Robot Welding Tips

7/14/2019 Robot Welding Tips

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Robot Welding Tips.

If you are a robot programmer, it helps in a confusedindustry to have a sense of humour,


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FOR FOUR DECADES, THE LACK OF INDUSTRIAL ARGON MIG GAS MIXES AND LACK OF MIG WELDPROCESS CONTROL EXPERTISE, WAS THE REASONS WHY THE JAPANESE MADE TERRIBLE MIG WELDS

AND THEN MADE TERRIBLE MIG EQUIPMENT:

Japan is a country that has had few industrial gas plants. Argon MIG gas mixes in Japan have een a rarity andwhen available were and still are very costly. For decades Japan utilized mostly straight CO2 gas for it's MIGwelds and the result was globular, erratic weld transfer that should have made any QA weld personnel cringe

In the last four decades, North America played sales games with it's MIG gas mixes and occasionally producegas mixes that actually helped optimize MIG welds. In contrast, during 1950 - 1990, Japan had minimalexperience with attaining optimum quality MIG Spray Transfer welds and these welds were the most widelyutilized welds made in manufacturing plants in North America and Europe.

Few Japanese auto plants had been able to produce optimum manual or automated quality MIG welds and wein the North American weld business saw the results of this when the Japanese delivered their robots and we

equipment to North American auto plants in the 1990s, It's important for weld personnel to keep in mind that iyou used Japanese MIG equipment in the last two decades you were using equipment that typically wasinferior to Miller / Lincoln / ESAB. Today in 2010 the Japanese MIG equipment is better than the earlier units,and with pulsed MIG equipment the cost effective Asian built OTC Daihen equipment is superior tomost North American pulsed MIG equipment.

Please note. The Pulsed MIG process is not required for most steel welds. Optimum MIG manual or automatedweld quality and productivity for the majority of steel welds is attained with much lower cost, more durable,easier to use and maintain MIG equipment using the traditional short circuit and spray transfer modes, and itdoes not matter if that MIG equipment utilized was purchased in 1960 or 2010.

The global lack of weld process cobtrol expertise has always effected MIG weld equipment selection and also theweld process logic that has been presented in automated MIG weld equipment software. When it comes toevaluating robot MIG weld software, Japanese and North Americanweld logic were rarely similar.


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ROBOTS AND WELD EQUIPMENT PURCHASE CONSIDERATIONS:

BEFORE YOU PURCHASE THAT ROBOT.... Those small to medium weld volume shops that are looking to purchaseand introduce robots to MIG weld their steel and stainless applications, should give consideration to the following;

[] When you examine each robot manufacture's product don't get caught up with the robot bells and whistles andfancy electronic pulsed MIG power source with it's glossy page weld benefits and ridiculous 1 billion wave forms.Today in 2013 I see no real world weld benefits from the pulsed MIG process for most steel and alloy steel welds,

[] When an integrator or a company that makes robots advises your organization to use pulsed MIG for a steel oralloy steel application, remember pulsed MIG is typically not necessary, and the pulsed mode in contrast to thetraditional spay transfer mode from much lower cost MIG equipment developed and in use since the 1950s, willproduce inferior weld fusion and inferior arc stability.

[] The complex electronics required in the pulsed MIG equipment offer minimal weld quality - productivity benefitsbut these electronics will be a costly concern for both your purchasing and maintenance departments.

[] Pulsed MIG will rarely achieve the weld deposition rate potential (weld speeds) that can be attained by the MIGspray mode

[] In comparing robots from different robot manufacturers, examine the simplicity and length of time required to boprogram a common part and especially the time required to make weld changes to different welds. TypicallyJapanese robots have been much slower to program than Swedish, more logical ABB robots and if you are not abeliever let ABB show you..

[] In comparing robots, examine the ease in which the MIG wire feed, voltage or pulsed parameter changes are madand how these important parameter are viewed and monitored.

[] In comparing robots, examine the logic layout of the welding program soft ware as this feature can be bothfrustrating and time consuming.

[] Examine the calibration accuracy between the robot pendant and power source weld data, Note most are notcalibrated correctly.

[] In comparing robots, examine the robot's automated TCP capability and repeatability.

[] Examine the ease or complexity of making touch sense and through the arc robot tracking changes. Also carefulexamine how effective and consistent these valuable features are.


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[] Examine the accuracy and repeatability of the robot with the positioner utilized.

[] Examine the complexity of programming the robot to work with secondary equipment such as the positioner andtorch cleaning stations.

[] Examine the robot instruction literature, the technical support, the training available and service capability. Most

important, figure out during your initial discussions with the integrator or robot company, who's' supplying the mosbovine faecal matter.

[] For those low to moderate volume, difficult to weld parts with a few small welds, it's important to alwaysremember, that a blind robot with limited dexterity can never produce the weld productivity or quality that a manualwelder can produce.

[] Never purchase a robot without a guarantee in the purchase contract that stipulates the robot will produce fourhours worth of weld production meeting the production quantity requirements with no down time and no more than2% weld rework.

Assume no one in the weld shop is an expert on robot best weld practices and robot weldprocess controls, and then think of the insanity in spending all that money on the costly robot -

weld equipment, and yet your organization has not considered spending a few dollars on theweld process control training that can optimize the robot weld quality and productivity..

Don't look to the auto - truck industries to lead the waywith robot good weld practices and process controls.

THE ROBOT YOU MAY BE CONSIDERING TO PURCHASE MAY WORK WELL IN AN AUTO PLANT WHERE WHERETHEY RARELY CHANGE THE WELD PROGRAMS, AND THE DAILY POOR INCONSISTENT ROBOT WELD QUALITYAND PRODUCTIVITY IS ADDRESSED BY ROBOT PERSONNEL WHO WILL PLAY AROUND WITH THE WELD DATA, OFROM ADDING MANUAL WORKERS TO THE END OF THE ROBOT LINE TO FIX THE EXTENSIVE WELD REWORK.


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HOWEVER THIESE SAME ROBOT MAY NOT MAKE THE GRADE IN A WELD JOB SHOP THAT'S SERIOUS ABOUTWELD QUALITY CONSISTENCY, WELD REPEATABILITY, EASYAND FAST ROBOT PROGRAMMINGCAPABILITY.

IF YOU WANT A GREAT COMPARISON OF CONFUSION VERSUS ROBOT WELD LOGIC, COMPARE THE SOFTWAREHARDWARE DIFFERENCES BETWEEN A JAPANESE PANASONIC OR MOTOMAN ROBOT, AND THE MORE LOGICASWEDISH SOFTWARE - HARDWARE USED IN ABB ROBOTS.

BY THE WAY, ON APPLICATIONS WITH A LARGE AMOUNT OF WELDS, I BELIEVE THAT IN CONTRAST TOJAPANESE ROBOTS THAT ITCAN TAKE 30 TO 50% LESS TIME TO PROGRAM THOSE WELDS WITH AN ABB ROBOT.

TO REVIEW THE IMPORTANT ABOVE JOB SHOP CONSIDERATIONS, SIMPLY SEND YOUR PARTS TO COMPANIESTHAT SUPPLY THE ROBOTS AND LET THEM GIVE YOU THE PROGRAMMING AND WELD RESULTS IN A VIDEO.

.

With robots, the weld quality - productivity opportunities are onlylimited by a manager's or engineer's weld process control knowledge.

ROBOTS AND WELDING ISSUES
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YOUR COMPANY PURCHASED AN $80,000 ROBOT CELL AND YET DID NOT HAVE

EMPLOYEESTHAT HAD ROBOT MIG WELD BEST PRACTICES & PROCESS CONTROL EXPERTISE,

COSTING $400?

ANY OF THE FOLLOWING 15 REASONS WILL INDICATE YOUR ORGANIZATIONLACKS WELD PROCESS CONTROLS AND BEST PRACTICES EXPERTISE.

[1] If you have robot weld rework is more than 2% of your parts.

[2] If your robot cells have a ROBOT DOWNTIME per shift, of more than 15 minutes per-robot.

[3] If you use gas shielded Flux Cored wires for welding clean carbon steels < 3/8 in the flat andhorizontal welding positions.

[4] If you utilize any three part gas mixes for MIG welding carbon steels or thin gage stainless.

[5] If you utilize Metal Cored wiresfor MIG welding carbon steels or for thin gage stainless.

[6] If you weld carbon steels and you use any MIG gas mixes containing oxygen.

[7] If you purchase your primary weld supplies from more than one supplier.

[8] If your purchasing manager is involved in the selection of your weld consumables.

[9] If the person who has full responsibility for the robot welds works in the maintenance department.

[10] If your company allows robot operators or anyone other than the programmer to make welding parameterchanges to the robot program.

[11] If the changes made to the robot welds are not immediately verified through macro samples,

[12] If there is no pre-weld qualification, weld parameter and weld manufacturing instructions postedon the walls of the robot cells.

