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SWATH
12-25-2011, 11:18 PM
I just read the latest blog post on CNCCookbook about using hardware based pulsing like a smoothstepper rather than the software based system like I have. It got me thinking since I have experienced some strange behavior with the axis motions.

One is when I would in put say an X2 or something in the MDI, it would make the move then the Z would immediately begin moving down until I stopped it. This happened every time I would move the X or Y, the Z would always begin moving down for no apparent reason. I rebooted and the issue went away but it could have caused me some major problems.

Another one is inexplicably the Z is off after zeroing on a surface by as much as a few tenths. I rebooted and tried again, this time the Z was off a few thousanths. I then re-zeroed and it was correct.

Cutting the same program multiple times on a flat sheet directly bolted to the table with no possibility that one side is higher or lower than the other resulted in one side sometimes not cutting deep enough and sometimes it cutting too deep.

Once, running a program that I have already run several times, in mid motion all the axes stopped, the spindle turned off, the coolant turned off, and the program just sat there, no errors, not alarms, nothing, like everything just paused. There was nothing in the code to do that, and I restarted the program and ran it again with no problems.

Sometimes when I do a G28 the Z rapidly goes down before going up to the top, this has caused me to break several probe tips. Now I manually back the probe off the part before sending it home. Although this has only happened once, when I manually pressed page up on the keyboard to move the Z up it rapidly went down a small amount before going up, this also crushed a probe tip.

Anyway this got me wondering if I could benefit from a smoothstepper. What are your thoughts and what is a good one to use, how do you set it up etc. I asked Phil about it when purchasing my mill and he indicated that it was not really necessary because their controller was so good but I'm rethinking that.

SCzEngrgGroup
12-30-2011, 12:27 AM
I just read the latest blog post on CNCCookbook about using hardware based pulsing like a smoothstepper rather than the software based system like I have. It got me thinking since I have experienced some strange behavior with the axis motions.

One is when I would in put say an X2 or something in the MDI, it would make the move then the Z would immediately begin moving down until I stopped it. This happened every time I would move the X or Y, the Z would always begin moving down for no apparent reason. I rebooted and the issue went away but it could have caused me some major problems.

Another one is inexplicably the Z is off after zeroing on a surface by as much as a few tenths. I rebooted and tried again, this time the Z was off a few thousanths. I then re-zeroed and it was correct.

Cutting the same program multiple times on a flat sheet directly bolted to the table with no possibility that one side is higher or lower than the other resulted in one side sometimes not cutting deep enough and sometimes it cutting too deep.

Once, running a program that I have already run several times, in mid motion all the axes stopped, the spindle turned off, the coolant turned off, and the program just sat there, no errors, not alarms, nothing, like everything just paused. There was nothing in the code to do that, and I restarted the program and ran it again with no problems.

Sometimes when I do a G28 the Z rapidly goes down before going up to the top, this has caused me to break several probe tips. Now I manually back the probe off the part before sending it home. Although this has only happened once, when I manually pressed page up on the keyboard to move the Z up it rapidly went down a small amount before going up, this also crushed a probe tip.

Anyway this got me wondering if I could benefit from a smoothstepper. What are your thoughts and what is a good one to use, how do you set it up etc. I asked Phil about it when purchasing my mill and he indicated that it was not really necessary because their controller was so good but I'm rethinking that.

I believe pretty much everything you describe are Mach3 bugs, and would not be helped by adding a SmoothStepper. I've seen most of those problems on my mill, and I've had several different SmoothSteppers on it, including a pre-production version of the new Ethernet SmoothStepper. Mach3 is just plain buggy, which is why I'm switching to a KFlop....

Regards,
Ray L.

SWATH
12-30-2011, 12:44 AM
I assume something like this?

Dynomotion | Motion Control Boards (http://dynomotion.com/index.htm)

Can you briefly explain the advantages? Is this only for servos?

howecnc
12-30-2011, 07:47 AM
Smooth stepper will just make sure the data transfer of the code gets from the PC to the axial motors quicker and smoother. This should allow you to run the machine faster especially with large 3d surfacing code.

If you are having problems in MDI then you have other problems. Maybe a setting in Mach3 or the PC or even a bad parallel port/cable.

Also keep in mind that the Mikini homing system is not meant to be accurate. I have found things off by .02" after homing on my machine.

As for Mach3 being buggy, I have had very few problems with it, especially with Tormach's version.