New case story: Pressings subcontractor replaces two CMMs with one Nikon VMA-4540
November 8, 2016
Optical inspection time halved and touch probing cycles cut 15-fold
Second-tier supplier of light pressings and small assemblies to the automotive industry, Berck Limited, has invested in a Nikon Metrology iNEXIV VMA-4540 CNC video measuring machine fitted with tactile probing capability. Installed at the subcontractor’s factory in West Bromwich, UK, the multi-sensor machine has greatly speeded the inspection of 2D and 3D sheet metal components, improved measuring accuracy, and facilitated the production of detailed quality reports for customers. It also allows manufacturing processes to be optimised by providing detailed historical measurement data to be compared with current inspection results.
Two-thirds of Berck’s output goes to the vehicle manufacturing industry in the UK and overseas, of which 40 per cent is bracketry for the engine compartment or wiring loom and the remainder comprises precision contacts for lights, windows, seats and other electrical equipment. The other third of production is delivered to customers manufacturing domestic electrical goods such as cookers, lighting and plugs. Components are stamped using up to 12-stage progression tools on 23 presses, including 12 high-speed models, mainly from coil between 10 and 150 mm wide, 0.1 to 3.5 mm thick. Materials encompass brass including tin-plated varieties, mild and spring steel, copper, beryllium copper, phosphor bronze and aluminium.
Inspection of one of Berck’s single-impression press tools using a star stylus in the Renishaw TP20 probe, which is offset from the optical axis but operates in the same XYZ coordinate system.
The subcontractor has for many years used a Mitutoyo Quick Vision Ace CNC optical coordinate measuring machine (CMM) and a Kemco manual touch-probe CMM to inspect sheet metal parts and tools. The former machine is nearing the end of its useful life, while the latter was recently dismantled as it was beyond economical repair. Last year (2015), realising that a new metrology solution would soon be required, Berck’s quality manager Steve Bettridge visited the Advanced Manufacturing Show at the National Exhibition Centre, Birmingham, to investigate what alternatives were available.
After discarding the idea of combined touch probing and laser scanning on a CMM, as that level of accuracy was not needed for pressed parts and the cost was too high, Mr Bettridge looked at various alternative video measuring machines and decided in favour of the Nikon Metrology iNEXIV. The machine had a larger stage than others on offer, so promised greater versatility use, the company’s proprietary software was considered easy to use, and the quality of the Nikon camera and objective lens was beyond question. It is noteworthy that, although laser technology has not been adopted, there is the option to fit laser autofocus if the need arises.
Since it was installed in April 2016, the iNEXIV has been a resounding success. Optical measuring routines are programmed conversationally in half the time required using G-code for the Quick Vision Ace. The stage on the Nikon instrument, with its 450 mm x 400 mm working area, is four times the size and the axis movements are considerably faster, so more components can be inspected in a shorter time.
iNEXIV EDF software allows 3D images of products to be created by stitching together multiple pictures taken at different Z-axis heights. Measurements can then be taken for investigation, problem-solving and archiving.
With the Nikon Metrology AutoMeasure software, it is easy to create programs and automatically compare results against CAD models. Deviation of contours can be checked by overlaying digital charts from 2D CAD data onto video images.
The software is surprisingly easy to pick up, provided that you have a basic knowledge of the principles of metrology. It is also reassuring that Nikon offers software updates for a minimum of 15 years, so our new inspection facility is future-proof.” – Mr. Bettridge, Quality Manager at Berck Ltd.
The Nikon full-frame colour camera captures highly detailed pictures that are saved to the server at West Bromwich to provide a reference for future process analyses and troubleshooting. They may also be embedded in customer inspection reports produced by the software. Files of accompanying statistical data are downloaded automatically to an Excel spreadsheet, saving time compared with the previous manual procedure. Many other standardised reporting formats are possible.