A Comprehensive Root Cause Analysis of Defective Welds in Chassis Assembly

Defective Welds in Chassis Assembly

• Materials
  • Inconsistent Material Thickness
  • Supplier quality issues
  • Varying sheet metal thickness
  • Poor Quality Welding Wire
  • Corrosion or contamination
  • Substandard material quality
• Machine/Equipment
  • Insufficient Clamping
  • Loose clamps during welding
  • Poor fixture design causing movement
  • Inadequate Heat Settings
  • Inconsistent welding parameters
  • Incorrect power or voltage applied
  • Malfunctioning Welding Equipment
  • Worn-out welding tips or electrodes
  • Out-of-calibration welding machines
• Method
  • Insufficient Weld Inspection
  • Visual inspection errors
  • Not following inspection protocols
  • Lack of Pre-Cleaning
  • Grease, oil, or debris on surfaces
  • Failure to remove contaminants before welding
  • Improper Welding Technique
  • Inconsistent travel speed
  • Incorrect angle or position of welding torch
• Environment
  • Temperature Fluctuations
  • Excessive heat leading to poor weld cooling
  • Cold environment affecting weld penetration
  • Welding in Poor Environmental Conditions
  • Dust or particles affecting weld quality
  • High humidity causing contamination
• People
  • Overworked Labor
  • Rushed work affecting weld quality
  • Fatigue leading to mistakes during welding
  • Inexperienced Welders
  • Failure to adhere to standards and procedures
  • Lack of training in proper welding techniques
• Measurement
  • Misalignment of Components
  • Lack of proper quality checks
  • Incorrect fixture alignment during measurement
  • Inaccurate Welding Parameters
  • Improper calibration of equipment
  • Wrong measurements for voltage/current

Suggested Actions Checklist

Here are some corrective actions, preventive actions and investigative actions that organizations may find useful:

