Front to back bed leveling

[grabredemeyer]

Hey guys, more than anything I just want to run something past you. I've noticed recently on very large prints (nearly the whole print bed) That my hot end nozzle is off the bed (z) too far towards the rear of the machine, and runs into the bed on the front of the machine. I read the thread on here about right to left bed leveling issues which looks like the same problem. It looked like the final resolution was rotation the towers in the firmware. Is it fair to assume this is the same issue? I have great 4 point leveling going on with my machine and my radius value seems pretty solid. Most prints aren't big enough for this to matter, but recently I've had the need to produce some very large prints and it's failing me. I'd like to use my max build envelope. Any thoughts outside of the left/right post? Or recommendations on how to go about that process?

[joecnc2006]

I calibrate the machine as per PDF which calibrates the bed height in front of the three towers, then calibrate the concave or convex of the bed, its a rinse and repeat thing until its spot on. and my layers are pretty even across length, granted I have not printed anything large but that what I did.

[grabredemeyer]

Yeah, that's the same process I use. The 4 point leveling as described by Gene. I'm spot on within a paper width's accuracy at all 4 points during that routine. I've also got the radius value tweaked. This is something above and beyond happening. I have great prints, it's only a problem at the outer edges of the bed.

[bubbasnow]

if you are getting lifting directly in front of a tower usually its an endstop adjustment on what ever tower the issue is on. if you have a dial indicator strap that baby onto the effector plate and get some exact measurements

[img]https://lh5.googleusercontent.com/-dXup ... 132101.jpg[/img]