definition of the shuttle accel, but it has something to do with the motors changing directions, judging by what i saw. I found on the Mach site that it is recommended to have the number as small as possible such as what i stated above .0001 is the smallest i could use. someone there stated that he had it at .000001 ! Setting tight does not give more speed or power it just makes the motor less efficient, If it sounds like the brakes are dragging then back off till all is quiet and smooth. I believe tight is heat !

[LUCKY13]

I fail to see how damping or gain can cause flat spots in your cuts. The Geckos will *always* drive to the commanded position, it's just a question of how hard they'll "push" to get there, and and hwo they'l react to counter-forces. You want gain as high as you can get it, without instability. If gain is too high, you'll have excessive noise, and perhaps over-shoot. Too much or too little damping will change how it approaches final position, and it's ability to hold that position.

I got all three of mine setup in about 10 minutes, entirely by ear. Start with both gain and damping at about 10 o'clock. Jog the axis back an forth at rapid speeds. Increase both gain an damping, and try again. At some point, you'll find the motors start growling when stopped, but still move nicely. At that point you're close on gain. When set properly, Geckos *will* growl periodically when stopped. About once every second or two seems to be the ideal setting. Now start doing some really heavy cuts, and very fast rapids, and you may find you sometimes lose position. If so, then reduce the damping, and try again. The best setting will have gain as high as possible (to make the axis really "stiff", and damping as low as possible (to make it very responsive). If the gain is too low, the axis will be too quiet when stopped, and will be prone to position loss. If too high, it will be maiking constant noise when stopped (and the motors will get hot). If the damping is too low, you'll get over-shoot, oscillation, or faulting when accelerating rapidly. If too high, response will be slow, and you won't be able to accelerate rapidly without faulting.

Doing this, I have my knee mill running almost 400 IPM rapids, and all three axes are nearly unstoppable - they'l break tools without losing position. The tuning is NOT difficult, and does not require an oscilloscope, just a good ear and some common sense. Remember - get gain as high as you can, then tune damping to get good stability.

Regards,
Ray L.

HimyKabibble, have you got your system up to 400ipm rapids now ? Geez these motors just don't give up do they.


Lets see if I am remembering right, 4 pitch screws, 2 1/2 ratio gearing on your belt drive. If you have reached 400ipm than you should be achiving 4000 RPM out of the motors. Thats impressive, the motors full RPM no load rating is 4200 rpm so your achiving almost full rated RPM.


Is it possible to reach more than rated RPM with the right power supply & tuning?


Sorry Runner440 I don't mean to highjack your thread. I wish I could help with your tuning but I am afriad I will be going through the same learning curve you are now when my motors get here. Hang in there you will get it. From the sounds of it the key is in, well, the sound.


Jess

[GaryCorlew]

From the Mach manual:

Shuttle Wheel Setting: Shuttle Accel controls the responsiveness of Mach3 to the MPG when it is
being used to control the execution of lines of GCode. Shuttle Accel is also used by Backlash.

I dont understand how that would have anything to do with tuning unless your using an mpg or backlash comp or the manual is wrong?

[Runner4404spd]

i'm not using an mpg or backlash comp on my setup.

[Cruiser]

Ah, Thats exactly right ! I guess Just because it worked for me and the info came off the machsupport.com forum to fix my issue ! Then how about the truth now ! It really is an issue with the material itself, the flats are there to begin with and you just uncovered them by accident and they are tough to cut and can really dull your tool. You'll figure it all out someday !

[Runner4404spd]

ok, i just got done running a sample circle program and it looks like it cut it without any flats. the only change i made was the shuttle accel. also just to note both time i cut the radius it was 6061 aluminum with a 1/2 cutter. also my mill now has a 3hp spindle motor. i will be attacking the tuning a little later tonight, but as of right now i have no problems hitting the 100 ipm rapids that are recommended by IH.

[Cruiser]

http://www.machsupport.com/forum/ind...ic,4726.0.html
http://www.machsupport.com/forum/ind...ic,2798.0.html
http://www.machsupport.com/forum/ind...ic,4606.0.html

[SCzEngrgGroup]

HimyKabibble, have you got your system up to 400ipm rapids now ? Geez these motors just don't give up do they.


Lets see if I am remembering right, 4 pitch screws, 2 1/2 ratio gearing on your belt drive. If you have reached 400ipm than you should be achiving 4000 RPM out of the motors. Thats impressive, the motors full RPM no load rating is 4200 rpm so your achiving almost full rated RPM.


Is it possible to reach more than rated RPM with the right power supply & tuning?


Sorry Runner440 I don't mean to highjack your thread. I wish I could help with your tuning but I am afriad I will be going through the same learning curve you are now when my motors get here. Hang in there you will get it. From the sounds of it the key is in, well, the sound.


Jess

Jess,

No, I have not actually run 400 IPM. But, I have run 330IPM, and it clearly had plenty left. 330IPM is the limit of my current 128kHz max pulse rate on the SmoothStepper, and 330IPM on something that big and heavy is plenty scary enough. I have no need to run faster, so I never upped that to 256kHz. I'm pretty confident it would do it, though. The motors are amazing. I see no reason you couldn't over-drive the motors to higher RPM, but of course heating would be an issue if you did so more than briefly.

Regards,
Ray L.