OM-4419 211 392M 2007−05 Processes Stick (SMAW) Welding MIG (GMAW) Welding Flux Cored (FCAW) Welding Non-Critical TIG (GTAW) Welding Description Engine Driven Welding Generator Bobcat 250 ™ File: Engine Drive Visit our website at www.MillerWelds.
From Miller to You Thank you and congratulations on choosing Miller. Now you can get the job done and get it done right. We know you don’t have time to do it any other way. That’s why when Niels Miller first started building arc welders in 1929, he made sure his products offered long-lasting value and superior quality. Like you, his customers couldn’t afford anything less. Miller products had to be more than the best they could be. They had to be the best you could buy.
TABLE OF CONTENTS SECTION 1 − SAFETY PRECAUTIONS − READ BEFORE USING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1. Symbol Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2. Arc Welding Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3. Engine Hazards . . . . . . . . . . . . . . . . . . . . . .
TABLE OF CONTENTS SECTION 8 − MAINTENANCE (ROBIN-POWERED UNITS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1. Routine Maintenance (Robin-Powered Units) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2. Maintenance Label (Robin-Powered Units) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3. Servicing Air Cleaner (Robin-Powered Units) . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 1 − SAFETY PRECAUTIONS − READ BEFORE USING rom_2007−04 Protect yourself and others from injury — read and follow these precautions. 1-1. Symbol Usage DANGER! − Indicates a hazardous situation which, if not avoided, will result in death or serious injury. The possible hazards are shown in the adjoining symbols or explained in the text. Indicates a hazardous situation which, if not avoided, could result in death or serious injury.
FUMES AND GASES can be hazardous. Welding produces fumes and gases. Breathing these fumes and gases can be hazardous to your health. Keep your head out of the fumes. Do not breathe the fumes. If inside, ventilate the area and/or use local forced ventilation at the arc to remove welding fumes and gases. If ventilation is poor, wear an approved air-supplied respirator.
1-3. Engine Hazards BATTERY EXPLOSION can BLIND. Always wear a face shield, rubber gloves, and protective clothing when working on a battery. Stop engine before disconnecting or connecting battery cables or servicing battery. Do not allow tools to cause sparks when working on a battery. Do not use welder to charge batteries or jump start vehicles. Observe correct polarity (+ and −) on batteries. Disconnect negative (−) cable first and connect it last. FUEL can cause fire or explosion.
HOT METAL from air arc cutting and gouging can cause fire or explosion. Do not cut or gouge near flammables. Watch for fire; keep extinguisher nearby. HOT PARTS can cause burns and injury. READ INSTRUCTIONS. Read Owner’s Manual before using or servicing unit. Stop engine and release air pressure before servicing. Use only genuine replacement parts from the manufacturer. Do not touch hot compressor or air system parts. Let system cool down before touching or servicing. 1-5.
H.F. RADIATION can cause interference. High-frequency (H.F.) can interfere with radio navigation, safety services, computers, and communications equipment. Have only qualified persons familiar with electronic equipment perform this installation. The user is responsible for having a qualified electrician promptly correct any interference problem resulting from the installation. If notified by the FCC about interference, stop using the equipment at once.
SECTION 2 − CONSIGNES DE SÉCURITÉ − LIRE AVANT UTILISATION rom_2007−04fre Se protéger, ainsi que toute autre personne travaillant sur les lieux, contre les étincelles et le métal chaud. 2-1. Signification des symboles DANGER! − Indique une situation dangereuse qui si on l’évite pas peut donner la mort ou des blessures graves. Les dangers possibles sont montrés par les symboles joints ou sont expliqués dans le texte.
Une tension DC importante subsiste à l’intérieur des onduleurs après avoir coupé l’alimentation. Couper l’alimentation du poste et décharger les condensateurs d’entrée comme indiqué dans la Section Maintenance avant de toucher des composants. DES PIÈCES CHAUDES peuvent provoquer des brûlures graves. Ne pas toucher à mains nues les parties chaudes. Prévoir une période de refroidissement avant de travailler à l’équipement.
Suivre les recommandations dans OSHA 1910.252(a)(2)(iv) et NFPA 51B pour les travaux à chaud et avoir de la surveillance et un extincteur à proximité. LE BRUIT peut affecter l’ouïe. Le bruit des processus et des équipements peut affec l’ouïe. Porter des protections approuvés pour les ore les si le niveau sonore est trop élevé. LES CHAMPS MAGNETIQUES peuvent affecter des implants médicaux. Porteur de simulateur cardiaque ou autre implants médicaux, rester à distance.
