Best Practices for Welding Contact Tips & Nozzles

May 20, 2018

There are many factors to look at when deciding on the best welding contact tips and nozzles for your production line. These include the specific materials chosen to include the hardness and conductivity, the threaded versus non-slip nozzles, and also the difference between drawn and drilled tips.

A lot of time and mon­ey will be spent on con­tact tips and noz­zles so it is impor­tant to look at how to bring the most val­ue to this process. This arti­cle will help to bring a deep­er knowl­edge on weld­ing con­tact tips and nozzles. 


Con­tact Tips 

Con­tact tips are respon­si­ble for guid­ing the wire and trans­fer­ring the cur­rent from the con­duc­tur tube (aka swan­neck) through the filler wire and to the work­piece. They are in charge of the cur­rent trans­fer and wire targeting. 

Under­stand­ing how to keep your con­tact tip per­form­ing at its best is crit­i­cal for your weld­ing appli­ca­tion needs. 

The mate­r­i­al cho­sen for the con­tact tip is impor­tant because a torch con­sum­able is the last line of con­duc­tiv­i­ty in the weld­ing cir­cuit between the part. This means choos­ing the right mate­r­i­al for your pro­duc­tion line needs will pro­vide a high­er qual­i­ty weld product.

The pop­u­lar mate­ri­als to choose from are cop­per, beryl­li­um, cop­per zir­co­ni­um, sil­ver plat­ed, and heavy-duty silver. 

Beryl­li­um cop­per: ben­e­fi­cial char­ac­ter­is­tics includ­ing dura­bil­i­ty, but it is con­sid­ered to be tox­ic as a con­sum­able to pro­duce so engi­neers shy away from using it.

Cop­per: great con­duc­tiv­i­ty, but lacks hard­ness, bet­ter arc char­ac­ter­is­tics lead­ing to bet­ter weld qual­i­ty and less touch-ups or rework. How­ev­er, you will change a pure cop­per tip far more fre­quent­ly than cop­per zir­co­ni­um. Increased down­time and less through­put on the weld­ing cell. 

Cop­per Zir­co­ni­um: greater hard­ness but less conductive. 

Sil­ver-plat­ed con­tact tips: Uses a micron sil­ver plat­ing as it is very hard and con­duc­tive. This can increase the con­tact life 9 times com­pared to a stan­dard cop­per tip. It has a low­er spat­ter adhe­sion and a smoother bore as a result of the drilling process, cre­at­ing a bet­ter heat and cur­rent transference. 

BINZEL’s con­tact tips have the fol­low­ing as a point of reference:

weld_torch_contact_tips_hardness.png#asset:88392Pic­ture Cred­it: The Defin­i­tive Guide to Robot­ic Weld­ing Torch­es by Abi­cor Binzel

Decid­ing Between Drawn vs. Drilled Con­tact Tips

Drawn: is a com­mon process for cre­at­ing con­tact tips; there is more vari­a­tion and less tol­er­ance con­trol. Cop­per is drawn and extrud­ed from a long cop­per bar and then cooled into the con­tact tip. This is less expen­sive because the drilling step is removed from the pro­duc­tion process. 

Drilled: The bore is indexed, drilled, and machined from a sol­id shape which gives the orfice greater integri­ty. Extrud­ed con­tact tips don’t last as long as drilled tips. 

Dif­fer­ences between Drawn and Drilled:

The integri­ty and repeata­bil­i­ty of the con­tact tip size is the true dif­fer­ence between drawn and drilled con­tact tips. 

For instance, a 0.045’ con­tact tip made from a drawn process is more prone to errors in both bore size and fin­ish. The wire, which always has a cast on it, is only hit­ting the high points of the tip fin­ish so it’s typ­i­cal­ly going to wear on one side. 

Also, the drawn process is not as reli­ably repeat­able or pre­cise as the drilled process. Mar­gins of error exist in the tip bore as an .045” con­tact tip bore may be as large as .049” or as small as .042”.

This incon­sis­ten­cy can lead to low qual­i­ty arc starts, rework, and decreased through­put. It can also lead to wire flip where the wire wan­ders out­side the weld joint entire­ly caus­ing scrap in the part because of incon­sis­tent tolerances.


One of the most com­mon issues with noz­zles is the spat­ter buildup. A poor noz­zle will incur great amounts of spat­ter build-up in a short amount of time. See below.


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

Mate­r­i­al selec­tion is also imper­a­tive when choos­ing the cor­rect noz­zles; the more the mate­r­i­al resists heat, the less spat­ter builds up in side the noz­zle. See below. 


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

For instance, pure cop­per or brass based mate­r­i­al with the weld­ing noz­zle with not last as long as a hard­er plat­ed noz­zle mate­r­i­al like a nick­el or chrome plat­ed noz­zle because of their spat­ter and heat resis­tant prop­er­ties (com­pare first pic­ture of a brass noz­zle above to the sec­ond picture). 

Typ­i­cal­ly, you will find a hard­er con­duc­tive mate­r­i­al that pro­tects against spat­ter and suf­fers less scal­ing such as nick­el. This will offer less ream cycles and ulti­mate­ly greater productivity. 

Slip-On Ver­sus Thread­ed Nozzles

There are two kinds of noz­zles: slip-on and thread­ed. The cost ben­e­fit analy­sis typ­i­cal­ly comes to down­time as it costs mon­ey, sac­ri­fices through­put, and keeps the robot from achiev­ing Return on Invest­ment (ROI).

Slip-on: slip-on noz­zles are believed to be eas­i­er to get on and off how­ev­er they may loosen over time and cause poros­i­ty in the weld. They are also not effec­tive for torch reaming. 

Thread­ed: The risk is min­i­mized to nonex­is­tent. There is a fine thread option and a coarse thread option. Both styles offer more advan­tages to slip-on noz­zles because they are less like­ly to fail. 

Fine thread­ed noz­zles are more dif­fi­cult to install and remove (bind­ing) while also hav­ing have a more dif­fi­cult time deal­ing with debris and spatter. 

Coarse thread­ed noz­zles don’t’ have much impact from spat­ter and debris.

Con­tact Robots​.com Today!

In sum­ma­ry, it is impor­tant to under­stand the fol­low­ing: are you using drawn or drilled con­tact tips? What is the hard­ness and con­duc­tiv­i­ty lev­els for con­tact tips? What is the tip mate­r­i­al and how often chang­ing con­tact tips? noz­zle mate­r­i­al? Are the noz­zles thread­ed or slip-on? How often are the noz­zles need­ing to be changed and what is the cost?

For more infor­ma­tion on weld­ing tips or noz­zles, con­tact Robots​.com experts online or at 8777626881.

Source: https://​cdn2​.hub​spot​.net/​hubfs…

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