[13] If there is no method to verify the weld amps - volts - WF for each weld with that recommended on the weld macharts that are supposed to be posted on the out side of the robot cell for easy verification,

[14] If your manual welders doing the repairs or simply manual welds daily use a whipping, skipping or weaveactions with their MIG guns.

[15] If you use pulsed MIG and don't understand the implications of each pulsed parameter adjustment.

ALL OF THE ABOVE IS COVERED IN MYROBOT WELD PROCESS CONTROL PROGRAM....


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THE AUTOMOTIVE ROBOT TIG APPLICATION: This weld report deals with robot TIG welding issues that wereoccurring on one of the big three cars. The parts required approx. 15 precise small welds and thethe parts weldseams were later |brazed. The TIG welds were made with a Fanuc Arc Mate 100 robot, and a Lincoln 350 amp"pulsed" square wave power source. The weld issues at this tier one part supplier were extensive. For more than ayear they had struggled to attain a production rate of only 40% of what they desired. The tack welds were frequently

missing. Arc starts issues were extensive, and the tack welds would leak. After I rectified the problem, I wrote thefollowingreport.

If you want the highest weld quality attainable TIG manual or robot welds and you are not using TIP TIG, you are nousing the correct process. Check out tip tig at www.tiptigusa.com.

"Robots and Programmer Weld Process Control Expertise".
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A question from an HR manager at a manufacturing facility that utilizes MIG welding robots

Ed. What type of "MIG Weld Process Control Expertise" should we expect when we hire a new a robot programmerwho will be in charge of our MIG welding robots?

Answer. Your anticipations in 2013 to hire a person with robot weld process control - best practices expertise shoube low as less than 1 in 10 persons who program MIG robots will have the necessary expertise.

[] It would be beneficial if the robot programmer was able to do the following. Lets say the weld application is aRobot MIG welded common, carbon steel, automotive part. The parts welded are 2 to 2.5 mm thick with gaps up to1.5 mm. Most of the welds are fillet welds. The programmer is informed that the last time your company weldedsimilar parts, weld burn-through issues were prevalent. With this in mind the programmer should know without"playing around" where to instantly set all the optimum robot weld parameters, wire feed, amps, volts travel speedsand be able to provide the best practice solutions necessary to rectify the weld issues. The programmer should beable to justify and explain the benefits of the weld transfer mode, weld gas and weld wire size selected and theprogrammer should be able to train the cell operators to recognize arc sounds that indicate weld faults.

A robot programmer should have the capability without playing around and without"reference to a weld text book"

to instantly;

[] Provide the most logical weld process and mode of weld transfer, short circuit, spray or pulsed and be aware ofthe optimum complete parameter working ranges for the wire size utilized.

[] Provide if using pulsed, expertise on the wide variety of pulsed parameter adjustments.

[] Provide the maximum robot weld travel speeds for each weld.

[] Provide weld voltages for each weld that will minimize weld spatter.

[] Be aware of how to minimize the effects of the weld heat on the part and how to prevent weld burn through.

[] Provide the optimum robot weld start / stop data.

[] Be aware of the robot MIG gun technique which can effect the arcs and welds.

[] Provide weld data that compensates for gaps or part alignment discrepancies.

[] Provide weld data that ensures consistent weld fusion.

[] Be aware of the weld deposition rates that can be attained and their influence on robot weld travel rates and theweld cost,

[] Be able to educate the fixture manufacturers and designers of welded parts on how to design for good weld abilit

[] Be able to answer my MIGweld questions.

A SMALL PRICE FOR KNOWLEGE: To train your robot personnel with all of the above data will cost your

organization approx. $400 and you will find it my manual or robot process control trainingresources.
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Oversize weld slots in this car seat, cause weld and strength results.I have never met a designer of auto - truck parts that understood

the requirements for optimum MIG weld results.

For those designers, engineers, managers, technicians or supervisors whohave an interest in MIG weld process control knowledge and requirements,

I recommend they take a look at my MIG self teaching and trainingresources.

THE WELD PROCESS EXPERTISE NECESSARY TO ESTABLISH ROBOT WELD BEST PRACTICES - PROCESSCONTROLS, IS FOUND IN MY ENGLISH AND SPANISH MIG SELF TEACHING AND TRAINING RESOURCES.

Note the poor design dimensions of the above car seat slot welds. The slots required for the lap weld are too wideand the short erratic weld length is only attached to one side of the slot. Any slot wider than 4 mm on gauge partswill reduce weld productivity (larger welds = slower weld speed), increase weld burn through potential and reducethe weld strength. Design such as above are an indication that the designer of these parts did not understand theMIG process.

Note with robot weld lengths less that 18 mm, its difficult to define the weld quality attained as the robot in a veryshort period has to communicate three sets of weld data, start - weld - stop, these welds require that the programmhave good weld process control - best practice knowledge..

PROCESS CHOICES FOR SHORT WELDS: To optimize short weld lengths, or avoid weld burn through on common1.6 to 2.5 mm gauge parts and optimize the robot weld productivity, you could could utilize high short circuitparameters, moderate pulsed parameters or low spray transfer parameters. If as a weld programmer you look at theabove common part, and you don't know the optimum weld parameters for each of the weld transfer modes
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mentioned, it's time to examine your value to your organization.

Panasonic Robot Concerns.

FOR SIX WEEKS, THE PANASONIC ROBOT TEAM COULD NOT GETTHE PANASONIC ROBOTS TO PRODUCE TWO SIMPLE EXHAUST WELDS.

For me, it was another one of those annoying Japanese, Panasonic robot applications. Thanks to the Panasonic


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engineers, and their obvious lack of understanding simple weld application requirements, we had another simpleweld application made complex for the robot end user.

After six weeks, the Panasonic engineers and Panasonic robot integrator could not get their robot to consistentlyplace two small controlled welds, 15 mm in length. The welds were made on a carbon steel rod to a thin gagegalvanealed part exhaust bracket. The exhaust hanger bracket was poorly designed by engineers at Honda howeve

was weldable. The Panasonic robot personnel had given up on the project and left the plant and the part supplierhad five days left before production was supposed begin. For the rest of the story clickhere.

Motoman and Robot Weld Concerns.

The following is an E mail sent to me March 2001. At the persons request, I have deleted hisand his companies names.

Ed, we are on our 4th generation of Motoman robots, and I didn't think they could get anyworse, however I was wrong.

I simply would not recommend the new UP/XRC Motoman robots to anyone. We have hadnothing but problems with them.

Motoman has a real problem with the encoders in their motors, and we have replacedeveryone at least once. In addition, I have a servo pack or motor go out on an average of onc

per week. They are also having wire harness problems with the insulation prematurelywearing out. I have had to replace four so far, and we have only been running since August. We have also had toreplace 13 boards in the main processor. They are saying that the Panasonic power sources are creating noise in thunit and taking out the boards, but we are not really buying it and neither is Panasonic. Now, let's compare this toour Canadian facility which uses mostly Fanuc on the same lines designed to produce the same product. I spokewith their technical manager last week and he has not had any warranty claims since startup. If you total up whatwould have been my repair expense, if the robots were not under warranty, I would have spent in excess of$175,000.00.

2003. Motoman also produced a sad excuse for a weld power source to be used with it's robots.

Notes from Ed: From 1985 to at least 2000, the majority of the global pulsed MIG equipment produced did nothave the electronics necessary to provide controlled pulsed MIG transfer and with common steel and alloysteel welds this equipment often caused more weld quality = productivity - down time issues than it resolved.Unfortunately the weld equipment manufacturers forgot to tell the welding industry this simple fact. For moreinfo evidencelink here.

If you company used Motoman robots, it's unfortunate that you may have purchased the MotoArc 350 MIG weldequipment. If you were welding thin gauge steel parts with this power source and you wanted poor to mediocre,inconsistent, globular type short circuit welds, you purchased the right equipment.
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If you wanted to produce poor to mediocre, inconsistent, globular typeshort circuit welds, purchase the above Motoman MIG equipment.


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MORE MOTOMAN ISSUES. REMEMBER THE MOST IMPORTANT TOOL IN THE ROBOT CELLIS THE POWER SOURCE, AND NOT ALL MIG POWER SOURCES ARE CREATED EQUAL:

At two separate plant locations during 2003, I had issues with the Motoman weld equipment. In Aug. 2003 itwas my unfortunate task to optimize a large welding cell that utilized Moto Man UP6 robots with the MotoArc350 welding equipment. I had no issue with the robots except the poor TCP controls and the length of timerequired with programming. I did witness and identify poor power source response time and erratic welds frothe 350 MIG equipment. The root cause of the weld problems were generated from the new Motoman 350 weldequipment. In one robot cell the 350 unit was was so erratic it had to be replaced. With the other cell the 350unit provided poor arc starting characteristics, inconsistent, erratic weld transfer and the required weld voltagrange was excessive resulting in globular type transfer instead of controlled short circuit .

