! Speed !

[Redline]

What kind of speed are you getting out of your Xylotex setup.

IPM - TPI - motor size - oz in

[mklb]

I have three machines currently running the xylotex boards. My machines are kind of like a lathe, running in two axis. I use them to turn pool cue shafts with a router. I do use the Xylotex to provide step and direction controls for the spindle that rotates the shafts. I use the 269 inch motors from Xylotex.

The large machine that cuts 4 shafts at once with table saw blades moves at 200 IPM with a 5 TPI ballscrew for the long axis.

I have two smaller machines, one with an acme 10TPI which runs at about 95 IPM, and the other with a 5TPI ballscrew that moves at 250IPM.

I have run all of the machines a little faster, but these numbers don't hang up if I keep the slides running free. I also have a 10 TPI 5 start acme screw with an anti backlash nut that I will put on my next machine. With a 1/2" lead, I expect it to move one of my small machines at over 400IPM. You can't cut a shaft at these speeds, but the rapids help when you have to get from one end to the other to start the next cut.

Royce Bunnell
www.obcues.com

[DDM]

what kind of voltage are you running with the board, btw those are some awsome looking pool cues, the craftsmanship really shows, good work.

[HayTay]

Xylotex 3 or 4-axis unipolar driver board (discontinued)

Runs consistantly, up to 60 IPM - 20 TPI - 100 oz. in. - 35 VDC

Mach 3 Version D1.90.050 (Registered)
JGRO CNC router table

[mklb]

DDM

I have a couple of different power supplies. On my 4 blade machine, I use the complete system from Xylotex. On one of the single spindle machines I use a power supply I bought locally that is very similar to the one Xylotex sells. On the second single spindle machine I use a different type of power supply also picked up locally. This one requires a power resister across the low volt side to keep the supply on.

All of them are 24 volt. If you can get 30 volts you can get even more power. But be careful, if you go to high, you will smoke something. If you use an AC transformer the voltage output will vary with the load. I went with the switchers because they were available and I did not have to worry about over voltage.

Thanks for the kind words about the cueshafts! The construction is complicated, but the end result is well worth it. We recently tripled our production and I am starting that it will not be enough.

Royce Bunnell
www.obcues.com

[js11110]

Just out of curiosity, what speeds should I be getting out of my setup? I have the Xylotex 4 axis plug and play setup with 5/8 5 TPI ballscrews and the 270 oz.-in. motors. In mach3 I have the acceleration turned down to 60% because I was getting some missed step. I can only get relyably 70 IPM. If Haytay can get 60 IPM with 20 TPI screws, shouldn't I be able to get much more than that? Or am I thinking wrong? Maybe I have some settings in Mach 3 I can tweak to get better performance. Any thoughts would be appreciated.


Jason

[HayTay]

Originally Posted by js11110 Just out of curiosity, what speeds should I be getting... If Haytay can get 60 IPM with 20 TPI screws, shouldn't I be able to get much more than that? Or am I thinking wrong? Maybe I have some settings in Mach 3 I can tweak to get better performance. Any thoughts would be appreciated.

Sounds like you should be getting a lot more speed than you are, Jason. Also compare your speed to MKLB, he has his 5 TPI ballscrews moving at 200 - 250 IPM.

I've been using Mach since version 2 and I've noticed that several versions have performed better (for me, anyway) than other versions. As noted above, I've currently settled on Mach 3 Version D1.90.050 (Registered). I've tried several newer releases, haven't been happy with their performance and reverted back to the D1.90.050 release running with a kernel speed of 45,000 Hz.

All three of my axis are set up with the same motor tuning parameters (see screen shot below). Of course, your tuning specs. will be different based on your screws TPI, larger motor size, power supply, cabling, PC performance, etc.

[js11110]

I'm not sure which version of Mach3 I'm running. I'll check it out tomorrow. I bought it about 1 month ago. I was expecting to get alot more speed, especially having ballscrews/nuts, linear ways, etc. When assembling machine(without motors) I could push with one hand on a axis and move it from end to end without any binding or backlash. As soon as I go over 75 IPM the motors lose steps big time. Over 100 and sometimes they wont even move. I'm going to have to play with it some more. I notice you have your acceleration at 15, I've never tried this low, what ill effects (if any) will this have on the quality of work?

Jason

[ger21]

Type of machine can make a big difference in speed as well.

[HayTay]

Originally Posted by js11110 I notice you have your acceleration at 15, I've never tried this low, what ill effects (if any) will this have on the quality of work?

