SAW Preventive Maintenance Procedures 3 — Questions and Answers
Question 1: What does a high-pitched squealing noise from the SAW wire feeder motor during operation typically indicate?
- Normal motor operation at high speed
- Worn or dry motor bearings requiring lubrication or replacement (Correct answer)
- Excessive wire back-tension from the reel brake
- Controller feedback oscillation
Correct answer: Worn or dry motor bearings requiring lubrication or replacement
High-pitched squealing from a feeder motor typically indicates worn or insufficiently lubricated bearings that must be addressed before failure occurs.
Question 2: During SAW preventive maintenance, which type of lubricant should NEVER be used on wire drive rolls?
- Dry graphite lubricant
- Petroleum-based grease
- Silicone spray lubricant
- Both B and C (Correct answer)
Correct answer: Both B and C
Petroleum-based greases and silicone sprays contaminate the wire and flux, causing porosity and weld contamination; only dry lubricants are acceptable near the wire path.
Question 3: What is the primary reason for periodically purging the SAW flux delivery hose with dry compressed air during maintenance?
- To check hose flow rate capacity
- To remove moisture and flux fines that can clog or contaminate the flux stream (Correct answer)
- To pressurize the hose for leak detection
- To cool the hose after welding operations
Correct answer: To remove moisture and flux fines that can clog or contaminate the flux stream
Moisture and fine flux particles accumulate in delivery hoses over time, and purging with dry air prevents clogging and moisture-induced porosity.
Question 4: A SAW machine's voltage sensing lead shows intermittent arc voltage readings during welding. What maintenance action addresses this?
- Replace the power source control board
- Clean and tighten the voltage sensing lead connections at both ends (Correct answer)
- Increase wire feed speed to stabilize the arc
- Replace the contact tip and nozzle assembly
Correct answer: Clean and tighten the voltage sensing lead connections at both ends
Loose or corroded voltage sensing connections cause erratic feedback to the controller, leading to unstable arc voltage; cleaning and tightening restores accurate sensing.
Question 5: What is the correct procedure for storing reclaimed SAW flux that has been recovered by the flux recovery system?
- Store in open bins to allow moisture to dissipate
- Blend immediately with new flux at a 50/50 ratio
- Screen to remove fines, then store in sealed moisture-proof containers (Correct answer)
- Rebake at 500°F for 4 hours before any storage
Correct answer: Screen to remove fines, then store in sealed moisture-proof containers
Reclaimed flux must be screened to remove fines that cause porosity, then stored in sealed containers to prevent moisture reabsorption before reuse.
Question 6: When inspecting the SAW flux backing system during preventive maintenance, what condition in the copper backing bar requires immediate attention?
- Minor discoloration from heat
- Grooves or gouges that exceed the specified root pass width (Correct answer)
- Surface oxidation on the copper
- Small flux deposits on the copper surface
Correct answer: Grooves or gouges that exceed the specified root pass width
Grooves or gouges in the copper backing bar wider than the specified root pass cause inadequate support of the weld pool, resulting in burn-through or incomplete fusion.
Question 7: How should the SAW oscillation mechanism's stroke length and frequency settings be verified during preventive maintenance?
- Visually observe the wire tip movement during a trial weld
- Measure actual oscillation width with a calibrated dial indicator at the wire tip (Correct answer)
- Check the control panel display readings only
- Run at maximum speed and verify no vibration occurs
Correct answer: Measure actual oscillation width with a calibrated dial indicator at the wire tip
A calibrated dial indicator at the wire tip provides accurate measurement of actual oscillation width, catching mechanical wear or calibration drift not visible on control displays.
SAW Preventive Maintenance Procedures 3
What does a high-pitched squealing noise from the SAW wire feeder motor during operation typically indicate?