Common Issues for Torch Cables

Under­stand­ing your weld­ing parts will help to reduce down­time and over­all wear while also increas­ing pro­duc­tiv­i­ty. Robot torch parts can come in a vari­ety of styles and build. Over time, there are some parts that have proven to be more effec­tive and more con­ducive to pro­duc­tiv­i­ty and user-friend­li­ness than oth­ers. Being updat­ed and knowl­edge­able on this infor­ma­tion will ensure opti­mal pro­duc­tion on your weld­ing pro­duc­tion line. This arti­cle will bring to light issues that relate to torch cables, lin­ers, tips, and noz­zles includ­ing how they fail and best prac­tices for them. 

One of the most crit­i­cal com­po­nents of a well-made robot torch cable is the out­er jack­et pro­tect­ing the cable. 

Out­er Jackets

The durable out­er jack­et is a very impor­tant to help pro­tect against abra­sion, cut­ting, and offer increased resis­tance to fail­ing if it ever catch­es on a clamp or fix­ture in the weld­ing cell.

The out­er jack­ets that have proven to offer incred­i­ble resis­tance to abra­sion and cut­ting are irra­di­at­ed with elec­tron beams or com­posed with a cross-linked poly­ester. Even if the out­er jack­ets are dam­aged, the dam­age won’t extend with these cable mate­ri­als because the cable doesn’t have a grain run­ning in one direc­tion. How­ev­er, the out­er coat­ing of a robot torch cable comes with trade-offs. These types of coat­ings are stur­dy, but they are less flexible.

If there were to be a cut or abra­sion on cables using neo­prene, it would read­i­ly extend and increase the chances of fail­ure for the robot torch cable. This would be one rea­son to make this mate­r­i­al less desir­able for a robot torch cable. How­ev­er, the advan­tage to neo­prene is that it is more flexible. 

Pro­tec­tive Sleeves

A pro­tec­tive sleeve on top of the torch cable out­er cov­er will pro­tect the cable and cable strands from rub­bing against the arm when the arm is in motion.

Cables that fea­ture cor­ru­gat­ed, Kevlar, or leather pro­tec­tive sleeves for robot torch­es are impor­tant to fur­ther pro­tect the torch cable espe­cial­ly if your weld­ing torch is rotat­ing or bending. 

Elec­tri­cal Connections

The elec­tri­cal con­nec­tion of the torch cable is a crit­i­cal piece in main­tain­ing con­sis­tent and reli­able pow­er from the cop­per to the torch neck and ulti­mate­ly to the con­tact tip and weld­ing wire.

Under­stand­ing if your torch cable can stand up to the man­u­fac­tur­ing demands also includes ensur­ing that the elec­tri­cal com­po­nents are up for the chal­lenge. These elec­tri­cal con­nec­tions are seen in two com­mon man­ners: a crimp of the cable at the end or a cone and a cone nut.

Crimp con­nec­tion: pro­duces a more sta­ble and reli­able elec­tri­cal con­nec­tion. A pad crimp will pro­vide even pres­sure and a strong and con­sis­tent elec­tri­cal con­nec­tion and current.

Con­nec­tor Cone and Cone Nut: This used to be the way to pro­vide the elec­tri­cal con­nec­tion as it allowed for rota­tion­al move­ment and also because it could be tak­en apart, short­ened, or mod­i­fied as need­ed. How­ev­er, peo­ple real­ized that this was not need­ed so the crimp con­nec­tion was seen as more ben­e­fi­cial and being used with greater success. 

Cable Strand­ing

Look­ing for cable strand­ing is one of the most impor­tant fac­tors to help deter­mine your cable qual­i­ty. Mul­ti-strand cables will last longer and resist tor­sion more than a sin­gle-strand cable.

Cables can be designed to rotate and with­stand tor­sion­al loads which is a crit­i­cal eval­u­a­tion fac­tor to look at when using a through-arm set­up. Eval­u­at­ing the need for cop­per or alu­minum and a mul­ti-strand or sin­gle strand are oth­er fac­tors to consider. 

