Understanding and Improving the Effectiveness of Your CMMs

When it comes to making the most of your coordinate measuring machines (CMMs), one of the best ways to track how well they’re performing is by looking at something called Overall Equipment Effectiveness, or OEE. Simply put, OEE is a score (expressed as a percentage) that tells you how effectively your machines are being used. You can calculate it for one CMM or across several machines, over any time period you choose.

Knowing your CMM’s OEE helps you spot where time or resources may be wasted, allowing you to improve performance, reduce downtime, and avoid unnecessary maintenance costs. But to make this easier, your asset management system needs to clearly show you the right data in a way that’s simple to understand and use.

How do you calculate OEE?

OEE is calculated using three key factors: Availability, Performance, and Quality. Here’s how each works:

1. Availability – How much time is the CMM actually running when it’s supposed to?

To figure this out, you compare the time your CMM is scheduled to be used (excluding holidays or planned shutdowns) with how much of that time it’s actually running measurement programs. This includes both automated runs and any manual work like one-off measurements or alignments.

Formula:

Availability = Operating Time ÷ Scheduled Time

2. Performance – Is your machine running as quickly as it should?

Performance looks at how fast your CMM runs compared to its “ideal” speed—the fastest it can complete a measurement program under perfect conditions. Since different machines (and programs) may run at different speeds, it’s important to set this ideal time separately for each program and CMM. You can manage this easily by organizing programs in PC-DMIS.

Formula:

Performance = (Number of Programs Run × Ideal Execution Time) ÷ Operating Time

3. Quality – How many programs completed without issues?

This factor looks at how often measurement programs run all the way through and finish successfully. Programs that get canceled or stop early count against the total.

Formula:

Quality = Programs Completed Successfully ÷ Total Programs Run

Making OEE Easy with Hexagon Tools

Hexagon’s Nexus Metrology Asset Manager was built to simplify OEE tracking. It pulls essential data—like availability, performance, and quality—directly from PC-DMIS. If you’re using PC-DMIS 2019 R2 or newer, it can even track completed and canceled programs automatically. This means you’ll spend less time digging through data and more time making smart, cost-saving decisions about your metrology equipment.