[Hunter12]

Thanks, guys, I was just about to post some frustration with my Z axis in the up direction. I was losing steps on the up path to home and then it would crash on the way down into a bore. I'll fool around with all of these thoughts this week.

[MechanoMan]

Thanks for listening. I hate needing help with this stuff... I mean, im used to just being able to do things..

Well, take a deep breath like I did. We jumped into a complicated piece of technology that the seller tried to make sound simple and trouble-free. If he didn't you might have burned up years doing work that could have been done far easier with the machine.

BUT... it's not beyond your skill set to get this all set up, not by any means. The gib is totally simple and doesn't require any special machinist gauges to set for example. Looks like backlash may take a bit longer, but it doesn't look "hard" as things go. And like I say, you'll probably need to know how to set them for maintenance purposes sooner or later anyways so it doesn't matter all that much if it's wrong out of the box.

You need to get the proper speed settings into Mach3 which is also totally easy.

[Fixittt]

the resonance issues I was referring that didnt make sense to you. If you run the motors they sound like they get a bit ROUGH. If you up the speed in motor tuning, eventually they will growl and stall. Typically (Depending on machine) around 18 to 25 IPM. The machine is capable of a little higher speeds if some sort of harmonic dampener is used. Here are some videos I made of my Maxnc and the fun of dealing with this issue. The allergro (SP) style stepper drivers do not compensate for this problem. Where the geckos solve this issue within the stepper driver itself.

[ame="http://www.youtube.com/watch?v=9RoOZs9LrYo"]YouTube - 20 inches per minute resonce in stepper[/ame]

[ame="http://www.youtube.com/watch?v=8Am69_F93yA"]YouTube - 65 ipm[/ame]

[ame="http://www.youtube.com/watch?v=ivDQTeGuduk"]YouTube - 50 ipm test[/ame]

[MechanoMan]

Huh. Are all 3 videos are of the Xylotex then? Do you have a reference page on what goes onto the harmonic dampeners? I mean I see a piece of aluminum and bolts and washers but don't quite comprehend yet. I was under the impression that adding inertial mass to the shaft was "bad" and would require decreasing the acceleration value to stay within the torque output of the stepper, but then that slows down the fine zig-zag detail work which the mill may be doing more often than straight-line work.

Is it practical to run this at 50 or 65 ipm like this, on real work? What acceleration value is practical? And this is Xylotex?

I heard mention that some people say that a Taig shouldn't be used above a certain ipm (like 30?) due to increased wear. Any truth there? I mean by running at 60 ipm you could be processing twice as many parts per day on it (or adding twice the movement to improve the detail within the budgeted working time). By that theory the leadscrew/nut is not wearing out any faster in terms of inches traveled, it's just getting done sooner which makes the wear per operating hour SEEM higher.

Well if I'm gonna consider switching to the Gecko drivers- but there's only like 2 hours left in their sale to decide. The price goes way up after today.

[Fixittt]

That dampener in the videos is something I crudly put together at 3 am of things I already had........ here is a very good thread about them and the design and construction
http://www.cnczone.com/forums/showthread.php?t=32284

G 540 will solve the problem as well.

as with anything else, higher speeds will increase wear. Or like the old hot rodders saying goes. Speed costs, how fast do you want to go?

[rowbare]

This has been a really informative thread. It inspired me to spend the evening tuning and tweaking. I have a deepgroove setup but have an G540 and the Keling 387s on order. I figured I would see what I can get out of it with the my current setup as a baseline and compare from there.

I am getting about 40 IPM rapids from my X though it might be setup a bit loosely. If I tighten the gibs any more it will stall rather quickly. I am getting a good 25-30 IPM on the Z and don't seem to have any appreciable backlash there so I am happy with that.

However the Y axis is a different story... It is fine when the X axis is centered however once I move the X axis to the right about 3 inches it will start to bind and lose steps. This is obviously due to the cantilevering effect with the motor hanging off the right. Has anyone else experienced this? I haven't tried any adjustment yet. Would tightening the Y gibs help?

