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General Mach Discussion / Re: Problems threading on the lathe
« on: September 28, 2009, 09:32:51 AM »
Hi Guys:
The threading is being re-investigated as of this coming week or two. John S has agreed to run some tests for me to see where the wander is at. We're goign to start with the
Printer port single pulse threading, then evaluate the multislot again to document the differences. The wander is caused by a varying of the time the computer see's the index time.
It seems on some computers there is an inherent delay and this causes an overcorrrection that creates a wandering Z position. On other computers it seems not to exist. I still
dont know though if its the computer or the machien causing the variance. The multislot gives me statistics to see how much variance. When I feed it a time based generated pulse
I see no variance here, but using my Emco lathe, I see the index pulse varying in time.
This means either my motor is varying in speed slightly, ( though I cant see or hear it..) or the sensor itself just isnt that solid in terms of when it activates. More test results should be
coing out soon.
In current versions the driver was modified to a new timing base, which is more solid. My #interrupts display has since read withing a close number of selected kernal speed. 25005 for 25Khz for example, and very solid. I suspect those with further away numbers, and more variance see worse threads. Perhaps future tests will tell us which it is.
Art
The threading is being re-investigated as of this coming week or two. John S has agreed to run some tests for me to see where the wander is at. We're goign to start with the
Printer port single pulse threading, then evaluate the multislot again to document the differences. The wander is caused by a varying of the time the computer see's the index time.
It seems on some computers there is an inherent delay and this causes an overcorrrection that creates a wandering Z position. On other computers it seems not to exist. I still
dont know though if its the computer or the machien causing the variance. The multislot gives me statistics to see how much variance. When I feed it a time based generated pulse
I see no variance here, but using my Emco lathe, I see the index pulse varying in time.
This means either my motor is varying in speed slightly, ( though I cant see or hear it..) or the sensor itself just isnt that solid in terms of when it activates. More test results should be
coing out soon.
In current versions the driver was modified to a new timing base, which is more solid. My #interrupts display has since read withing a close number of selected kernal speed. 25005 for 25Khz for example, and very solid. I suspect those with further away numbers, and more variance see worse threads. Perhaps future tests will tell us which it is.
Art