Pic­ture Cred­it: The Defin­i­tive Guide to Robot­ic Weld­ing Torch­es by Abi­cor Binzel

A robot torch with 5 inde­pen­dent­ly strand­ed cables will work less to pro­duce a strong elec­tri­cal cur­rent when there’s tor­sion on one anoth­er and cause less fric­tion when trans­fer­ring to the out­er shield. The solu­tion would be a mul­ti­strand design and build that will last longer than a sol­id, or sin­gle, strand cable.

Through-arm torch cables com­mon­ly fail because of over-rota­tion of the cable while in oper­a­tion on robot axis 4 and axis 6. The greater amount of rota­tion, the greater the impact on the integri­ty of the cable build. The strands inside the cable can break and cre­ate heat in areas of the cable it is not designed for.

If a robot torch cable is capa­ble of rotat­ing +/- 210 degrees con­sis­tent­ly while in oper­a­tion, then it should be con­sid­ered a qual­i­ty torch cable for through-arm.

Infi­nite or End­less Rota­tion torch­es are becom­ing more main­stream as there is no wor­ry about what the cable is doing because the wrist manip­u­lates the front end of the torch inde­pen­dent of the robot cable. There are nec­es­sary ser­vo motor adjust­ments that are nec­es­sary to accom­mo­date this torch tech­nol­o­gy, how­ev­er it pro­vides a greater val­ue out of the life of their torch cable. These torch­es would specif­i­cal­ly ben­e­fit oper­a­tions in the oil and gas, auto­mo­tive, irri­ga­tion, pipe, or agri­cul­tur­al industry.

Com­mon Issues with Over-Arm Cables:

Unsched­uled down­time and cost­ly repairs can occur when weld­ing torch cables are not prop­er­ly adjust­ed and placed. It is impor­tant to under­stand the nec­es­sary length for your over-arm cables so that they can give you the most life. To achieve prop­er length, make sure the robot can achieve full move­ment with­out the torch cable hang­ing from the side.

Too long of a cable and it will get caught, expe­ri­ence a lot of rub­bing onto tool­ing, and quick­ly wear out. Long cables can also expe­ri­ence exces­sive heat and tor­sion­al force from it mov­ing too vio­lent­ly, caus­ing failure.

Too short of a cable will lim­it the rota­tion axis 4 and axis 6 pro­vid­ing for access issues, incur more stress, and fail prematurely.

Besides the cable length, it is also impor­tant to look the place­ment and sup­port of your wire feed­ing unit. This unit can be placed at spe­cif­ic loca­tions or angles to help cre­ate fur­ther effi­cien­cies with the robot torch cable. The sup­port can help the cable main­tain a sta­ble arc instead of hang­ing in a way that com­pro­mis­es the cable’s integri­ty and wire feeding.

Ben­e­fits of Through-Arm Cables:

There is less mar­gin for error on cable length with through-arm cables so choos­ing the cor­rect length is the most impor­tant step. It is crit­i­cal to keep the dif­fer­ence between the torch body and the wire feed inter­face to no more than 5 mm.

How Cables Fail:

• Abra­sion: When a cable rubs up against the part and even­tu­al­ly fails. A cable abrades when the robot puts a torch cable through the same cycle over and over mul­ti­ple times.
• Cut­ting: When the cable comes in con­tact with a sharp edge to a part over and over .
• Caught: If the cable isn’t installed prop­er­ly, the cable can get caught on a fix­ture or part and halt production.

In sum­ma­ry, it is impor­tant to ensure your torch cable has a prop­er out­er jack­et; A pro­tec­tive cor­ru­gat­ed sleeve; Has either a strong crimped or coned con­nec­tion; Is a sin­gle strand or mul­ti-strand; Is at the cor­rect length for your robot; The cable is set-up for the prop­er +/- torch cable length; and The wire feed­ing unit is placed properly. 

For more infor­ma­tion on cables, con­tact Robots​.com experts online or at 877−762−6881.

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