Partially Solved Calibrating seems to be off on Y axis

No, it always knows where Y0 (or X or Z) is because there is a physical switch that gets triggered to tell it "HOME"
It knows how big the Y axis is (lets say 240mm) So Y max = Y HOME (the switch) + 240mm of steps

If something is in the way and causes the switch to get triggered incorrectly (like a wire) then that would be a problem.
If something is in the way of the bed travelling the full Y distance (like a wire) then it will grind when it is forced to stop too soon.

 

Actually @Jeff Ortakales It always knows where Y0 is and that is the only location guaranteed. It is Y_MAX_POS that is incorrect. It is simply too big. Note Robo says Y_MAX_POS is 254. You can determine this for yourself by doing the following in a terminal screen.

Code:

G28 Y
G1 Y200
G1 Y220
G1 Y225
G1 Y230
...

Keep moving it a few mm until it stops and starts to grind. Then you will know exactly how big the bed is in the Y axis. I think you will be surprised to find that Y probably only moves to about 235 mm. That is about 19 mm shorter than the claimed 254 mm and would move the mathematical center forward about 9.5 mm if the correct number were in place. Just as an FYI my Robo is fine at Y236 and grinds at Y237.

You can do the same thing for X, and you will see a similar discrepancy (marketing vs. reality).
You can do the same thing for Z, and you will see a similar discrepancy (marketing vs. reality).

Once you change it to the correct values, Marlin then knows exactly how big the bed is. But that is only half the issue. Your slicer needs to know the accurate dimensions also. So you need to go into the slicer's printer profile and change the dimensions there to the ones you discovered in your test. Only then will the Robo center prints in the proper location.

 

@Jeff Ortakales

Marlin in Configuration.h lines that read:

Code:

// Travel limits after homing
#define X_MAX_POS 240
#define X_MIN_POS 0
#define Y_MAX_POS 254
#define Y_MIN_POS 0
#define Z_MAX_POS 240
#define Z_MIN_POS 0

Of course you just measured Y, the minimum will always be 0 but the maximum will now be 247 (I would err on the side of caution and maybe make it 246, 2 mm won't make much difference).

I don't know what slicer you use so I can't help you there, but it is usually in printer configuration.

 

Likely

 

?Lines?

If you mean the actual heated area, OK, if you mean the graphic on the build plate -- it is meaningless. A pretty design graphic, not indicative of where the heater actually is mounted on any one machine. If they meant for it to be, then it is a manufacturing fail because it seldom lines up with anything

Will your large part fit completely over the heated area or does some of it overhang regardless of placement? You can look under the bed ad see where the heater pad is physically mounted and make a note of it. Then center you model on it.

You can control with most all software exactly where the model is placed on the bed so making sure it is placed center of the heated area is what you would do.

Even then, in all fairness, if bed heat is really critical you may have issues because the style of bed heater we have is not the best. You may find the heat is uneven across the bed by some degrees. In the center of the heater (or close to the thermistor) it will be what you set it at, but it will fall off quickly around the edges.