Dual Extrusion with Marlin and Pronterface by doctek

Last crawled date: 2 years, 12 months ago

As promised in http://www.thingiverse.com/thing:123609 showing my dual extruder in successful operation, here is a version of Marlin to support dual extrusion on a Printrboard. Basically, the hard work was done by Denis Bakin (dob71) https://github.com/dob71/Marlin/tree/m (I refer to this as €œMarlin-M) , but was not merged into the version of Marlin used on the Printrboard ( http://blog.lincomatic.com/?p=537). If you are using Printrboard, you are probably already familiar with Lincomatic. If not, please refer to the Lincomatic link for build instructions. I have merged the Marlin M code with the Lincomatic code to provide control for dual extruders. You can download the code, called Marlin LM, as a zip file from the downloads area for this Thing. Use the code in the zip file in place of any other Marlin code you may be using with your dual extruder.
While I have not intentionally done anything to limit the use of the code to Printrboards only, I have no way to test it on other boards. Note that I have not tested it with SD cards nor with LCD panels. Use at your own risk in those applications.
Details of Extensions
G-codes T0 and T1 select one or the other of the dual extruders. Mostly, you won't have to worry about this. Slic3r uses these g-codes appropriately. We will add controls to Pronterface in a few paragraphs for switching extruders.
Default settings for Steps per Unit, Max Feedrate, etc. are still set in Configuration.h. The only change is that five values can be set instead of four. The fifth, of course, is for the second extruder. There are two values (one for each extruder) for Retraction Acceleration and Ejerk.
Note that Marlin-M allows the extruder offset (between extruder 0 and extruder 1) to be included in the Marlin code so Marlin will automatically move the selected extruder to the position of the previous one. That is, if you stop printing with one nozzle and switch to the other, the newly selected nozzle will be moved automatically to the position where the first nozzle was when the switch occurred. I did not consider this to be a desirable feature and did not fully implement it. Therefore, leave the Extruder_Offset values in Configuration_adv.h set to 0. Slic3r handles the needed offset perfectly and is easier to tweak if needed. I didn't want my extruders to jump while I was priming or calibrating them with Pronterface.