Stepper missing a step or overstepping

JoeyInCali

JoeyInCali

Maker of Joey Bautista Cues
Silver Member
Is there a way to avoid them?
I have a Xylotex controller.
The setup cuts straight fine within .002".
But, in tapering, even a dwell before heading out to the next angle, I get about 5 thou of misstep.
 
How fast are you going? I have a Xylotech on my Taig Mill. I don't trust it to cut over 15 inches per minute. When buying stuff for my two new machines I'm building, I did some research and it's a common problem with the Xylotech's. I bought a Gecko Controller and Motors for my other machines.

Have you calibrated it in Mach 3 and then set your backlash? That could be the problem too.
 
As Tony said backlash could be one problem. Second check the set screws. Third make sure there are no ac power cords running close to the motor wires. Direct drive or belt?

How do you know it is losing steps? When losing steps the machine will continually get worse the more you run it. If something is loose it will shift back and forth.

John
 
JoeyInCali said:
Is there a way to avoid them?
I have a Xylotex controller.
The setup cuts straight fine within .002".
But, in tapering, even a dwell before heading out to the next angle, I get about 5 thou of misstep.
Click to expand...

Are you using a Gantry or a Mill? Sometimes the set-ups, for cuemaking on a mill can cause binding and misteps due to weight distribution etc.. I know Dickie had fits with that originally, using a small cnc mill. Now he's built a gantry to alleviate those problems.


just more hot air!

Sherm
 
Tony Zinzola said:
How fast are you going? I have a Xylotech on my Taig Mill. I don't trust it to cut over 15 inches per minute. When buying stuff for my two new machines I'm building, I did some research and it's a common problem with the Xylotech's. I bought a Gecko Controller and Motors for my other machines.

Have you calibrated it in Mach 3 and then set your backlash? That could be the problem too.
Click to expand...

F15 is as fast as I go when tapering.
I use THK actuator with ballscrews.
Backlash might still be there.
I'll see what happens when I set it on Mach3.

Thank you all for the tips.
 
JoeyInCali said:
Is there a way to avoid them?
I have a Xylotex controller.
The setup cuts straight fine within .002".
But, in tapering, even a dwell before heading out to the next angle, I get about 5 thou of misstep.
Click to expand...

Joey, how are you checking that you are off .005"? Are you actully using an indicator or just measuring a piece of wood that you are turning? If you are missing steps with simulanious movement, thats multiply axes moving at the same time, then concider that your computer printer port is at fault. Please give detailed information as to how you can reproduce your error.

Jim.
 
Mc2 said:
Joey, how are you checking that you are off .005"? Are you actully using an indicator or just measuring a piece of wood that you are turning? If you are missing steps with simulanious movement, thats multiply axes moving at the same time, then concider that your computer printer port is at fault. Please give detailed information as to how you can reproduce your error.

Jim.
Click to expand...

Hi Jim,
The more I think about it, the more I think it's backlash b/c the error seems to be on the second movement of the Y axis.
From Y1.0 ( 1 inch from the center ) I can accurately get down to .510 ( diam. for the tip ) but it's a little oversized when it gets to the next step but not the one after that.
Basically the command goes this way ( Y0 is dead center of Y axis )
XOY1,
G0 X29
G01 Y.255 F5
G01 X23Y.260 F15

At Y.260 it seems like it's going Y.265.

I can only replicate with when tapering. I can stick an indicator on there of course. I'll see more tonite if I have time.

Thank you again for all the tips.
I've ruled out level or binding problems.
Printer port, is a possibility. I can stick a PCI card in there if I have to instead of using the built-in printer port.
 
JoeyInCali said:
Printer port, is a possibility. I can stick a PCI card in there if I have to instead of using the built-in printer port.
Click to expand...

I'm not sure how well the Xylotex plays with PCI add-on cards, but I know that the Gecko G540 doesn't play well. EPP mode and Charge Pump issues are a factor with add-ons. I don't have a Xylotex so I can't offer any help there, but I've been through too many cards trying to get the Gecko to function 100% and just basically went with a motherboard with a parallel output.

FWIW (not much most likely)

Frank
 
Voltage

Jr's Farm said:
I'm not sure how well the Xylotex plays with PCI add-on cards, but I know that the Gecko G540 doesn't play well. EPP mode and Charge Pump issues are a factor with add-ons. I don't have a Xylotex so I can't offer any help there, but I've been through too many cards trying to get the Gecko to function 100% and just basically went with a motherboard with a parallel output.

FWIW (not much most likely)

Frank
Click to expand...

Frank most of the problems there spawn from there not being a full 5 V output on the add on card. For most but not all drivers you need a full 5 v output from the pc or a power booster board.

John
 
Jr's Farm said:
I'm not sure how well the Xylotex plays with PCI add-on cards, but I know that the Gecko G540 doesn't play well. EPP mode and Charge Pump issues are a factor with add-ons. I don't have a Xylotex so I can't offer any help there, but I've been through too many cards trying to get the Gecko to function 100% and just basically went with a motherboard with a parallel output.

FWIW (not much most likely)

Frank
Click to expand...

Frank, I would have suggested this to Joey except I am not convinced he is loosing steps yet. Check out the smooth stepper from warp 9. This is a usb to pp converter. The pulse train from the smooth stepper is cleaner and will run your machine faster and with less vibration on the motors. This will plug into the Xylotex or the G540 controller. The G540 will need a gender changer if you want to just jumber board over with ribbon cable. In fact the smooth stepper will even work for an up to date laptop or computer with no printer port.

Jim.
 
