--- title: "Cobot Welding Troubleshooting: Fix Common Issues | Intouch" url: https://www.intouchray.com/cobot-welding-troubleshooting-fix-common-issues-intouch/ date: 2026-11-08 modified: 2026-11-03 lang: en author: "Allan Hill" description: "Troubleshooting Cobot Welding Systems: What to Do When Things Go Wrong When a collaborative welding cell stops producing sound seams, the fix is almost always one of six things: a..." categories: - "Laser Welding Machine" image: https://www.intouchray.com/wp-content/uploads/2026/11/intouchray-f3f6d7af.jpg word_count: 1694 --- # Cobot Welding Troubleshooting: Fix Common Issues | Intouch # Troubleshooting Cobot Welding Systems: What to Do When Things Go Wrong When a collaborative welding cell stops producing sound seams, the fix is almost always one of six things: a burnt-back contact tip, dirty or wrongly tensioned wire feed, a chafed power cable, a drifted tool center point, a stuck peripheral, or a parameter that no longer matches the joint. Work through that list in order and most downtime disappears within an hour. We write this from the factory floor at Intouch. Since 2001 we have built fiber laser welding machines and [robotic laser welding](https://www.intouchray.com/robotic-laser-welding-machine/) cells in Dongguan, and the service calls we take follow patterns that repeat across every customer, every continent. This guide walks through each fault, why it happens, and what to do about it. ## Why a Fault-Finding Order Matters ![Cobot Welding Troubleshooting: Fix Common Issues | Intouch](https://www.intouchray.com/wp-content/uploads/2026/11/intouchray-ced66878.jpg) Cobots fail differently from fixed industrial robots. They move between workpieces, they get nudged by operators, and their consumables wear faster because the same cell often runs three different part families in a shift. Jump straight to a random fix and you will chase symptoms all afternoon. Start with the cheapest, most common cause and work outward — that is how our own technicians run a service call. ## The Six Faults We See Most in Welding Cobots ### 1. Burnback and Contact Tip Wear The wire fuses to the tip, or the tip is eaten out after only a few hundred arcs. Usually this means the gas post-flow time is too short, so the wire tip oxidises and sticks at arc-out. Check the burnback setting in the weld program first — on most units it should hold a brief reverse-feed or gas purge after the arc stops. Other causes to tick off in order: - Contact tip one size too large for the wire, letting the arc wander off-centre - Stick-out set longer than the procedure calls for, which overheats the tip - Cheap tips with inconsistent bore diameter — we have opened boxes of "identical" tips where half were visibly out of round under the lamp - Wrong polarity or excessive current for the wire diameter Practical fix: stock tips from one batch, replace on a counted-hour schedule rather than waiting for failure, and log how long each batch lasts. The question buyers ask us most at trade stands is not about the robot arm at all — it is how fast consumables burn on mixed-material jobs. Honest answer: faster, so schedule for it. ### 2. Wire Feed Problems Erratic feed shows up as a stuttering arc, porosity, and an unstable bead. Nine times out of ten it is mechanical, not electrical. - **Drive rolls**: wrong groove size, worn grooves, or tension set by feel instead of by a calibrated gauge. Tension high enough to flatten a hard wire slightly is correct; any more and you slip, deform, or shave the wire. - **Liner**: contaminated, kinked, or cut too short. Blow liners out with dry compressed air at every wire spool change and replace them on a schedule, not when they jam. - **Spool drag**: a sticky brake makes the motor fight the spool and the feed becomes uneven. - **Wire quality**: rusty or poorly wound wire sheds debris into the liner. Store spools sealed and indoors. On our floor, when a customer's feed fault cannot be reproduced on the bench, the first thing we ask for is a photo of the wire path from spool to tip. The problem is visible in that photo more often than not. ### 3. Power Cable Failures That Come Too Early A torch cable rated for months of service dies in weeks. That is almost always routing. A cobot arm that loops the cable through a tight radius, drags it across a fixture, or lets it hang unsupported puts cyclic stress on the conductor and the jacket. - Route the cable through the arm's dedicated dress-pack channel, never around the outside - Respect the minimum bend radius printed on the cable — usually several times the cable diameter - Use strain reliefs at both ends so flexing loads the clamp, not the conductor - Keep cables off hot workpieces and away from spatter zones If a cable fails early despite good routing, inspect for oil contamination or pinch points in the dress-pack. Replace with the manufacturer's specified cable; an improvised substitute will fail again. ### 4. Tool Center Point Drift TCP loss is the silent fault. The cell welds, but the seam sits half a millimetre off and the reject pile grows before anyone notices why. TCP shifts when the torch is bumped during loading, when a nozzle or tip is changed, or when a mounting flange works loose. Re-teach the TCP using the standard four-point method: move the tip to a fixed reference point from four distinct orientations and let the controller compute the offset. Do it after every torch service, after any collision, and weekly on cells that run multi-part schedules. Verify with a single test weld on a sacrificial coupon before releasing the cell to production — a thirty-second check that