Later in 2003 I was asked by one tier one auto supplier of thin parts to help them resolve their numerous roboweld issues. The parts being welded were carbon steels, 0.045 (1.2 mm) thick. The weld wire was 0.035 (1 mmThe weld mode selected was short circuit. I noted again with the MotoArc 350 MIG equipment that at the

required low wire feed short circuit wire feed settings, that the minimum stable weld voltage required from thiequipment was 1.5 to 3 volts higher than that required from CV MIG equipment with more suited Volt - AmpSlope Curves. The required, higher weld volts from the Japanese MIG equipment caused in low to mediumweld current applications, (gauge welds), erratic spatter producing, globular transfer. Also the additionalrequired voltage provided higher weld energy which added to the "weld burn through potential on parts 1 to 2mm.

Please Note: In the land of the rising sun, the relationship between MIG equipment optimum slope curves andweld transfer modes and argon mixes was not well understood in 2003 and I doubt that in 2013 that most AsiaMIG equipment companies have yet to figure out how to design an optimum MIG power source.

Question: Ed we are using a Motoman robot with the MotoArc 350. We are welding 1 to 2.5 mm carbon steelparts, and 1.2 mm is the most common. We use argon with 5% oxygen and the short circuit with an 0.035 wire

Some of the welds are subject to weld burn through and we need to use weld settings around 100 amps with volts. We don't like the short circuit weld performance from the Motoman power source at 100 amps with thisequipment and when we set the MotoArc equipment at the 0.035 pulsed mode the weld performance is notoptimum any suggestions.

Answer: With this MotoArc welding equipment, use the 0.035 (1mm) wire but change the setting on the pulsedcontrol panel to the"0.030 pulsed steel setting"and you will get reasonable pulsed weld results in thisparameter range. By the way this was a logical short circuit application but then you would have needed adecent power source to get short circuit with minimum weld spatter. Regards Ed.


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If you paid for pulsed MIG equipment, this is likely what you got.

Erratic Volt - Amp performance with optimum weld settings.

FEW WELD SHOPS RECOGNIZED THAT FROM THE 1980s TO 2000, THEELECTRONICS IN THE PULSED EQUIPMENT COULD NOT MEET THEDEMANDS OF STABLE, CONSISTENT PULSED WELD TRANSFER.


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IF MANAGEMENT DOES NOT TAKE RESPONSIBILITY AND OWNERSHIP OF THAT WELDEQUIPMENT, THEY SHOULD EXPECT WELD QUALITY - PRODUCTIVITY ISSUES.

Your company purchased a costly robot cell, yet because those that managed the robot

purchase did not stipulate the correct questions on the PO, the robot integrator did not apply thappropriate tests to prove that the robot could consistently produce, optimum weld quality -productivity. Or perhaps your company did stipulate the correct questions on the PO and therobot integrator was simply incapable of the task.

From lack of essential calibration issues, to poor arc command response times and erratic poor performing MIGweld transfer modes, for more than two decades the major robot manufacturers like Motoman - Panasonic - Fanuc Cloos and ABB selected MIG welding equipment that was the root cause of many of the global robot weld qualityand productivity issues that were common throughout the weld industry. However the good news for the robot andweld equipment manufacturers, was thanks to the general customer MIG weld process ignorance which wasespecially common in auto - truck plants, few company managers using the poor performing weld equipmentrecognized the real root causes of many of their weld issues. Therefore few managers or company owners took legactions against the robot and weld equipment suppliers for their weld quality cost issues and production losses.The common robot weld problems I had to deal with;

[] Poor power source characteristics.[] Slow power source to robot communication.[] Poor weld parameters selected.[] Poor choice of consumables.[] Poor robot / weld equipment calibration.[] No best practices or process controls.[] Lack of weld process expertise by all involved.

Weld quality and productivity responsibility starts in the front office.When I visit a plant I work with the robot programmer. After a quick assessment of the weld issues, I would

then make the robot weld program changes necessary to compensate for the parts, weld or robot equipmentinadequacies. My process changes always improved the weld quality and increased the weld production. AfteI create the new weld programs and check the welds, I then provide the process control training. As managerand engineers are supposed to be responsible (few are), I insist that allmanagement, engineers and supervision involved with the welds take part in the training.

When making robot changes, its frustrating to see with specific robots how slow those program changes arebeing made especially with Japanese robots. Keep in mind, I have worked with every possible global robottype. If you are a "job shop making frequent new robot weld programs" I firmly believe that the ABB robotsthanks to the joy stick control and logical Swedish weld soft ware, will require with parts that have many weldtypically 30 to 60% less robot programming times

EVEN ONE OF THE WORLD'S LARGEST ENGINEERING COMPANIES ABB,

AND ESAB A GLOBAL WELD EQUIP MANUFACTURER DID NOT KNOW WHAT THEY WERE DOING.

As some of you are aware I was the North American weld manager at ABB robots. While I had much admiratiofor their robots ABB also had issue with the MIG weld equipment it utilized. ABB got together with ESAB tointegrate an Erratic MIG weld power source into the ABB controls. The ESAB equipment marriage would resuin the first robot system produced in which the weld power source and robot control would become a singleunit. When the ESAB / ABB robot controls arrived in North America in late 1990's, I was responsible for testinthe weld equipment and found numerous major weld issues with the ESAB equipment. The ESAB powersources had unsuitable slope dynamics for most MIG welds and irrespective of the optimum weld data


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used,the results were unstable, inconsistent, poor quality welds especially on parts > 3 mm. Even though thepower source was built into the robot control, the weld parameter change response time was too slowdramatically impacting the control of weld starts / ends. The bottom line was the power sources sold by ESABfor the ABB robots was better suited to manual stick welding than for optimum robot MIG welds. The salespersonnel at ABB could readily see the ESAB weld issues in the test lab. My blunt advice to the salesmen " ifyou want to get and keep your robot business, recommend the robots with Miller Delta Weld Equipment". ABB

sold the units with the poor ESAB weld equipment to the USA industry and other users knowing the powersources were substandard.

WHY DIDN'T THE GLOBAL WELD SHOP CUSTOMERS COMPLAINABOUT THE ROBOTS AND MIG WELD EQUIPMENT?

The majority of the ABB / ESAB weld power source units were typically sold in the auto plantsthat had little understanding of the weld process requirements for optimum MIG weld quality /productivity. Remember these were the companies that are used to and have through ignorancealways lived with both manual and robot MIG weld quality - productivity issues. And lets face it,managers, engineers and supervisors who lack MIG process control expertise will think it's

natural for their weld personnel to play around with the robots and MIG weld data. When you geta chance, visit the MIG equipment sections of this site to read about the sub standardperformance of pulsed MIG weld equipment from 1980 to 2005. It's 2013 and while electronicadvances are making vast improvements in PULSED MIG equipment performance, there is stilllittle justification for this costly, difficult to maintain equipment and I still weekly see many of thsame old problems.


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More ABB Robots and the ESAB Arcitec MIG Power Source Issues.

Robot Welds on Ford6061 Aluminium Car Seats.

During 2000, I was requested by an engineer at VAW a tier one supplier, to evaluate the weld performance of theirABB robots and ESAB Arcitec weld equipment. This plant produces extruded aluminium parts. The aluminiumwelded car seats were for manufactured for Ford. The car seats and parts required small welds which were made othin gage 6061 aluminium. Since the installation of the robot cells, continuous production of optimum weld qualityparts has been impossible as a result of the weld issues documented in the following report. The weld reject ratesaveraged sixty percent and the robot down time per hour averaged 20 to 30 minutes. To see the rest of the ESABArcitec story,click here.

SOLUTION TO A COMMON ROBOT MIG PROBLEM. "INCONSISTENT ARCSTARTS"

Info like this in Ed's Robot Training Program..
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Weld Question:Ed, we frequently have poor robot arc starts on our MIG spray transfer, carbon steel or stainlessweld applications. Often the arc does not initiate. We weld carbon steel parts 3 to 5 mm thick. The typical fillet weldsize is 3/16, (5mm). For the 3/16 fillets we use an 0.045 (1.2mm) wire set at 450 in./min. The weld travel rates varyfrom 40 to 60 in./min. The gas used is an argon - 5% oxygen gas mix and the weld / start volts vary from 24 to 25volts.

Answer. The part thickness you weld and the 3/16 fillet weld size requirement allows " higher thannormal manual weld travel rates". Weld speed affects the weld voltage used, the faster the speed thelower the weld volts. Two things here are effecting your weld start issues. The argon - oxy gas usedrequires" lower weld voltages" than the more common argon 10 - 20% C02 mixes. As the fast weldspeeds require "lower weld voltages" and the gas requires lower weld volts "therefore the weldvoltage you are using is lower than normal for the high wire feed rate delivered".For starting the arc with the high wire feed used with the 045 wire, you typically would require 28 - 30volts. Examine your other options below.

