When Dorothy uttered the famous phrase “Lions and tigers and bears, oh my!” she was overwhelmed and scared of the many dangers she and her companions might face on their journey to the Emerald City. When a customer once asked me to explain the difference between AIAG versus VDA, I felt a similar sense of worry. After all, how does one explain to an engineer that a Gage R&R, which literally stands for repeatability and reproducibility, could be performed in two different ways? Well, here goes.
What are AIAG and VDA?
AIAG (the Automotive Industry Action Group) and VDA (Verband der Automobilindustrie or the German Association of the Automotive Industry) are both automotive industry associations. The AIAG is a U.S. not-for-profit founded in 1982 by the Ford, GM and Chrysler to develop common methods and standards across the North American auto supply chain. Today it publishes the “Core Tools” (APQP, PPAP, MSA, SPC) and other manuals. The VDA is Germany’s national automotive association, founded in 1901, representing OEMs and suppliers (e.g., VW, BMW, Mercedes-Benz). VDA’s Quality Management Center (QMC) publishes the well-known “VDA volumes” (e.g., VDA 6.x, VDA 5 for measurement).
For decades, AIAG and VDA each maintained their own guidance for core quality methods. Suppliers serving both U.S. and German OEMs often had to build two versions of the same documents—notably for FMEA—because the methods and forms differed. In June 2019, the AIAG and VDA released the AIAG & VDA FMEA Handbook (1st ed.) in June 2019, creating a single, harmonized global approach to FMEA. The FMEA available in The Minitab Solution Center through Minitab Workspace meets these latest standards.
Get the Latest FMEA in The Minitab Solution Center
What’s The Difference in Frameworks and Why?
In general, both the AIAG and the VDA create a quality framework, but several methods differ in scope, outputs and what the customers expect. For the most part, customer requirements, often based on history and geography, dictate the appropriate framework to choose. The VDA also integrates traceability and measurement uncertainty in accordance with ISO/IEC 17025 (Calibration Lab competence) and GUM (Guide to the Expression of Uncertainty in Measurement), making it more rigorous for labs and accredited facilities. In today’s global economy, it is best to be prepared to use both frameworks; that’s why Minitab just added VDA 5 Support to its Type 2 Gage Study.
A Deeper Dive of a Key Example: Type 2 Gage R&R Studies
A Type 2 Gage R&R (Repeatability & Reproducibility) is one of the most common forms of measurement system analysis. It effectively answers the question: “If multiple operators measure the same parts multiple times, how much of the total variation is due to the measurement system itself?”
In both the AIAG and VDA frameworks you select a sample of parts representing your process, have multiple operators measure each part multiple times and then statistically break down the total variation into: Part-to-Part (true process variation), Repeatability (equipment variation) and Reproducibility (operator variation).
Under the AIAG method, you are seeking to answer the question whether or not the gage is acceptable for process control. Said differently, you answering the question of whether or not the measurement system is consistent and repeatable. With the VDA Type 2 Study, you are measuring the entire measurement process capability, not just the gage itself. The VDA answers what the quantified uncertainty and decision risk to the entire measurement process. In sum, both confirm suitability, but only the VDA quantifies risk and uncertainty.
When it Comes to AIAG and VDA There’s No Place Like Home
Fundamentally, both the AIAG and VDA provide leading and proven quality frameworks. Whereas the AIAG Measurement System Analysis focuses on manufacturing consistency, the VDA adds traceability, accreditation and risk quantification. While geography probably plays the largest role in determining the proper framework, remember that “the customer is always right,” so be sure to understand quality requirements of your customers to meet their expectations.
Minitab Has Type 2 Gage Studies For AIAG and VDA