The Low Down on Dual Extruders
Good news in the way of dual extrusion is here. Repetier knows the importance of making multi extrusion more user friendly. They recently released Repetier Host V1.0.0 which has a ton of dual or multi extrusion add ons. For the cost of a few parts and an app you can download Repetier Informer. It will send free push notifications to your iPad or iPhone updating you on the status of your printer.
Slic3r has also gotten in the game with all kinds of new options for multi head extrusion. You can now switch nozzle size on your extra extruders. It also has an option to put a larger nozzle on and use it for quick infill. This dramatically saves on print time. CuraEngine is also included along side Skienforge.
Slic3r 1.1.7 stable us out or for the guy who has to check out the newest tech – Slic3r 1.1.2 experimental is also available. Find both versions as well as past versions by clicking HERE
A lot of the issues described below are
One of the most annoying problems with the dual extruder printing is the plastic leaking from the idle extruder. It is especially noticeable with PLA that flows easier than ABS. Lowering the temperature of the idle extruder while it is not needed and restore it when it is time to start printing with that extruder again helps to deal with leaking. It is tricky though since leaking has to be prevented during the teperature changes.
Slic3r has an option to help prevent oozing. It will lower the temps of the unused extruder slightly to help eliminate this issue. They have come a long way in battling the issues involved with the idle hotends. Other options that are usually considered to battle these issues are wiping stations and using a “Parking place.” Both techniques are described below.
The technique being used with the current generation of the RepRap X2 printers (S/N: 020*) is to print a “parking space” besides the actual object. That “parking space” serves two purposes, one is to plug the nozzles while the temperature changes and the other is to “prime” the extruders (i.e. establish the consistent flow of plastic) before printing the actual object after the temperature change.
Wipe Station Idea
I think I have said this already but event the big boys have a wipe station in the back left corner to wipe ooze from the unused extruder. That is a rubber and wire brush wiper at a set height. I suppose that would cut some area out of the bed, hmm… Others have suggested a wiper mechanism on the extruder. Not a cap where pressure would build up but a little wiper.
If you have a dual (or even more than two) extruder setup, Slic3r can be used in several different ways:
You can print a normal single-material object by assigning different features to different extruders: for example multiple colors for perimeter/infill/support material; You can print a multi-material object by assigning each material to an extruder.
How to make a multi-material file
If your CAD program is not able to export a multi-material AMF file, Slic3r provides a convenient way to merge multiple STL files, representing material regions of the same object, to a single AMF file. The STL files must share the same coordinates and origin, of course. This feature is easily accessed by using the Combine multiple STL files… item from the File menu item.
You can also explore “ditto printing,” depending on your extruder spacing. This is less common due to the required extruder positioning which limits the size of your ditto prints.
Dual and multi head extrusion has come a long way since I first started to explore it through Printrbot’s Dual Extrusion Beta program. The hardware side had made leaps and bounds but, it always seemed to be too far ahead of the software side. Repetier and Slic3r have now caught up. By caught up, I mean way up! This helps to bring more usability to multi head extrusion. It’s still something for more advanced users but, if you have determination – you too can master multi extrusion.