[CROSSHATCH]

This might be a huge task too take on but may also be very fun, frustrating and in all, maybe a huge accomplishment.

So the Taig CNC has 20 TPI, apparently this is almost inadequate with steppers motors: http://www.kelinginc.net/KL23H276-30-8B.pdf . The use of a Xylotex board did not help my machine because it was not a good combination between steppers, PS and the board. So I have thought of new drivers: Gecko 540's which from what I hear will be good for me but some people also feel it may not be the best. I was going too run the Gecko 540's with my steppers listed above with a 48 volt Power-Supply from EMC2 putting out a 43,000-45,000 Ghz step rate.

But again, people say that the 20 TPI screw is a huge set back for gaining high rapids. I am only looking too increase my rapids too at least 30 IPM. Cutting speeds? Between 3-7+, I mainly cut aluminum, when I cut deep, I cut slow. But would like too rapid too another position quickly.


So the idea of leadscrew conversions has been brought up, I have spoke too Nick of cartertools, he agrees the TASK too be very difficult.


Here is my plan:
The only thing that needs too be changed is,
1. leadscrew in my Taig currently.
2. Leadscrew Nut
3. Ends of the Acme thread too allow the couplings too fit.


Enco offers two types of Acme thread I'm interested in: Which is 1/2-10 TPI:

1. Thread Size: 1/2-10
Rotation: Right Hand
Length Ft. (Feet): 3
Material: Alloy Steel $19.40 ea

2. Thread Size: 1/2-10
Rotation: Right Hand
Length Ft. (Feet): 3
Material: Oil Finish Steel $4.99 ea

Enco has the Tap needed as well: However, Do I combine a roughing and finishing tap in one tool. Or do I purchase a Finishing tap? I'll most likely be making my nut from Delrin. (If thats smart...)

Thread Size: 1/2-10
Style: Roughing and Finishing
Rotation: Right Hand
Material: HSS
Thread Length (Inch): 2-9/16
Overall Length (Inch): 5
Number of Flutes: 4 $54.28 ea



As far as the Taig "Nuts" go for the leadscrew, these will need too be manufactured and tapped. I guess I would go with the same shape and design as the stock and make them out of brass or Delrin (Whichever is best) and have them precisely tapped with the Enco tap.


At this point it does not seem too bad, the final stage is more complicated. It seems that the end of rod must be tapered down and threaded for the "coupler nut". I would imagine the acme thread needs too be machined down so that the bearings can slide nicely and smooth while the end needs too be thread. This again, all the same as the stock screw.


What I mentioned above, if thats what is all that is needed. My girlfriends father is a machinist. I'm sure if I spoke too him and let him know about my project, he would have no trouble doing the ends for me as the stock Taig leadscrews are. This seems too be the biggest "part"



Does this sound like I'm on the right track or am I way in over my head? If I mill the Nuts correctly and keep too the stock size. Will tapping it precisely be too difficult with the aid of a tapping press?



-Jason

[jalessi]

Jason,

Don't waste your time, the Taig is going to be plenty fast with new drivers!

And a set of 2 to 1 timing pulleys would be much simpler.

http://tinyurl.com/5lmhqn

http://tinyurl.com/584onz

Jeff...

[Crevice Reamer]

This all sounds feasible to me. I wonder if anyone else has done this with a Taig? Surely someone has installed ball screws in one.

CR.

[jalessi]

Jason,

The Taig spindle motor wont handle 60 ipm with a large end mill cutting aluminum so why bother.

Jeff...

[jalessi]

Jason,

Your statement is way off base, there are thousands of happy customers using the Taig CNC mill!

"So the Taig CNC has 20 TPI, apparently this is almost inadequate"

Total B.S.

Get the right stepper drivers and quit making up stories!

Jeff...

[CROSSHATCH]

Jalessi: My full statement...

So the Taig CNC has 20 TPI, apparently this is almost inadequate "with" steppers motors: http://www.kelinginc.net/KL23H276-30-8B.pdf

Thats what I was saying. I know the Taig is great, it's an amazing machine.

I don't want too cut at 60 IPM or even rapid that high, I just want too rapid at roughly 30 IPM. Not cut at 30 IPM...


So I guess I'll forget it all and just get the right drivers. Again though, I don't want too spend 500.00 on Drivers and new steppers. I would like too keep my steppers and work around them, if possible.


-Jason

[Stepper Monkey]

That particular motor actually looks like an excellent choice for a Taig, 20 TPI and all, you simply need to drive it at a higher voltage. 4.2A at at least 36v or better would be ideal, as would 2.1A at 48v or better (higher voltage is even more important when wired in series due to the higher inductance of this configuration).

Proper matching of drivers and power supply to the steppers is important, and ANY driver at only 24v is not going to do your torque curve any favors even if properly matched. Improperly matched and it may not want to move very fast at all.

My Taigs all have had stock screws and I set the rapids at 40 ipm as a default. That isn't tuned to any limit or anything, its just the nice safe conservative number I generally set them to and leave it when I first assemble them and set up Mach. So at least somewhat higher would certainly be possible if you needed it I guess.
I have often thought it would be useful to install different pitch screws for some purposes, but it doesn't sound like the answer in your case.

