burn back mig

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Spray, Robots & MIG Wire Burn Backs to the Tip.

Ed, I work at Monroe, we are one of the largest producers in North America of auto / truck shocks. Our robots weld on average 200 to 400 partsper-shift. At some plants we average 2 to 5 burn backs per robot per shift. The burn backs requires that we replace the MIG gun contact tips. As

the robot down time and time required to rectify the problem takes 5 - 10 minutes per burn back you can imagine the

What is the primary cause of this common robot problem? Also why does this not happen as frequently with manual welders?

The common reasons for carbon or stainless steel MIG Wire Burn-Backs to the Contact Tip:

Wire burn backs due to the use of oversized MIG wires in which the weld current cannot be used welds are made in the "globular mode". The excessive weld spatter globs block the contact tip orifice and restrict the wire.

Wire burn backs caused by the use of globular weld data at the robot weld start or weld end data.

Wire burn backs caused at the robot " weld starts". At a weld start the wire may not have enough forward feed momentum

caused by any number of causes.

Wire burn backs " during the weld". One common cause of burn-back during a weld is when the MIG wire is restricted in the liner, or the tip or from lack

of sufficient wire tension from the drive rolls. Restricted gun liners or a robot axis issues in which the gun cable is twisted are a frequent robot causes

for wire restriction. These problems frequently result in a wire burn back which can melt the end of the contact tip. These problems can occur at the arc

start or during the a weld.

Robot influence on burn backs. When welding with a robot especially when using an 0.035 (1mm) wire, sometimes

cable restricting the wire. This is noted more with the small wire diameters and specifically when the burn back consistently

location.

Common reasons for Wire Burn Backs.

Factors that can influence both wire burn backs and arc starts.

1. Wire stick out almost touches the part at the start. At the start the wire short circuits and before the wire can run into the weld it burns back to the

tip. Adjust the burn back control in the weld program.

2. Poor arc start weld data in the robot weld program. Programmers will benefit from the data found in my Robot Process Control Program.

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3. Lack or insufficient shielding gas at the weld starts. Shielding gas helps electron flow through ionization.

4. Wire feed restrictions or poor wire feed tension.

5. Parameters set in the globular mode, leave a ball of weld on wire tip which if oxidized through poor post flow gas coverage will prevent arc starts..

The following weld data and much more is found in my

Best Practices - Process Control books - training programs. Click.

More info on the Wire Stick Out (ESO) influence on burn-backs.

When the robot weld starts, the robot control sends a signal to the power source to open the contactor to provide

current to energize the weld wire. When the wire makes contact with the work, the wire feed should be feeding

forward with full inertia. The current arrives at the wire tip before the wire feed has it's full inertia and momentum and

torque from the feeder. The high start current available during the wires contact with the work causes a short circuit

that can melt the MIG weld wire back to the tip.

The MIG wire stick out at a weld completion is controlled by the "wire burn-back control data". The wire stick out at the weld completion should always bekept as short as possible. The wire burn back should be set so the wire stick out is approx. 3 - 6mm from the end of the nozzle. A normal nozzle to work

distance should 1/2 to 3/4 (12 - 18 mm) depending on the welding circumstances. With these settings you allow a gap between the wire tip and work

Remember. At the robot weld start, there should be sufficient wire to work distance of

4 - 6 mm to ensure the wire is feeding forward before the wire makes contact with the work.

If you like this type of weld process control data, you are only scratching the surface of what you would learn with Resources.

Contact Tip Stick - Out. For almost twenty years, the standard robot MIG gun produced in North America and Europe had the contact tips locatedeither flush with the gun nozzle or sticking outside the nozzle by approx. 3mm. The lack of understanding of the influence of Wire Stick Out

(WSO) and resulting poor contact tip placements were simply a result of the robot weld process ignorance by the gun manufactures and therobot integrators. Both of these contact tip positions caused numerous robot down time and productivity issues with the world's most common

MIG weld transfer modes, spray and pulsed.

