LK Metrology diversifies into 3D articulated measuring arms

2 mins read

LK Metrology, which has been manufacturing static CMMs in the UK since 1963, has for the first time diversified into the supply of 3D articulating arm metrology systems, otherwise known as portable arms, with the launch of a range of 24 machines called Freedom arm.

There is a 6-axis model for touch probing and a 7-axis version for multi-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. International sales and support is through the company's offices in the UK, North America, Belgium, France, Germany, Italy and China, as well as via a worldwide distributor network.

Marketing manager Dave Robinson, who is based at the firm's CMM factory near Derby, says: "The solutions we can offer customers are greatly expanded by the range of arms. Their portability makes them suited to 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,” he adds. “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."

LK’s 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. The 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 aluminium and carbon-fibre probe kits, styli, mounting rings (including some with a magnetic or vacuum base), tripods, rolling stands, and carts with a granite top.

Carbon-fibre tubular construction ensures stability under challenging conditions, while infinite rotation and a proprietary counterbalance makes manual movements light, which promotes ease-of-use, even when trying to access awkward component features. Wi-Fi connectivity and battery power allow portable wireless touch probing. The arm can be stowed and locked in place between measurements, and when it is being relocated. Even the largest Freedom arm weighs less than 11 kg, making set-up 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 capability raises productivity, as does the repeatable connection that allows probes to be swapped quickly without interrupting the measuring process to recalibrate. Also contributing to efficiency and convenience is an LCD display with a quick-access menu on the probe wrist, putting 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 Freedom arms, including InnovMetric's PolyWorks Inspector, which has the ability to swap programs 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.