Dévisser le bouchon légèrement et laisser la vapeur s’échapper avant d’enlever le bouchon. L’utilisation d’un groupe autonome à l’intérieur PEUT VOUS TUER EN QUELQUES MINUTES. Les fumées d’un groupe autonome contient du monoxyde de carbone. C’est un poison invisible et inodore. JAMAIS utiliser dans une maison ou garage, même avec les portes et fenêtres ouvertes. Uniquement utiliser à l’EXTERIEUR, loin des portes, fenêtres et bouches aération.
UNE REMORQUE QUI BASCULE peut entraîner des blessures. LE SURCHAUFFEMENT peut endommager le moteur électrique. Utiliser les supports de la remorque ou des blocs pour soutenir le poids. Installer convenablement le poste sur la remorque comme indiqué dans le manuel s’y rapportant. Arrêter ou déconnecter l’équipement avant de démarrer ou d’arrêter le moteur.
2-6. Proposition californienne 65 Avertissements Les équipements de soudage et de coupage produisent des fumées et des gaz qui contiennent des produits chimiques dont l’État de Californie reconnaît qu’ils provoquent des malformations congénitales et, dans certains cas, des cancers. (Code de santé et de sécurité de Californie, chapitre 25249.
A complete Parts List is available at www.MillerWelds.com SECTION 3 − DEFINITIONS 3-1.
A complete Parts List is available at www.MillerWelds.com 4-2. Dimensions, Weights, and Operating Angles Dimensions Height 33-1/2 in (851 mm) (To Top Of Exhaust) Width 20 in (508 mm) Depth 45-3/8 in (1153 mm) A 20 in (508 mm) B 16-1/2 in (419 mm) C 1-3/4 in (44 mm) D 6-1/16 in (154 mm) E 32-3/4 in (832 mm) F 45-3/8 in (1153 mm) 25° G 13/32 in (10 mm) Dia. 25° A B C D G 4 Holes F ! Do not exceed tilt angles or engine could be damaged or unit could tip.
A complete Parts List is available at www.MillerWelds.com 4-4. Fuel Consumption (Robin-Powered Units) On a typical job using 1/8 in 7018 electrodes (125 amps, 20% duty cycle), expect about 20 hours of operation. Welding at 150 amps at 40% duty cycle uses approximately 3/4 gallon per hour, or about 16 hours of operation. 220 571 4-5. Fuel Consumption (Kohler-Powered Units) On a typical job using 1/8 in 7018 electrodes (125 amps, 20% duty cycle), expect about 20 hours of operation.
A complete Parts List is available at www.MillerWelds.com 4-6. Volt-Ampere Curves A. For CC/AC Mode The volt-ampere curve shows the minimum and maximum voltage and amperage output capabilities of the welding generator. Curves of all other settings fall between the curves shown. B. For CC/DC Mode C.
A complete Parts List is available at www.MillerWelds.com 4-7. Generator Power Curve The generator power curve shows the generator power in amperes available at the receptacles. 200 294 4-8. Duty Cycle Duty cycle is the percentage of 10 minutes that unit can weld at rated load without overheating. NOTICE − Exceeding duty cycle can damage unit and void warranty.
A complete Parts List is available at www.MillerWelds.com SECTION 5 − INSTALLATION 5-1. Installing Welding Generator Movement ! Do not lift unit from end. ! Do not weld on base. Welding on base can cause fuel tank fire or explosion. Bolt unit down using holes provided in base. ! Always securely fasten welding generator onto transport vehicle or trailer and comply with all DOT and other applicable codes. ! Do not mount unit by supporting the base only at the four mounting holes.
A complete Parts List is available at www.MillerWelds.com 5-2. Engine Prestart Checks (Robin-Powered Units) Check all fluids daily. Engine must be cold and on a level surface. Unit is shipped with 10W30 engine oil. Follow run-in procedure in en- Oil Fill Oil Check gine manual. NOTICE − This unit has a low oil pressure shutdown switch. However, some conditions may cause engine damage before the engine shuts down.