If MIG equipment manufactures show little understanding of the MIG process, It should be no surprise that the MIG gun manufactures and the

robot integrators who delivered their robot guns with the contact tips sticking outside the gun nozzles simply did not know better. Also someoneneeds to ask why for decades, did the MIG gun manufacturers classify their MIG guns for use with straight CO2, when less than one percent of

the MIG welds were carried out with straight CO2.

At most of the plants I visited that were using spray transfer on parts > 3 mm, the robot MIG guns would be welding with the contact tip stuck

outside the nozzle and numerous contact tip issues would be occurring. I would tell the people on the floor to take a hack saw and cut 3 to 6 mmoff the contact tips.

It should not have taken a rocket scientist to figure out that if you stick a contact tip too close to that spray weld, with the high weld parameters,the high weld heat and spatter will increase the potential for contact tip issues.

As for that pulsed MIG weld, if the contact tip extends outside that nozzle that typically means less wire to work distance is available to create that

stupid little weld drop. A drop that needs a greater arc gap than spray, so the pulsed droplets can transfer uninterupted across the arc gapwithout being in contact with both the wire tip and work.

Many factors influence arc start with robots. All MIG robot programmers should be aware of the factors that effect

optimum start welding parameters of each available mode of transfer and for each wire diameter used. All the data you need is training resources.

How many companies are aware that pulsed MIG welding is much more prone to wire burn back then traditional MIG weld spray transfer?.

The primary reason there is a contact tip concern with many pulsed weld power sources and robots, is with the pulsed process there areelectronic time factors and weld wire arc length requirements necessary to create and transfer a pulsed weld droplet, a weld drop that

provides no carbon steel weld benefits.

For a spatter free pulsed weld transfer, the pulsed weld droplet has to cascade across an arc gap into the weld without contacting the wire tip and

weld at the same time.

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If a pulsed weld drop makes contact with the work and wire at the same time an explosive short circuit in the pulsed weld drop will occur. The

pulsed drop short circuit explosion will cause spatter and possibly disrupt the controlled formation of the next weld drop. These issues (whichcan typically be heard in the arc sound) can effect the weld and fusion consistency. This situation gets worse as the wire feed rates increase.

The pulsed MIG mode requires a longer arc gap than that is necessary for spray transfer, two to three times the length. a shorter wire stick out from the end of the contact tip. The shorter wire stick out increases the potential for wire burn backs. Want

why pulsed can cause weld issues you won't get this data from Lincoln, Miller or ESAB, you will get it from my 600 page "Managers andEngineers Guide to MIG book"

A common problem. Companies which allow robot welds with contact tips in which the tip bore diameter is worn to twice the diameter of theMIG weld wire?

When you understand WSO you can often increase your robot weld speeds in the range of 50 to 100%.

My Management Engineers book has over 600 pages on how to consistently control both manual - robotweld quality. This book also shows you how to increase traditional MIG robot weld weld speeds) in the range of 50 to 100% If you want best practices - process controls for MIG and flux coredwelds, this is it. ."Management Engineers Guide To MIG"

The weld speed rates for fillet welds are obviously first determined by the weld size which influences the required welddeposition rate. Another restriction is the weld fusion requirements. Travel too fast with that robot and irrespective ofthe weld current or weld mode utilized you will have a weld fusion issue. The weld surface condition, the weld length

and the shape of the steel (round components are more sensitive to lack of fusion than plate), will also influence the weld fusion.

How fast does a manual welder weld? Typically manualwelds are made in the 8 to 20 in./min travel speed range.

How fast does a robot weld? In contrast single wire robotMIG welds are made at typical weld travel rates from 10 to

60 ipm.

If you want to attain weld speeds over 75inch/min the solutions are in my Management

Engineers Book.

Lets hope the Shock Welds are OK.

