Dear Tom,
Thanks for the information.
Regarding backlash: It seems your INIT file has 78 steps of backlash for both x and y. Shouldn't they be different?
Yes we tried with same values and also with different values. But there is no improvements. Its explained in detail below.
Please be more clear about what you are doing and what happens.
In beginning, the Backlash mode was OFF, (Mentioned Values is only for reference and its not experimental value)
While homing every time we are getting different values for all the axis and there is no repeatability.
We tried to move X or Y axis manually and measured using Dial Guage. In one direction if we move for 1mm its moved 1mm distance and its measured using dial Gauge. If we change the direction, if we move for 1mm its moved 0.5mm distance for first step then its move 1mm correctly from the second step) This will be happens whenever we change the direction.
To overcome the above issue we have find the Backlash value by using manual Jog Mode and we fixed the above issue. After using backlash for both the direction it can move by 1mm distance even if we change the direction. As per the manual (Jog Mode) Trials-testing we found X backlash should be 78.8 and Y Backlash should be 23.6.
For testing we have chosen two jobs. 1. to cut the wood in Rectangle Shape 2. Cut the wood in Circular Shape. and each explained below.
1.
RECTANGLE SHAPE CUTTING:
By using manual cutting (Jog Mode) method, We tried to
cut the rectangle shape and we achieved within 30micron tolerance. even we tried same backlash values (X=78 and Y=23) by machine cutting(NC Program) and we achieved with the same tolerance i.e 30 micron.
If we disable the Backlash or change the backlash value or X and Y backlash values are equal: In these 3 cases The cutting result will be Rectangular shape but the X and Y dimensions of the rectangle will not be the expected value( Inaccurate like 0.1 to 0.3 mm tolerance) like X=correct, Y=Small/Big or Y=Correct, X=small/big .
Even though Rectangle shape cutting was good with accepted tolerance we are doubting ourself whether rectangle shape cutting was correct or wrong because of the below cases in Circular shape cutting.
2)
CIRCULAR SHAPE CUTTING:
But, We tried the same(X=Y=78 or X=Y=23 or X=Y=xx) and different(X=78 and Y=23 and we tried with some other values also) backlash value for X and Y
FOR Circular Shape Cutting, we are found 3 case issues here,(Expected Cutting result should be Circular shape with <30micron dimension accuracy/tolerance), But we found:
1. If X and Y Backlash values are different: Circle will be two semi-circles(Shifting) as shown in Image.
2. If X and Y values are same: Circle will be an Elipse(X & Y diameters are different) shape and the dimensions will be unexpected values like +/- 0.1 to 0.3mm tolerance as shown in the image(Given Dimensions in the image is only for reference and its not correct value).
3. Backlash=OFF: The Cutting result will be Elipse shape (X & Y diameters are different).
What is the resolution of your Axes?
0.01mm for X,Y,Z axis and 0.01degree for rotary axis.
How fast are you cutting the circle?
2000mm/minute
The backlash rate of 78 steps/sec seems slow. That would take 78 (steps) / 78 (steps/second) = 1 second to correct. Try a backlash rate of 780 to correct in 0.1 seconds. Is it improved?
We tried Backlash Rate=780 and even tried with some other different values from 100 to 15000, Its not improved. If the backlash rate increases, Backlash feature will be skipped(We are guessing, because this cutting result is same as the results when the backlash was OFF).
As shown in the In C configuration file has been attached before, we have configured only
Backlash
Velocity, Accel, Jerk
Limit Switch, Soft Limit,
Output Mode, Output Channel.
Remaining parameters we have not tried because we don't know whether its required or not.
If you need more information kindly ask we will provide.
Kindly Please help us to solve this issue.