OM-263 706A 2013−11 Processes TIG (GTAW) Welding Stick (SMAW) Welding Description Arc Welding Power Source STi 270 And STi 270C CE
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 1-1. Symbol Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1-2. Arc Welding Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1-3.
DECLARATION OF CONFORMITY for European Community (CE marked) products. ITW Welding Italy S.r.l Via Privata Iseo 6/E, 20098 San Giuliano M.se, (MI) Italy declares that the prod uct(s) identified in this declaration conform to the essential requirements and provisions of the stat ed Council Directive(s) and Standard(s).
SECTION 1 − SAFETY PRECAUTIONS - READ BEFORE USING som 2013−09 7 Protect yourself and others from injury — read, follow, and save these important safety precautions and operating instructions. 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. D Keep your head out of the fumes. Do not breathe the fumes. D If inside, ventilate the area and/or use local forced ventilation at the arc to remove welding fumes and gases. The recommended way to determine adequate ventilation is to sample for the composition and quantity of fumes and gases to which personnel are exposed.
1-3. Additional Symbols For Installation, Operation, And Maintenance FIRE OR EXPLOSION hazard. D Do not install or place unit on, over, or near combustible surfaces. D Do not install unit near flammables. D Do not overload building wiring − be sure power supply system is properly sized, rated, and protected to handle this unit. FALLING EQUIPMENT can injure. D Use lifting eye to lift unit only, NOT running gear, gas cylinders, or any other accessories.
1-4. California Proposition 65 Warnings Welding or cutting equipment produces fumes or gases which contain chemicals known to the State of California to cause birth defects and, in some cases, cancer. (California Health & Safety Code Section 25249.5 et seq.) This product contains chemicals, including lead, known to the state of California to cause cancer, birth defects, or other reproductive harm. Wash hands after use. 1-5.
SECTION 2 − DEFINITIONS 2-1. Additional Safety Symbols And Definitions . Some symbols are found only on CE products. Warning! Watch Out! There are possible hazards as shown by the symbols. Safe1 2012−05 Do not discard product (where applicable) with general waste. Reuse or recycle Waste Electrical and Electronic Equipment (WEEE) by disposing at a designated collection facility. Contact your local recycling office or your local distributor for further information.
Do not weld on drums or any closed containers. Safe16 2012−05 Do not remove or paint over (cover) the label. Safe20 2012−05 Wear hat and safety glasses. Use ear protection and button shirt collar. Use welding helmet with correct shade of filter. Wear complete body protection. Safe38 2012−05 Become trained and read the instructions before working on the machine or welding. Safe40 2012−05 2-2.
SECTION 3 − SPECIFICATIONS 3-1. Important Information Regarding CE Products (Sold Within The EU) A. Information On Electromagnetic Fields (EMF) ! This equipment shall not be used by the general public as the EMF limits for the general public might be exceeded during welding.
3-4. Volt-Ampere Curves Volt-ampere curves show minimum and maximum voltage and amperage output capabilities of welding power source. Curves of other settings fall between curves shown. DC Voltage (V) All Models 54 52 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 0 10 20 30 40 50 60 70 80 90 100110 120 130140150 160170180 190200 210 220230240250 260270280 DC Amperage (A) 3-5.
SECTION 4 − INSTALLATION 4-1. Serial Number And Rating Label Location The serial number and rating information for the power source is located on the bottom of the machine. Use the rating labels to determine input power requirements and/or rated output. For future reference, write serial number in space provided on back cover of this manual. 4-2. Selecting A Location ! Special installation may be required where gasoline or volatile liquids are present − see NEC Article 511 or CEC Section 20.
4-3. Weld Output Terminals And Selecting Cable Sizes* NOTICE − The Total Cable Length in Weld Circuit (see table below) is the combined length of both weld cables. For example, if the power source is 30 m (100 ft) from the workpiece, the total cable length in the weld circuit is 60 m (2 cables x 30 m). Use the 60 m (200 ft) column to determine cable size.
4-5. Stick DCEP (Direct Current Electrode Positive) Connections ! Turn off power before making connections. 1 Negative (−) Weld Output Terminal Connect work lead to negative weld output terminal. 2 Positive (+) Weld Output Terminal Connect electrode holder to positive weld output terminal. 2 1 4-6. Electrical Service Guide . Actual input voltage cannot exceed -10% of minimum, or +10% of maximum input voltages indicated in table.
4-7.
4-7. Connecting 3-Phase Input Power (Continued) ! Installation must meet all National and Local Codes − have only qualified persons make this installation. See rating label on unit and check input voltage available at site. ! Disconnect and lockout/tagout input power before connecting input conductors from unit. Follow established procedures regarding the installation and removal of lockout/tagout devices.