Robot Arc Start Solution: Just because you are welding with a high wire feed rate for the weld does not mean youhave to use a high wire feed rate at the weld arc start. You could reduce the 0.045 wire feed rate at the arc start to a

low spray rate of 370 ipm instead of the 450 ipm. This would require a lower start voltage of 26 to 28 volts. Thisaction not only improves arc starts, it will reduce wire burn back potential and stop over size welds at the start.

Robot Arc Start Solution: For a spray weld ensure the arc delay time is sufficient for the arc ignition. Typically 0.2 to0.4 seconds. Remember robot micro times are rarely accurate, if you don't hear your arc start data the time youselected is typically not effective.

Robot Arc Start Solution: The larger the weld the longer the arc ignition delay time. The smaller the weld the shortethe ignition time. On gage applications I rarely use ignition delay times

Robot Arc Start Solution:Ensure the pre-flow gas time is sufficient. Without gas ionization arcs donexist

Robot Arc Start Solution: If you don't want to build up a glob on the end of your weld wire, remember that good arcstart data requires good end weld data. Optimum weld end data ensures the completed weld wire stick out isminimum and there is no ball of weld on the wire tip.

We are touching a miniscule amount of the process control - best practice

data that I provide for approx. $400.Ed's Resources.

Lincoln Equipment and Robot Axle Weld Cracks.


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2000: If you want to make your weld manufacturing life more expensive, morecomplex and less meaningful than it needs to be, you could have listened to a

salesman and purchased a Lincoln Power Wave for your robot or manual MIGapplications.It was 1999 or 2000. My weld task appeared simple. A tier one, axlemanufacturer located in Michigan ordered two robot systems to weld truckaxles. The company I worked for ABB, supplied the robots. The robot cellswould provide one million axles annually. When the robot cells were complete,as per the contract, ABB was required to provide a few thousand welded axlesas part of the robot cell run off. Little did we know about the serious axle, WeldCracking issues

that were about to occur. For the rest of the story clickhere.

The Lincoln Powerwave and Ford, robot frame MIG weldson the world's best selling trucks.

When you utilize so called sophisticated MIG power sources with robots,and

your organization lacks weld process expertise you get unnaceptable weldslike above.
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There were 6 major issues with the Ford robot frame "pulsed welds" made at a USA tier one supplier. The weldswere made with an 0.052 (1.4 mm) MIG wire and a Lincoln Power Wave. Can you look at the welds and identify theprocess issues? Could you instantly provide the data to correct these sad Frame welds. All the process control dat

you need for optimum robot weld quality and productivity for any application is available in my low cost, CDtrainingprograms.

Robot weld issues because sometimes in robot cells, "TIME accumulates.

For robot welding small fillet / butt welds < 3/16 (< 5 mm) in size, it's often beneficial to use"No Arc Ignition Delay Times". A robot ignition delay time in combination with arc weld startdelay time and the pre flow gas time can create too much of a delay at the weld start leadingto a larger weld usually in the first 9 mm at the start, (look in the photo above). Remember thtimes put into that robot program our rarely accurate and can be much higer or lower than th

programmer expects.

For two decades the timing issues have been an issue with all robots and needs more consideration from botthe robot / MIG equipment manufacturers. Some robot manufactures believe their robots will provide thecontrols necessary for the weld starts and stops, while in contrast the MIG equipment manufactures believetheir power source should provide these controls, it's been this way for two decades, Ying versus Yang, andscrew the weld shop.

In contrast with larger welds as typical on parts > 5 mm, the longer the arc start times and pre-gas flowrequired. To establish the weld puddle with welds larger than 5 mm, an ignition delay time of 0.3 to 1 second. typical. if you cannot hear the start time data change to the weld data your times are innefective.

Aluminium welds require long start delays, this is necessary to break up the aluminium surface oxides.

Note. In robot cells, often at weld starts, the most troublesome robot weld is often the very first weld, or a welmade after a long weld pause. The problem occurs because the welding wire is "cold", electrons travel betterwhen the wire is hot. For this situation you may benefit from using a shorter wire stick out at these programpoints. Always have a least 2 robot arc re-strikes programmed for all welds.

Optimum Robot Spray Start Data for carbon steels with 0.035 (1mm) wire welds on parts > 4 mm. For the 0.035 spraweld arc start, set the wire feed at 500 in./min with 27 to 30 volts. This recommendation purposely utilizes low spraytransfer wire feed rates, settings which require "minimum spray volts". The low wire feed rate and moderate (not tohigh) voltage is the best combination for weld start data. This weld data not only provides optimum arc starts it alsoreduces the potential for wire burn backs to the tip at the arc starts.

There are many factors that influence robot weld profiles at arc starts and at arc ends and thesewith the resolutions are addressed in all my robot weld process trainingbooks. resources.

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Robots and MIG equipment. Premature Interface Communication.

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Motoman - Fanuc Robot Weld Question.

Ed I am a weld consultant. I came across a weld problem with Fanuc and Motorman robots. At theplant I was assisting there was a Fanuc robot which was 5 years old and it was utilizing a LincolnPower Wave power source. The plant also had a Motorman robot which was brand new and the powesource was a Miller Invision 11. The weld problem was notable on both 3/16 - 1/4 fillet, stitch welds.The welds were 2 to 4 inches in (5 - 10 cm) length and it would appear that 50 to 75% along the weld

length the weld appearance would change. Ed what do you think is happening?

Answer. What do you expect from North American designed MIG weld equipment that is tryinto communicate with the land of Japan.

I believe you have a case of what I would term as PRC (Premature Robot Cmmunication). Thepoor interface with this equipment between the robot and power source has left it's mark onyour welds. Instead of the robot going to the end of the weld and "instantly" bringing up thepre-programmed Weld End / Crater Fill data, your robots like many of us are premature and

bring up the weld end data too soon. Try this, place an additional robot program point about 3 mm fromthe end of the weld and make sure you complain to that robot company or integrator as this is their

SOFTWARE - HARDWARE issue, not yours..

There are many factors that influence robot weld profiles at arc starts / arc ends and these are addressed with manysolutions in all my robot weld process trainingbooks. resources.

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STAINLESS MIG GAS SELECTION AND ROBOT MIG WELDS;

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Robot Weld Question:

Ed, we robot weld 300 series stainless. The parts are 1.8 to 2.5mm used in an exhaust manifoldThe parts have inconsistent fit and gaps. We have been using an 0.045 (1.2mm) wire with a 90%helium - 7,5% Ar - 2.5% CO2 tri-mix with short circuit. Many of the welds are lap welds with gapand we often find the extremes like either lack of weld fusionor weld burn through and always distortion. Are we using the correct consumables and whichpulsed MIG equipment, would you recommend for this application?

Ed's Weld Answer:

First, stop wasting money on that useless Helium Tri-mix. This gas mix which requires the highest weld voltagealong with other things is adding to your weld burn through - distortion issues. See my two part weld gasrecommendations in the MIG gas section at this web site. The choice of 0.045 wire on these applications was notcorrect, the 0.035 wire with higher weld current density - and low to high current short circuit current capabilitywould have been fine. However with this stainless thickness range, this is one of the few welding applications thatcan justify the use of pulsed MIG.

Reference the pulsed power equipment and consumables. I like the performance and price of OTC pulsed MIGequipment. Use the pulsed mode with an 0.045 wire, and use a simple but honest two part gas mix of 98 argon 2%

CO2 which is suited to both pulsed MIG and short circuit. I developed this argon CO2 mix for the North Americanweld industry back in the 1980s, when I worked for AGA. The weld reality is most gas distributors are simply sellingcommodities they dont understand and they are either ignorant about the 2% CO2 mix, or they are happy that youare paying a premium for your poorly selected tri mix....

Using the pulsed mode will in contrast to short circuit provide superior weld wetting for the sluggish stainlessthicker gage welds especially those welds > 2 mm. The higher pulsed wire feed rates than short circuit should alsoallow you higher weld travel rates than the short circuit welds which will decrease weld burn through and lower theweld cycle times and decrease distortion.

Remember when welding less than 14 gage or gage parts with gaps you can always switch back the weld transfermode to short circuit. The argon CO2 mix will again benefit the short circuit as it will reduce weld burn through. Asfor that poor fit and inconsistent weld gaps in your parts I have a simple solution, fire the engineer responsible forthose parts.

There are many factors that influence weld gas selection. If you visit the MIG gas section at this site you will notethat I developed three of the major gas mixes sold in North America. Appropriate MIG gas selection without

salesmanship is in all my Robot Weld Process Control TrainingResources.


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Drive Roll Groove Question:Ed I believe you need differentguide rolls for different MIG wire types, what'srecommended?. Thanks for the site, JH. Manchester UK.?

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Ed's Answer on MIG Drive Rolls:

[] For solid hard wires use a Vee Groove rolls built for the wire OD. Two large rolls are just as effectivea four smaller rolls. Note for MIG welds there is no MIG weld that should ever require using a wirediamter smaller than 0.035 (0.9 - 1mm)

[] For flux core wires use a Vee Groove with at least onE roll providing a serrated surface to improvethe grip. Watch you do not apply too much drive roll pressure to these wires.