Many years ago a major USA shock manufacturer called Monroe requested my assistance



as they could not get their robot MIG spray welds on their shock bracket welds to qualify a Chrysler "shock load test spec"

The Chrysler engineers required the bracket welds on the shocks absorb at least a 13,000 lb

test load. After robot welding the steel brackets with 5 mm fillet welds on the shocks thatwere only 2 to 3mm thick, Monroe found that their shocks bracket welds would fail

prematurely, typically in the 7000 to 9000 lb range.

While the Chrysler weld specification for the shock bracket welds required that the weldedbrackets pass a test load of 13,000 lbs, it took me less than two days of welding and testing

on the shock bracket welds to reveal that any test load of less than 19,000 lbs, indicated lack

of weld fusion in one of the four bracket welds.

There were three reasons that the Monroe shocks could not meet the minimum shock weld

test load requirements,

[1] the robot spray transfer welds were made on "cold rolled round parts",

[2] the robot weld speeds for the small weld lengths were "set too high",

[3] the robot weld lengths on the brackets "were to small".

After I figured out the weld problems, I changed the weld wire size to a smaller wire which

increased the weld current density. I reset the spray parameters, extended the shock bracketweld length by another 3 mm. After my changes, the shocks bracket welds failed at an

average load test of 21,000 lbs.

How fast, how slow should the robot go?

If all MIG welds were evaluated for the internal weld fusion, there would be more focus on the

weld speeds utilized. Many robots today are either welding too fast or too slow. A common

problem is that the MIG wire size may be wrong, or maybe it's because pulsed, globular or

short circuit is being utilized when spray would be superior. Maybe the weld issue is the partdesign, joint type, part thickness or ridiculous gaps many auto / truck companies present to

the robot weld cell. Optimum weld speeds for all applications and weld compensation data

for potential weld issues are covered in my books.

Be aware of the Good Sounds of MIG SPRAY TRANSFER.

As most of you are aware to fine tune that MIG weld voltage,the best weld calibration device can be one's ear.

For MIG spray transfer welds including all carbon steel, stainless,aluminum and nickel wires, the optimum spray transfer arc is setwhen a consistent, quite, smooth crackle sound is attained. The cracklesound is derived from the weld drops - stream short circuiting as they travel across thesmall arc gap.

If the MIG spray "arc length" is set too long, (weld volts set too high).In this situation the spray weld drops and weld stream transfers

uninterrupted from the wire tip to the weld. An excess arc length will produce a quite(whoosh) spray sound. A long spray arc length will also result in a wider plasma on thepart surface. This plasma can result in too much energy on the weld surface resulting inhigh weld surface fluidity and possibly weld undercut.

If the spray current is sufficient. and the arc length (distance fromthe wire tip to the weld) is too short, (weld voltage set too low). Inthis condition the weld wire is driven into the weld causingexplosive short circuits, resulting in weld expulsion, (spatter) andan inconsistent harsh crackle sound.

To set the optimum spray volts. The tip of the spray transfer MIGwire (arc length) should be less than < 0.050 from the weld

surface. As the weld stream transfers from the wire tip, part of the weld stream will shortcircuit with the weld producing a consistent crackle sound.

Spray transfer. Typical 2-4mm application.



Automotive - Truck Frame Welds.

This is a Ford truck frame with the welds made by robots. In this

instance you see complete lack of process controls in which

poor robot welds have been repaired with poor manual MIG

welds.

The next photo shows poor manual MIG weld repairs on frames.

As you can see with the manual MIG weld repairs, the parameters

utilized are producing more weld spatter than weld.

The manual welders making the frame repair welds below had

just finished a MIG training course from a well known Detroit weldtraining facility. The training company provides MIG training for

the big three companies and their suppliers. The manual MIG welds are actually globular

transfer as evident by the globs at the end of the sparks.

The repair welders were provided with MIG weld training, the

trouble was like most of the training provided in this industry,

the training was ineffective.

