'Freedom' Portable Measuring Arm

February 12, 2020
'Freedom' Portable Measuring Arm

CMM manufacturer LK Metrology has for the first time diversified into the supply of 3D articulating arm metrology systems with the launch of a range of 24 portable measuring arms called “Freedom.”

There is a 6-axis model for touch probing and a 7-axis version for multiple-sensor metrology including laser scanning. Both are available in two accuracy levels and the four products come in six sizes with a reach of up to 5 m (196.85 inches). International sales and support are through the company's offices in the U.K., North America, Belgium, France, Germany, Italy and China, as well as via a worldwide distributor network.

North American Managing Director Brian Samson said, "The solutions we can offer customers is greatly expanded by the new range of arms. Their portability is especially well suited for line-side measuring and inspection in factories, while their compactness makes them ideal for use on machine tools for in-process quality control.

"The platform is also particularly appropriate for reverse engineering applications, virtual assembly design environments and 3D modelling. Moreover, if very high precision tolerances do not have to be measured, a portable arm is a cost-effective way to progress from manual to CNC metrology."

The two 6-axis arms for tactile inspection are named Freedom classic and Freedom select, the former being the entry-level model and the latter the enhanced accuracy version which is supplied with a calibration bar. Addition of an extra degree of freedom provides infinite movement and enables laser scanning with a Nikon Metrology ModelMaker H120, MMDx100 or MMDx200. These 7-axis arms, again in two accuracy versions, are called Freedom classic scan and Freedom select scan. The touch probing accuracy of all Freedom arms is certified to ISO 10360-12 before delivery and may be supplied with a variety of aluminum and carbon fiber probe kits, styli, mounting rings including some with a magnetic or vacuum base, tripods, rolling stands and carts with a granite top.

Carbon fiber tubular construction ensures stability under challenging conditions. Infinite rotation and a proprietary counterbalance make manual movements light, which promotes ease of use even when trying to access awkward areas of a component. Wi-Fi connectivity and battery power allow completely portable wireless touch probing for maximum flexibility. The arm can be stowed and locked in place between measurements and when it is being relocated. Even the largest Freedom arm model weighs less than 11 kg (24.25 lbs.), making setup and repositioning quick and easy.

A notable feature of the arms is the inclusion of absolute rather than incremental rotary encoders to feed back the angular position of every joint to the control software. The equipment may therefore be used immediately on start-up, avoiding the need to calibrate the probe before use every time. This raises productivity, as does the highly repeatable probe connection that allows them to be swapped quickly without interrupting the measuring process to recalibrate. Contributing also to efficiency and convenience is an LCD display with a quick-access menu on the probe wrist, putting the most useful information directly in the hands of the operator during measurement.

A strong line-up of third-party inspection software can be supplied by LK Metrology with its new Freedom arms, including InnovMetric's PolyWorks Inspector, which has the ability to swap programs seamlessly between portable and static CMM platforms. ArcoCAD metrology software from Metrostaff is also available, as is Nikon Metrology's Focus Inspection for data acquisition and analysis, while the latter's CMM Manager inspection package may be used for touch probing only.

Related Glossary Terms

  • calibration


    Checking measuring instruments and devices against a master set to ensure that, over time, they have remained dimensionally stable and nominally accurate.

  • computer numerical control ( CNC)

    computer numerical control ( CNC)

    Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.

  • feed


    Rate of change of position of the tool as a whole, relative to the workpiece while cutting.

  • metrology


    Science of measurement; the principles on which precision machining, quality control and inspection are based. See precision machining, measurement.

  • quality assurance ( quality control)

    quality assurance ( quality control)

    Terms denoting a formal program for monitoring product quality. The denotations are the same, but QC typically connotes a more traditional postmachining inspection system, while QA implies a more comprehensive approach, with emphasis on “total quality,” broad quality principles, statistical process control and other statistical methods.