[] For aluminium wires use a U Groove with smooth surface again don't use excess drive roll pressure. Withaluminium ensure minimum gaps between the inlet, drive rolls and outlet guides to avoid buckling. If using a regulaMIG gun use a rigid plastic liner and when possible use a maximum gun length of 10 - 12 feet.

Note: The best MIG gun length for any difficult weld wire is a 10 foot length.What is the value of the free


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information that you are reading? Will you improve your companies weld quality - productivity and career

prospects with the process control - best practices knowlege such as this? Visit Ed'sResources.


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Robot Programmer asks a weld $alary Question.

03/23/2000: Ed, I have been working with robots for almost ten years. I am a highly qualified robotprogrammer. I have extensive MIG weld process expertise based over 20 years of MIG experience.As you are aware there are many career opportunities available to me at this time, particularly inplants that supply auto - truck, robot welded parts.

I have been looking at many different job opportunities mostly in the auto / truck industry. When I go for a jobinterview, I usually find the plants will have numerous robot weld issues. All the plants I visit employ engineerswho obviously do not have the expertise to address the daily, costly, robot or weld issues. I know that I can improvtheir weld quality - productivity and have a big impact on these companies, however, and here's my gripe. When itcomes to the salary offered no one offers to pay me more than they pay their entry level engineers who seem to halittle influence on improving anything. The bottom line the salary offered is typically not much more than they paytheir manual welders who work few hours overtime. By the way as a salary individual, the only timeI can make "major changes" to the robot programs is on the weekends. So on Saturdays and often Sundays, whenthe managers and engineers are at home, I get to work without over time pay alongside the hourly paid trades peop

who get time and a half. Rrgards and thanks for what you do. Mike James.

Ed's Reply:Mike lets face it. when you work for management that do not understand what you do, youremuneration and responsibilities will reflect this. The salaries today offered to the few, experiencedrobot arc weld programmers (programmers with process control expertise) in North America are notmuch different than 25 years ago, and in reality are a sad reflection of how out of touch the majority oengineering and manufacturing managers are from the real world requirements for optimized weldautomation. Lets face it, to figure out how much your management will understand what you do daily to take a look at the common two paragraph simple, job descriptions or perhaps like many technician

you wont have a job description. In automotive plants, where managers and engineers waste so much time dailyrunning around putting out fires that they cause, you will typically find that weld quality and productivityresponsibility is rarely clearly defined. In too many manufacturing plants that do a large amount of welds, hands ofmanagers and engineers tend to shy away from weld process and equipment ownership.

It's a global weld reality that few manufacturing or HR managers are familiar with the expertise levels necessary foroptimum robot arc welding process optimization. From a weld career perspective, If I was in your shoes and lookinto improve my job satisfaction, increasing my salary and quality of life. I would look outside the auto industry toindustries which offer a higher calibre of management for example manufactures of medical equipment or valves.

Today many companies use robots in the medical, defence, electronic, power and oil industries. With thesecompanies in contrast to the automotive industry, you will typically find a more relaxed, intelligent approach tomanufacturing, with better wages, shorter hours and less dead wood management.

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YOUR JOB DESCRIPTIONS ALAWAYS DEFINES THE EXPERTISE OFYOUR MANAGEMENT:

In many manufacturing plants where minimal focus or understanding is placed onthe expertise necessary to attain optimum, consistent weld quality andproductivity from a robot, all you have to do is examine the job descriptions to figureout the management awareness.

IF A JOB DESCRIPTION AND RESPONSIBILITY IS CLEARLY DEFINED FOR HIGH TECHINDIVIDUALS, THE WELD QUALITY - PRODUCTIVITY RESPONSIBILITY, ACCONTABILITYAND SALARY WILL TYPICALLY BE AS IT SHOULD BE.

For those technicians or engineers who understand how their daily functions have agreat impact on the weld quality / production attained, and you are frustrated but wish tostay with your knuckle head employer, my message to you is simple, educate yourpeers as to what you do and show your managers with weld production and quality data

the money you daily save your company. As for that working Sat - Sun for free, be a mantake pride in your expertise and learn to say no when you think its relevant.

Remember in today's bean counters world, if you don't show the beans saved you havelittle value.

To help those mangers who wish to put things right and feel the need to actually managewhat they are responsible for, I recommend my "Management Engineers Guide to MIG"book and CDresource

NEW TECHNOLOGY IS OFTEN NOT BETTER.


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A Robot plus the Lincoln Power Waveand Street Lamp automated weld Issues.

Hey folks you may not like the message, but you know you won't get this kind of info fromyour local weld equipment mfg or supplier. More practical robot weld data to follow I can writhis stuff forever, but what the heck why can't you miss a dinner and invest in my books or i

my self teaching CD trainingresourcesthat way you have acess to the real valuable info thatdon't provide at this site.

If you were going to set a robot to weld inside a sophisticated vessel or container, I hope you would not set the MIGweld data like that shown in the ABB robot photo below. Remember for code quality welds that we now also have TTIG which provides superior weld quality and productivity than regular manual and automated Hot and Cold Wire

TIG. TIP TIG is very compatible with robots and weld automation. (www.tiptigusa.com).

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The Excess Spatter Window (a spatter window should be set for all welds)reveals poor MIG weld parameter selection.
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This company purchased good robots but lacks MIG weld process control expertise

MIG WELDS AND CONTACT TIP ISSUES:

082007. E-mail:

Hello Ed.I recently purchased your "Management and Engineers Guide to MIG Welding book". The 600 page book ieverything I had hoped it would be...and then some! The company I work for has a handful of welding engineersscattered throughout North America. Over the past few months I have had a growing number express satisfactionwith using 0.030 tips with 0.035 wire robot welds. My issue is this, no one has given me a specific engineering orscientific reason for the contact tip change. Simply, "So-and-so told me to try it. It works for him so I do it to." (Ibelieve the idea originated with a suggestion from one of the consumable sales reps.) This concerns me. I foresee number of problems including increased uneven tip wear, restricted wire feed, spatter blockage issues, etc and Idon't see where current flow would be influenced significantly.


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Am I missing something? By the way Ed, thank-you for having the motivation and courage to make this kind ofinformation available. I have not yet come across an opinion from you that I did not share or a concept I did not

admire. Regards. Fraser Rock.Weld Eng:

Ed's Reply: Fraser: Thanks for kind words. For the five decades I have worked with the MIG process have never had to use smaller tips unless there was something wrong with the wire diameter or the t

bore dimensions, and in theses situations, i would change the supplier of the consumables. I havefound in many plants that a common issue like this is usually a "distraction or crutch" for plant peop(including engineers) who frequently lack the ability to get to the real root cause of their daily weldissues.

Most robot contact tip issues typically result from wire burn backs, poor weld start and end data, incorrect wire sticouts, poor parameters or wire cast - helix issues. A contact tip bore needs to be approx. 0.008 to 0.01 larger than thmax wire diam. When you purchase smaller tips than those recommended it's important to remember that withtoday's inconsistent weld wire quality, the weld wire OD is inconsistent and could be on the plus side. No contact tshould be put on a robot without the robot operators or weld personnel manually running the weld wire through thetip. If the wire and snags, the wire is too large or the tip is too small. If the wire is manually fed through the tip andmakes consistent, unrestricted contact, it's fine. If the tip bore is not the correct size, (check with drill gauge),

change your contact tip manufacturer, Remember that many of the contact tips sold in North America are made inChina and you will find that like most Chinese products, the tip bore dimensions are often all over the place. If theMIG wire OD is too big, change the wire manufacturer and for god's sake get rid of weld distributor that provides yowith these poor quality products.

As for those so called weld engineers. For the last decade, there has been in North America many weld qualityissues with offshore manufactured, substandard weld consumables. The role of an engineer is not to provide BS oadd to the numerous weld shop myths, but to get to the root cause of all welding issues. Regards Ed:

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E-mail:

Question: Ref MIG wire burn backs to the Gun Tip.

Ed, we are one of the largest producers in North America of automotive Shocks. I wouldsay that our robots on average weld 200 to 400 parts per-shift. In each robot cell weaverage 2 to 5 wire burn backs per shift. The burn backs require that we frequently replacthe contact tips. As the down time and time required to rectify the problem takes anaverage of 5 to 10 minutes per burn back you can imagine the production and weld qualitconsequences. What is the primary cause of this common robot problem, why does thisnot happen as frequently with manual welders, and are there practical solutions?

Ed's Answer: There are many factors that influence weld wire burn backs and this is one of the primcauses of robot down time. These issues are easily resolved To quickly get to the root cause of allyour contact tip issues, attain Ed's Robot Weld Process Control TrainingResources.