As with most MIG training programs, the training focus was on

the welder's skills rather than on best practices and weld

process control expertise The bottom line is the welders did not

know how to optimize MIG weld settings, and you know if theworkers don't know how to optimize a weld, the engineers

managers, technicians and supervisors in this frame plant also

know nothing about MIG weld best practices and weld processcontrols.

A Message to all major auto / truck manufacturers and part suppliers. You may have spent

millions on training programs for your employees, yet you could line up all the weld decisionmakers in your global plants and I doubt you could find one or two individuals who could

establish effective MIG Robot Weld Process Controls.

The visual approach to setting optimum MIG weld parameters.

With a spray transfer weld, imagine a frame orwindow around the gun nozzle in the center of the

window as the gun welds. (as shown in the frame

weld photo above). If that frame is 12 square inchesand the spray transfer weld voltage is set correctly,

the weld spatter produced is contained in that 12 inch

window.

If the weld spatter profile you see is outside a 12 inchwindow and round ball shapes are evident at the end

of the weld spatter streaks, you are watching a weld

set with globular weld parameters. With globulartransfer the weld voltage is typically less than 24

volts and the weld current is less than that required for spray transfer for the electrode wire

diameter selected. If the weld spatter profile is straight streaks and outside the 12 inch

window as in this picture, the spray parameters are set with the weld voltage set too low andthe weld wire is driving into the weld.

Remember with "short circuit transfer welds" that the prime cause of weldspatter results when the welder sets the weld voltage too high.

With "spray transfer welds" we have the opposite, with spray the prime causeof weld spatter occurs when the weld volts are set too low.

This Web site or Blog whatever, has taken thousands of hours to produce and itwill take you many hours to cover. Why not consider purchasing one of mybooks so you can spend some more time with your family?



The above Motorman robot is producing terrible welds with excess weld spatter The companyspent over $200,000 on the Motorman robot cell, they should have invested another $400 on Ed'sRobot Weld Process Control Training Program.

Lets see, to reduce weld spatter with short circuit transfer you typicallyhave to decrease the welding voltage. To reduce weld spatter with sprayyou typically have to increase the weld volts.

I should put this information on a bloody big sign in the middle of the weldshop, or maybe I could invest $90 for each of my welders, and providethem with Ed's process control training book. God what am I thinking? I better not dothat, if these guys start reading about weld process controls the next thing you know,they will want my job.

Why are many in the weld industry using STICK practices and techniques for their MIG welds?

Over 60 years ago, most welds were made with the SMAW (stick) weld

process and then MIG was introduced. After 60 years, the MIG process daily

accounts for more than 80% of the global welds produced.

Another indication of the lack of focus on MIG weld weld best practices andprocess control expertise is today in 2012, it's common to find a large portion of welders

who are using stick welding techniques for their MIG welds. Also a survey of most weld

schools will reveal that inappropriate SMAW practices - techniques are being applied to MIG

and flux cored welds. Many of you will know the following scenario, the plant weld

supervisor or school weld instructor was hired because he had extensive experience as a

stick pipe welder. These are the supervisors who made sure all the MIG welders in the plant

are using a "whipping or skipping weld technique". This is a technique he used whenwelding with his stick electrodes.

Note: It's common in North America, for many of the weld school instructors to recommend

the inappropriate whipping or weaving actions when they teach the manual MIG process.

Manual MIG weld Whipping the MIG gun back and forth in the direction of the weld, not only producethat distinctive "whoosh whoosh" sound, it also leaves a distinct freeze pattern in the weld. The clearlydefined freeze lines on the weld surface are typically 1 to 3 mm apart. The problem with the whippingtechnique is whenever you take a IG gun away from the leading edge of the weld you reduce the weldroot and side fusion potential When using the whipping technique, the thicker the part the greater thepotential for lack of weld fusion.