Thanks. I hope this isn't diverging too much from the topic....

[TOTALLYRC]

This has been a really informative thread. It inspired me to spend the evening tuning and tweaking. I have a deepgroove setup but have an G540 and the Keling 387s on order. I figured I would see what I can get out of it with the my current setup as a baseline and compare from there.

I am getting about 40 IPM rapids from my X though it might be setup a bit loosely. If I tighten the gibs any more it will stall rather quickly. I am getting a good 25-30 IPM on the Z and don't seem to have any appreciable backlash there so I am happy with that.

However the Y axis is a different story... It is fine when the X axis is centered however once I move the X axis to the right about 3 inches it will start to bind and lose steps. This is obviously due to the cantilevering effect with the motor hanging off the right. Has anyone else experienced this? I haven't tried any adjustment yet. Would tightening the Y gibs help?

Thanks. I hope this isn't diverging too much from the topic....

If you are running the y at 40 ipm, that is the problem. You are most likely on the ragged edge of stalling, just like the x. Try tuning the y to 15 ipm and see if it still stalls.
When you get the g540, you will be able to run much more reliably.

Mike

[Stepper Monkey]

I would agree, not only are you likely running the system on the ragged edge at those speeds with an Allegro system, if things are too loose they can tend to bind too!
Running gibs too loose at first can seem to be a trade of consistency for speed, but not always. If things are set up too loose, the movement caused by things like the cantilevering effect of the X can cause a binding as well - in this case through stress concentrations. What happens is that if something is allowed to tilt or rack enough, you get uneven pressures, and so instead of the force being borne acrosss the full bearing surface it is just being applied to very small contact areas. Usually the edges. This equates to a dramatic increase in PSI and much greater tendency to bind, so it is the worst of both worlds.
Get the machine to a happy balance, regardless of whether your current drivers can handle it. This will mean that likely the Allegros will have problems over 10 IPM on the Z, and over more than 15 or 20 on the X and Y, but this is where the machine needs to be. Get it there first, then up the drivers if they can't cut it, as you've already figured out.
Geckos with a new PS will simply scream on a Taig. No more need to sacrifice proper adjustment to get adequate function!

[S_J_H]

hmmm, I have a x3 and use a xylotex system with 425oz steppers and custom dampers which were well covered on this site.
Had the system on the mill over 2 years and is used 3-4 times per week. 100IPM rapids on the table( ballscrews) and 20 on the z( acme). The head of the x3 weighs about as much as an entire taig mill. Enough power to bury a 3/4" endmill as deep as the x3 spindle motor can power it. Certainly enough power to snap 3/8" endmills with ease.

Also use a xylotex with 269's on my custom made cnc lathe and that'll run 150ipm rapids and never lose a step.

Honestly, the xylotex system is low tech and entry level.No doubt about that.
But not a reason in the world it can't run perfectly on a little taig!
Proper setup is very important. More muscle is not always the answer!
Steve

[Stepper Monkey]

More muscle is definitely not the answer, but more voltage is in his specific case. You have 5tpi screws and the Taig 20tpi, so the motors have to spin four times faster for the same IPM. The motors that he has been supplied by Deepgroove are so ill-matched to the low voltage of the Xylotex, they aren't performing at a fraction of thier potential and can't get up to speed. The new drivers do have more oomph, but what he'll really notice is by raising the voltage from 24 to 50 volts those same motors will wake up and really toss that little machine around.

It isn't about the muscle, as he would actually do better if Deepgroove had originally supplied much smaller 110-150 oz motors. They do quite well with a Xylotex and a Taig as they have lower inductance and so can spin faster as required by the thread pitch. The high thread pitch also helps with the mechanical advantage so even a 100 oz motor has more than enough kick. This was really more what the machine was originally intended for, small, light, fast motors.

