What does increasing the contact tube to work distance do?

• A. Increases the wire melt off rate, and result in a higher narrow bead
• B. Decreases shielding gas coverage
• C. Increases current
• D. Decreases deposition accuracy

Answer: (A)

Increasing the contact tube to work distance lengthens the arc. A longer arc requires more energy to maintain, so the arc voltage rises and more heat is delivered toward the melting zone. That extra heat causes the filler wire to melt more rapidly, increasing the wire melt-off rate. With more metal entering the weld pool per unit time, the deposited filler tends to form a bead that is narrower, since the energy is focused along a longer arc and the transfer is more concentrated. In short, longer distance boosts heat input at the wire tip, increasing metal transfer and producing a narrower bead.