So you recognize that with your bad back, you dont want to be handling steel when you are in your 60s and you decide to apply for a job running a weld shop that has both manual - robot MIG - FCA welders. It's possible, that some of these 30 MIG questions may come up. Are you ready to provide the answers?
 Welding common 1/16 (1.6 mm) sheet metal ducts made out of both carbon steels and stainless. The welders are using digital wire feeders in which the wire feed rate is indicated in inch/min or m/min. You tell the welders who are using 0.035 (0.9mm) MIG wires and argon - 20% CO2 to use the optimum, Short Circuit wire feed, and voltage which is?.
Answer. Opt Short Circuit Wire feed setting is______Opt Weld Volts_________
 With an 0.035 (0.9 mm) MIG wire, and argon - 20% CO2 gas mix, the robot technician has to set robot parameters to weld common, 0.080, (2 mm) gage carbon steel parts. As with many pulsed MIG power sources, the pulsed part of the MIG equipment in the robot cell has not been working well and the decision has been made to use regular CV MIG settings. For the required thin "lap welds", what MIG weld transfer mode should be selected, what wire feed setting, (or amps), volts and weld travel speed would be set?
Answer. Weld Mode__Wire feed__ Approx. Amps.__ Volts___ Weld Travel____ ipm.
This is what the transition or start point of spray looks like.
Note 1980s video no spatter when set right.
 With the manual welds, the "start point of spray transfer" (see above) can be readily used on the 1/8 to 3/16 (3 to 5 mm) carbon steel parts. The welder has 0.045 (1.2mm) wires, he asks what is the spray transfer start point wire feed and the voltage? Also as the weld supervisor, you want to know how much MIG wire to order. The welder will average 30 minutes arc on time each hour, and the job is expected to last for 100 hours.
Answer. WF ___ inch/min. Volts__ Hourly Deposition Rate _____lb/hr x 100hrs =
 Which of the following is considered an optimum short circuit "weld voltage range" for either an 0.035 or 0.045 (1 - 1.2 mm) wire?
[a] 12 - 18 volts [b] 17 - 24 volts
[c] 13 - 18 volts [d] 16 - 20 volts.
 Why should welders avoid the back hand technique when MIG welding thin gauge steels or stainless parts < 2 mm?
[5a] What is the best "weld position" to weld the out side edge welds an 18 gage, one meter steel or stainless box?
Answer. _______________________________________ [a]________
Short Circ Video from the 1980s.
Note if set correct, no spatter.
 You want the welders to "know when to use the short circuit mode". Which of the following is the manual welded recommended "part thickness range" when using an 0.035 (1mm) wire and the short circuit transfer?
[6a] 26 gauge to 16 gauge, [b] 18 gauge to 12 gauge, [c] 14 gauge to 8 gauge.
 Provide robot weld data for the some 1/8 (3 mm) carbon steel fillet welds. The fillet joints will be welded vertical down. Most parts have a 0.040 to 0.060 weld gaps. Conventional CV. MIG power source is utilized using an 0.035. (1mm) wire and Ar - 20% CO2. Provide:
[a] wire feed setting.
[c] weld travel rate,
Answer. Wire Feed Rate____ Volts____ Weld Travel Rate_____
 What is the minimum steel thickness that can you manual MIG weld with an 0.035 wire and argon - 15 - 20% CO2 using the spray transfer mode?
 Which of these MIG gases will provide "Dissociation benefits" in the weld arc?
[a] oxygen, argon, helium, hydrogen, carbon dioxide.
[b] What is MIG gas dissociation and how does it benefit a MIG weld?
[c] Which gas mix provides higher oxidation, argon - 2% Oxy or argon 15 % CO2?
 The 1/8 (3.2mm) stainless MIG application can be welded using a low spray transfer setting with an E316. 0.035 (0.9mm) MIG wire. Provide the wire feed rate and weld voltage. The welder has an arc on time that averages of 20 minutes each hour. How much weld wire is required, for each 8 hour shift.
Answer. WF_____ inch/min. Volts____Deposition___lb/hr
 The welder is ready to weld a 3/16 (5mm) carbon steel fillet weld. Using spray transfer and an 0.045 (1.2mm) carbon steel wire with argon 10 - 20 % CO2, select the wire feed rate, voltage, weld deposition.
Answer. WF ___inch/min. Volts__ Deposition__ lb/hr.
 Using argon 10 - 20% with an 0.045 (1.2mm) E70S-3 wire, provide an optimum, manual 1/4 (6 mm) fillet weld with the spray transfer mode. On the digital feeder, provide the wire feed setting, voltage and deposition rate.
Answer. Wire feed __inch/min. Voltage___ Deposition Rate___ lb/hr.
 What robot wire feed rate, weld voltage, travel rate and part position would you use for common lap welds on thin gage, 0.035 (1 mm) galvanealed steel parts? The MIG wire is 0.035 E70S-6 and the gas mix was argon - 25% CO2.
Answer. Wire Feed___Voltage__ Weld Travel ___Best Part Position___
Why is the 75-25% CO2 gas mix a poor choice?__________________
Ed's robot process control training program, click here.
 Without changing the MIG wire feed setting, the robot technician decided the weld could be a little smaller and so he increased the robot weld travel rate. Which of the following would that technician have to adjust to compensate for the increase in that robot weld travel rate?.
[a] increase the weld volts, [b] decrease the weld volts.