Any quality driver and appropriate supply and you will see unbelievable increases immediately. I don't think hardware mods like screw replacement is necessary here, but even if they were there are always simple bolt-on 2:1 pulley sets meant for mounting servos. I would just go with the Geckos though - without even trying very hard they will run a Taig faster than the stock 1/2HP spindle can handle, then your limiting factor isn't your drive system anymore.

[jalessi]

Jason,

Sorry to be so harsh, however getting your attention has not been easy.

Gecko has the G251 being released in the next couple of weeks, the intro price is $39.00 per drive 3.5 amps 50 volts.

C10 breakout board $26.00

http://www.cnc4pc.com/Bidirectional_Breakout_Board.htm

Your Taig is going to have very good performance.

These are the reasons.

#1 50 volts is going to double your performance

#2 running your steppers wired in parallel doubles your performance again.

#3 The anti resonance ability's of the Gecko's

Total cost $145.00

-minus money recovered from selling xylotex.

This is not rocket science there are hundreds of Taig users running Gecko's on Taig CNC machines and they have awesome results.

If the performance is still not to your liking you can take a ten dollar loss on eBay and sell your steppers and trade up to larger units that match up to the Gecko's a better.

Even if you tossed them in the garbage new 425 ounce units cost about $150.00

Total cost $295.00

Jeff...

[jalessi]

Stepper Monkey,

Answered with eloquence and facts,

I hit him with a brick!


Jeff..

[CROSSHATCH]

Sweet, just what I wanted too hear. I get it, I just need the quality drivers and Power Supply.

Thanks for posting and helping!

-Jason

[Crevice Reamer]

In the meantime, while you are waiting for the cheap drives, maybe you CAN work better with the Zylotex. You are presently running (in Series) a 95 Volt motor with 24V. Bipolar Parallel wiring would be best for 24V, and give you more torque at higher RPM but your board can't handle the 4.2A that would be needed.

I think your best bet with this existing setup is to wire the motors in half winding. Half winding is nearly as good as Bipolar Parallel, but requires less amps.

To do this, with your motors, connect the Blue and Red wires as the first coil pair. Connect the Brown and Black wires as the second coil pair. Tape the ends of the other wires and don't use them. Now set the Vref for 2.5A. This is 1/2A less than the 3 A the motors will want, but is max for your board and should work. It won't hurt the motor or driver. Try this on one motor and see if things improve.

Here, in the Zylotex data sheet, it shows how to wire in half winding and how to set the VRef:

http://www.xylotex.com/XS3525V202.pdf

Also, with a 20 TPI screw, (20 to one gearing) SURELY you can run with less microsteps than 1/8.

CR.

[ger21]

Also, with a 20 TPI screw, (20 to one gearing) SURELY you can run with less microsteps than 1/8.

CR.

But keep in mind that resonance may be an issue if you do. Xylotex always recommends using 1/8 mode, because it's smoother.

[Crevice Reamer]

Good point, Gerry! But IIRC, he has made an anti-resonance flywheel. That should help. Lesser microsteps SHOULD speed up the rapids, and I really think the half coil wiring (With more torque available at higher rpm) will also.

CR.

[ger21]

Lesser microsteps SHOULD speed up the rapids,

Why would that be? Unless he's trying to run faster than the PC can send steps, then changing the microsteps should have no effect on speed.

[CROSSHATCH]

My Pc outputs 43-45,000 Khz steps.


I wonder how much more performance I could get? I mean, I could test it all, but I mean... I would rather ship everything back all at once. Davis will probably test it, he told me he would.

I don't mind using my stock set-up.


-Jason

[cyclestart]

If going with the new geckos you will probably be the first emc user to do so. I can think of no reason it would be a problem. Then again I don't understand why the Xylotex gave such poor performance. Just thinking out loud mostly.....

[CROSSHATCH]

nvm

[CROSSHATCH]

nvm

[CROSSHATCH]

I'm still toying with the idea of trying this conversion. No one has seem too done it and it's not that hard too do. Two key elements involved. Ea' nut has too be machined precisely but more importantly, drilled and tapped even more precise. Again, if everything is done on a mill, I can see this going pretty well. The nuts are important. The final and other crucial part is, machining the end of the acme thread for the Taig couplers, bearings etc...Again, not that difficult when I have access too a machinist who could do it.


Just my two cents. Toying with the idea still....


-Jason

[jalessi]

Jason,

There is not enough room to fit a ball nut in place of the factory nut unless you machine pockets for the ball nuts.

See the attached link for the conversion process.

http://www.chicobritish.org/CNC/

Do you understand that retrofitting your Tiag to 10 tpi screws is going to reduce the effective stepper torque by 50 percent?

Although there could be a positive trade off if you use ball screws because of there better efficiency.

Are you aware of the fact that it is going to lose half the resolution per step by doubling the distance of movement per step.

Then there is the stock spindle motor issue to contend with, it will not allow you to cut faster because it does not have enough horse power so plan on upgrading that also.

Why do you think the engineers at Taig spec out 20 TPI screws?

Could it be because they did a enormous amount of research and testing or maybe they where just guessing?

All of the Micro Mini Mills like the Taig, Sherline , MaxNc etc use 20 TPI screws, don't you wonder why?

Is it because they are cheaper than 10 TPI screws?

Have fun with the experiment.

Jeff...