Complex marine valve solution created by one-hit mill/turn cycles

An important turn-key project to produce special development marine valve blocks out of 316 stainless steel with a three micron final bore tolerance and a complex network of intersecting compound angle holes for oil feed has been completed by Rodmatic Hytek of Reading.

As Jonathan Imm production manager outlines: "We were able to combine eight operations into one single cycle on our Daewoo Puma MX 2000ST mill/turn centre and produce burr free components straight from the machine. Also as part of the turnkey we had to take responsibility for heat treatment and arrange micro finishing of the bore with a specialist contractor." The 70 mm by 70 mm by 100 mm valve blocks turned and milled from 150 mm diameter x 130 mm long billets of 316 stainless steel were solid modelled from a PDF drawing using EdgeCAM Part Modeller and programmed via EdgeCAM Solid Machinist. There were numerous cut outs to be milled in the 18 mm high tolerance bore, a host of compound oil feed holes that had to accurately intersect in order to maintain maximum oil flow and sharp edges had to be maintained on critical areas of the component. The whole operation had to be completely burr free.

Once proven, each part required 1 ½ hours machining time to complete. However, because it came from the mill/turn centre in one operation ready for heat treatment and final bore finishing, the tolerances and geometric relationships of the different features was easily maintained. The lead time for the batch, which was produced using mostly standard tooling, was also far shorter than could be achieved with normal multi-operational methods that would require extensive fixturing, work queues and inspection.

And as Jonathan Imm maintains: "Some features would have had to be jig-bored to achieve the relationship and geometrical positioning and that would have been a very expensive and drawn out process."