LK Metrology has reduced three published accuracy error measures for its L100NX laser line scanner, which is manufactured at Castle Donington in Derbyshire and used on co-ordinate measuring machines (CMMs). The update concerns the measurement specification of an existing blue laser sensor rather than the launch of a replacement instrument.
The stated probing form error has fallen from 15 to 10 micrometres (µm), point-cloud dispersion from 26 to 16 µm, and probing size error from 20 to 15 µm. These changes represent reductions of approximately 33%, 38% and 25%, respectively. Each is a different test quantity, so the figures should not be combined into a single percentage improvement in general CMM accuracy.
Form error concerns the deviation of measured points from a reference geometry after fitting, while dispersion describes the spread of the point data. Probing size error concerns how closely a measured feature corresponds to its known dimension. A system can show low scatter but still carry a systematic dimensional offset, which is why separating the metrics is essential when comparing scanners for inspection work.
An earlier LK technical datasheet recorded the original 15, 26 and 20 µm figures under specified tests referencing ISO 10360-8:2013. Those measurements used defined tests using reference spheres and a qualifying CMM. The revised figures were communicated in the company’s 20 October product information, but the public product page and earlier downloadable datasheet have not independently established a complete new test certificate for every configuration.
A line scanner produces surface measurements by projecting a 450 nm blue laser stripe onto a part and capturing its reflected profile while the CMM moves the sensor along a programmed path. Successive profiles are combined with the measuring machine’s position information to build a three-dimensional point cloud. The approach gathers many surface points without touching the workpiece, although hidden faces and obstructed recesses still require a change of viewing angle or an alternative measurement method.
LK specifies acquisition of up to 420,000 points per second across the scanner’s full field of view, using a laser stripe approximately 110 mm wide. A reduced field of view permits a maximum quoted rate of 530,000 points per second. Those are different operating modes; the higher point rate is not available across the full scan width at the same time. The listed 42 µm point resolution describes sampling, not the new 10 µm form error.
Optical exposure control is important when a single part combines reflective and darker surfaces. LK’s fourth-generation Enhanced Sensor Performance system adjusts laser output for individual measured points in response to the reflected signal, while a reflection filter suppresses unwanted returns from shiny areas. The scanner also uses dedicated Nikon optics and a projected field-of-view guide for scan path setup. These capabilities already formed part of the L100NX platform before the current accuracy revision.
When inspecting machined castings, formed panels or complex aerospace surfaces, a dense point cloud can expose local shape variation between the limited features selected for a conventional contact probing routine. That benefit depends on suitable coverage, calibration and alignment. Critical bores, sharp edges or deeply recessed features can still need tactile probes, alternate scanner positions or independent confirmation when the required uncertainty is tighter than an optical scan supports.
LK’s Focus Inspection software processes captured point clouds for alignment with computer-aided design geometry, surface comparisons, sectional analysis and measurement reports. Feature extraction and geometric tolerancing depend on the software’s fitting and datum choices, as well as the captured data. Better scanner specifications cannot compensate for an incorrect datum system or a programme that misses a relevant part feature.
The stated reductions in form error and dispersion could reduce the sensor’s contribution to measurement uncertainty when profiles are fitted or features extracted. Overall uncertainty also includes the measuring machine’s motion performance, fixture stability, thermal conditions, part reflectivity and the adopted scanning strategy. LK has not published a quantified improvement in complete inspection cycle time attributable solely to the revised accuracy values.
The L100NX is supplied with LK’s measuring machines and can be considered for retrofit onto compatible equipment from other manufacturers. Adding an optical sensor to an existing CMM can extend the range of surface measurements obtained without replacing the whole installation, but mechanical mounting, control compatibility, software integration and qualification must be established before a production inspection programme is transferred.
Kristof Peeters, LK Metrology’s product manager for laser scanning, said the revised accuracy specification was intended to give customers greater confidence in measurement data. The change gives users three more precise published comparison points against the earlier values, while the existing scan rates and field-of-view arrangements remain separately specified. Customers assessing a particular tolerance must still qualify the complete CMM and sensor combination under the intended inspection conditions.
