I had my rostock perfectly calibrated with one print head. Now that I have upgraded to two print heads I cannot seem to get the horizontal radius figured out. Using repetier my Y offset in the eeprom is set to 1014 steps (extr1) and -1014 (extr2).
The problem Im encountering my center point is accurate when I run g0 z0 x0 y90 f3500
The problem is calculating the outer points
when I run g0 z0 x0 y90 f3500 my extr2 touches the glass before the extr1 can be adjusted close enough.
when I run the below two commands the extr2 is higher than extr1
g0 z0 x-77.94 y-45 f3500
g0 z0 x77.94 y-45 f3500
Can anyone give me some guidance on calibrating two print heads properly? Do you calibrate it before setting the Y offset or any other such method?
Calibrating the print heads on a dual extruder
-
sunkenbier
- Plasticator
- Posts: 16
- Joined: Tue Jun 18, 2013 4:32 pm
-
Polygonhell
- ULTIMATE 3D JEDI
- Posts: 2417
- Joined: Mon Mar 26, 2012 1:44 pm
- Location: Redmond WA
Re: Calibrating the print heads on a dual extruder
The short version is you'll have issues at the edge of the build area with dual extruders.
The rostock geometry "guarantees" the effector platform stays level in theory, however, the effectiveness of those constraints are heavily reduced as the arms get close to horizontal, you'll find if you move the effector to the edge of the build area and try and wiggle the platform, it has a LOT more rotational play in it than at the center of the build area. In fact if you have any rotational load on the platform you'll see that it won't be flat relative to the glass build plate.
With a single centrally mounted extruder this isn't much of an issue, because the rotation doesn't translate to significant vertical displacement. However when you have dual hotends and both are offset from the center, you'll start to see significant Z differences at the edge of the build area between the two hotends which you will not be able to easily tune out.
To minimize the issue, you need to make sure there is no rotational load on the platform, that pretty much means everything connected to the effector plate (hotend wiring, bowden tubes and if using a Kraken, the water cooling lines) have to be coming in vertically.
I personally set the delta radius with a single centrally mounted hotend, it won't change for dual extruders. I set both hotend offsets to 0 in the eeprom and use the offsets in the Slicer to select the extruder because it causes less problems.
The rostock geometry "guarantees" the effector platform stays level in theory, however, the effectiveness of those constraints are heavily reduced as the arms get close to horizontal, you'll find if you move the effector to the edge of the build area and try and wiggle the platform, it has a LOT more rotational play in it than at the center of the build area. In fact if you have any rotational load on the platform you'll see that it won't be flat relative to the glass build plate.
With a single centrally mounted extruder this isn't much of an issue, because the rotation doesn't translate to significant vertical displacement. However when you have dual hotends and both are offset from the center, you'll start to see significant Z differences at the edge of the build area between the two hotends which you will not be able to easily tune out.
To minimize the issue, you need to make sure there is no rotational load on the platform, that pretty much means everything connected to the effector plate (hotend wiring, bowden tubes and if using a Kraken, the water cooling lines) have to be coming in vertically.
I personally set the delta radius with a single centrally mounted hotend, it won't change for dual extruders. I set both hotend offsets to 0 in the eeprom and use the offsets in the Slicer to select the extruder because it causes less problems.
Last edited by Polygonhell on Tue Aug 05, 2014 3:48 pm, edited 1 time in total.
Printer blog http://3dprinterhell.blogspot.com/
Re: Calibrating the print heads on a dual extruder
When i was calibrating my duals, i used my single nozzle calibrated radius. then installed the dual mount and just shimmed so both z heights were the same. in firmware i set my nozzle 1 offset in y axis offset = 1000, and nozzle 2 offset =-1000 (for my mount, yours might be different). then i set z height with t0, and shimmed t1 in the center until they were the same.