By the way I had one robot technician tell me the other day that he could not purchase my roboweld process control resources because his Tier One company that had paid over a hundredmillion dollars for it's robot weld line refused to pay the $390. Its a shame that a company that likely loosing millions annualy with robot weld quality - productivity issues thinks like this. It's

also a shame that the young engineer that likely spent at thousands on his weld education will not invest a fewhuindred dollars in attaining the real education he really needs so he can get away from those managers that
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have their head in the sand...


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The so called MIG weld benefits from SpecialAlloy Contact Tips for Robot Welds?

Ed contact tip issues is a prime cause of robot down time at our plant. We make steel aut/ truck shock components. I figure each shift we are loosing 40 to 60 minutes of robotproduction per- robot cell due to the contact tip issues. We had a saleman tell us about h

companies special alloy tips and their influence on tip longevity. My question is should wbe doing more work on tip evaluation?

Signed Simon, a frustrated robot weld tech.

Ed's Answer. Thanks to different alloy additions to copper of course some contact tips will offedifferent properties that can affect wear or conductivity, however and you can take this to thebank, the alloy composition of the tip is rarely relevant to the contact tip life. A larger, thickercontact tip does enable less weld heat to form in the tip in contrast to thinner tips. The real issuin most robot weld cells is to first recognize the root cause of the contact tip failure. You will finthat most of the contact tips being replaced are due to wire burn backs and to weld spatter

blocking the tip bores.

WHY LET ONE DOLLAR ITEM EFFECT WELD QUALITY AND PRODUCTIVITY?

Every robot operator should start each shift with a new, $1 contact tip and again replace the tip immediatelyafter lunch. Each Technicain or Engineer responsible for the robots should at least twice a week, check thecontact tip bore diameters and the quality of the tips purchased. The complete check list and my seven stepprogram to prevent costly robot down time is item 4 and you know where that is. As for the special alloy tips iyou continue to purhase them, give me a call, I have a bidge I can sell you in Brookyln for less than a $100.

Note: By the way, I created a patent on ceramic - Cu tips, and those tips were designed to allow extended MIGwire stick outs. This enables higher wire feed rates (faster weld travel rates) with lower MIG weld current..These are two real world weld benefits for robot gauge welds. but don't go looking for them..

Robots and Gas Flow Issues.

Question.Ed I'm having a hard time keeping flow meters from "blowing their lids" in my plant. We've run both ESAB andRexarc flow meters and over time they are both failing. At the start of the weld the solenoid opens letting the gasflow into the flowmeter...pegs the BB out on the top of the unit then settles to the set flow rate. I have tried snubberand I have tried placing the FM before the solenoid. We have 50 psi of 90%AR - 10%CO2 coming down from ceiling each weld cell. Then provide a 10-15 ft flex hose to the solenoid. The flow meter is hard plumbed to solenoid, then 4flex to 8' Torch bundle. Do I need to rearrange? Is this common? Surely not! FYI, we have 2000 arc starts/day onthese FM's, some last 4 months, others last 4 days! Should I remove the FM altogether and get a set calibratedorifice like at www.okcc.com? I did turn down my pressure leaving my gas mixer to 40psi but all FM's are calibratedat 50psi, so it throws off my readings. (Help)..

Ed's Answer. Most MIG gas flow meters have the pressure regulated at 20 to 30 psi. I wouldinstall a pressure gauge at your outlets and lower your gas pressure to 20 - 30 psi. The onlyconcern for MIG gas flow is the flow rate coming out of the MIG gun nozzle, and the robotoperators should chaeck this at the start of each shift. This flow rate should be 30 - 35 cuft /hr.


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Question. WELD POROSITY:

Ed we have an extensive porosity issue with our robot welds would appreciate your thoughts on the subject.

MIG WELDS AND POROSITY: What is weld porosity, it's a cavity, pore or manydiscontinuities that form in a weld from a gas and metal reaction. The porosity can trappedin the weld or at the weld surface. The porosity is typically round in shape but can also beelongated. The primary cause of porosity in auto - truck plants is lubricants on the partsand the result of fast weld speeds and poor weld data.

ROBOTS AND MIG POROSITY.When you find the robot weld porosity occurs on each part at the samelocation, and it's not at the weld start or the weld end, 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 restrictiodue to the narrow orrifice gas line connections. In a robot cell it's critical that at the start of each shift that thecell operator measures gas flow as it "exits the gun nozzle". If the porosity is at the weld start or stop increasthe gas pre flow and post flow times.

ALIGNED OR RANDOM WELD POROSITY.The common causes of localized oraligned group of gas pores with random distribution. If the weld surface is cleathis porosity is typically a result of part contamination. If the weld surfcae isoxidized (grey) then look to insufficient gas flow issues. Also small weld

lengths and small fast freeze welds and arc blow will contribute to this porosity

ELONGATED WELD POROSITY. (Wagon Tracks). This porosity is typically found parallel to the weld axis. Thiclassic porosity is evident when moisture is found in the gas shielded flux cored wires, (a too common issue)The pores rise to the suface of the welds, (usually in the weld center) and before they can pass into thesolifying flux cored slag, the ores which can be large and small will form a rough line typically called WaggonTracks. Increasing the flux cored wire stick out and increasing the wire feed rate will help. Storing wires in adry environment also reduces potential. If however this is a common problem with the FCA wires change youFCA brand and change your supplier. The bottom line, avoid weaves and adding arc and weld energy decreasthe weld cooling rate and should produce less porosity.

LARGE PORE WELD POROSITY. If weld surface is clean and does not look oxidized, the large pore MIG andFCAW porosity is usually a result of excessive gas flow. Gas turbulence occurs with gas flow greater than 40cuft/hr and is especially prevelant in Vee - j groove welds.. If weld surface is grey and dirty, the cause is otfen

result of insufficient gas less than 20 cuft /hr. Gas flow must be measured at the gun nozzle.


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The apathetic management at this tier one company, allowed theselection of an oversized 0.052 (1.4mm) MIG wire for the robot framegauge welds.

This hydro formed Ford Trucl Frame weld is more than a bad weld,it's an indication of poor management and a weld process out of

control.


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Can you identify the root cause of cold truck frame welds?

A manager, engineer, supervisor or robot technician that had weld process controlexpertise would look at the above robot welds on the big three hydro formed truckframes, and instanly know what the weld issues and resolutions were.

The above tier one, Ford frame, globular welds with evident lack of weld fusion are not the fault of therobots or the over priced Lincoln Power Wave MIG equipment utilized. These and the other similarglobular welds on the truck frames were the result of inexperienced, hands off managers andengineers who selected oversize MIG weld wires and used undertrained robot personnel to provide

thousands of welds that jepodized the structural integrity with some of the world's most expensivetruck frames.

Fanuc and Lincoln Power Wave.

and 2004 Ford 500 Cradle / Frame Welds.


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Date 23. July 2004. 2004 Ford 500 Cradle / Frame Welds..This report is a condensed review (changed with a littleadded humour too keep things sane) of a Ford robot weld line used to MIG weld the Ford 500 steel cradles and subassemblies. I evaluated this new robot line to establish the root cause of the many weld issues that were impacting

the cradle and frame robot weld quality and production.

This mid west, Ford plant purchased approx 100 Fanuc robots with Lincoln Power Wave weld equipment. The weldwire type was E70S-6, and size 0.045 (1.2 mm). It was notable the the Fanuc robots at this plant did not haveautomated TCP controls or any weld joint tracking equipment. The hourly production range was 60 to 70% of it'sgoal, and the daily weld rework was > 40%.

When purchasing robots for an auto or any high volume manufacturing facility, it's important that the managementand engineers responsible do a weld risk assessment and that they understand how the parts or the robotequipment selected can impact either the weld quality or production. It was evident at this Ford plant that themanufacturing management and engineers responsible for the robot welds had little expertise or interest in owningthe processes or the equipment that make their profits.

Note: With robot MIG welds, the primary concerns with common auto truck parts welding 2 to 4 mm is the attainme

of acceptable and consistent weld fusion. Its a sad fact that on steel parts > 2 mm, one in three or four welds in theauto industry will typically will reveal marginal or lack of weld fusion. In contrast the weld concerns for parts lessthan < 2 mm, is typically to avoid weld burn through.

The Ford plant provided numerous welds on steel parts < 2 mm. On these parts the MIG weld burn through riskpotential was high, and it was compounded by the poor weld data, oversized weld wire, unnaceptable partdimensional issues, plus lack of ability for the robots to track the weld joints, no control of the robot Tool CenterPoint (TCP), along with management and engineering process ignorance.

As the Ford plant ramps up to try and attain its 100% robot production goal, thanks to the apathetic engineeringinvolved in producing stamped parts to the design dimensions, the reality is that it's unlikely that the partdimensions will improve, (most welded part dimension issues increase with amount of stamped parts provided).Therefore the weld issues, unless radically addressed will increase daily.

