Using Process Failure Mode Effects Analysis to Evaluate Risk and Opportunities in Manufacturing 

Presenter: Patsy Brown, Quality Director, Lennox Industries, Stuttgart, AR, USA 

Keywords: PFMEA, Risk, Quality Assessment

Industry: Automotive, Customer Service, Manufacturing

Level: Intermediate


At Lennox Industries, we chose to re-create our quality evaluation system into a risk and opportunity based system, using the severity and detection criteria that are defined in the PFMEA process. Since the PFMEA process is well defined and targets corrections and improvements opportunities with the highest risk, it is a natural tool to utilize as a model for this activity.

Steps include:

  • Develop new process flowcharts, refine existing ones as needed
  • Conduct the Process FMEA for each assembly station, including on-line and off-line operations
  1. Determine severity, based on automotive industry criteria for each failure mode. Evaluate from customer’s perspective and impact on assembly lines
  2. Define and record rationale for each severity rating
  3. Determine detection ratings, based on the automotive industry criteria, due to the type of evaluations and degree of error proofing present in the process
  4. Calculate RPNs and take appropriate actions
  • Develop risk-based Product Quality Audit defect classification system and audit strategy, based on the severity rankings from the PFMEAs.
  1. Re-define defect descriptions and classify according to severity ratings from PFMEA
  2. Include rationale for each defect description
  3. Develop online reporting scheme utilizing scoring criteria and collecting data on number of occurrences
  • Develop risk-based Process Audit scheme based on the failures likely to impact customer and manufacturing
  1. Focus process quality auditors on steps with greatest assembly risk
  2. Add process evaluations to those with poor detection methods
  • Develop opportunity-based continual improvement system for the assembly lines.
  • Deploy the defect classification system to Field Quality technicians.