MK4 x-carriage with wider cable channel

When swapping complete nozzle assemblies on the MK4 it is necessary to remove the thermistor and heater cables from the cable channel in the x-carriage, and then feed the replacements into this channel.  The opening of the cable channel is narrow, presumably to ensure that the cables remain trapped within it, but it makes inserting the cables quite fiddly.

This model is my attempt to make the cable insertion easier.  I have modified the original x-carriage to make the mouth of the cable channel wider.  Clearly, this not only makes removing/inserting the cables easier, but it also traps them less effectively, so there is the potential for the cables to pop out.  In practice I have found that the cables are stiff enough that they don't tend to pop out, especially if the stiffer heater cables are inserted after thermistor cables.  Furthermore, the print fan assembly provides an effective trap, so as long as the cables are fully inside the channel when the print fan is closed (making sure that the print fan doesn't pinch them), there is no danger of the cables coming out of the channel.  

Photos 2 and 3 show the original cable channel compared to this wider version.  Photos 4 and 5 compare the original and modified parts in situ, and photo 6 shows how the print fan assembly prevents the cables from popping out.

I've included the very simple OpenSCAD script that I used to produce this part, in case you wish to modify the cable channel opening yourself.  I've also included Prusa's original part, since the OpenSCAD script depends on it.

Printing

Print the STL in the supplied orientation.  No supports are needed.

For the original part, Prusa recommend:

• Print settings: 0.20mm QUALITY
• Filament: PETG (tested on Prusament)
• 15% Grid infill

On my MK4 I used:

• Print settings: 0.20mm STRUCTURAL
• Filament: PETG
• 15% Cubic infill

Assembly

If you assembled your MK4 from a kit, you will know that it's quite a long job to swap the x-carriage, since there are many parts attached to it, including the x-axis bearings and the x-axis belt, which will need to be re-tensioned after the swap.  If you need to refer to the manual, you can find it here.  

MK4 x-carriage with wider cable channel