Arc-On Time

Managing Arc-On Time: How to Find and Recover Lost Weld Minutes

Arc-on minutes are the only minutes that earn money in a weld shop. How to estimate them accurately and recover the ones you are losing.

Arc-on time is the only time a welding operation earns money. Every minute the arc is lit, metal goes into a joint someone is paying for; every other minute is cost. A typical manual weld shop pays for a 480 minute shift and gets 50 to 90 arc minutes out of it, which means 80 to 90 percent of the payroll buys handling, fitup, grinding, and waiting. Until you can state arc-on time per part and per shift as a hard number, you cannot quote cycle time accurately, load the shop realistically, or tell whether an improvement actually improved anything. The estimate starts with weld length and travel speed, and it decides schedule and cost together.

The base math is weld length divided by travel speed. A weldment with 480 inches of total weld at 12 inches per minute needs 40 arc minutes. But nobody welds 40 straight minutes, so you add a setup and handling allowance. At a 150 percent allowance the job consumes 100 total minutes: 40 arcing plus 60 handling. The Arc-On Time calculator handles the arithmetic; your job is grounding the inputs. Measure travel speed from actual production welds, not the wire manufacturer's catalog, and build the allowance from a real time study rather than a guess. Shops that guess the allowance typically miss total cycle time by 30 to 50 percent.

Multipass work is where estimates fall apart. A 36 inch groove joint welded in three passes is 108 inches of travel, not 36, and interpass temperature limits can force cooling waits of 2 to 5 minutes between passes on thick sections. Weave beads cut effective travel speed 30 to 40 percent compared to stringers at the same wire feed. Out of position work slows travel another 20 to 50 percent versus flat. Build your weld length inventory joint by joint from the print: joint type, size, length, pass count, and position. That inventory takes an hour per new weldment and makes every future estimate on that family nearly automatic.

Benchmark the ratio, not just the minutes. Manual and semiautomatic shops typically run 10 to 20 percent arc-on across a full shift. A disciplined shop with good fixturing and material presentation reaches 25 to 30 percent. Mechanized and submerged arc stations run 40 to 60 percent, and robotic cells hit 50 to 85 percent within the cell cycle. On the per-job level, a handling allowance of 100 to 200 percent of arc time is normal for one-off fabrication, while repetitive production with dedicated fixtures should get the allowance under 60 percent. If your allowance exceeds 250 percent, the constraint is flow and fixturing, not welders.

The levers that recover lost minutes are mostly outside the weld puddle. Dedicated fixtures cut handling and fitup time 20 to 40 percent on repeat work and pay back in weeks on any job running monthly. Batching tack operations separately from final welding keeps the welder arcing instead of clamping. Staging wire, gas, and tips at the booth eliminates 10 to 20 minutes per shift of walking. Positioners that rotate work into the flat position both raise travel speed and cut repositioning stops. A crane shared across six welders can add 15 to 30 wait minutes per welder per shift; measure it before buying anything.

Watch the standard failure modes. Estimating with catalog travel speeds overstates arcing pace 20 to 30 percent because production welders adjust for fitup gaps and position. Forgetting pass counts on groove welds understates arc time by half or worse. Applying one blended allowance across both fixtured production work and loose one-off fabrication guarantees both estimates are wrong. And treating arc-on time as a welder performance score rather than a process measurement kills the data quality fast: welders who feel timed will game the number, while welders who see it used to fix fixtures and flow will help you collect it.

Deploy it on a cadence. Daily, compare estimated arc minutes against actual for completed jobs; modern power sources log arc time automatically and the data costs nothing to pull. Weekly, review the three jobs with the biggest gap and walk the booth to see why: bad fitup, missing material, crane waits. Monthly, update travel speeds and allowances in your estimating standards from the actuals, one weld family at a time. Quarterly, run a structured time study on your highest volume weldment. Within two quarters the estimate-to-actual gap should close from 40 percent to inside 10 percent.

World class arc-on management looks boring and precise. Every quoted weldment carries a weld length inventory, travel speeds come from logged production data, allowances are set per work cell, and estimates land within 10 percent of actuals on 90 percent of jobs. Shift level arc-on percentage is posted and trending up 2 to 4 points per year. The financial stakes justify the discipline: in a ten welder shop at 60 dollars per hour burdened, moving from 90 to 120 arc minutes per shift per welder is the output of adding three welders, about 375,000 dollars a year of capacity, without hiring anyone.

Published 2026-07-02.