komar1970,
COMPUTER
1. I have major concerns about your Dell GX 520 since I have that one and also tried other Dells and found them to be
problematic for CNC use. All the comments that follow will assume that the pc is not a problem.
So trying to set the steps per unit correctly will be useless if one of the main components of the system is bad.
Skipping steps, reduced velocity and accel are just a few tell tale signs. It would be nice to be able to
substitute / try a different pc ( no laptops or other Dells) to confirm. You could use a digital o'scope to have a look
at the pc output signal.
2. Even though you do have the Bios set for EPP mode per Gecko recomendations, there is no way to remove
the signal which is causing a bad pulse. You may be able to use a different video card and pp card.You can also
use an external device such as a SS, but, I would recommend a new / different computer at current pc prices today.
3. Your pic of the driver test at 25k seemed ok ,but what happens if you move your mouse, I am also guessing
that the kernel speed is probably changing significantly when running Mach.
4.BTW, never noted that you have a break out board, etc. , so I assume the connection path is pc to drive to steppers.
MACH
1.Suggest that you upgrade from 2.58 to a current lock down. Have a look at the current revision listing to see all the
changes that have been made.
2. Configuration - based on your xml file that you posted:
Steps per unit - 400 is correct based on calculations.
3. In the attached xml i changed the velocity to 250 / accel to 100 / step and dir us to 4
Couldn't find a recommended pulse and step setting for the drives, would think that 2us would be min and
longer like 3-5us should be ok.
4. Fix the attached XML since you have wrong pins assigned:
- for input signals you are using PIN 16.....( must be 10,11,12,13,15)
- for output #2 you are using PIN 1....( only use the pins that are listed below the table)
- Do not duplicate Pin assignments
DRIVES- MOTORS - POWER SUPPLY
1. Don't think it's a G540 drive problem. Swapping cables to different motors would quickly pinpoint if there was a bad drive.
2. Couldn't find a recommended pulse and step setting for the drives, would think that 2us would be min and
longer like 3-5us should be ok.
3.The 3.5 K resistor provides for max drive current output which is ok.
4.You have 3 motors wired in series @ 3.5a each. ( 3.5 x 3=10.5 amps max x60%= 6.3 or more required min)
6.3 amps x 48 volts =302 watt supply. Your switching supply is rated at 400 watts. So the power supply
should be is adequte in both voltage and amps. We will only test one axis so more than enough.
3.Same motors for all the axis. You never remarked about the Z axis. Dosen't matter since we only want to get
one axis running correct at this time and the others can follow later.
4.I found info on your motors from the EBAY info link but here is a link specific to the motors
http://www.modelshopcnc.com/index_files/motors.htm.
You have them wired in series and the drive current is set appropriately for the motor. No motor curve is
available, so what actual torque & rpm relative to the stated 620 in / oz is not known.
Will just need to find what the max velocity.
Mill - AXIS COMPONENTS
1.Don't have any comments on the X3 mill. Run out of the end mill is not a concern at this time and can be addressed later.
2. Ground NSK C1 16MM PINCH 5MM is high end on the lead accuracy and with a matching ball nut you should not have
linear inaccuracies during axis moves unless the step per unit is incorrect, the screw is not manufactured to spec or worn,
or you have axial play in the thrust bearings. You will always have some small amount backlash.
Thus i will assume that the ball screw is mounted / supported correctly, and the bearings are preloaded.
You did note that the backlash was: Y axis is 0.01mm ( .0004") and on X 0.017mm (.00067")
So given the above see my next posted reply,
RICH
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