QUALITY & INSPECTION


century. It will be manufactured from start to finish under one roof at the company’s workshop near Heathfield, East Sussex.


Close association Charles Frodsham has a longstanding business relationship with Microtec. The subcontractor regularly wire-erodes gold watch cases and produces springs for the clockmaker, which in turn carries out micro-scale turning, milling and drilling that is beyond the capabilities of Microtec’s production equipment.


A smaller Nikon Metrology CNC video measuring machine has been in use at Charles Frodsham’s Hastings workshop for about five years. Mr Whyte recommended this make of instrument to Microtec due to its reliability and precision, as well as the strength of after-sales support. Mr Cranfield benchmarked other


potential suppliers’ equipment but could not see a better option. In the process, he discovered that some other makes of machine on the market for video metrology actually incorporate Nikon’s apochromatic lens, which has better correction of chromatic and spherical aberration than conventional achromatic lenses. It helped him to come to the conclusion that the Nikon Metrology offering was optimal.


Multiple target markets led by aerospace Aerospace and defence contracts are the mainstay of Microtec’s business, Rolls-Royce, BAE Systems, Selex Galileo and Astrium being regular clients. It is the principal reason for Microtec seeking AS9100 accreditation, a process that will be assisted by the purchase of the Nikon Metrology iNEXIV machine. It will be especially important for speeding production of first article inspection reports. The Nikon Metrology VMA AutoMeasure software automatically compares measured results against CAD models and allows such reports to be produced quickly and in standardised format. Motorsport, closely related


technologically with aerospace, is becoming an increasingly important target market for the subcontractor. Medical and dental industry work, which is often defined by complex machining in difficult materials, is another specialism. A current contract involves producing very small tweezers with serrations that are eroded with 20 µm wire, five times thinner than an average human hair. Another medical job requires a plastic filter mould to be produced with 0.25 mm ribs. Mould and tool manufacture in the 1990s accounted for 80 per cent of Microtec’s turnover, dropping to 20 per cent in subsequent years as China absorbed much of the business. Recently, however, the percentage is increasing as mouldmaking is reshored due to an increase in the cost of production overseas as well as problems with quality and logistics.


Projects are also carried out


in other industries, such as for premium vehicles including Mercedes and for top-end hifi equipment manufacturer, Rega Research, Southend, for which Microtec manufactures parts for a moving coil cartridge. Production continues 24/7 at


SHEET METAL


A molybdenum grid for an electron beam gun is inspected on the iNEXIV VMA-4540.


the Basildon factory in a range of materials from aluminium, copper and steel to titanium and exotic alloys. Eight Agie Charmlles EDM machines provide a majority of manufacturing capacity, assisted by Hurco vertical machining centres, a Ghiringhelli centerless grinder and various manual machine tools.


Non-contact


2D and 3D measuring Most wire-cut EDM work requires 2D inspection, for which video measuring is ideal. However, some spark eroded components need


to be measured in 3D and one of the advantages of iNEXIV video inspection is the ability to measure heights using the instrument’s generous 73.5 mm working distance. Inspection in 3D extends to mouldmaking. Early in January 2015, Microtec was tasked with refurbishing a plastic injection mould for producing electrical plug sockets for the British manufacturer, MK. No drawings or CAD model were available, so the mould’s broken upstands were remanufactured in tool steel by measuring the height and width of the relevant sections


Close-up of the wire-eroded, molybdenum grid for an electron beam gun on the table of the iNEXIV. www.internationalmetaltube.com


IMT June 2015 35


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