Highly complex connectors for oil and gas exploration are now being processed at Mollart Engineering in Chessington. The components made of difficult to machine Inconel 625 Plus, a heat and chemical resisting alloy, from billets 100 mm diameter by 770 mm long involve more than 20 separate machining operations that also include special processes. Eight operations involve turn-milling and gundrilling on two of Mollart's seven Mazak Integrex e-500H-II turn-mill centres.
The Integrex machines incorporate Mollart's deep hole drilling expertise to gundrill a series of feed holes between 4 and 12 mm diameter through the length of the part or to various depth positions where they break into a series of six different connection ports that are machined around the outside periphery of the component.
Seven compound angle holes 2.4 and 4 mm diameter are also gundrilled from the outside diameter and then drilled and thread milled with sealing faces, chamfers, cones, undercuts, milled cut-outs and relief areas.
One turn-milling process involves the component being held in an offset fixture that enables a 70 mm diameter by 80 mm long area to be turned 5 mm off-centre. A series of slots are milled and grooves turned on the different centre line.
A further operation involves milling a large location face section in the centre of the component 120 mm long by 60 mm wide with drilled and tapped holes around its perimeter. Tolerances are as tight as 0.02 mm with bores held within 0.05 mm, sealing diameters and faces have to be within 0.8 µm CLA.
The numerous hole breakthroughs, internal features and grooves are automatically deburred during each turn-mill cycle. However, with the installation of its abrasive flow deburring and ultrasonic washing, Mollart is able to deburr and clean each hole, feature intersection and internal cavities to a consistently high standard.