I would agree that a Xylotex can be perfectly functional if properly set up for the machine, the motors, and the screw pitch, his just isn't. I guess that a new driver to match the motors is only one option. You have reminded me that there is indeed second way - he could also just get much smaller and lower inductance motors to match the Xylotex instead, and still have a pretty competent machine.
Given the choice between the two I'd still take route of getting a new driver over new motors, as it will be a far better handling machine in the end, but it is possible to make the Xylotex work as well.

I had great luck Xylotex for years, but then again I was using 116/oz motors too so they spun fast quite happily! Wouldn't want to go back to using them though now given the choice.

[rowbare]

I received my G540 today. What a nice piece of gear... I hogged out my case to fit it and did some temporary wiring to test it using the 28V supply from my original setup and the original deepgroove steppers. I only had time to do a little bit of motor tuning and make a couple of cuts but I am pleased so far.

My new keling 387s should be here in a few days. I know they are big for a Taig but I ordered them since they are listed as a good match for the G540. However after reading your last post I went back to the keling site and looked at some smaller motors and found KL23H256-21-8B which is 185 oz/in at 3 amps with a 2.4 mh inductance when wired bipolar parallel. This makes it an almost perfect match for a 50V power supply. I am tempted to order a set of these (in the interest of science of course) to try them out. I can always sell one set or the other later. Or build another machine...

Tomorrow I will do a bit more work on the box and will hook up my 50V supply and see what that gives me... Fun times.

[Fixittt]

LOLOL I for see someone ordering new backlash nuts, screws and gib strips soon!!!! In the interest of science that is!

[Stepper Monkey]

You will be pleased with the performance with either set of those motors, as long as you run a 48v supply. I would just stick with the 387's you ordered, it isn't a bad setup at all.
If you are really interested in experimenting and getting every last bit of speed, I would suggest only putting the 185's on X and Y and leaving a 387 on the Z if you keep the heavy stock spindle motor. That combo will seriously haul, so much so you will likely run into limitations with the speed of your computers ability to keep up unless its really fast and jammed with RAM, not the motors! I have had that problem on my normal Taig with a similar setup (I think its two 160-ish motors and around a 300/oz on Z if I remember right).
My light material cutting Taig is set up using two 116's on X and Y. At 4 amps at only 0.8 inductance I cut at a bit over six feet a minute with enough oomph to still snap 1/4" mills, but it isn't set up to handle harder materials either.

[S_J_H]

Stepper Monkey,
Thanks for the info (post#30)! That clears up my confusion why the xylotex system was not working well on his machine.

Steve

[kbillan]

Okay-- im ready to open an artery here.

I thought all was fixed... I ran a part a few days ago-== flawless. Last night i ran a part and half way through.. lost steps again..

I am running the tooling at 20.ipm with the X speed at 20., the Y at 20. and the Z at 15....

I cant take anymore.

what exactly do I need to buy from Gecko? Do i need new motors too? does this all just plug in? please-- i beg- make it stop.

Keith

[rowbare]

Okay-- im ready to open an artery here.

I thought all was fixed... I ran a part a few days ago-== flawless. Last night i ran a part and half way through.. lost steps again..

I am running the tooling at 20.ipm with the X speed at 20., the Y at 20. and the Z at 15....

I cant take anymore.

what exactly do I need to buy from Gecko? Do i need new motors too? does this all just plug in? please-- i beg- make it stop.

Keith

I ordered a G540 from Gecko. I place the order Monday night and had it in my hands Wednesday morning. That will cost you $300 plus shipping.

Besides that, you will need some resistors. I believe that 2.7K is a standard value so they would be easy to find and would work well with the 2.8 amp motors you have.

I would suggest using the motors you have since they are bought and paid for. You will have to cut off the existing connectors and solder on a the new ones that are supplied with the G540.