A complete Parts List is available at www.MillerWelds.com 5-3. Engine Prestart Checks (Kohler-Powered Units) Check all fluids daily. Engine must be cold and on a level surface. Unit is shipped with 10W30 engine oil. Follow run-in procedure in en- gine manual. NOTICE − This unit has a low oil pressure shutdown switch. However, some conditions may cause engine damage before the engine shuts down. Check oil level often and do not use the oil pressure shutdown system to monitor oil level.
A complete Parts List is available at www.MillerWelds.com 5-4. Installing Exhaust Pipe ! Engine backfire can cause severe burns or other injuries. Do not point exhaust pipe toward control panel. Keep away from exhaust outlet. ! Point exhaust pipe in desired direction but always away from front panel and direction of travel. Be sure to tighten exhaust clamp nuts. Exhaust clamp supplied with muffler. Tools Needed: 1/2 in 803 751 / Ref. 228 201-B 5-5.
A complete Parts List is available at www.MillerWelds.com 5-6. Connecting to Weld Output Terminals ! Stop engine. 1 2 Work Weld Output Terminal Electrode Weld Output Terminal Connect work cable to Work terminal. Connect electrode holder cable or electrode weld cable to Electrode terminal for Stick and MIG welding. Connect torch cable to Electrode terminal for TIG welding. Use Process Selector switch to select type of weld output (see Section 6-1).
A complete Parts List is available at www.MillerWelds.com 5-7. Selecting Weld Cable Sizes* Weld Cable Size** and Total Cable (Copper) Length in Weld Circuit Not Exceeding*** Weld Output Terminals ! Turn off power before connecting to weld output terminals. ! Do not use worn, damaged, undersized, or poorly spliced cables.
A complete Parts List is available at www.MillerWelds.com SECTION 6 − OPERATING THE WELDING GENERATOR 6-1. Front Panel Controls 5 4 6 3 2 1 1 Engine Control Switch Ref. 228 201-B Hour Meter: With engine off, place Engine Control switch in Run/Idle position to view engine hours. 5 Place switch in Run position to operate Oil Change Interval: With engine off, place Engine Control switch in the Run position to see hours before next oil change.
A complete Parts List is available at www.MillerWelds.com 6-2. Cold Weather Engine Operation 1 Engine Control Switch Carburetor Icing 1 Infrequently Loaded Carburetor icing causes the unit to drop below the normal idle speed and then stall. This condition occurs when the temperature is near freezing and the relative humidity is high. Ice forms on the throttle plate and inner bore of the carburetor. The engine typically restarts without problems but soon stalls again.
A complete Parts List is available at www.MillerWelds.com 6-3. Typical Stick Welding Connections And Control Settings ! Stop engine. This For best arc starts and best results using weld and generator power together, use a low Coarse Range setting and the Fine control set at 7 or higher. section provides general guidelines and may not suit all applications. The control panel shows the typi- 1 2 cal settings for welding with a 7018 (1/8 in) electrode.
A complete Parts List is available at www.MillerWelds.com 6-4. Typical MIG Welding Connections And Settings A. Solid Wire Applications ! Stop engine. This section provides general guideTypical Control Settings For .035 (ER70S-3) Solid Wire − Short Circuit Transfer Note Coarse Range, Fine Control, and Weld Process switch settings. lines and may not suit all applications. The control panel shows the typical 1 2 3 settings for welding with .035 (ER70S-3) solid wire. Use Argonbased shielding gas.
A complete Parts List is available at www.MillerWelds.com B. Self-Shielded Flux Core Wire Applications ! Stop engine. This Typical Control Settings For .045 (71T-11) Self-Shielded Flux Core Wire Note Coarse Range, Fine Control, and Weld Process switch settings. section provides general guidelines and may not suit all applications. The control panel shows the typi1 2 3 cal settings for welding with .045 (71T-11) self-shielded flux core wire.
A complete Parts List is available at www.MillerWelds.com 6-5. Typical MIG Connections And Settings Using Weld Control And Spoolgun Typical Settings For 4043 (.035) Aluminum On 1/8 in Material: Tools Needed: 3/4 in Note Coarse Range and Weld Process switch settings. 10 9 8 Connect to unused contactor terminal. Work 12 5 Plug and sensing lead not used in this application. 6 Left Side View 2 1 3 11 4 This section provides general guidelines and may not suit all applications.
