TPT November 2018

I NSPE C T I ON , T E S T I NG & QUA L I T Y CONT R OL

Computed tomography for quality control INDUSTRIAL lighting manufacturer Nordic Lights uses computed tomogra- phy (CT) to avoid the expense of de- structive testing and to eliminate critical measurement errors caused by powder spraying for part preparation.

have been possible with the white light system. Test engineer Carl-Anton Manns, who took part in the search for the new inspection system, explained, “The instrument needed to be able to analyse smooth reflective surfaces with high precision, which the XT H 225 ST does with repeatable accuracy. Being a non-destructive process was a big plus. “Verifying the tool that makes the prototype part at the beginning of a project avoids a lot of trouble later on. With Nikon CT, we can easily verify all dimensions and check for defects without having to destroy samples, which is important so they can be preserved for other inspection tests. There are also important savings in time and money by avoiding sample preparation such as painting or cutting.” A major factor in the decision-making process was the open tube source of the Nikon machine, which allows straightforward maintenance and results in lower costs and downtime. The availability of rapid and comprehensive service from Nikon support engineers was also a critical factor. A further advantage of the CT system is that it can provide precise results for dimensions and tolerances that Nordic Lights customers demand for optical parts, lenses, light guides and reflectors. During the development phase, defects can be identified, traced and eliminated before parts pass to production. Similarly, samples from suppliers, new parts or new moulds can be compared to their CAD models before assembly.

The Finnish company manufactures lights for the workplace and for heavy- duty vehicles deployed in extreme con- ditions. Its products are used throughout the mining, construction, forestry, mate- rial handling and agricultural industries. Lighting assemblies are typically made from aluminium, steel, plastic and glass, and their components are manufactured by a range of processes including die-casting, injection moulding and machining. Products are subject to rigorous testing and rely on inspection methods for quality assurance. Tests include lumen output and light distribution, resistance to chemicals, vibration, shock, dust, humidity, heat and cold, thermal cycling, thermal protection, electromagnetic compatibility, functionality and usability, and performance under abnormal conditions. Many components incorporate ribs, pins and cylindrical holes that Nordic Lights previously inspected using a white light system. However, scanning components with narrow or tight features is difficult when the details are too deep for the light to detect. Another problem with this inspection solution was that, to avoid unwanted reflections, smooth surfaces had to be painted or powder sprayed. This introduced measurement errors on critical surfaces where precise tolerances were required, slowing the whole process. Furthermore, as the white light system was only capable of line-of-sight external surface inspection, THE MarkStar Pro is a handheld fibre laser marking system designed for portability in the field or warehouse, operating off a low-voltage power source. It can be used for any application where bringing the parts to the marking/ engraving station is not possible or uneconomical. The system has been used on conveyer lines for marking IDs on large assemblies, and service marks on aircraft, marine vehicles and

internal defects were neglected. To gain a comprehensive picture of the inside, samples and products were subject to expensive and time-consuming destructive testing. A new measurement solution was required that could deal efficiently with a variety of materials as well as both internal and external feature inspection. The company consulted various sup- pliers to determine the best solution. A Nikon CT machine, XT H 225 ST, with dual reflection and transmission targets has since been installed at Nordic Lights to inspect and approve components before assembly. The primary purpose of the CT system is to validate samples from suppliers, new parts and modified parts from new moulds. A secondary purpose is troubleshooting. During the test phase, if there are any failures, complete assemblies can be scanned to identify the cause without having to open or destroy the product. The system has, for example, been used to search for air pockets or voids in the silicone glue between the aluminium housing and the lens of a light that has suffered water leakage. This would not Dimensional inspection of a connector, including areas with no or limited line-of-sight components, missiles and bomb shells, pressure vessels and nuclear plants. It is effective in oil and gas applications to ‘stamp’ un-erasable marks of weld quality, high-pressure test results, service dates and records. The standard configuration of the laser marking machine allows for many different options. The versatile unit can be moved easily for convenient operation from any location and is

Nikon Metrology NV – Belgium Website: www.nikonmetrology.com Portable handheld laser marking system

capable of marking materials ranging in size from minuscule to considerably large equipment that would not fit into traditional marking systems. Additional features include ease of installation, allowing for quick start-up, and graphic- based programming. Laser Photonics – USA Email: fiber@laserphotonics.com Website: www.laserphotonics.com

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NOVEMBER 2018