saves a scrap bin. ### 5. Peripherals Misbehaving The arm often gets the blame for a fault living elsewhere. Fixtures, positioners, fume extraction, wire feeders, and safety interlocks all stop cells, and they fail for boring reasons: a tripped breaker, a sensor blocked by spatter, a loose connector after transport. - Confirm the peripheral has power and its status LED reads healthy before touching the robot program - Clean photo-eyes and proximity sensors — spatter film is a common culprit - Check interlock chains after any layout change; a door sensor wired into the wrong input halts the whole cell - Re-seat connectors on anything recently moved or serviced Keep a printed one-page fault map of the cell — which input belongs to which device. When a line is down, nobody wants to read a 60-page manual. ### 6. Weld Defects and Quality Problems Porosity, undercut, incomplete fusion, and cracking point to process, not hardware. Match the defect to its cause: | Defect | Most likely causes | | ------ | ------------------ | | Porosity | Gas leaks, blocked nozzle, drafts across the arc, oily surface | | Undercut | Excess current, travel speed too high, wrong torch angle | | Incomplete fusion | Low heat input, poor joint fit-up, wire aimed at the wrong edge | | Cracking | Wrong filler chemistry, restraint stress, rapid cooling on hardenable grades | Cleanliness is the cheap half of the fix: degrease every joint, grind mill scale off, and fit parts properly. Parameters are the other half. As reference points, fibre sources at the common 1070 nm wavelength dominate hand-held and robotic laser welding equipment, and a 1 kW fibre system typically welds about 1 mm stainless at several metres per minute, while 6 kW-class sources push past 2 m/min on thicker sections (manufacturer data). MIG/MAG consumables on cobots follow ISO and AWS filler-matching guidance — when in doubt, match the filler to the base metal's strength and corrosion requirements rather than to whatever spool is on the shelf. ## A Working Troubleshooting Routine Write the sequence down and pin it to the cell: - Record the fault exactly — error code, seam photo, wire and gas settings, what changed last - Rule out consumables first (tip, liner, wire, gas) - Check power and signal connections end to end - Re-verify the TCP - Test peripherals one at a time - Only then touch the weld program - Confirm the fix with a test coupon and log it That log matters. After three similar faults you have a maintenance interval, not a mystery. ## Preventive Maintenance That Actually Prevents - Daily: check gas flow, visually inspect tip and nozzle, wipe the sensor window, confirm the wire path is clean - Weekly: re-teach TCP, inspect cable routing, test emergency stops and interlocks - Monthly: replace liner and tip batch on schedule, calibrate wire-feed tension against a gauge, inspect the dress-pack - Per batch of consumables: record hours to failure, so replacement becomes prediction - Housekeeping: spatter film on a fixture is a TCP fault waiting to happen. We prefer a two-minute end-of-shift wipe-down over a Monday-morning TCP drama — it is the cheapest insurance in the shop. Per ISO 11553 and IEC 60825-1, laser welding equipment must carry defined safety classifications and enclosures, and control wiring should conform to EN 60204-1 — build your preventive checks around the machine's own compliance documentation, because that is what the safety chain was validated against. A closing word from experience: most cobot downtime we trace is not exotic. It is a worn tip, a dirty liner, a bumped torch. The shops with the least downtime are the ones that treat a twenty-minute daily checklist as seriously as the weld schedule itself. Known limitation: no checklist catches everything — collisions, firmware faults and source failures still need the manufacturer's service channel. ## FAQ **How often should I replace the contact tip on a welding cobot?** Replace on counted hours rather than visible failure — many shops swap tips every 4–8 arc hours in mixed production. Track actual life per batch and let your own data set the interval. **Why does my wire keep feeding unevenly even after changing the spool?** Check drive roll tension against a gauge and inspect the liner for debris or kinks. A short or contaminated liner is the most common hidden cause. **How do I know if my TCP has drifted?** Run a test coupon against a known-good program. If the seam sits consistently off-line in the same direction, re-teach the TCP with the four-point method. **Can cobots weld aluminium and stainless reliably?** Yes, with the right wire, clean joints, correct gas and tuned parameters. Aluminium is less forgiving of surface contamination and feed resistance, so expect tighter housekeeping. **What is the first thing to check when the whole cell stops?** Safety chain and power. Confirm interlocks, e-stops and breakers before assuming the controller or the robot program has failed. --- If you are evaluating robotic laser welding or a handheld laser welder for your shop, or you need help spec'ing a cell around your parts, tell us the material, thickness and throughput target and we will answer in plain numbers — info@intouchray.com or www.intouchray.com. Intouch has built laser welding equipment and automation since 2001, ISO 9001:2015 certified with EU CE on multiple product series. **Related reading:** [laser applications by industry](https://www.intouchray.com/applications/) · [cobot laser welding workstations](https://www.intouchray.com/cobot-laser-welding-machine/) · [laser welding machines](https://www.intouchray.com/category/laser-welding-machine/)