Cut and macro the welded parts in which a whipping technique has been used and you will likely find seriouslack of fusion issues especially with fillet welds. The MIG weld penetration is greatly influenced by the forceand concentrated heat of the MIG arc plasma. Welders should keep their forward motion as steady aspossible, with the MIG wire always on the leading edge of the weld. The only logical time to use a whippingtechnique is on gage welds with gaps and you want to avoid weld burn through so you utilize a technique thatminimizes weld fusion.

Manual MIG Weld Weaves:

When should you use a manual MIG weld weave? When manual MIG welding, manual welders too oftenprovide inconsistent weld weaves that will result in inconsistent side wall weld fusion. The best techniques formost manual MIG welds is use stringers with the MIG gun on the leading edge of the weld pool.

In contrast to manual MIG welds, with a robot you will attain many weld benefits from controlled, consistent



weaves. The reason a robot can use a weld weave successfully is the robot weld weave - speed functions arecontrolled. The robot weld weave can benefit sidewall weld fusion on fillet welds > 5 mm, or the weave canbe used to reduce weld burn through on gage parts or parts with gaps. If a robot weld weave is necessary, trya slight oscillation in the center of the weld puddle, (pushes the weld outwards) rather than setting a widerweave that visits the weld edges.

MIG Welds and Galvanized.

Question: Ed. Using a robot, I was wondering what is the best MIG weld transfer mode to use oncoated, galvanized steels < 2.5mm and what is the best way to get the best weld quality and dealwith the zinc to avoid weld porosity? We currently use E70S-6 wire with 92% Ar - 8% CO2.

Answer: The first thing to consider is the part thickness. If the parts are less than 0.070 short circuitis the logical choice as it reduces weld burn through potential especially when those thin gageparts have gaps.

When welding parts > 0.070 with robots, the pulsed mode, globular or spray transfer may be used.Please remember f you have zinc on the weld surface there is no such thing as a quality weld. Withzinc on the surface you have zinc in the welds irrespective of what the weld consumable salesmaninforms you, or which weld transfer mode utilized.

It's logical when welding on galvanized parts to;

[a] Provide as much weld energy as possible to burn off and reduce the weld porosity potential. [b] Maximize weld current density by using the smallest weld wire diameter.[c] Use the highest possible weld current.[d] Remember fast weld speeds result in fast weld solidification which adds to the porosity trap. [e] Avoid concave fillet welds. Convex welds will be stronger and help compensate for the poorinternal weld quality. Also if possible make the welds a little larger or longer than they need to be. [f] Use 0.035, E70S-3 wire as it has less silicon than E70S-6, (reduces silicon zinc cracking potential).[g] Use high energy 80 argon - 20 CO2 for your short circuit and spray applications. [h] Use short wire stake out 3/8 - . [i] If the galvanized coating is really thick consider two weld passes.[j] When the arc becomes very unstable use the back hand technique as it will improve arc stability.

Galvanizing a part is a cheap method of corrosion protection, and the minute a weld is made on thepart that weld destroys the corrosion protection in the weld area (becomes weakest link) and theweld integrity is jeopardized by the coating.

Designers who expect quality welds on galvanized parts are people who should be runningdoughnut shops. If an engineer wanted good weld quality they would spec out that the parts begalvanized after welding. The bottom line, as a galvanized weld will always contain excesscontaminates in the weld. Any welder who takes pride in their welds would take a grinder andremove as much of the galvanized coating from the welding area. From a weld quality perspective,keep your focus of porosity and to compensate for the poor engineering decisions, provide a littlemore weld, and ensure the welds you produce at least provide consistent weld penetration.

Special mention should be made with welding galvanealed. Typically it's not necessary to removethese primers, and good weld quality is possible. However if the primer is put on too thick, porositycan result.

Weld Porosity:

Weld porosity is caused by the absorption of oxygen, nitrogen and hydrogen into the molten

weld pool. The gases react with alloys and elements in the welds. Si - Mn oxides are

common. Some of the gas reaction are released during the weld solidification while others

may become trapped in the weld metal. The porosity is typically round in shape but can alsobe an elongated or irregular shape.