A complete Parts List is available at www.MillerWelds.com SECTION 7 − OPERATING AUXILIARY EQUIPMENT 7-1. Generator Power Receptacles ! If unit does not have GFCI receptacles, use GFCI-protected extension cord. Generator power decreases as weld current increases. 1 Set Fine Control R1 at 10 for full generator power. 240 V 50 A AC Receptacle RC1 RC1 supplies 60 Hz single-phase power at weld/power speed. Maximum output is 10.5 kVA/kW.
A complete Parts List is available at www.MillerWelds.com 7-2. Simultaneous Weld And Power Weld Current in Amperes Total Power in Watts 120 V Full kVA Receptacle Amperes 240 V Full kVA Receptacle Amperes 250 2200 18 9 180 3500 29 14 125 5200 43 21 90 8000 66 33 0 10,500 87 43 7-3. Wiring Optional 240 Volt Plug The plug can be wired for a 240 V, 2-wire load or a 120/240V, 3-wire load. See circuit diagram.
A complete Parts List is available at www.MillerWelds.com SECTION 8 − MAINTENANCE (ROBIN-POWERED UNITS) 8-1. Routine Maintenance (Robin-Powered Units) ! Recycle engine fluids. = Check = Change = Clean * To be done by Factory Authorized Service Agent Stop engine before maintaining. See Engine Manual and Maintenance Label for important start-up, service, and storage information. Service engine more often if used in severe conditions.
A complete Parts List is available at www.MillerWelds.com 8-2.
A complete Parts List is available at www.MillerWelds.com 8-3. Servicing Air Cleaner (Robin-Powered Units) ! Stop engine. NOTICE − Do not run engine without air cleaner or with dirty element. 1 Precleaner 1 Wash precleaner with soap and water solution. Allow precleaner to air dry completely. 2 Spread 1 tablespoon SAE 30 oil evenly into precleaner. Squeeze out excess oil. 2 Element Replace element if damaged, dirty, or oily. oil aircleaner3 11/04 − 803 070 / S-0759 8-4.
A complete Parts List is available at www.MillerWelds.com 8-5. Changing Engine Oil, Oil Filter, and Fuel Filter (Robin-Powered Units) ! Stop engine and let cool. 1 Oil Drain Valve 2 1/2 ID x 7 in Hose 3 Oil Filter Change engine oil and filter according to engine owner’s manual. ! Oil Fill Close valve and valve cap before adding oil and running engine. Fill crankcase with new oil to full mark on dipstick (see Section 8-2).
A complete Parts List is available at www.MillerWelds.com 8-6. Adjusting Engine Speed (Robin-Powered Units) 2200 − 2300 rpm (36.6 − 38.3 Hz) 3675 − 3750 rpm (61.3 − 62.5 Hz) After tuning engine, check engine speeds with a tachometer (see table). If necessary, adjust speeds as follows: Start engine and run until warm. Remove rear panel and air cleaner to access idle speed adjustments. Remove top cover to access weld/ power speed adjustments.
A complete Parts List is available at www.MillerWelds.com 8-7. Servicing Optional Spark Arrestor (Robin-Powered Units) ! Stop engine and let cool. 1 Spark Arrestor Screen Clean and inspect screen. Replace spark arrestor if screen wires are broken or missing. 1 Tools Needed: 1/4 in Ref. 801 682-A / Ref. 183 175−A Notes MATERIAL THICKNESS REFERENCE CHART 24 Gauge (.025 in) 22 Gauge (.031 in) 20 Gauge (.037 in) 18 Gauge (.050 in) 16 Gauge (.063 in) 14 Gauge (.078 in) 1/8 in (.125 in) 3/16 in (.
A complete Parts List is available at www.MillerWelds.com SECTION 9 − MAINTENANCE − (KOHLER-POWERED UNITS) 9-1. Routine Maintenance (Kohler-Powered Units) ! Recycle engine fluids. = Check = Change = Clean * To be done by Factory Authorized Service Agent Stop engine before maintaining. See Engine Manual and Maintenance Label for important start-up, service, and storage information. Service engine more often if used in severe conditions.
A complete Parts List is available at www.MillerWelds.com 9-2.
A complete Parts List is available at www.MillerWelds.com 9-3. Servicing Air Cleaner (Kohler−Powered Units) ! Stop engine. NOTICE − Do not run engine without air cleaner or with dirty element. 1 1 2 Precleaner Wash precleaner with soap and water solution. Allow precleaner to air dry completely. Spread 1 tablespoon SAE 30 oil evenly into precleaner. Squeeze out excess oil. 2 Element Replace element if damaged, dirty, or oily.