• Materials
  • Inconsistent Material Thickness
    • Corrective Actions:
    • Reject or replace inconsistent materials upon detection.
    • Review supplier quality standards and demand immediate corrective measures.
    • Preventive Actions:
    • Implement stringent incoming material inspections.
    • Standardize material specifications and communicate them clearly to suppliers.
    • Investigative Actions:
    • Analyze trends in material nonconformities from suppliers.
    • Conduct audits to identify gaps in supplier quality processes.
  • Poor Quality Welding Wire
    • Corrective Actions:
    • Replace contaminated or substandard wire immediately.
    • Clean or recondition corroded wires if feasible.
    • Preventive Actions:
    • Use quality-approved welding wire suppliers.
    • Ensure proper storage to avoid corrosion or contamination.
    • Investigative Actions:
    • Inspect storage conditions for welding wire at the facility.
    • Trace the batch history of poor-quality welding wire.
• Machine/Equipment
  • Insufficient Clamping
    • Corrective Actions:
    • Tighten or replace loose clamps immediately.
    • Modify fixtures to prevent movement during welding.
    • Preventive Actions:
    • Design fixtures to ensure secure and consistent clamping.
    • Perform regular inspections and maintenance on clamps and fixtures.
    • Investigative Actions:
    • Evaluate fixture designs for mechanical deficiencies.
    • Conduct root cause analysis for clamp failures.
  • Inadequate Heat Settings
    • Corrective Actions:
    • Adjust welding machine parameters to optimal settings.
    • Reweld defective joints where permissible.
    • Preventive Actions:
    • Establish standard operating procedures for setting machine parameters.
    • Provide training on setting appropriate power and voltage levels.
    • Investigative Actions:
    • Analyze trends of weld defects due to parameter inconsistencies.
    • Check for operator errors or machine calibration issues.
  • Malfunctioning Welding Equipment
    • Corrective Actions:
    • Repair or replace worn-out welding tips, electrodes, or faulty machines.
    • Perform emergency recalibration of equipment.
    • Preventive Actions:
    • Implement a preventive maintenance schedule for welding machines.
    • Keep a record of machine calibration history.
    • Investigative Actions:
    • Review maintenance logs for signs of neglect or overdue checks.
    • Perform failure analysis on defective equipment.
• Method
  • Insufficient Weld Inspection
    • Corrective Actions:
    • Reinspect welds using proper protocols and tools.
    • Address errors identified during visual inspections.
    • Preventive Actions:
    • Establish clear inspection protocols with checklists.
    • Provide training for inspectors on proper inspection methods.
    • Investigative Actions:
    • Audit the weld inspection process for procedural gaps.
    • Investigate instances of overlooked defects.
  • Lack of Pre-Cleaning
    • Corrective Actions:
    • Clean welding surfaces thoroughly before proceeding.
    • Remove grease, oil, and debris from components.
    • Preventive Actions:
    • Include cleaning steps in standard operating procedures.
    • Use appropriate cleaning agents and equipment for pre-weld cleaning.
    • Investigative Actions:
    • Check for deviations in pre-cleaning processes.
    • Identify root causes of contamination on welding surfaces.
  • Improper Welding Technique
    • Corrective Actions:
    • Correct operator technique by realigning the torch or adjusting speed.
    • Reweld sections where defects have been identified.
    • Preventive Actions:
    • Conduct periodic training and skill assessments for welders.
    • Use templates or guides to standardize torch positioning and speed.
    • Investigative Actions:
    • Monitor operator performance for technique consistency.
    • Review the adequacy of training programs.
• Environment
  • Temperature Fluctuations
    • Corrective Actions:
    • Stabilize the environment with controlled heating or cooling.
    • Use post-weld heat treatments to address cooling issues.
    • Preventive Actions:
    • Install environmental controls in welding areas.
    • Monitor ambient temperature regularly to ensure consistency.
    • Investigative Actions:
    • Analyze temperature data during welding operations.
    • Check for changes in environmental conditions causing fluctuations.
  • Welding in Poor Environmental Conditions
    • Corrective Actions:
    • Remove contaminants from the environment before welding.
    • Pause welding operations during high humidity or dust conditions.
    • Preventive Actions:
    • Implement ventilation and dust control systems.
    • Schedule welding during optimal environmental conditions.
    • Investigative Actions:
    • Inspect welding zones for compliance with environmental standards.
    • Identify root causes of environmental contamination.
• People
  • Overworked Labor
    • Corrective Actions:
    • Adjust work schedules to reduce overtime and allow adequate rest.
    • Redistribute tasks to balance workload among workers.
    • Preventive Actions:
    • Implement shift rotations and rest breaks.
    • Monitor and manage workloads effectively.
    • Investigative Actions:
    • Conduct surveys to identify worker fatigue levels.
    • Analyze trends in errors correlating with excessive workloads.
  • Inexperienced Welders
    • Corrective Actions:
    • Provide on-the-job training and mentoring to inexperienced welders.
    • Supervise welding processes closely until standards are met.
    • Preventive Actions:
    • Conduct regular training programs on welding techniques and standards.
    • Maintain a competency matrix for welders to match tasks with skill levels.
    • Investigative Actions:
    • Review welder certification and training records.
    • Investigate reasons for skill gaps among welding personnel.
• Measurement
  • Temperature Fluctuations
    • Corrective Actions:
    • Realign and reseat components before welding.
    • Adjust fixtures to ensure proper alignment.
    • Preventive Actions:
    • Use jigs and tools designed for accurate alignment.
    • Train operators on proper alignment techniques.
    • Investigative Actions:
    • Check fixture design for alignment-related flaws.
    • Analyze historical misalignment trends and corrective actions.
  • Inaccurate Welding Parameters
    • Corrective Actions:
    • Recalibrate equipment to ensure accurate settings.
    • Adjust voltage/current parameters for optimal performance.
    • Preventive Actions:
    • Implement periodic calibration schedules.
    • Use equipment with automated parameter settings to minimize errors.
    • Investigative Actions:
    • Review equipment calibration logs for irregularities.
    • Examine operator understanding of welding parameter setup.