Hypercar Engine Oil Pump

Overview

We were asked by Sarginsons Industries, an aluminium foundry, to find a machining solution for a challenging casting for the brand new engine of a £3m supercar. The complexity and fine tolerances of this component demanded several innovative approaches, in both casting and CNC machining, made more difficult by an extremely tight time frame.

Requirement

The component was an extremely compact oil pump, whose size dictated the need for very involved, tight curves and complex cooling fins, but whose power output dictated the need for top end performance. There was no room for any error as the tolerances usual for Hypercar performance were testing to say the least. 

Initial Challenges Faced

The problem was controlling the petrol flow through very tight and complex internal cavities which could not be accessed courtesy of the cooling fins and tight turns. The machining challenge included the problem of swarf being trapped internally which, potentially, was dangerous as well as damaging to the engine and component. 

Exacerbating this problem were the abrasiveness of the component, which demanded very high end and original tooling solutions, and the unusual datum specifics on both operations.

Specific Challenges Faced

Traditional tooling could not be used on this component as access was extremely difficult. The need to upgrade traditional tooling from HSS to carbide. The use of self centering holders was needed to keep within tolerance.

Traditional CAD software was not sufficient for 5 axis simultaneous machining. 

Traditional coolant lent itself to foaming because of the very high machining speeds required. 

The interior of pump could trap swarf and particulates waste which could only be detected by X-Ray analysis and, once detected, could not be removed. The challenge was to find a machining methodology that was 100% guaranteed to be contaminant free with difficult access thanks to tight dimensions and datum indications that were very specific. 

Being a high performance engine the operating pressures and temperatures were well above the standard and necessitated pressure testing of an unusually high standard. 

Solutions Presented

Finding the correct tooling demanded visits by a number of suppliers before the appropriate tooling could be found. Specific abrasive resistant coated tipped tooling made to our design was the only way of developing suitable tools. 

A change in machine coolant was made to an aerospace specification which uses as less percentage of oil and reduces foaming under the extreme conditions we used for this part. A fine particle liquid skimming machine was purchased and used to remove all fine particles from the coolant to avoid any chance of particulate entrapment. The component apertures were plugged with made to measure rubber stops. 

Fixturing was designed around the future manufacturing of this component ensuring easy placement and removal, whilst negating the distortion and twist that occurred introduced whilst the casting cooled. We were able to use Sarginsons Digital Twin YTE Simulation software to predict this distortion which helped design fixturing that could correct such. 

We developed a new pressure testing station was developed for ease of use following Poke Yoke principles so nothing would be overlooked. 

Conclusion 

Due to time constraints, this was a quick turn around project involving prototype supply before moving to production, Whilst many challenges were faced in respect of time, resource, material supply & tooling supply this project was successful because we were open minded and capable of challenging industry standards and assumptions. We learnt the huge importance of tooling in finding solutions and the massive choice and options that are available; great tooling not only makes the impossible possible, it makes a huge difference to cost as well. 

Machine used

Mazak CV5 500

The Mazal CV5 500 is a high-performance (simultaneous) 5-axis machining centre equipped with a powerful, oil-cooled and directly-driven BT40 spindle, a 500mm diameter direct-drive rotary tilting table with a 1000kg maximum table load, a servo-driven ATC, roller LM guideways and integrated thermal compensation.

The machine supplied to NuMachine was also equipped with the Smooth mazak control, as well as a 15,000rpm spindle and a touch spindle probe and 3D tool probe package.