Both DFMEA and PFMEA have similar principles and follow identical steps. Both involve identifying potential failures, their impact, and corrective measures to be taken for reducing or eliminating these potential failures.
DFMEA focuses on potential failures related to product design changes. The main focus is on finding potential failures that can result in malfunctions and safety hazards while using the product. It is also applied to identify potential causes that may curtail the life of the product. It must be conducted throughout the entire design process, starting at the preliminary design as soon as the design concept has been selected to the production.
PFMEA focus on potential failures associated with processes and changes to them. The main focus is on finding potential failures related to a process that can affect the quality of a product or cause safety or environmental hazards and result in customer dissatisfaction. It is also applied to identify potential causes that reduce the reliability of the process.