Robots and MIG Porosity. The most common cause of porosity with robot welds is the

stamping or forming lubricants that are on the part surfaces. The solution to this is simple,

it's called "weld management".

When you find the robot weld porosity is always at the same location on the part and the

porosity is not at the weld starts or ends, (time and pre - post flow gas problem) examine the

robot movement and see if the robot arm is causing a restriction of the gas flow line. Also it's

common with robot cells to see a severe gas flow restriction due to the narrow orifice found

in the gas line connections.

Note: In a robot cell it's critical to measure gas flow not at the flow meter, measure the gas asit exits the gun. That flow should be 25 to 35 cuft/hr.



MIG & Flux Cored Weld Porosity:

Nitrogen, hydrogen and oxygen absorption in the weld pool usually

originates from contaminated gas mixes or poor weld shielding.

Porosity is also influenced by leaks in the MIG gas lines, excess gas

flow rates, draughts and the common part contaminatio. The most

common cause of porosity with gas shieldedflux cored wires is

moisture in the wire's flux.

Hydrogen can originate from a number of sources including moisture from the electrode

surface, moisture in those gas cylinders that you assume are made to some gas filling spec.

Moisture is common on cold parts and also found trapped in rust or mill scale and from

contaminates found on the work piece surface.

With steel welds, the hydrogen typically has time to escape, in contrast with the lower melttemp, faster freeze aluminum welds hydrogen entrapment is common.

Cluster Porosity.

A localized group of pores with random distribution. Causes. Arc

blow, insufficient, inconsistent or excessive weld gas flow, materialor weld wire contamination, (low) weld parameters and poor weld

technique.

Worm Holes and Waggon Tracks porosity. Wagon tracks are typically found in a line in the

the center of the weld and run parallel to the weld axis. Classic waggon track porosity is

easily achieved when moisture is evident in gas shielded flux cored wire flux. Typically the

cheaper the product the more prone you will find it is to wagon tracks. When I have to weld personnel with Lincoln and Hobart all position gas shielded flux cored products, I was

always concerned about the excess porosity and worm tracks that would appear in my

welds.

Worm holes are elongated gas pores producing a herring bone appearance on a radiograph.

Worm hole porosity is common in gas shielded flux cored welds when the electrodes have

too much moisture in the wire flux.

Welds and root porosity. Weld root porosity frequently occurs when MIG welding using two

or three component argon mixes that utilize oxygen. With these oxidizing gas mixes, the

resulting root is typically narrow, finger shaped. The root finger area solidifies rapidly

trapping porosity. To reduce the root weld porosity, change to a gas mix that does not have

oxygen, use a higher energy,argon 15 - 20 CO2 gas mix, you can also increase the weld

parameters, slow the weld speed and avoid thin welds that result from weld weaves.

Aligned weld porosity. Linear porosity is an array of small round pores typically found in a

line. Often this is caused from the base metal lubricants or metal surface contaminate.

Remember the last part of the weld to solidify is the weld center and this porosity did not

have the time or energy to exit the weld. Add weld energy,decrease WSO, and increase push

angle allowing the arc to break up surface oxides ahead of weld.

Scattered Porosity. This weld porosity will be found scattered randomly

throughout the welds. When you find this porosity, if the MIG weld surface

is gray and looks oxidized, the porosity is typically a result of insufficient

gas flow. If however the weld surface looks clean, the porosity is usually

caused by the base metal part or electrode contamination. Also a common

cause is the welds are too thin or the weld data used causes the weld to

freeze too rapidly.

Large Pore Porosity. If weld surface is clean and does not look oxidized,

the large pore MIG / FCAW porosity could be a result of excessive gasflow. Gas turbulence is caused with gas flow greater than 40 CFH/hr..

