Wire Protection


The wires and cables need to be supported so they will not snag on the machine.

A simple option uses a spring and dowel to hold the cable.

The arrow in the image points to a spring that is pressed into a hole that is drilled in the end of the gantry.

A dowel is inserted into the spring, and the cable is secured to this mast.

This holds the cable above the machine while allowing the mast to flex as the cable tightens.
Spring supporting a rod
Spring supports mast.
 
The cable is attached to the top of the carriage, stepper and gantry end with cable clamps that are made of thin metal, such as drink cans or flashing.

The clamps route the wire so it will not fatigue as the axis moves.

There are threaded holes in the ends of some steppers that are for the long screws that hold the steppers together. When there is room, the extra threaded section can support a short screw that ties a clamp to the stepper, as shown here.
Wire in clip.
Clip supports cable.

 
This next system uses a strip of plastic to support the stepper's cable.

The plastic is a nailing strip that was cut from a piece of vinyl siding J channel. Plastic banding strap and corner strips for drywall also work well as flexible guides.

The plastic holds its shape and prevents the cables from kinking and falling into the work.

One end of the strip is screwed to the middle of the top of the gantry, and the other end is attached to the stepper or carriage.

Zip ties hold the cable to the plastic. The ties are loose so the cable can shift as the plastic moves.
Plastic strip supports the wire
Plastic strip supports cable.

Wire supported with plastic strip.
Cable held above gantry.
 
The cables can be bundled in split corrugated conduit. This product is found in home entertainment sections of department stores and in auto supply stores.

Plastic tubing also serves well as flexible conduit.

The limit wires and stepper cables are run separately.
Corrugated conduit.
Wires in conduit.
 
For longer spans, the cable can be attached to rods that are held together with springs.

Cord Supported by Rods
Cable supported by rods with springs.

As shown here, the rod to gantry attachment permits the rods to swivel. This base is made of soldered together copper tubing and flashing.

Plug on Gantry
Rod swivels in copper tubing.
 
This homemade cable carrier was made by dadoing a 2x4 that had been ripped to 3 inches wide.

Cable carrier made of 2x4
Cable carrier made of 2x4.
The wood was cut into sections with 5° ends. A strip cut from a piece of vinyl siding was screwed to the bottom of the channel.

Cable Carrier
Cable carrier on 4x8 machine.

The carrier is attached to the gantry and rests on a ledge on the side of the table.
 
The servo and encoder cables were originally bundled together, but this caused encoder problems.

The symptom was the inability of the machine to hold position.
The servos moved but the motion was erratic.

The encoder wires were replaced with shielded cable. They were also run on the outside of the cable carrier, as shown in the bottom photo.

This eliminated the interference.

Another option builders have used is clamping ferrite chokes around the cables.


Wires bundled together
Bundled cables cause problems.

Wires are Separated
Separated encoder and servo cables.