I have been working on converting a BigBox to dual Independent X axis, and DuetWifi at the same time. Most of the work was done by the e3d and BigBox team, already in designing the beta dual independent X axis modifications. For a lot more detail this thread on the e3d forum is the place to start:
For DuetWifi IDEX discussion not limited to the BigBox check out:
and specific to BigBox and DuetWifi:
I won't detail the mechanical build changes here, suffice to say it is relatively straight forward if you are used to modifying 3d printers. The forum thread details the additional hardware you need to buy (other than the DuetWifi and Duex2). The plastic parts print well in ABS and e3d Edge however I really recommend Edge or something with excellent layer adhesion because I found some of the parts were a bit prone to splitting along stress lines when printed in generic ABS.
There is plenty of space to install the DuetWifi and Duex2/ in the base of the BigBox. I drilled new mounting holes and used standoffs however Alex9779 designed some simple adaptors that allow you to use the existing mounting holes for the DuetWifi:
He also has a great picture showing the electronics mounted in the base of the BigBox:
David has done really good work on the RepRapFirmware and documentation. See the wiki page here:
By configuring a tool for each axis and a tool with both axis, it is as simple as selecting which tool you want to use to either print 1 object with two filaments:
or the same object at twice:
This process is detailed in the Wiki, along with some examples of how to go about calibrating the axis offsets.
A issue with all multiple head FFF printers is what to do with the hotends that are not being used. Generally they get in the way and ooze over the object being printed. The IDEX configuration solves much of this by moving the unused head out of the way, however the unused hotend can still ooze. Printers like the BCN3D Sigma have the space for a ooze bucket and wipe underneath each nozzle park position so that the nozzle can be purged and wiped each time. The BigBox is more limited in space so I am testing using a price of silicone positioned to block the nozzle when parked. This is still a work in progress.
Two videos showing the printing in general and the silicone blocks are here:
I will add to this thread as I progress with the build