Flashcut to Geckodrive 210

[steveald]

Hi Donny,

I'm glad you have things working, although I'm disappointed you had to get rid of Flashcut. I really like the interface. Which version of the software were you using? Did you try 1.x or just 2.x? Maybe it's a bug in the new(er) software. I have heard that they have had constant contouring problems in the past. My motors go postal without the SG turned on, so I have that problem to fix. When I get that looked after, if I'm still having problems, I'll try Mach2. Flashcut was a lot of money to just put in a box

Thanks for sharing your experience,

Steve

[stanleyr]

Originally Posted by whiteriver Any hard science on what to set the Step Pulse Poliarty, Step Pulse Width or Enable Signal Poliarty in regards to Flashcut to Gecko? Anyone else using Flashcut to Gecko? Any problems? Any sucess? What are your settings? What works? What doesn't. Donny

I know this is more than a year later. If others are having a problem with FlashCut this may help.

Step pulse polarity and continuous contouring (for 3D) will have a big effect on lost steps. I found using the high polarity was a problem with the G210s. Low polarity was a vast improvement.

Set the continuous contouring down to a very low value along with your stop/start rate. Start both of them at 5 and work up in increments of 5 until you see you are skipping steps. Back off to the previous value or somewhere between the current value and last value.

A G210 needs a minimum of 4us of pulse width. You can set FC to 6us of pulse width.

If you use the dynamic enable feature, (I think) the disable input wire will ground out at the G210 and it will shut off the power to the stepper motor - causing lost steps.

Other items will be the quality of the stepper motor, the voltage you run the motors at, and the amperage. The G210's can handle a lot of voltage if your motors can. You can read about this on Gecko's web site in the 'Support' page: The Step Motor Basics White Paper: Power Supplies (page 2) http://www.geckodrives.com/ycom/docu...r_supplies.pdf. The literature will indicate running the G210 voltage up to 25 times the motor winding voltage (BE SURE YOU UNDERSTAND WHAT THAT MEANS). I am NOT talking about a 24V motor times 25. Rather, it is a formula based on the resistance of the winding and the rated amperage. Anyway, you can try running at 20 (for safety) times the winding voltage to see if that improves your torque too.

Don't know if this would have helped before you went to Mach2, but it is good that you are happy with your system now.

[CNCadmin]

I just got my system today, and plan on using it with gecko steppers and servos drives.

[stanleyr]

Just ran my system FC with Gecko and open loop steppers @ 10uSteps this weekend after spending some time with the motor/driver settings (voltage and amperage). Ended up with 60,000 lines of contouring code and the motors did extremely well - within .0005 at the end of the day.

I also wanted to tell you another way of setting "Continuous Contouring" that is slightly more scientific than just bumping it up from the start/stop feed rate value:

Run some code with predictable contouring in it and listen to the motors. Lower the Continous Contouring (CC) value until the motors start to hesitate and chop their way through the contour. Change the CC value to a higher amount in small increments until you hear your motors blend together without hesitation through the contouring movement. As long as the motors are blending smoothly and not missing steps, that CC value should be good.

My CC values are set at 3.85 for X and Y and 2.75 for Z. My machine is not a barn burner (25 IPM for example tops at 10uS), but is suitable for my needs.

[CNCadmin]

What is the fastest IPM that can be run for a stepper set-up?

[stanleyr]

That depends on many things such as the mass of the axis movement; the thread pitch of the driving screw; the gear reduction; the software's capabilities of generating pulses to command the motor drivers; the minimum pulse width necessary for the motor driver, etc.

I have a 10 turns/inch lead screw, with a 2.5 to 1 reduction. So my machine is really set up for fine movements. My stepper must turn the equivalent of 5000 steps or 50,000 micro steps at the 10uStep setting just to go 1 inch! . So you can see that in order to go 20ipm on my machine for 1 axis, the software must generate enough pulses to produce 1,000,000 uSteps in a minute or 16,666 uSteps in one second. That's !

Back to your question though: If you think of it in RPM, my stepper is actually turning 500 RPM when the axis is at 20ipm. You can do your own math as to what your axis speed will be. But my motors are Nema 34 motors and are perfectly happy at that speed for rapid movement. This is on a Wabeco benchtop mill with a 80lb Kurt vise on the xy table. I generally cut at 5 to 15ipm. After many hours of running, the x and y motors peak out at 125 DegF (65 DegF rise) and the z motor reaches 145 DegF (85 DegF rise), measured at the case. This is well below the point!

I have run the motors at faster speeds than this by reducing the micro step setting at the driver - say from 10uStp to 5uStp or 2uStp. I was able to (rapid) move near 50ipm at 2uStp, which I believe comes out to 1250 RPM, 500,000 pulses in a minute or 8333 pulses/second . I don't need to run this fast (saves the ACME screw and nut for more important things); and although my machine ran reliably at that speed, it does increase the chance of resonance and lost steps for my particular machine ; so why bother?

I found through trial and error that my setup behaves much better when I use the 10uStp setting; higher motor driver regulated voltage of 50-55VDC; and incrementally increasing amperage settings - keeping a watchful eye on the motor's case temperatures.