I found In this plant, that lke many, the weld consumable selection was influenced more by the purchasingdepartment than by knowleable engineers, just as the robot and weld equipment selection for this plant has hadmore to do with salesmanship than it did with weld - robot engineering logic.

THE IMPORTANCE OF ROBOT TCP CONTROLS.


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THE FORD PLANT WAS LOOSING 20 - 30 MINUTES PER-ROBOT HOURPRODUCTION LOSS BECAUSE THE FORD MANAGEMENT AND ENGINEERSLACKED THE BASIC KNOWLEGE NECESSARY TO ORDER THE CORRECTEQUIPMENT AND IMPLEMENT EFFECTIVE WELD BEST PRACTICES ANDPROCESS CONTROLS:Part dimension ACCURACY and TCP controls are critical when welding thingage applications. The thinner the gage, the greater the weld gap sensitivity.Thin gage requires smaller welds which require faster weld speeds thatrequire stable joint dimensions.Torch Control Point (TCP), apart from maintaining the robot program pointaccuracy of the wire to work, also enables an altered program to be put back

to the original approved program. In this Ford facility, with the robot cells purchased, there are

no means for accurately checking the robot TCP, and you will find programmers constantlymaking changes to the welds, none of which have anything in common with the original socalled pre-qualified weld program.

While I was at this plant, the plant typically was loosing slightly over 20 minutes/hr of robotdown time. The lost production from the 33 robots in opertion (33 x 20 minutes = 660 min/ hr)The bottom line was each hour the plant was loosing > 30% of its production.

Note: On robot welded parts with gaps or inconsistent dimensions, to compensate, you typicallyhave to be able to place "oversized weave welds". Over sized welds not only decrease weldtravel rates, they can increase the weld burn through potential, especially on the 1.5 - 2 mmparts. To avoid weld burn through with the larger welds, aggressive weld weaves are beneficial,the plant programmers made no use of the weld weaves in any of the robot programs.

Unfortunately with the numerous weld burn through issues, the resulting holes in the parts weredisrupting the weld arcs, causing the weld wire to end up with excess length (excess wire stickout) which was a root cause for poor arc start and for the contact tip issues.

To minimize the potential robot weld issues that will occur, the Ford plant management needsmore focus on the implementation of best robot weld practices and knowlege about processcontrols (cost a whopping $400 at this site).


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FORD AND THE LINCOLN PULSED MIG EQUIPMENT.2004: For more than two decades, the major MIG equipment manufactures have been developing and p

pulsed MIG equipment for "steel applications".

When so called engineers have to rely on "sales advice" for technical answere they get what they desreLincoln pulsed equipment purchased for your robot weld lines has undergone years of development, yprovides "poor arc stability" along with arc length sensitivity. The pulsed arc length sensitivity makes tmode unsuitable for most of your high weld speed steel applications. It's ironic that the weld equipmencompany purchased has cost >50% more than the available superior, stable, traditional CV equipment have been used. The pulsed weld equipment purchased will also likely cost three times as much to repwill need to keep more spare equipment than normally would have been required with traditional, moreequipment.

FORD AND THE PULSED MIG AND HIGH SPEED WELD CONCERNS:

When using an 0.045 (1.2mm) MIG wire and pulsed welding on the cross members, to attain the deminimum weld travel rate of 45 ipm, on the 1.6 mm lap welds, the MIG weld wire has to have a "verlength" and virtually make contact with the weld surface. This required wire to work contact not onthe pulsed transfer, it causes extensive weld spatter which negatively impacts the contact tip life. spatter is also contaminating your fixtures causing part assembly and fit issues.

When establishing the Power Wave pulsed trim voltage, (the arc length) with this high speed pulseapplication, if the pulsed weld voltage (arc length) is set to a none weld spatter condition, (requirearc length), the pulsed weld transfer and instability at 45 - 50 ipm weld travel rates will cause "skip(missed welds and weld blobs on the parts).

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Typically with this 2004 pulsed MIG power source technology, when pulsed welding we need a sufficiento enable the pulsed MIG weld drops to form and transfer across an arc gap without making a short circwith the work and with the wire tip. With the Lincoln pulsed MIG equipment selected the desired minimrequired for optimum pulsed weld transfers is detrimental when pulsed welding thin gage parts using 0the "high weld speeds". If logic and ownership had been applied by the Ford engineers, the weld equiprobots would have been tested before the purchase order was produced for the equipment and also thecontracts should have stipulated that the weld quality - productivity goals be produced at least for 4 horobots and weld equipment was delivered to Ford.

The thin gage parts also limit the allowed pulsed wire feed rates which limit the Lincoln Power Wave pufrequency utilized. The low pulsed frequency with the large wire diameters and a weld which for 50% ofa background current of less than 100 amps resulted in an unstable weld transfer mode unsuited to higspeeds on the Ford 500 cradle welds.


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The robot, high speed skip weld issues at the Ford plant are the same pulsed weld issues that every whmanufacturer and torque converter manufacture has had to deal with for almost two decades. Another when you use the Lincoln pulsed equipment in the traditional spray transfer modes which provides impstability is the weld decision maker may not beaware that the slope influenced performance of the traditional spray mode from the pulsed MIG equipmtypically inferior to the lower cost traditional CV equipment.

To attain high robot weld speeds with weld transfer stability, I recommend the pulsed mode should be the more stable, less arc length sensitive "spray transfer mode". While the spray mode runs hotter thanthis is not a concern for the welds on lap welded parts in which the two parts combine for > 2mm. The tcan be reduced through the use ofsmaller MIG wire diameter such as an 0.040 or 0.035.

Note: Remember this time period is 2004 for pulsed MIG equipment, and although I had been describingsimilar pulsed issues on this site for at least seven years, managers and engineers in the auto industryto get advice from the people who made and sold the equipment. Poor performing pulsed equipment wcompanies like MIller. ESAB and Lincolndid not discuss in public. There is not be the same pulsed MIG electronic and weld transfer concerns wthe pulsed equipment sold > 2006.

CONCLUSION FOR THE FORD PLANT: I could waste my time and show you the numerous list of weld iresolutions I provided for this plant. An ironic point also is Ford spends millions every year on trainingweld applications such as this, and it's clearly evident that the management lack the technical ability totraining that will attain the results they desire. I would hope that one day an intelligant, pragmatic Ford sits in his ivory tower and does not have ego issues will read this stuff and will then come to the concluwhere the responsibility lies and what has to be done.


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As I wrote the above Ford report, I was also involved with a tier one company that was using

0.052 (1.4 mm) weld wires on Ford truck frames that were typically 2 to 4 mm thick. Thiscompany was also using the same Lincoln pulsed MIG Lincoln equipment. They also wentthrough the consequences of the pulsed arc instability, and they were unable to use high sprparameters required as a result of management selecting an oversize 0.052 wire.

As they could not dial in the required MIG spray parameters, the robot programmers at theplant unknowingly dialled in lower "globular parameters" which started to cause all types of production and qualityproblems, (see frame plant report at this site).The globular transfer caused over 80% weld rework. The globulardrops on the wire tips also caused extensive robot down time.

A reasonable question that could be asked was which idiot at the Ford and Tier One company ordered the oversize0.052 wire, and dont be surprised if the answer was found not in the management offices and engineeringdepartments (no process ownership) but was found in the purchasing department.

July 30-04. E Mail to Ed. Ref Miller Pulsed MIG issues,

Miller Accu-Pulse / Auto Axcess Issues.

Ed: Your description of arc sensitivity with high speed pulsed welds is exactly whI am experiencing with our robots and the new Miller Accu-Pulse process / AutoAxcess.

The new auto bumpers we are welding are thin gage, 1/16 (1.6mm) HSLA and wehave weld heat martensite concerns.


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To minimize the weld heat into our parts, I tried to weld above 40 IPM with the Accu-Pulse using Miller'srecommended weld settings we could not do the welds due to weld skipping and arc instability.We went to an 0.035 wire and could not get the travel speeds so we changed back to 0.045 wire (1.2mm) wire and hto run the pulsed arc with the arc length buried in the part. The small arc resulted in extensive weld spatter, also thpart could not handle the pulsed weld transfer and with the resulting high weld heat we had weld burn through holeall over the place.

With the disappointing Miller pulsed weld equipment results. we took your advice and changed the weld transfermode to CV, using high circuit with the 0.045 wires. We are attaining 40 IPM travel rates and I have no spatter of anyconsequences on the parts. Also we are having no arc stability problems with the short circuit.m I hate to admit itbut this is is another pulsed failure in my book. I am also pissed of at the fact that we could have got these shortcircuit weld results from much lower cost CV weld equipment without all the costly head aches.

Regards from a fan but a frustrated robot tech... G.S.

BEST WELD PRACTICES SHOULD NOT INCLUDE PURCHASING MANAGERS.


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I can understand why third world country weld shops get uptight about weld

consumable costs, however in many North American auto - truck plants engineers should nothave to worry about saving pennies on it's MIG wire costs.

