Undercut Solution Maximises Tool Life and Productivity for Metaltech

Smooth progress using reliable processes is critical to efficient manufacturing.  At Hailsham-based Metaltech Precision Engineers Ltd, the application of Horn 314 special inserts to machine the bore face and undercut in a range of stainless steel pump rotor cases has significantly enhanced the process through reduced cycle time, greatly extended tool edge life and improved surface quality.

Metaltech is a highly successful supplier of major components to leading stainless steel pump manufacturers, working with both billet and precision castings. The products are high value added precision items often required at short notice and vary considerably in size.  A common feature of the rotor bodies is the need for an undercut which ‘separates’ the wall from the flat base.

Richard Page, Metaltech’s production engineering manager explains.  “We have been producing this feature for some years using custom-built tooling which relied on a non-standard insert.  Increases in customer demand/production volume to around 250 parts per month highlighted shortcomings in that method.  Tool life was poor – at around one undercut per cutting edge - and we were losing time on tip indexing and re-setting.  In addition there were issues with insert supply.  Essentially we were coping, whereas we needed a solution that could provide a reliable response to changes in demand.”

Horn Cutting Tools has an established history of providing tooling solutions for Metaltech and it was Horn that the company turned to in this instance.  The solution uses a mix of standard and special Type 380 holders, enabling through coolant supply directly to the cutting edge. Type 314 milling inserts, which have the latest AS45 coating, finish all the faces on the component and produce the required industry standard undercut. 

Trials conducted at Metaltech demonstrated that the Horn tool was capable of running faster than the previous tool package. It is also capable of machining up to eight rotor bodies per edge consistently whereas the original tooling had to be indexed or exchanged after one or two components. In addition the Horn tool supplies a burr-free undercut so the part is finished as it comes off the machine.

Chris Smith, Horn Applications Engineer added, “The tool not only produces an undercut but also finishes the top face and bore face; both of these require a surface finish of less than 0.8 µm Ra. During the trials we were able to make significant improvements to the insert geometry to further enhance the level of the surface finish whilst continually reducing the cycle time. We can now consistently achieve between 0.3 to 0.4 µm Ra.”

Mr Page commented.  ‘The aims of the exercise had nothing to do with reducing costs but in the end the Horn insert cost is around a third of the previous tooling.  However the big gain for us is in the reliability of the process and the increase in the number of cases that can be machined per cutting edge, which saves us a lot of time.  The task is ‘bread and butter’ work in that every rotor case we produce has that feature so ideally we need to have complete confidence in the process – which we now do. We’re also very confident about reliability of insert supply from Horn”

He concluded.  “Ultimately the project has brought us more benefits than we expected and demonstrates how much the performance of modern tooling technology has progressed compared with what was available only a few years ago.”

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