Lincoln Electric SVM140-A service manual Thick Sections of Metal

B-8 B-8

OPERATION

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THICK SECTIONS OF METAL

Torch Standoff Machine Output Setting

1/8" thru 3/16"￿	Output Setting￿
Standoff	Mid. thru Max. Range

Output set above mid-range.

•The best quality and consumable life will be obtained by holding the torch off the surface about 3/16 in. (4.7mm). Too long an arc may compromise cut quality and consumable life. The nozzle should NOT be dragged on the work.

•Use of the S22151 Drag Cup will maintain the prop- er standoff. The only time not to use the drag cup when the output control is set above mid-range is in special, tight corners. Always hold at least a 1/8 in. (3.2mm) standoff in those situations.

•If piercing is required, slowly lower the torch at an angle of about 30° to blow the dross away from the torch tip and slowly rotate the torch to a vertical position as the arc becomes deeper. This process will blow a lot of molten metal and dross. Be care- ful! Blow the dross away from the torch, the opera- tor and any flammable objects.

•Where possible, start the cut from the edge of the workpiece.

•Keep moving! A steady speed is necessary. Do not pause.

•Do not allow the torch cable or body to contact a hot surface.

SUGGESTIONS FOR EXTRA UTILITY FROM THE PRO-CUT SYSTEM

WARNING

ELECTRIC SHOCK can kill.

•Turn off machine at the disconnect switch on the front of the machine before tightening, cleaning or replac- ing consumables.

1.Occasionally an oxide layer may form over the tip of the electrode, creating an insulating barrier between the electrode and nozzle. This will result in the tripping of the Pro-Cut's safety circuit. When this happens, turn the power off, remove the noz- zle and electrode and use the electrode to rub against the inside bottom surface of the nozzle. This will help remove any oxide buildup. Replace the nozzle, turn on the power and continue cutting. If the Parts-in-Place circuit (safety status indicator light) continues to trip after cleaning the consum- ables, replace them with a new set. Do not contin- ue to cut with excessively worn consumables as this can cause damage to the torch head and will degrade cut quality.

2.To improve consumable life, here are some sug- gestions that may be useful:

a.Never drag the nozzle on the work surface if the output control knob is above the mid- range setting.

b.Make sure the air supply to the Pro-Cut is clean and free of oil. Use several extra in-line filters if necessary.

c.Use the lowest output setting possible to make a good quality cut at the desired cut speed.

d.Minimize dross buildup on the nozzle tip by starting the cut from the edge of the plate when possible.

e.Pierce cutting should be done only when nec- essary. If piercing, angle the torch about 30° from the plane perpendicular to the work- piece, transfer the arc, then bring the torch perpendicular to the work and begin parallel movement.

f.Reduce the number of pilot arc starts without transferring to the work.

g.Reduce the pilot arc time before transferring to the work.

h.Set air pressure to recommended setting. A higher or lower pressure will cause turbulence in the plasma arc, eroding the orifice of the nozzle tip.

i.Use only Lincoln consumable parts. These parts are patented. Using any other replace- ment consumables may cause damage to the torch or reduce cut quality.

PRO-CUT 55