Coordinate Measuring

Coordinate Measuring Machines (CMMs)

Definition
- High-precision measuring instruments used to capture the physical geometry of an object by sensing discrete points on its surface with a probe.

Types of CMMs
- Bridge Type – Most common; ideal for precision parts
- Cantilever Type – Suitable for smaller parts and open access
- Gantry Type – Designed for large and heavy workpieces
- Horizontal Arm Type – Used for measuring large sheet metal and car bodies
- Portable CMM (Articulated Arm / Laser Tracker) – Flexible and mobile for on-site inspection

Probing Systems
- Touch Trigger Probe – Captures discrete points on contact
- Scanning Probe – Continuously collects data as it moves along the surface
- Optical/Non-Contact Probe – Uses cameras or lasers for delicate or small components

Key Functions
- 3D measurement of dimensions, form, and position
- Inspection of geometric tolerances (GD&T)
- Reverse engineering and part-to-CAD comparison

Applications
- Aerospace, automotive, tool & die, electronics, medical devices
- In-process and final inspection stages

Advantages
- High accuracy and repeatability
- Automatable for high-throughput environments
- Minimizes human error in complex inspections

Software Integration
- CMMs use advanced metrology software (e.g., PC-DMIS, CALYPSO, PolyWorks)
- Enables automated routines, 3D visualization, and data reporting