Mollart completes first batch of complex parts for French defence industry

Completed at the company's Resolven, Wales site, so complex were two key parts in the contract - a thin wall housing and a mounting plate - both were machined in three operations out of solid billets of 6082 aluminium on Mollart's Mazak Integrex machines, involving cycle times of 3 and 2.5 hours respectively. Said director Wayne Thomas: "There was considerable development work to produce prototype parts, due to the final use of these components, and this involved a lot of co-operation with the customer. But, due to the flexibility of the Integrex, we were able to incorporate changes as they progressed with their development programme. Then, with the ability to combine so many different features into each cycle once our production started, machining times were less than half had we used more conventional methods." And he added: "Being able to combine so many different features into the machining cycles, we were also able to maintain relationships and geometric tolerance requirements between the different features." These involved tolerances of 0.02 mm on certain sizes, 0.05 mm TIR on concentricity, high orders of flatness plus surface finish requirements of 0.4 Ra. The housing component involved removing more than 90% of the original billet material. Added to the complexity were the very thin wall thicknesses (8 mm nominal), with interruptions that involved milled reliefs and cut-outs in the main bore. According to Mr Thomas: "These features demanded considerable respect in planning the machining strategy to prevent distortion." Within the machining cycle, in addition to turning and boring, multiple features required milling, pocketing and recessing plus drilling, together with counterboring and tapping of holes in both the front and back faces, and the previously milled features. Holes on the outside diameter also had to be drilled and tapped. The mounting plate was produced in three operations from a solid billet, with a high ratio of pocket milling involving different features set inside other features. Drilling and tapping and reaming of a multitude of holes in both faces was required, as well as in the outside diameter. This involved added problems of access to the part due to the workholding on the machine. Following machining, all parts were cleaned to a high standard, using the recently installed ultrasonic facility and 10 micron clean room facilities recently installed at Resolven for its semiconductor production contracts. Image: 15 initial prototype kits included two key components, produced at the Mollart Resolven facility in South WalesM/b>