SECTION 5 − OPERATION 5-1. Controls (STi 270 Model Shown) 4 11 2 2 3 4 5 6 1 7 1 8 8a 15 14 9 1 13 12 17 16 10 11 1 956172127_2-A 1 Voltage/Amperage Selector Switch Use switch to display welding voltage or welding amperage. 2 Power On Pilot Light 3 High Temperature Indicator Light Light comes on if unit overheats. Welding can resume when unit has cooled (see Section 3-5). 4 Ammeter/Voltage Display (Meter) Meter displays actual amperage/voltage while welding.
5-2. Preparing Unit For Stick (SMAW) Welding (STi 270 Model Shown) 7 8 6 9 5 9a 10 1 4 3 1 1 Positive Weld Output Receptacle 2 Negative Weld Output Receptacle 3 Amperage/Parameter Control 4 Arc Force Indicator Light 5 Hot Start Indicator Light 6 Amperage Indicator Light 7 Ammeter/Voltage Display (Meter) 8 Process Control See Section 5-4.
5-3. Preparing Unit For TIG (GTAW) Welding (STi 270 Model Shown) 4 5 Current (A) Remote 2T Trigger Operation (All Models) Main Amps 3 Time P 1 1 2 3 4 R 2 Positive Weld Output Terminal Negative Weld Output Terminal Amperage/Parameter Control Ammeter/Voltage Display (Meter) 5 Process Selector Switch Prepare unit for TIG welding as follows: connect electrode holder and work clamp (see Section4-4). Turn power on. Allow time for unit to complete its start-up cycle.
5-4. Process Control 1 Process Control Use control to select Stick, or the TIG Lift Arc process. Stick (SMAW) - This is a DCEP (direct current electrode positive) process (see Section 5-6). Make connections according to Section 4-5. 1 TIG Lift-Arct - This is a DCEN (direct current electrode negative) process in which the electrode must come in contact with the work piece to initiate an arc (see Section 5-5). Make connections according to Section 4-4. 5-5.
5-6. Stick Start Procedure − Scratch Start Technique With Stick selected, start arc as follows: 1 2 3 Electrode Workpiece Arc Drag electrode across workpiece like striking a match; lift electrode slightly after touching work. If arc goes out electrode was lifted to high. If electrode sticks to workpiece, use a quick twist to free it. 1 ! 2 When VRD is off, normal open-circuit voltage (50 volts) is present before electrode touches workpiece.
SECTION 6 − MAINTENANCE AND TROUBLESHOOTING 6-1. Routine Maintenance ! Disconnect power before maintaining. . Maintain more often during severe conditions. A. Welding Power Source n = Check Z = Change ~ = Clean * To be done by Factory Authorized Service Agent Δ = Repair l = Replace Every 3 Months nl Labels n l Gas Hoses Every 3 Months nΔ lCables And Cords Every 6 Months ! Do not remove case when blowing out inside of unit (see Section 6-2) . ~:Durning heavy service, clean monthly. 6-2.
6-3. Troubleshooting Trouble No weld output; unit completely inoperative. Remedy Place line disconnect switch in On position (see Section 4-7). Check and replace line fuse(s), if necessary, or reset circuit breaker (see Section 4-7). Check for proper input power connections (see Section 4-7). No weld output. Input voltage outside acceptable range of variation (see Section 4-6). No weld output; Overtemp LED on. Unit overheated. Allow unit to cool with fan On (see Sections 3-5).
SECTION 7 − ELECTRICAL DIAGRAMS Figure 7-1.
956172129_A Figure 7-2.
SECTION 8 − SELECTING AND PREPARING A TUNGSTEN FOR DC OR AC WELDING WITH INVERTER MACHINES gtaw_Inverter_2011-06 Whenever possible and practical, use DC weld output instead of AC weld output. 8-1. Selecting Tungsten Electrode (Wear Clean Gloves To Prevent Contamination Of Tungsten ) . Not all tungsten electrode manufacturers use the same colors to identify tungsten type. Contact the tungsten electrode manufacturer or reference the product packaging to identify the tungsten you are using.
SECTION 9 − GUIDELINES FOR TIG WELDING (GTAW) 9-1. Positioning The Torch ! Grinding the tungsten electrode produces dust and flying sparks which can cause injury and start fires. Use local exhaust (forced ventilation) at the grinder or wear an approved respirator. Read MSDS for safety information. Consider using cerium or lanthanum based tungsten instead of thoriated. Thorium dust contains low-level radioactive material. Properly dispose of grinder dust in an environmentally safe way.
9-2. Torch Movement During Welding Tungsten Without Filler Rod 75° Welding direction Form pool Tilt torch Move torch to front of pool. Repeat process. Tungsten With Filler Rod 75° Welding direction Form pool 15° Tilt torch Remove rod Add filler metal Move torch to front of pool. Repeat process. ST-162 002-B 9-3.
SECTION 10 − STICK WELDING (SMAW) GUIDELINES 10-1. Stick Welding Procedure ! 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. Equipment Needed: Tools Needed: . Always wear appropriate per1 sonal protective clothing. Workpiece Make sure workpiece is clean before welding.
