Overbraiding a wire harness bundle

Braiding a wiring harness

5.1 Threading

 

Collect all threads of each carrier as each carrier is threaded and pull towards the centre of the machine and temporarily tie to the quick release pulley.

 

After this operation is accomplished on ALL of the carriers/bobbins, grasp the entire group of threads with one hand and pull upward while turning the hand wheel (located on the left hand side of the machine) until approximately 4” (100 mm) of braid is made. (This braid can be known as “pigtail”). Using the jog facility maybe easier.

The machine is now ready for braiding.

 

If the optional take up system is used. Attach this “pigtail” to the cord that was previously wound around the capstan wheel and threaded around the pulley suspended directly over the centre of the machine.

 

5.2 Typical quality requirements

Refer to your own specification requirements

 

5.3 Back braiding and overlapping:

 

Grasping the bundle by hand and pushing it downward accomplish back braiding.

 

5.4 Braiding:

 

CAUTION: The operator must plan the sequence of braiding each wire bundle mentally before starting to braid. (Usually, the branches are braided first.)

 

 

Place one branch of the wire bundle in the centre ring.

 

Grasp the wire bundle.

 

Start the machine moving the bundle down and then up to obtain the specified overlap. (“Pigtail” is to be cut off as braiding proceeds).

 

Continue braiding until the branch joins the main bundle. Continue to braid over the main bundle approximately 1” (25.4 mm) and be under the main bundle, or terminate as closely as possible to the main bundle with half of the braid threads extended and taped against the main bundle to the left and the other half to the right.

 

Secure the threads to the main bundle for a distance of approximately 1” (25.4 mm) with several layers of tape. Cut threads outside of tape.

 

Repeat this process for each branch.

 

After all branches have been braided, place one end of the main bundle in the centre ring.

 

Grasp the wire bundle. Start the machine moving the bundle down and then up to obtain the overlap described earlier

 

Continue braiding until the braiding is within the proper distance from the end connector.

 

Now, lift the bundle up through the threads to a horizontal position. Braid a “pigtail” approximately 4” (100 mm) long. Cut “pigtail” in half and remove bundle.

 

 

The haul-off is arranged to the rear so that the braider operator will not have any obstructions in case the operator wants to manually take up the braid, as this is necessary when braiding short lengths of branches or on the main bundle.

 

As soon as the harness had been finished, the “turtle” clamp or hook is released and is now ready to be attached to the next harness to be braided.

 

A footswitch is provided so that the braider operator will have both hands free to manipulate the harness assembly while it is being braided.

 

There are other techniques used by skilled operators.

 

5.5 Special notes on machine operation:

 

Malfunction of the machine (broken threads, snags, or empty bobbins) will automatically shut off the machine. Correct the fault and tighten all loose ends before proceeding.

 

When braiding, bundles must be pulled through the machine at an even rate. The speed shall be such as will allow the threads to form a small cone. Pulling threads too high will cause loose or open braiding.

 

When braiding long continuous lengths, pick gears furnished with the machine should be used. The proper combination can be determined by reference to the Pick Chart.

 

5.6 Starting of threads/wires broken during braiding:

 

When a broken single thread/wire is detected, the machine will stop automatically.

 

If the broken thread/wire is long enough, weave it into the bundle by following the same routing as the unbroken thread/wires from the same bobbin. Then, hold the thread/wire securely against the braid and start the machine.

 

Continue holding the broken thread/wire against the braid until it has been securely woven into the braid.

 

If the broken thread/wire is not long enough to reach the braid, twisting it around the remaining wires from the same bobbin can restart it.

 

When too many individual threads/wires/ends from the same carrier are broken, cut the remaining ends and re-thread the bobbin and hold the new threads/wires/ends firmly against the braid starting the machine until the new threads are interwoven into the braid. After the bundle is removed from the machine, cut any loose ends flush with the braid. (With wire braid, wipe the soldering iron over the cut ends to provide a smooth joint).