Statistical Process Control (SPC)

SPC is a tool to help companies study their operations so they can continually improve. SPC uses structured statistical analysis to determine and control variance in a process. Studying the variances shows if a process is in control and capable to produce product that satisfies customers.

This outline and the accompanying example demonstrate the process for implementing Statistical Process Control (SPC).

How to Implement SPC 

  • Define the objectives – ensuring they are specific and measurable
  • Define the tasks
  • Determine the duration – establish starting and ending dates
  • Name the person responsible for each task, making them accountable
  • Develop your plan/timeline with the tasks, assigned resources, duration and time phasing (a Gantt chart works well for this)
  • Implement the performance measurement
  • Assess the project on a regular basis

The SPC Process

  • Select the characteristics to be monitored (a dimension, surface finish, etc.)
  • Select the appropriate technique (x bar r, x bar s, etc.)
  • Implement monitoring
  • Improve the process continuously

Here is an example of the process we used with one client.:

Objectives and Process for the SPC Project 

  1. Refine, document, and implement statistical techniques, ensuring conformity with ISO 9001.
  2. Complete all employee education required including: SPC basics, data collection/charting, and problem solving.
  3. Ensure operator ownership of applicable SPC processes.
  4. Align support functions with the production SPC effort, i.e., Engineering, Program Management, and Marketing.
  5. Identify implementation opportunities in priority order.
  6. Measure project effectiveness by the individual process and overall company cpk improvements.