Optimum MIG and flux cored gas flow for carbon steels is 25 to 35

CFH/hr., the gas flow should be measured as it exits the gun nozzle. If the weld surface is

dirty (oxidized) the cause of larger pore porosity is often a result of insufficient gas flow,

than 20 CFH /hr..

Many automated - robot cells suffer from arc blow?



Welding hot rolled steels? Mill scale and corporate Liaability.

Every weld shop has a choice when welding, weld thematerials as is or prepare the metals to enable the highestpossible weld quality. The following are typical concernsgenerated when MIG welding hot rolled carbon steels with millscale which can influence and create;

[a] lack of weld fusion,[b] sluggish weld that has an inferior external weld appearance,

[c] welds with excess weld spatter (parameter adjustments can help if thewelder knows which parameters to adjust), [d] increased porosity,[e] slower weld travel rates.

Many weld shops don't realize that optimum MIG weld fusion is too often marginal weldfusion, and this fusion is greatly influenced by mill scale.

I am always amazed by the weld shops that are quick to inform me they have no time devote to "grinding the steel before the welds are made", however after welding thewelders typically spend extensive time grinding the spatter and weld profiles that wasinfluenced by the mill scale. If every weld was evaluated for weld fusion welding on millscale would never be allowed.

The wise weld decision maker does not allow MIG welds on steel applications in whichthe surface condition of the steel can negatively influence the weld quality. Automatedplate blast equipment can today be purchased for around $100,000.00 and lets face grinders can be purchased for less than $80.

When it comes to welding on mill scale or contaminated plate there is an alternative tothe MIG process, "flux cored". The FCAW process can provide more deoxidizers andenable higher current density, however the mill scale and the flux cored weld slag canboth negatively influence the weld fusion.

The bottom line, the influence of the mill scale or any contamination to a weld should begiven careful consideration by management. The liability consequences of weld failuresshould be of concern to all in the front office.

Ed's Weld Clock method for weld process controls. If weld process control expertise has beenlacking for decades someone needs to simplify the subject so every person can easily understandhow to set optimum MIG and flux cored weld parameters. I started on this project 30 years ago, it'scalled the "Weld Clock Method".

The Clock Method. Spray Transfer Weld Current and Wire Feed Settings



Great start point. 3 o'clock with 27 cups of coffee, (27v).

The following is an example of the way I used my clock method to simplify setting spraytransfer weld parameters with the 0.035 wire. Just as short circuit has an optimumnarrow weld parameter range so does spray transfer.

For decades most wire feeders have provided a maximum wire feed rate of 600 to 800in./min The average wire feed rate is 700 in./min (18 m/min). With the wire feed controlthink of it like a clock face with the wire feed starting at 7 o'clock and finishing at 5o'clock. With those 10 settings, each turn on the control is typically around 70inches/min (1.8 m/min). With the clock method provided in my self teaching resources and trainingprograms, for each turn I provide the weld mode, the current, the voltage, the part thickness, thedeposition rate and weld travel rate. With this method you will typically readily remember that anoptimum start point for spray with that 0.035 wire is 3 o'clock with 27 cups of coffee and 3 o'clock isthe eighth turn (1lb/turn) so the deposition rate is 8 lb/hr.

A MIG weld decision maker should always beaware for a specific electrode diameter:

[a] the weld transfer mode, weld current "start point"[b] the weld transfer mode wire feed "start point"[c] the weld transfer mode start voltage,[d] the weld transfer mode weld "parameter range", [e] the weld transfer mode "optimum" wire feed and voltage startpoints.

Understand the MIG settings, now that would be a fresh approach to MIG weldingin my shop. You know this weld process control stuff is starting to make sense.

So instead of paying a few bucks to learn the profession thatwill pay for your future, you carry on with that free weld advice.

More than twenty years after the MIG process was developed,in a time when I was starting to develop the MIG weld clockmethod, the most popular welding book available to NorthAmerican welding shops was the Lincoln "ProcedureHandbook of Arc Welding" twelve edition. Many Lincoln employees refer to theProcedure Handbook as their "welding bible". This book provided four whole pages onthe MIG process welding carbon steels. This was at a time when I wrote myManagement book on MIG process controls and it had 600 pages.

