Octoprint settings

Hey guys

Setup an octoprint for my robo 3d + and it seems i have the wrong bed demensions as on large prints it seems to bouunce off the slide....
my settings are


x= 200
y= 250
z= 200


Can anyone who has one please confirm my settings?

thanks,
Aaron

 

hmm I use 220 x 254 x 200,

Is it homing properly?

 

it must not be since i have my settings smaller than yours.... anything i should be doing to home it? i thought octo did that automagically......

 

Did you hit the home button?

Unless it homes the printer would have no way of knowing where it is in the world and happily crash into all boundries if it wasn't given the home reference.

 

yeah the home buttons on the x/y and the z respectively... ill change the bed size to match yours and rehome... see what i get

 

I'd suggest testing your dimensions manually (G codes). My R1+Plus's usable dimensions are 225x246 in X/Y, Z could only get up to about 180 before wires started unplugging themselves at the Z-limiters and the X stepper motor. I determined my printer's limits just by first homing using G28, then sending G1 Xnnn or G1 Ynnn or G1 Znnn commands (through Cura's Pronterface UI or OctoPrint for example) in small steps as I got closer to the end until I found the step that caused stepper grinding. Both of the examples I listed also have UIs to do large or small motions in each axis, and you can use M114 to have the printer report back its current position (which is right until you start grinding things, then you need to do another G28 before you can trust the readings again).

For my X the newer pivoting plate for easy removal of the hotend is the thing that extends the farthest to the right and hits the Z carriage first. For my Y that was the end-to-end travel of my bed without any obstructions, not sure why other people's carriages seem to have more travel than mine does, maybe Robo shrunk it at some point? Certainly not the 10" they claim for this printer.

On my Z when I finally opened up the bottom of my unit I found a lot of slack on the wiring in the base, so I fed more cable through to the top openings and I could go higher on the Z now without anything coming unplugged, but the dual fan ducts I'm using right now hit the case and my usable Z is even less than before. I need to move to something more compact like @Marquis Johnson 's "v11" duct design, but I think I'm going to design my own version of it (wish I could grab his 123D model but the link to the model on his thingiverse page is dead and I tried messaging him on this forum but haven't heard back yet).

I'll also note that when you say "bounce off the side", that's expected in the direction of the stops (X carriage all the way to the left, bed all the way back and Z all the way down), as the homing technique is to move quickly until the limit switch fires, back off a bit, then move a bit more slowly until it fires again and take that as the zero position for that axis. On the opposite end of each axis that's where something will eventually extend too far and hit and you'll get gear grinding (I wouldn't call that a "bounce" personally, the grinding I've heard sounds like you're breaking things, I can't imagine it's good for the steppers).

Oh, and if you have one of the LCD controllers and use it to adjust the steppers, be VERY careful, at least with the full graphic display it seems the Robo ignores its limit switches while under this manual control, so you can grind things even in the direction of the limiters, and I really screwed-up my Z axis settings over-extending in the 0 direction the first time I played with using the knob to move the head around. I noticed there seems to be a setting in the Marlin firmware where the limit switches are only used during homing and that seems to be active here, that seems really stupid to me, I don't understand why they wouldn't be active all the time. So I'll probably try changing that setting next time I re-flash my Robo to see if it helps.

 

thanks fo rthe info guys. New to this and would rather not have my work PC controlling my printer.