A less steep acceleration slope should result in more consistant cuts with less wear and tear on your machine, motors, router, bits, etc.

Consider the car analogy, which is preferrable under normal driving conditions, going from 0 - 60 MPH in 2 seconds (steep slope) or 15 seconds (gentle slope)? Under normal driving conditions most (I said most) would prefer the 15 second acceleration time. Better fuel economy, less wear and tear on the engine, drive train, transmission, etc. Also increased traction and less burnt rubber (possibly lost steps in your case). Try lowering your acceleration value in Mach3 and see if it has any effect. Don't forget the higher the Mach3 acceleration value the quicker the motors get to full speed, opposite of the car example above.

Originally Posted by js11110 I'm going to have to play with [the motor tuning/setup] some more.

You'll be glad you did. If you're using the same motors and TPI on all three axis like I am, once you find the "sweet spot" on one axis all of the others should be the same. I slowly tweaked the motor tuning until I got to the point where I noticed lost steps playing around with different accelerations. Once I was satisfied with the IPM I set the velocity to 75-80% of my limit. And yes, my setup with 20 TPI allthread will actually go up to between 72 and 80 IPM cutting air without losing steps using 100 oz in unipolar stepper motors. You'll also notice my acceleration is set to 25% of my velocity of 60 IPM. It's what works for me. I've spent more than several hours tweaking my settings in Mach3. Have fun.

[mklb]

JS11110

A couple of things to look at.

Your PC. I had one computer that I could only get about half speed out of. It was only 500 mega hertz if I recall, but I know that some computers just don't do well running a cnc machine.

Acceleration. As Haytay described very well, acceleration is a key factor in the performance of your machine.

Axis movement. How free is your axis, and how heavy is it? On my machines, the axis move on THK rails and are very free. I also don't have much weight moving around. I would say mine are les than 15 pounds.

Screw binding. Check your ballscrew alignment. If the nut is a little high or low or off to one side, it will cause a bind. Also check your screw thrust bearings. Once, I was having a problem and found it to be the thrust bearings being to tight.


After all that just play with the settings and see what happens. I don't think that setting the kernel speed any higher than 25000 htz helps. Remember that stepper motors need time to make that move for each pulse. If the pulses are to short, you get missed steps. I don't microstep my motors for that reason. I like to use 1/4 or even 1/2 step. At 200IPM with a 5 TPI screw a motor gets 26,666 steps per second if it is microstepped. If your motor is 1/4 stepped it gets 13,333 steps per second. With 1/4 stepping your motor just gets more time to complete the move for each step, not to mention being easier on your computer.

I hope that helps.

Royce
www.obcues.com

[js11110]

Originally Posted by mklb JS11110 A couple of things to look at. Your PC. I had one computer that I could only get about half speed out of. It was only 500 mega hertz if I recall, but I know that some computers just don't do well running a cnc machine. Acceleration. As Haytay described very well, acceleration is a key factor in the performance of your machine. Axis movement. How free is your axis, and how heavy is it? On my machines, the axis move on THK rails and are very free. I also don't have much weight moving around. I would say mine are les than 15 pounds. Screw binding. Check your ballscrew alignment. If the nut is a little high or low or off to one side, it will cause a bind. Also check your screw thrust bearings. Once, I was having a problem and found it to be the thrust bearings being to tight. After all that just play with the settings and see what happens. I don't think that setting the kernel speed any higher than 25000 htz helps. Remember that stepper motors need time to make that move for each pulse. If the pulses are to short, you get missed steps. I don't microstep my motors for that reason. I like to use 1/4 or even 1/2 step. At 200IPM with a 5 TPI screw a motor gets 26,666 steps per second if it is microstepped. If your motor is 1/4 stepped it gets 13,333 steps per second. With 1/4 stepping your motor just gets more time to complete the move for each step, not to mention being easier on your computer. I hope that helps. Royce www.obcues.com

I don't think its my computer. Its a 1.5 gHZ with 1 gig of ram. The screws and nuts are really good.(thats the first thing I checked.) The weight of the gantry I'm moving is probably part of the problem. I'm not sure how much it weighs, but I would guess 30+ lbs. The Xylotex kit shipped in 1/8 stepping mode, so I left it at that not wanting to mess around with it. What difference in the resolution would changing it to 1/4 stepping make, and how much would this affect the speed? Any thoughts would be appreciated!

Jason