Enhancements - X and Z axis cable chains

This is a well-tested solution to replacing the poor X-carriage umbilical from the standard printer. This comprises two separate but connected cable chains for both the X and Z axes.

There is a dual-axis mount which fixes over the X-axis stepper on the left-hand side of the printer. This provides a connection point between the two axes. The released version doesn't require the spacers shown in the prototype version in the photo above. It is only required to replace the standard M3 x 20 screws with M3 x 25 to accommodate the extra thickness of the mount. 

This video shows the layout of the mount itself. 

For the X axis, the chain is suspended between here and the X carriage. On the X carriage itself is another mount. This mount is slightly canted (at 10°) to correct for sag in the chain. 

The chain links themselves are a custom design which have a number of desirable features

• Easy to print - no supports required
• Removable cap to allow in situ installation and removal
• Compact - only 20mm wide to match the Z extrusion where they run vertically

For the X axis, 34 chain links are required to traverse the entire axis. 

For the Z axis, 40 chain links are required. 

There are two variants of the chain links. One is a standard which works in all locations. There is a separate one which has extended "axles" which can be installed at the X carriage end to provide better retention. This may be needed due to the cant which has been built into the mount there. The extra length makes the next chains less likely to twist away from each other. 

Similarly there are two variants of the chain caps. The standard ones should be used normally. However the tolerances are very dependent upon how accurately they print. In case they prove too loose, there is also a tighter version which can be used. 

The links simply slot together and due to having removable caps can be added after the mounts and even replaced in situ if necessary. 

The X carriage mount is in two parts. This makes it easy to install and remove without having to dismantle the entire carriage each time. One part of the mount fits to the right-hand top bearing mount and can stay in place. The other, main, part of the mount then slots into this and is held in place with two M3 screws and nuts. 

These are also designed to not need support. In practice a small amount is needed at the base of the mounting flange, but it's very little. 

As with the chain links, there are two variants of this mount. The standard one has a single cable tie base which may be sufficient. The augmented one has two additional ones each side of the chain mounting to provide additional fixings for the separate cables as they come up to the carriage. Each option fits the same bearing mount plate. 

For the Z axis, the chains run upwards from the common stepper mount before looping back down and running along the length of the vertical extrusion. The spacing between the mount and the chains is maintained by the normal curvature of the chain links. 

The links terminate in a simple mount at the base of the chain which fixes to the extrusion with a standard pair of M4 screws and T-nuts.

As with the other mounts, this Z axis one includes a built-in cable tie base and needs no supports for printing. 

The timelapse video below shows the cable chains in use. It doesn't show much movement on the Z axis, due to its length, but it shows a full extension of the X axis and its motion during a print. 

All of the models for this design can be downloaded from Cults3D.

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