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Laser Scanning CMM Provides Increased Throughput

Contract inspection and reverse engineering capacity has doubled in terms of throughput, while the size of component that can be measured has increased more than five-fold at Laser Scanning Ltd, based in Chapeltown, near Sheffield, UK. It follows the installation of a second, larger coordinate measuring machine (CMM) from LK Metrology.

The latest LK 20.12.10 ceramic-bridge CMM with 2,000 x 1,200 x 1,000 mm working volume has joined a smaller 8.7.6 model. When Laser Scanning’s managing director Johnathan Rigby started the company in September 2016, he brought the original machine with him from his previous employer, PMS Diecasting. This firm now subcontracts much of its metrology requirement to Laser Scanning, both firms being members of the Glide Group.

As the inspection provider’s name implies, most data acquisition is by laser scanning on both of the LK CMMs as well as on two Nikon Metrology articulated arms CMMs. All of the equipment is housed in a temperature-controlled room held at 20 ± 1°C in the facility. Parts delivered for inspection are acclimatized in for 24 hours to reduce measurement uncertainty.

Three types of non-contact sensor from Nikon Metrology are in use on the CMMs: an XC65D cross scanner and line scanner models L100 and LC15Dx with measuring accuracies of 13.0, 6.5 and 1.8 µm . The latter provides performance equivalent to tactile probing, which is also utilized for capturing physical dimensions, such as hole diameters, using Renishaw’s TP20 touch probe and SP25 scanning probe. A changing rack mounted on the CMM table allows automatic sensor exchange within an inspection cycle.

The larger CMM purchase was prompted by a new contract from JCB Power Systems to assist with the quality control of cylinder blocks and cylinder heads for the engines that power the OEM’s off-road vehicles. JCB has its own LK machine equipped with a touch probe that serves its production line. Laser Scanning Ltd also assists by providing measurement and inspection of goods-in to the plant, where it has a QC engineer permanently stationed.

Additionally, Laser Scanning Ltd helps prepares new CMM programs, as well as inspecting prototypes to support JCB’s research and development department. The service provider is able to furnish much more comprehensive and accurate information about a new component than is possible using touch probing techniques at JCB Power Systems.

Although the engine plant does have laser scanning capability on an articulated arm, the level of detail that can be acquired is less, as its scanning resolution is 23 µm, much lower than the CMM-mounted scanner in use at Laser Scanning Ltd. Inspection using an arm would also be a manual process and almost impossible to replicate on subsequent occasions, whereas running a program on the CMM is automated and highly repeatable.

Mr Rigby explained, “By working with JCB’s Inspection department and R&D team, we have been able to free up our customer’s machine to concentrate on production QC. They also appreciate the greater detail we are able to provide about new prototypes, as laser scanning allows us to show them the form of a component as well as supply measurement data. For example, they recently asked us to help them with a new rocker cover housing that had been plastic injection moulded to determine whether the gasket area was within tolerance after shrinkage in the manufacturing process.”

“Inspecting a planar surface such as the gasket area by touch probing at multiple points would not give an overall idea of its flatness and in all probability if the exercise were repeated the results would be different. In contrast, scanning generates millions of points to give a detailed 3D picture of the entire surface to a very high level of precision and the deviations can be quantified. It enables JCB to show its mould tool supplier exactly where any inaccuracies are.”

Source: Metrology News