You will probably want to upgrade to a 48-50V power supply but the one you have now will get you cutting. I only had time for a couple of cuts once I assembled things last night but I made a 1/8" deep cut in some UHMW with a 3/8" cutter at 50IPM using the 28V PS. Note that my machine is probably on the loose side and I was using a really good cutter but still... It was fun to watch those curls of plastic flying all over the place.

In the long term, you might want try different motors but I would suggest holding off for a while. I have some 387s coming and I ordered some 185s as well so will be doing some testing with these as will others. I think that over the next couple of months some really good combinations will emerge for use with the G540. I think StepperMonkeys observations in post #33 will prove to be bang on.

If you choose to go with Keling for the power supply, they have a nice mushroom E-Stop switch for about $10.

bob

[kbillan]

so the 540 is all i need. where do you get the resistors? Size?

i looked at the gecko stuff, I was under the impression i would need one for each axis....


and then once I have this, how do you set up mach3 to it, or is all of this info in the manual that comes along?

Same interface to the computer (parallel)

[rowbare]

The G540 is basically 4 G250/251 drives plus a breakout board in one neat little package. The resistors are used to limit the current output of the drives and are soldered across two of the pins in the connector. You should be able to get them at Radio Shack.

For the motors you have, you would most easily find 2.7K ohm 1/4 watt resistors. That will limit the current to 2.7 amps which is close enough to the 2.8 amps motor rating.

As well the G540 supports such niceties as E-Stop, Variable speed motor drives etc...

Oh one more thing you need is a DB25 Male-Male adapter since the parallel connector on the Gecko is female as opposed to the male on your current setup.

I re-used the case I had. I made a big rectangular cutout where the old connectors were and fit the Gecko in there.

Here is the G540 page:
http://www.geckodrive.com/product.aspx?c=3&i=14469

This is the owners manual:
http://www.geckodrive.com/upload/G54...3%20MANUAL.pdf

bob

[kbillan]

1 Gecko G540 is being airlifted to me as we speak. This is a CNC EMERGENCY.

It will be here tomorrow and I plan on having this thing running at 500 IPM tommorrow night. (exageration- obviously)

So a few NEW questions.. what will i set the motor speed and accelleration to in Mach3 with this new controller? (cutting wax)

Do you all think i can get any money out of the deepgroove controller? Would it be in my best interest to use the case and power supply from it?

What will be the dissadvantages to using the powersupply i have? In speed terms..

I cant spend any more money on this project until start recovering the investment. So- i need this to be 100% useable this weekend. I am going to get the adaptor after school tomorrow.. probably just get a whole new cable actually, with the proper fittings.. while im at radio shack getting the resistors.. i hope that is self explainatory as well.

Thanks for everyones help

Keith

[Stepper Monkey]

I'd sell the whole extra driver as a unit. If you use the power supply from the old unit the performance will only be about the same as you had. The greatest asset the Geckos have is that they run at twice the voltage, which is what you need! The Xylotex does have fewer features, runs less current, and is less robust, but it's only serious limitation holding you back is that 24 volt ceiling!

Top motor speed is going to be something to set second, work on acceleration first. This is actually most important anyway. Just keep bumping it up until you get missed steps on a movement start - you'll hear them, trust me. Once you get to that point, back it off about 20% to be on the very safe side , a little less if you want to live dangerously.
After the accel is set, raise the top speeds up. Use the same method as above and fall back 20%. Probably can go as high as you like without a stall. In reality, on a machine this small the machine won't usually ever get to those speeds anyway before it makes a direction change. At any rate you want to know what your top WORKING speeds are, not just what it can rapid at, so give it a practical test. Once you get a nice stable high speed chosen, push on the axis and give some resistance as if you were trying to stop it as it's moving toward you. See if you get stalling then. It will probably actually just gently push the whole machine away from you if it's set right. It doesn't have to have a ton of oomph, just more than is required to snap a bit. Any more than that is wasted anyway!
Have fun!