A complete Parts List is available at www.MillerWelds.com 9-4. Changing Engine Oil, Oil Filter, and Fuel Filter (Kohler-Powered Units) ! Stop engine and let cool. 1 Oil Drain Valve 2 1/2 ID x 7 in Hose 3 Oil Filter Change engine oil and filter according to engine owner’s manual. ! Full Close valve and valve cap before adding oil and running engine. Fill crankcase with new oil to full mark on dipstick (see Section 5-3). 4 Fuel Filter 5 Fuel Line Replace line if cracked or worn.
A complete Parts List is available at www.MillerWelds.com 9-5. Adjusting Engine Speed (Kohler-Powered Units) 2200 − 2300 rpm (36.6 − 38.3 Hz) 3675 − 3750 rpm (61.3 − 62.5 Hz) 1 After tuning engine, check engine speeds with a tachometer (see table). If necessary, adjust speeds as follows: Start engine and run until warm. Turn Fine Control to 10. Remove rear panel and air cleaner to access idle speed adjustments. Remove top cover to access weld/ power speed adjustments.
A complete Parts List is available at www.MillerWelds.com 9-6. Overload Protection (Kohler-Powered Units) 2 1 Fuse F6 located in harness behind left side door. 3 ! Stop engine. Disconnect negative (−) battery cable. 1 Fuse F1 (See Section 11-1) F1 protects the weld excitation winding from overload. If F1 opens, weld output stops or is low. 2 Fuse F2 (See Section 11-1) F2 protects the generator power excitation winding from overload. If F2 opens, generator power output stops or is low.
A complete Parts List is available at www.MillerWelds.com SECTION 10 − TROUBLESHOOTING 10-1. Welding Troubleshooting Trouble Low or no weld output; generator power output okay at ac receptacles. Remedy Check control settings. Check weld connections. Check fuse F1, and replace if open (see Section 8-4 or 9-6). Have Factory Authorized Service Agent check brushes, slip rings, and integrated rectifiers SR2 and SR3. No weld output or generator power output at ac receptacles.
A complete Parts List is available at www.MillerWelds.com Trouble Low power output at ac receptacles. Remedy Check fuse F2, and replace if open (see Section 8-4 or 9-6). Increase Fine control R1 setting to max. High power output at ac receptacles. Check engine speed, and adjust if necessary (see Section 8-6 or 9-5). Erratic power output at ac receptacles. Check fuel level. Check engine speed, and adjust if necessary (see Section 8-6 or 9-5). Check receptacle wiring and connections.
A complete Parts List is available at www.MillerWelds.com Trouble Remedy Unstable or sluggish engine speeds. Readjust throttle linkage if necessary. Check throttle solenoid TS1 for smooth operation. Check oil level. Oil level should not exceed Full mark on dipstick. Fuel pump will operate erratically if crankcase is overfilled. Tune-up engine according to engine manual. Engine does not return to idle speed. Remove weld and generator power loads.
SECTION 12 − ELECTRICAL DIAGRAMS Figure 12-1.
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SECTION 13 − GENERATOR POWER GUIDELINES The views in this section are intended to be representative of all engine-driven welding generators. Your unit may differ from those shown. 13-1. Selecting Equipment 1 2 3 Generator Power Receptacles − Neutral Bonded To Frame 3-Prong Plug From Case Grounded Equipment 2-Prong Plug From Double Insulated Equipment Be sure equipment has double insulated symbol and/or wording on it. 1 2 ! Do not use 2-prong plug unless equipment is double insulated.
13-3. Grounding When Supplying Building Systems 1 1 2 2 GND/PE Equipment Grounding Terminal Grounding Cable Use #10 AWG or larger insulated copper wire. 3 Ground Device Use ground device as stated in electrical codes. 2 3 ! Ground generator to system earth ground if supplying power to a premises (home, shop, farm) wiring system. ! Also see AWS Safety & Health Fact Sheet No. 29, Grounding of Portable And Vehicle Mounted Welding Generators. ST-800 576-B 13-4.
13-5.
13-7. Approximate Power Requirements For Contractor Equipment Contractor Hand Drill Circular Saw Table Saw Band Saw Bench Grinder Air Compressor Electric Chain Saw Electric Trimmer Electric Cultivator Elec.
