Help - Program Not Maintaining 'Y'???

I checked the machine squareness using 3-4-5 method and it was good enough for my purposes, less than a MIL.

I loaded the program, set X & Y zero.  Being my first program ever, I manually jogged to all the bores hole locations, marking the X-min an X-max (as specified in the program) with lines delineating the expected positioning and hole diameter.  I just ran my program, 2 of 5 rows each with 12 holes per row.  The first row runs left to right and second row right to left  The positioning along x-axis is as expected matching the previously made marks for both rows.  The issue is that when the program is running, the Y-position of the second rows creeps towards the first row not matching the previously marked expected position, the spacing between the holes is decreasing moving right to left.

I just stopped the program and issued G0 X0, Y0.  Unanticipated was the crashing of the Y, subsequently re-squaring of the machine will need to completed again.

Post processor is EMC2 and I am using F360.

Attached is the NGC file if needed.

Sounds like a mechanical or lost step issue

I would verify that jogging Y back and forth does not
result in accumulated position errors

Aciera wrote:

Sounds like you are loosing steps on the y axis during actual machining which leads to a positional offset between the actual machine and the controller. That would then lead to the Y axis exceeding it's soft limit when issuing G0 X0 Y0 (presuming your machine has no positional feedback like encoders or scales).
Which is why hardware limit switches are useful.

[edit]
Could you provide some information about the motors and drives?
First thing you could try is to reduce acceleration and velocities for the Y axis/joint and try again.
 

Stepper Drivers: DM542, Leadshine knock-offs.  Microstep: 8.  Steps/Rev: 1600 for 1.8 degree motor.
Stepper Motors: NEMA 23.  HLTNC.  4-wire, Step Angle 1.8 degrees.  Rated: 3V, 3A

The second part of your response, should that be changing the microstep to 4 at 800 steps/rev on driver or is that a change in the INI file?  Attached in my machine INI file.

 

PCW wrote:

Sounds like a mechanical or lost step issue

I would verify that jogging Y back and forth does not
result in accumulated position errors
 

I was thinking the same (losing steps) and went ahead and bought replacement DM542 drivers.
I think I have been doing what you suggested moving to each Y position as shown in the sketch across all five rows, but will give it another go and take note of the Y value within the DRO display.
 

Aciera wrote:

Actually since your rapids seem to be ok you may want to try running the job again with a reduced cutting feed rate (eg feed override at say 70%).

Will do.  F360 tooling specs imported from Genmitsu web site for flat end mill I am using sets Cutting Feedrate at 1000 mm/min, I'll set it to 700 and give it a go.  Transition Feedrate default on import is 1000mm/min.  I am not making consecutive passes, based on F360 pop-up help for this field I don't think this input is a factor in my current dilemma and will leave as-is.  Lead-In and -Out Feedrates are set to 800mm/min on import.  F360 help states these values should be same (or lower based on job clearance needs) than the Cutting Feedrate.  I don't like changing too many parameters at one time without seeing/knowing impact of the previous changes if can be prevented, as these will be close to the new Cutting Feedrate I leave them as they are on import as well.

@PCW : Machine checked for square twice after an adjustment to Y2 (right Y-axis); the second time using the 3-4-5 via mirrored transformation and hypotenuse segment lengths were accurate enough for my purposes.  Following your recommendation, I jogged Y alone and then with X to max extents and in between as well as crisscrossing; DRO and manually measured (as accurate as I can get at least) distances and straight paths seem to be jiving up.  I am not pushing the drivers or steppers hard like a program would, so my efforts may not substantiate much of anything.

Appreciate the assistance.