Mc2 said:
Frank, I would have suggested this to Joey except I am not convinced he is loosing steps yet. Check out the smooth stepper from warp 9. This is a usb to pp converter. The pulse train from the smooth stepper is cleaner and will run your machine faster and with less vibration on the motors. This will plug into the Xylotex or the G540 controller. The G540 will need a gender changer if you want to just jumber board over with ribbon cable. In fact the smooth stepper will even work for an up to date laptop or computer with no printer port.

Jim.
Click to expand...

http://www.warp9td.com/
I don't see a USP to PP converter. I just see a controller.
And if it's as good as it says, it'd be nice.
 
JoeyInCali said:
http://www.warp9td.com/
I don't see a USP to PP converter. I just see a controller.
And if it's as good as it says, it'd be nice.
Click to expand...

Well it is the front end of the controller. It actually is equivalant to two printer ports and a break out board. You can use the first one to control your stepper controller and the other for inputs and outputs. This unit will use the 5v from your usb port or external. You just load correct plug in, usb driver, and cables. The usb cable goes to the smooth stepper, then the printer ribbon cables goes to your Xylotec board. You could use a printer cable if you wanted to and mount the smooth stepper inside your computer. It isn't all that complicated. You will use the same pin in and pin outs as your old configuration. Motor tunning is a little different but I can get you through that.

Jim.
 
Mc2 said:
Well it is the front end of the controller. It actually is equivalant to two printer ports and a break out board. You can use the first one to control your stepper controller and the other for inputs and outputs. This unit will use the 5v from your usb port or external. You just load correct plug in, usb driver, and cables. The usb cable goes to the smooth stepper, then the printer ribbon cables goes to your Xylotec board. You could use a printer cable if you wanted to and mount the smooth stepper inside your computer. It isn't all that complicated. You will use the same pin in and pin outs as your old configuration. Motor tunning is a little different but I can get you through that.

Jim.
Click to expand...

Hi Jim,

Would you mind expanding on how motor tuning is different? Inquiring minds want to know.:confused:

David
 
dchristal said:
Hi Jim,

Would you mind expanding on how motor tuning is different? Inquiring minds want to know.:confused:

David
Click to expand...

Good question. I have found that when you go into the motor tunning area every thing works the same except that when you job the motor speed doesn't update every time. I instead will save settings and jump back into Mach 3 and then job the axis. This actually may have been changed on the last plug-in but I am now used to it. I will when I get a chance verify that. By the way, I am also using the Gecko 540. I will never get another Xylotec again.

Jim.
 
Mc2 said:
Good question. I have found that when you go into the motor tunning area every thing works the same except that when you job the motor speed doesn't update every time. I instead will save settings and jump back into Mach 3 and then job the axis. This actually may have been changed on the last plug-in but I am now used to it. I will when I get a chance verify that. By the way, I am also using the Gecko 540. I will never get another Xylotec again.
Jim.
Click to expand...

OUCH!
Me neither. It gets hot, I added another fan.
And the designer couldn't tell me jack how to add limit switches.
Gecko is definitely better.
If I build another taper, I'll go with Gecko or SmoothStepper you recommended.
 
Mc2 said:
Good question. I have found that when you go into the motor tunning area every thing works the same except that when you job the motor speed doesn't update every time. I instead will save settings and jump back into Mach 3 and then job the axis. This actually may have been changed on the last plug-in but I am now used to it. I will when I get a chance verify that. By the way, I am also using the Gecko 540. I will never get another Xylotec again.

Jim.
Click to expand...

Thanks.

I've always used geckos and never looked back. They just work.
 
I know Jim and we talk quite a bit about cnc stuff. He has me convinced to try the gecko's as well, but I have to say that I have at least 4 machines running 8 hours a day 5 days a week with the xylotex systems and no real issues. We have unplugged them while powered up and smoked the chip, but that really is our fault. It's happened several times, and only blown the board one time.

I like them because they are cheap and pretty reliable. I just keep an extra box on hand and if we have an issue I just swap it out. I would have to do the same thing with the 540. In all honesty, I have to put bearing in the stepper motors more often than anything else!

In the past the gecko's, like the 201's etc, all required you to build a power supply and enclosure, wire up break out boards and such, and also cost a fair amount more money. With the new 540, the drives are built into a break out board and it can be mounted out of the way so you don't really need a box. You can buy power supply's that work great for little money, so I will lean that way on my next machine.

I will try the smooth stepper though as I think it will clean up the pulse stream for either drive.

Royce Bunnell
www.obcues.com
 
Just chipping in..

I have not used your board Joey, but I thought I could at least give another
alternative if you are looking to get rid of a old Parallel port setup.

Here is what I'm working on after my DSP controller bugged me enough to
say enough is enough : www.usbcnc.com

I have not hooked everything up yet, but the idea is that the real time part
(of controlling the machine) is ported out to the RISC processor.
I'm hoping in this way to have a rock stable setup where the "dangerous" part
is run outside the Micro$oft world and the easy part is on the PC.

The board is connected by USB to the PC and you then connect your drivers
directly to the board (through small break out boards with screw connectors).

Bert which have designed this has a daily job at Philips (in motion control)
and is extremely responsive and helpful on email...

Just another option for you, but I hope you work it out.

Kent
 
Hi Joey, if removing the backlash to near zero is not an option,then program so the axis is always loaded and go in 1 direction. If the always loaded direction is away from cl,then come in more than needed on x so feed is always out. Make sure it is in feed not rapid.
For precision turning , backlash is still a problem even on 100k lathes.The difference is the backlash may only be 1/10000 , but still needs to be compensated for.In such cases, I have always programed off the part and then come back in the direction with a compensation on x and z axis for the error. It seemed to be the only way to make the accurate stuff right.
Neil
 
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