13-8. Power Required To Start Motor Single-Phase Induction Motor Starting Requirements Motor Start Code G H J K L M N P KVA/HP 6.3 7.1 8.0 9.0 10.0 11.2 12.5 14.0 4 1 3 AC MOTOR VOLTS 230 AMPS 2.5 CODE M Hz 60 HP 1/4 PHASE 1 1 2 3 4 2 Motor Start Code Running Amperage Motor HP Motor Voltage To find starting amperage: Step 1: Find code and use table to find kVA/HP. If code is not listed, multiply running amperage by six to find starting amperage. Step 2: Find Motor HP and Volts.
13-10. Typical Connections To Supply Standby Power 1 2 Utility Electrical Service Have only qualified persons perform these connections according to all applicable codes and safety practices. ! Properly install and ground this equipment according to its Owner’s Manual and national, state, and local codes.
13-11. Selecting Extension Cord (Use Shortest Cord Possible) Cord Lengths for 120 Volt Loads If unit does not have GFCI receptacles, use GFCI-protected extension cord.
SECTION 14 − STICK WELDING (SMAW) GUIDELINES 14-1. Stick Welding Procedure 5 ! Weld current starts when electrode touches workpiece. ! Weld current can damage electronic parts in vehicles. Disconnect both battery cables before welding on a vehicle. Place work clamp as close to the weld as possible. 1 Workpiece Make sure workpiece is clean before welding. 4 2 3 2 Work Clamp Electrode A small diameter electrode requires less current than a large one.
7014 7018 7024 Ni-Cl 308L ALL DEEP EP ALL DEEP 6013 EP,EN ALL LOW GENERAL 7014 EP,EN ALL MED 7018 EP ALL LOW SMOOTH, EASY, FAST LOW HYDROGEN, STRONG 7024 EP,EN NI-CL EP FLAT HORIZ FILLET ALL 308L EP ALL USAGE PENETRATION EP 6011 AC 3/32 1/8 5/32 3/16 7/32 1/4 1/16 5/64 3/32 1/8 5/32 3/16 7/32 1/4 3/32 1/8 5/32 3/16 7/32 1/4 3/32 1/8 5/32 3/16 7/32 1/4 3/32 1/8 5/32 3/16 7/32 1/4 3/32 1/8 5/32 3/16 3/32 1/8 5/32 DC* 450 400 350 300 AMPERAGE RANGE 250 200 150 POSI
14-5. Positioning Electrode Holder 10°-30° 90° 90° End View of Work Angle Side View of Electrode Angle GROOVE WELDS 10°-30° 45° 45° End View of Work Angle Side View of Electrode Angle FILLET WELDS S-0060 14-6. Poor Weld Bead Characteristics 1 2 3 4 5 Large Spatter Deposits Rough, Uneven Bead Slight Crater During Welding Bad Overlap Poor Penetration 1 2 4 3 5 S-0053-A 14-7.
14-8. Conditions That Affect Weld Bead Shape Weld bead shape is affected by electrode angle, arc length, travel speed, and thickness of base metal. Angle Too Small Correct Angle 10° - 30° Angle Too Large Drag ELECTRODE ANGLE Spatter Normal Too Short Too Long ARC LENGTH Normal Slow Fast TRAVEL SPEED S-0061 14-9.
14-10. Butt Joints 1 1 2 Tack Welds Prevent edges of joint from drawing together ahead of electrode by tack welding the materials in position before final weld. 2 Square Groove Weld Good for materials up to 3/16 in (5 mm) thick. 3 1/16 in (1.6 mm) Single V-Groove Weld Good for materials 3/16 − 3/4 in (5-19 mm) thick. Cut bevel with oxyacetylene or plasma cutting equipment. Remove scale from material after cutting. A grinder can also be used to prepare bevels.
14-13. Weld Test 1 2 3 3 Strike weld joint in direction shown. A good weld bends over but does not break. 3 2 To 3 in (51-76 mm) 1/4 in (6.4 mm) Vise Weld Joint Hammer 2 To 3 in (51-76 mm) 2 2 1 1 S-0057-B 14-14. Troubleshooting − Porosity Porosity − small cavities or holes resulting from gas pockets in weld metal. Possible Causes Corrective Actions Arc length too long. Reduce arc length. Damp electrode. Use dry electrode. Workpiece dirty.