Answer. _____ Explain why.______________________________________ _________
 With robot welds, the robot operator has to change the contact tip too often during the shifts. Also the daily weld production was greatly influenced by the robot down time due to the MIG wire burn backs to the contact tips. Most of the wire burn backs occurred during the weld starts. The weld and weld start data with an Argon – 20% CO2 mix and the 0.045 (1.2mm) wire, was WF 420 ipm. The volts were 30Vs. What changes would the technician have to make to the weld start data to reduce the amount of contact tip changes and to eliminate the wire burn backs?
Answer. Robot Start Wire Feed ________Start Volts __________
The reason this change in the start data works is_________________
 The robot cell is using an 0.045, E70S-6 wire, with an 80 argon 20% CO2 mix. Both the weld and the weld end data wire feed is set at 320 inch/min. The volts were 24V. There is a large drop on the end of the wire at each weld end. Weld start issues are frequent in this robot cell. Explain why the issues are occurring, and what is the parameter solution?.
Answer: ___________________________________The solution is ____________
Ed introduced these important gas mixes in North America,
Visit the MIG gas section for gas info.
 Which of these MIG gas mixes will provide the most weld fusion and lowest weld porosity when welding with an 0.035 or 0.045 carbon steel wire set in the spray transfer mode, and why?
 argon - 2 oxy  argon - 5 oxy  argon - 10 CO2
 argon - 8 C02 - 2 oxy  argon - 20 CO2.
|Most companies that have weld settings in the spatter producing globular mode, are not aware of what globular transfer is or how to set parameters to rectify the welds.
 The manual MIG weld transfer is an erratic, globular mode producing lots of hard to remove spatter. The weld wire is 0.035 (1 mm) and gas is 80% argon - 20% CO2. The carbon steel parts welded are 3 - 4 mm. The weld data is 180 amps at 24 volts, what adjustments to the weld parameters do you make to reduce the globular transfer and explain why?
 The robot welder is setting multi-pass welds on a 60 degree Vee Groove plates that are one inch, (25 mm) thick. The robot multi-pass groove welds will be in the flat position. With the 0.045 (1.2mm) MIG wire and 15% CO2 gas, provide the wire feed rate, voltage, travel rate, for the optimum stringer fill passes.
Answer. Wire Feed___ inch/min. Weld Volts____ Weld Travel________________
 The weld shop has to MIG weld thin gauge (0.040 - 0.080), 300 series stainless parts with an 0.035, (1 mm) E309 MIG wire. The gas salesman has recommended the common three part helium tri-mix, (90% He - 7.5% Ar - 2.5% CO2). Why is this global tri-mix the wrong gas choice, and what is the optimum gas mix and why?
Answer. The Tri Mix is the worst choice because.__________________
The correct gas choice for thin stainless parts should be_______________
 The welders will manually MIG weld 1/8 to 1/2 (3 - 12 mm) aluminum parts. The weld shop has both pulsed MIG and regular CV MIG equipment. The aluminum parts are clean, however a common problem with both the pulsed MIG and spray welds is extensive black soot occurs either side of the welds. What simple weld parameter adjustment will instantly decrease the black soot, and why does this weld parameter adjustment work?
Answer. The MIG weld parameter adjustment is_______
Answer. This parameter adjustment works because,_______
 The manual welder is using argon - 25% CO2, with 0.045 steel wire welding clean carbon steels > 4 mm. No matter what the parameters are there is extensive weld spatter, why?
Answer.________________________And the solution is ________________________Why________________
 With a manual MIG weld, what should be the maximum single pass fillet weld size for;
[a] a horizontal fillet_______ Why_____?
 What is the minimum weld voltage required when robot welds are made with spray transfer, using an 0.045 (1.2 mm) wire with argon - 20% CO2?
[a] 22 volts [b] 24 volts [c] 26 volts [d] 28 volts [e] 30 volts [f] 32 volts
 Using an 0.052, (1.4 mm) steel MIG wire, what is the minimum part thickness you can manually spray weld without weld burn through issues.
[a] Also what is the minimum weld current required for spray with that 0.052 wire?
Answer. _________________[a] min_____amps
 With an 0.045 (1.2 mm) MIG wire and argon - 15 to 20% CO2 gas, the welders are welding a 10 gauge carbon steel part to a 3/16 (5 mm) part. The weld current is 240 amps with 24 volts. The parts are covered with spatter and the contact tips need changing frequently. Why?
 The pulsed MIG stainless welds are providing less weld fusion than what used to be attained when the MIG spray welds were made with the same wire and similar wires feed rate. Provide an explanation why?
 The paint department is complaining that the robot carbon steel MIG welds have too many shiny black slag islands on the surface. Explain why you will need to change the E70S-6 wire and that gas mixes that contains oxygen. Also what MIG wire and gas mix would you recommend?
Answer. ________________________Wire___________ Gas Mix_________
 To cut down on the weld spatter, you need to inform the welders about the globular MIG weld transfer that occurs with the common, 0.035 - 0.045, E70S-6 wires and argon 15 to 20% CO2
Answer. The glob wire feed and voltage range for 0.035 is ______For the 0.045 wire its_____
 You rotate your steel pipes and want to start using MIG short circuit for the open roots. Provide the optimum SC weld parameters for an 0.035 wire and argon - 25% CO2. Provide the wire feed, volts and travel rate.