Bigger MIG wires require less drawing so they do cost less than smaller diameter wires.Bigger weld wires also require higher weld current which typically depending on the size willnot be suited to the gauge parts.

It's a sad reality, that with the common hands off, lack of ownership managers - engineers thatare found in too many auto - truck plants, that a purchasing manager rather than a qualified engineer may decide othe MIG wire diameters and gas mixes selected for the robots or manual welders.

A typical auto cradle may today use approx. 1 to 2 lbs of weld wire per cradle. So the purchasing manager can save

20 to 30 cents a cradle by recommending an 0.045 or 0.052 wire instead of the 0.040 or 0.035 wires. When we use thcorrect wire diameters, we can optimize the weld heat, the weld quality and the productivity and therefore minimzeweld rework. So while the purchasing manager is trying to save a few cents per part the robots daily churn out arobot weld production of typically less than 60% with 20 to 70% weld rework.

Question. Ed I read above that the Ford people were not using weaves on the robot cradle welds. When should weconsider weld weaves.

Three important weld benefits are attained from the weld weaves on gage parts;

Answer: "Controlled weld weaves" avaialble ifrom automated applications enable

[1] Reduce weld burn through potential.[2] Help compensate for gaps.[3] Helps compensate for part dimensional deviations.[4] Help control fusion

THIN PARTS AND WELD WEAVES. Typically weld weaves which slow down weld production are a good toolfor poor part design, poor fixtures and poor parts, all of which are a refection on the expertise of the engineerresponsible. Weld weave requirements and weld weave types are discussed in my robot process control, bespractices, self teaching and training resources.


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This manager is a common reason for the lack of robotbest weld practices and process controls in his plant.

How unqualified individuals and inflated egos influence welds:


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THESE COMPANIES HAVE INFLATED WELD PROCESS CONFIDENCE, WHY?BECAUSE THEIR PARTS ARE EASY TO WELD.

At North American auto - truck parts plants, companies such GM, Ford Honda, Toyota and Chrysler and of course TiOne companies such as Magna which is one of the world's largest suppliers of auto - truck components, when the

robot welded parts are typically >2 mm, some times the robot MIG welds will be a very simple task, especially whenthose companies utilize a combination of good manufacturing practices that result in part fit that actually meets thedesign, dimensional specifications, and use fixtures designed by engineers who actually understand the automatedweld requirements of the job they are paid create the fixtures for. With this rare combination, the weld burn throughrisk would be very low and therefore the weld quality and productivity potential is often at a reasonable (but rarelyoptimum) level. The reader at this site should also be aware that in most automotive plants >95% of the weldsproduced are not subject to a macro weld evaluations and typically a great portion of those welds would reveal serodefects like lack of fusion and excess porosity. It should therefore come as no surprise that in this manufacturingenvironment that you will often find that many executives, managers, engineers and technicians will have an inflatedego on their abilities to manage and control robot welds. The sad reality in this environment is that the majority of throbot technicians making the daily weld changes will typically have minimal robot MIG weld Process Control - BestPractice expertise.

HOW IMPORTANT IS PROCESS LNOWLEGE TO YOUR CAREER OR TO THE PLANT YOU WORK AT:

If GM, Chrysler and Ford and the other major auto - truck manufacturers were capable of managing essential mfg..processes such as robot MIG welding, painting and stamping cost efficiently, then there would be no need for tier onsuppliers. With these major manufacturers, controlling costs means, cutting people, reducing wages or benefits,shutting plants or getting government or state loans, a great portion of their profits is derived from decreasing theprices made for their parts from their suppliers. With the primary part suppliers, in contrast profits are made when daproduction - quality goals are consistently attained within budgets, and if the suppliers cannot bring their processcosts down annually, unlike the big three, the suppliers will eventually be driven out of business.

I have visited a few of the Magna plants and talked with many young robot technicians who typically had one to fouryears of robot weld programming expertise. I found that many of the rookie robot weld warriors while enthusiasticabout their careers, had unwarranted swollen egos about what they knew. These guys, (women tend not to have theego problems) had made a decision sometime in their short life that they knew all the weld knowledge they required,therefore had nothing to learn from someone like me. By the way, this was at a time I was considered a process contexpert with 40 plus expertise, which was (the reason I was invited to the plants. It's a sad situation when amanufacturing generation is happy to get by with a little knowledge and when technicians, supervisors, engineers anmanagers with a few years under their belt decide they no longer need to further their very limited weld process coneducation with the world's most important welding process.

IF YOU EVER FEEL IN YOUR CAREER THAT YOU HAVE NO MORE TO LEARN, YOU DON'T BELONG IN THEENGINEERING OR SCIENCE FIELDS, YOU WOULD BE BETTER SUITED TO WORKING IN A DONUT SHOP.E Craig 2013.

I don't blame the young technicians I bumped into at Magna for there unwarranted ego's or their sad know it allattitudes, after all my generation raised too many of these young buggers to believe that no matter what theirperformance is, it's all good, and therefore there is little need for them excel. Lets face it, to excel would mean that th

would require a depth of knowledge that actually requires some intense study and they would also have to askquestions from old farts like me.

I have great respect for the founder and owner of Magna who I believe at one time must have been a great tool make(likely the reason Magna consistently produces good stampings). However it's been my experience from the 1000 plucompanies that I've provided weld production - quality improvements for, that when that large manufacturingcorporations allow hands off, middle management who usually don't understand the meaning of process ownershipenable their workers, supervisors, technicians and engineers to get by with minimal process expertise such as thatfound around the MIG process, which is a critical process that typically generates a good portion of their companies


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profits, then it's not rocket science to figure out that Magna, as with many of it's tier one predecessors, eventually paan unnecessary premium for the parts it produces. Those premium may be derived from;[a] Paying for overpriced automated and weld equipment that provides costly, unnecessary bells and whistles, asfound on overpriced pulsed MIG equipment. These are the products which are usually influenced by someone in sale[b] The general lack of understanding of weld process controls and the lack of best practices expertise means thewelds will not always be established to achieve a robot's full weld or quality production potential. In too many auto

plants it takes two robots to do the work of one. If a robot spends more than 10 minutes downtime each shift it's undutilized.[c] Weld rework may be generated that increases the part costs. Anything above one percent rework is not acceptab[d] Weld quality issues could involve future recall and liability cost consequences.

Lets face it, and this logic applies to any weld shop, if a company purchases a robot and there is not one person on weld shop floor or one supervisor or manager can tell the deposition rate potential for a common weld or the cost ofsimple, yet common 3/16 (4.8mm) fillet weld, how can that costly e equipment or process be maximized?

We all know there are a few good robot technicians that have extensive MIG weld process controls and best practiceexpertise, (I have trained many), however and managers don't like to hear this, these guys are the minority. For thoserobot weld programmers, technicians, supervisors, engineers or managers that figure they don't need robot processbest practice expertise, try the following fundamental, yet important MIG process controltest, and after the test askyour self, "is this info important to my company and to my career.

MANAGERS - ENGINEERS - SUPERVISORS AND TECHNICIANS, TO AVOID ROBOT WELD PROBLEMS, IT'S LOGICAYOU WOULD WANT TO TAKE OWNERSHIP AND BE ACCOUNTABLE FOR THE PROCESSES AND AUTOMATEDEQUIPMENT USED IN YOUR ORGANIZATION.

THE PROBLEMS DREQUENTLY START AT THE ROBOT INTEGRATOR: It's a reality that with the major auto / truckcompanies that many of the robot weld issues are caused before the robots get to the plants.

WHY WOULD ANYONE IN THE AUTO - TRUCK INDUSTRY ORDER A ROBOT WITHOUT FIRST HAVING THE ROBOTAND FIXTURE SUPPLIERS PROVE THEIR PRODUCTS AND CONSUMABLES CAN CONSISTENTLY PRODUCE;

[a] FOUR HRS PRODUCTION MEETING THE WELD PRODUCTION CYCLE TIME AND WITH NO MORE THAN 5 MINUTDOWN TIME,

[b] FOUR HRS PRODUCTION WITH NO MORE THAN 1% WELD REWORK.

[c] ALL PARTS WITH 100% QUALITY WELDS, (ALL WELDS FULLY FUSED WITH ACCEPTABLE POROSITY LEVELS)

As mentioned, it's not uncommon to find the robot weld issues that result from the selection of oversized MIG weldconsumables and poor performing weld equipment and fixtures. Many times the robots will not be calibrated corrector lack essential options which are necessary to deal with the parts. The robots, weld equipment, fixtures andconsumable selection is often influenced by project engineers (mechanical or electrical engineer), or by purchasingindividuals that don't understand the MIG process and it's automated needs. Other issues will arise from managerswho have to ask a salesmen about a weld issue.Add the above issues that result from inexperienced weld decision makers and then throw in the pot manufacturing

engineers that lack the ability to provide stamped or formed parts that meet the design dimensional specifications.Finally add to the mix, ine

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Robot Welding Tips