14-16. Troubleshooting − Incomplete Fusion Incomplete Fusion − failure of weld metal to fuse completely with base metal or a preceeding weld bead. Possible Causes Corrective Actions Insufficient heat input. Increase amperage. Select larger electrode and increase amperage. Improper welding technique. Place stringer bead in proper location(s) at joint during welding. Adjust work angle or widen groove to access bottom during welding.
14-19. Troubleshooting − Burn-Through Burn-Through − weld metal melting completely through base metal resulting in holes where no metal remains. Possible Causes Excessive heat input. Corrective Actions Select lower amperage. Use smaller electrode. Increase and/or maintain steady travel speed. 14-20. Troubleshooting − Waviness Of Bead Waviness Of Bead − weld metal that is not parallel and does not cover joint formed by base metal. Possible Causes Unsteady hand. Corrective Actions Use two hands.
SECTION 15 − MIG WELDING (GMAW) GUIDELINES 15-1. Typical MIG Process Connections Using A Voltage-Sensing Wire Feeder ! Constant Current (CC) Or Constant Voltage (CV) Power Source Voltage sensing wire feeders are used with constant current (CC) or constant voltage (CV) power sources (14 pin receptacle not required). If using a CC or CV welding power source without a weld output contactor, use optional secondary contactor.
15-3. Conditions That Affect Weld Bead Shape Weld bead shape depends on gun angle, direction of travel, electrode extension (stickout), travel speed, thickness of base metal, wire feed speed (weld current), and voltage.
15-4. Gun Movement During Welding Normally, a single stringer bead is satisfactory for most narrow groove weld joints; however, for wide groove weld joints or bridging across gaps, a weave bead or multiple stringer beads works better. 1 1 2 2 3 Stringer Bead − Steady Movement Along Seam Weave Bead − Side To Side Movement Along Seam Weave Patterns Use weave patterns to cover a wide area in one pass of the electrode. 3 S-0054-A 15-5.
15-7. Troubleshooting − Excessive Spatter Excessive Spatter − scattering of molten metal particles that cool to solid form near weld bead. S-0636 Possible Causes Corrective Actions Wire feed speed too high. Select lower wire feed speed. Voltage too high. Select lower voltage range. Electrode extension (stickout) too long. Use shorter electrode extension (stickout). Workpiece dirty. Remove all grease, oil, moisture, rust, paint, undercoating, and dirt from work surface before welding.
15-10. Troubleshooting − Lack Of Penetration Lack Of Penetration − shallow fusion between weld metal and base metal. Lack of Penetration Good Penetration S-0638 Possible Causes Corrective Actions Improper joint preparation. Material too thick. Joint preparation and design must provide access to bottom of groove while maintaining proper welding wire extension and arc characteristics. Improper weld technique. Maintain normal gun angle of 0 to 15 degrees to achieve maximum penetration.
15-13. Troubleshooting − Waviness Of Bead Waviness Of Bead − weld metal that is not parallel and does not cover joint formed by base metal. S-0641 Possible Causes Corrective Actions Welding wire extends too far out of nozzle. Be sure welding wire extends not more than 1/2 in (13 mm) beyond nozzle. Unsteady hand. Support hand on solid surface or use two hands. 15-14. Troubleshooting − Distortion Distortion − contraction of weld metal during welding that forces base metal to move.
15-15. Common MIG Shielding Gases This is a general chart for common gases and where they are used. Many different combinations (mixtures) of shielding gases have been developed over the years. The most commonly used shielding gases are listed in the following table.
Effective January 1, 2007 (Equipment with a serial number preface of “LH” or newer) Warranty Questions? Call 1-800-4-A-MILLER for your local Miller distributor. Your distributor also gives you ... Service You always get the fast, reliable response you need. Most replacement parts can be in your hands in 24 hours. Support Need fast answers to the tough welding questions? Contact your distributor. The expertise of the distributor and Miller is there to help you, every step of the way.
Owner’s Record Please complete and retain with your personal records. Model Name Serial/Style Number Purchase Date (Date which equipment was delivered to original customer.) Distributor Address City State Zip For Service Contact a DISTRIBUTOR or SERVICE AGENCY near you. Always provide Model Name and Serial/Style Number. Contact your Distributor for: Welding Supplies and Consumables Options and Accessories Personal Safety Equipment Service and Repair Miller Electric Mfg. Co.
