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R&D project

The Virtual Coordinate Measuring Machine VCMM – A Digital Twin to determine the task-specific measurement uncertainty in coordinate metrology

Project description

Knowledge about the measurement uncertainty is a fundamental requirement in quality-driven and economic production and is relevant throughout the entire production technology. By knowing the measurement uncertainty, tolerances can be used more efficiently, and thus, create an economic benefit. However, in coordinate metrology, determination of the measurement uncertainty must be performed for each task and can therefore be very challenging and time consuming. Size, shape, form deviations and accessibility all play an important role in the achievable uncertainty. Particularly large part varieties and variants along with narrowly defined tolerances increase the demand for means to assess measurement uncertainty easily, efficiently, and universally.

In general, the determination of the measurement uncertainty is described by the “Guide to the expression of uncertainty in measurement” (GUM) and can follow one of three approaches:

  1. Analytical budgets
  2. Experimental determination
  3. Numerical simulations

All these approaches require sophisticated mathematical models and suitable descriptions and quantification of the uncertainty contributions. A well-established method for the uncertainty determination by numerical simulation is the Virtual Coordinate Measuring Machine VCMM. PTB developed the Monte-Carlo-based software in close collaboration with machine manufacturers and users. The VCMM is an independent software that provides interfaces for the communication with the manufacturer’s application and analysis software allowing for the exchange of parameters and results of the Monte Carlo Simulations.

Since 2003, the VCMM is used by DAkkS-accredited calibration laboratories. Following the ongoing development of coordinate measuring machines and the continuing growth of importance in digitalized industry, economy, and society, constant reevaluations of the existing models and expansion to new uncertainty contributions are necessary. All extensions and modifications are validated using reference data and intercomparison measurements using calibrated measurement standards.

Since the VCMM is independent of manufacturers and CMM brands, the research cooperation is open for new participants and contributors.

Current project partners

Carl Zeiss Industrielle Messtechnik GmbH

Eumetron GmbH

Hexagon Manufacturing Intelligence


Dr. Daniel Heißelmann, Dr. Katharina Janzen, Matthias Franke