FARO | Understanding Measurement Arms

The world relies on measurement to operate, and for hundreds of years this has been accomplished by the tools of the time — hand tools such as calipers and micrometers, which provided basic measurements but struggled with more complex dimensions (like an unusual geometry, organic shapes, etc.).

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But as advancements in technology accelerated industrial growth dramatically, companies needed new tools to help them keep up the pace. It was critical to develop solutions that produced repeatable, accurate results that could align to rigorous global standards of measurement.

Coordinate measuring machines (CMMs) were introduced in the 1960s to capture those complex geometries with a much higher rate of accuracy using a measurement bed, a probe, a computer and software to operate the probe. Measurement was, and continues to be, confined to the range of the probe on the bed, however, and the probe can only move in three axes, limiting its maneuverability.

Portable articulated CMMs, also commonly known as measurement arms, are 3D measurement devices developed in response to growing need for a probing solution that provided more portability and flexibility than a fixed CMM. Portable measurement arms determine and record the location of a probe in 3D space and report the results through software. The arm calculates the exact position of the probe at each point through embedded encoders on each axis (or joint) in the arm.

Measurement arms are available in multiple working volumes, typically from 4 feet to 12 feet (with a radial reach from 2 to 6 feet in any direction). They are also characterized by the number of rotational axes – arms typically come in 6 or 7-Axis configurations, with 6-Axis models used in high accuracy, hard probing applications and 7-Axis models used when additional articulation is needed for use with laser scanning attachments and specialty probes. FARO® offers an exclusive 8-Axis configuration that includes a satellite rotating measurement platform.

Using a portable measurement arm allows you to:

• Enjoy the combined benefits of a traditional CMM — reliability, repeatability and accuracy with the versatility and portability of hand tools
• Measure full parts quickly and easily, including those with complex geometries
• Measure on-demand, without needing to program a specific routine first
• Operate in a variety of environments, unlike a traditional CMM that requires a temperature-controlled room
• Transport the arm to where the part is made rather than bringing each part to a special room, decreasing inspection bottlenecks and increasing productivity
• Perform a full digital analysis and review the data at any time
• Produce inspection reports to document and share
  
  

Taken altogether, this translates into more time saved: with data capture, analysis and inspection time all greatly reduced, users can put that time saved into more production, diversifying product lines, streamlining workforce efforts and more.

A best-in-class portable measurement arm should come in a variety of sizes and configurations to meet a diverse range of needs. Companies producing portable arms should continue to iterate as technology evolves and customers’ needs change. At FARO, our lineup includes>

The FaroArm

The FaroArm is offered in three different models and a spectrum of system integrations that allow the user to customize it even further for use across a variety of applications:

• Dimensional analysis: Collect information on parts to compare data to drawings and blueprints
• CAD-based inspection: Measure against CAD model data to gain real-time feedback
• On-machine inspection: Inspect a part before, during and after its production, on the machine tool producing it
• First article inspection: Review pre-production samples and compare against nominal data
• Alignment: Align tools and fixtures to the correct orientation
• Reverse engineering: Capture and digitize parts and objects to create a CAD model

The ScanArm

FARO offers a Laser Line Probe (LLP), which attaches to the 7-Axis FaroArm to become a ScanArm. By attaching the laser line probe directly to the articulated arm, data can be fully captured without contact with an object. Measurement points are captured by projecting a beam onto the object's surface, and a camera then "looks" at the beam to determine its location. The laser line probe is fully encoded to the arm, allowing for uninterrupted data transfer.

And because the laser captures data at a high rate, users can quickly and easily obtain large amounts of point cloud data (also called a scan) that contains millions of points in a grid.

Non-contact applications include all the applications of the FaroArm, plus non-contact inspection for inspecting soft, deformable or complex shapes or performing cloud-to-CAD comparison, rapid prototyping, reverse engineering and 3D modeling.

The bottom line: Portable measurement arms should deliver superior 3D data capture performance for any object, no matter how geometrically complex. It should meet the highest caliber global standard for an articulated arm, ISO 10360-12, and provide a certificate of traceability. It should be easy to use, with on-demand reporting and reproducible results.

Want to learn more about our portable measurement arms, laser line probes and additional resources?