After the MIG process had been in use for almost three decades, the following is theMIG advice Lincoln Electric provided it's weld customers from it's Welding Bible

[a] Lincoln advised that spray transfer is not attainable with argon CO2 mixes. All theother major weld equipment, consumable and gas companies, would make similarstatements, such as spray transfer is not attainable with argon plus 25 - 20 CO2 or with



15% CO2.

Ed's weld reality check. With specific settings and wire diameters spray is attainablewith 25% CO2and with all wire diameters spray was always attainable with any argonmixes with up to 20% CO2.

The ridiculous CO2 gas statements were common right up to the late nineties. by mostmajor weld equipment and consumable suppliers. It's obvious that the weld decisionmakers in the welding product companies never bothered to put on a welding shield evaluate the MIG spray arc. The bottom line was most of the individuals responsible forthe written materials from the corporations that produced welding equipment andconsumables simply lacked the necessary MIG process expertise to provide real world,practical MIG welding facts.

[b] Lincoln advised that for MIG spray transfer on carbon steel welds use a MIG weldinggas flow rates set at 40 to 60 CFH/hr.

Weld reality check. A gas flow rate of >50 CFH/hr would possibly cause weld puddleturbulence leading to porosity, also it could almost double the weld gas bill. Gas flow ratesat the gun nozzle of 25 - 35 CFH/hr are recommended.

[c] Lincoln advised for short circuit welding use a gas flow rate of 10 to 15 CFH/hr.

Weld reality check. These flow rates are simply inadequate, see above.

[d] Lincoln advised for spray welding 3/16 (5mm) plate use an 062 wire at 375 amps.

Weld reality check. Would you recommend a 0.062 wire for a 3/16 weld, if you did itwould take a few moments before you melt through the 3/16 part.

[e] Lincoln advised For short circuit welding 062 (1.6mm) gage use an 0.030 MIG wire ata wire speed of 170 in./min.

Weld reality check. With an 0.030 wire the practical setting would be close to 300in./min. Also why would one of the world's largest wire producers recommend the morecostly 0.030 wire with its higher costs feed issues. By the way the recommendationshould have been an 0.035 wire at 10 to 11 o'clock with 17 cups of coffee.

Yesterday. It was not just Lincoln that had no clue on the fundamentals of the MIGprocess. Linde, Miller, Hobart, Liquid Air, BOC, Air Products, Liquid Carbonic all mademajor inappropriate welding process statements about the welding and consumablerequirements necessary for optimum MIG welds.

Decades later in 2013, many of the companies mentioned still have minimal depth in theMIG process and the requirements for optimum weld quality and productivity. If thesecompanies have welding employees with MIG process expertise, typically their opinionswill be less important than what comes out of the mouths of the individuals in their salesand marketing departments.

Ed's granson has found out how to solve the great mystery of MIG welding. Heuses weld process control expertise and best weld practices instead oflistening to BS and sales advice.

I hope that if you have got this far, you will have got the message. The weld reality is



weld process expertise will not typically come from a salesman or from someone with afast track AWS certificate. If you are a weld decision maker focus should always bemaintained on your level of weld process and application expertise.

Of the 10,000 to 20,000 weld decision makers that visit this site each day, I would guessthat nine out of ten may this week spend $30 - 40 on booze, $60 in a restaurant, $10 coffee, $30 for cigarettes, $40 on cable TV, and $6 for videos. It's a sad statement thatonly a few individuals will consider investing a few dollars in their careers and purchasea practical weld book or video to control the process.

Career opportunities occur sometimes through fate, sometimes by being in the rightplace at the right time, sometimes from knowing someone. The greatest opportunitiesfor career advancement in the welding industry will always come to those individualswith the most weld process control expertise. Click here for your keys.

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