6013 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 MED SMOOTH, EASY, FAST LOW HYDROGEN, STRONG 7024 EP,EN NI-CL EP FLAT HORIZ FILLET ALL 308L EP ALL USAGE EP 6011 AC PENETRATION 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* 6010 ELECTRODE 450 400 350 300 AMPERAGE RA
10-4. Positioning Electrode Holder 1 2 After learning to start and hold an arc, practice running beads of weld metal on flat plates using a full electrode. 1 10°-30° 90° End View Of Work Angle Side View Of Electrode Angle Hold the electrode nearly perpendicular to the work, although tilting it ahead (in the direction of travel) will be helpful. 2 90° . To produce the best results, hold a short arc, travel at a uniform speed, and feed the electrode downward at a constant rate as it melts.
10-7. 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 Electrode Angle Drag Spatter Arc Length Too Short Normal Too Long Slow Normal Fast Travel Speed S-0061 10-8. Electrode Movement During Welding .
10-10. Welding Groove (Butt) Joints 1 Tack Welds Prevent butt joint distortion by tack welding the materials in position before final weld. Workpiece distortion occurs when heat is applied locally to a joint. One side of a metal plate will “curl” up toward the weld. Distortion will also cause the edges of a butt joint to pull together ahead of the electrode as the weld cools. 1 2 2 1/16 in. (1.6 mm) Single V-Groove Weld 4 Double V-Groove Weld Materials up to 3/16 in.
10-12. Weld Test 1 2 3 Strike the weld joint in the direction shown. A good weld bends over but does not break. 3 If the weld breaks, examine it to determine the cause. If the weld is porous (many holes), the arc length was probably too long. 3 If the weld contains bits of slag, the arc may have been too long or the electrode was moved incorrectly which allowed molten slag to be trapped in the weld.
Lack Of Penetration − shallow fusion between weld metal and base metal. Lack of Penetration Good Penetration Possible Causes Corrective Actions Improper joint preparation. Material too thick. Joint preparation and design must provide access to bottom of groove. Improper weld technique. Keep arc on leading edge of weld puddle. Insufficient heat input. Increase amperage. Select larger electrode and increase amperage. Reduce travel speed.
SECTION 11 − PARTS LIST . Hardware is common and not available unless listed. 2 18 3 19 17 4 5 15 20 16 14 21 6 13 1 12 23 22 24 11 25 10 9 26 8 7 27 29 38 31 39 28 37 40 43 32 30 42 33 36 35 34 41 40 956172127_7-A Figure 11-1. Main Assembly For STi 270 Item No. Dia. Mkgs. Part No. Description Quantity Figure 11-1. Main Assembly For STi 270 ... ... ... ... ... ... ... ... ... ... ... ... ... 1 2 3 4 5 6 7 8 9 10 11 12 13 . . . . . . . . . . . . . 057116003 . . . . . . . .
Item No. Dia. Mkgs. Part No. Description Quantity Figure 11-1. Main Assembly For STi 270 (continued) . . . . . . . . . . . . . 156005193 . . . . PC4 . . 057084198 . . . . . S1 . . . . . . . 244920 . . . . . . . . . . . . . 156118096 . . . . . . . . . . . . . 356029264 . . . . . . . . . . . . . 656089046 . . . . . . . . . . . . . 256071011 . . . . . . . . . . . . . . . . . 246624 . . . . . LF . . . 156160003 . . . . . FM . . . 057035023 . . . . . . . . . . . . . 156122098 . . . . . . . . . . . . .
. Hardware is common and not available unless listed. 2 20 19 3 18 5 4 16 21 17 15 22 6 1 14 13 24 23 25 11 12 26 10 9 27 8 7 30 28 31 34 29 42 41 40 46 43 32 33 35 45 36 39 38 37 44 43 956172127_8-A Figure 11-2. Main Assembly For STi 270C Item No. Dia. Mkgs. Part No. Description Quantity Figure 11-2. Main Assembly For STi 270C ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 . . . . . . . . . . . . . 057116003 . . .
Item No. Dia. Mkgs. Part No. Description Quantity Figure 11-2. Main Assembly For STi 270C (continued) . . . . . S1 . . . . . . . 244920 . . . . . . . . . . . . . 156118096 . . . . . . . . . . . . . 356029264 . . . . . . . . . . . . . 656089046 . . . . . . . . . . . . . 256071011 . . . . . . . . . . . . . . . . . 246624 . . . . . LF . . . 156160003 . . . . . FM . . . 057035023 . . . . . . . . . . . . . 156122098 . . . . . . . . . . . . . 756033060 . . . . . . . . . . . . . 156005194 . . . . PC7 . . .
Effective January 1, 2013 (Equipment with a serial number preface of MD or newer) This limited warranty supersedes all previous Miller warranties and is exclusive with no other guarantees or warranties expressed or implied.
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 Country Zip/Postal Code 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 Service and Repair Replacement Parts Owner’s Manuals ITW Welding Italy S.r.l.
