Wire Erosion – Impeller Splining

Project Name: Wire Erosion – Impeller Splining

Industry Sector: Mining, Dredging etc (Slurry Collection)

Type of Work: Wire Erosion

Client Requirements:
A client approached Cheshire Wire Erosion wanting us to make some impellers with the splines. The challenge was that rather than one or two impellers they required large quantities of them and within a short time frame.

An impeller is the rotating part of a centrifugal pump. It forms a spirally shape with a bore in the middle which allows the shaft to be connected to the impeller and the angular rotary motion from the shaft can then be transferred to the impeller.

An impellers job is to change kinetic energy into pressure energy, so velocity is exchanged for pressure. Energy is transferred from the motor that works the pump to the fluid being pumped. The impeller increases the pressure and flow of the fluid. The negative pressure draws the fluid into the impeller and because it is rotating it is pushed out due to the centrifugal force from the impeller.

Inside each impeller are gear like teeth which create the impeller spline which the drive shaft fits into. To make the impellers with the splines this project involved impeller splining. Our clients required a critical surface finish.

Work Carried Out:
In order to complete this project, we used two of our “wire” machines, the AG 600L and the AG 600LH. These EDM machines feature rigid linear motors that maximise cutting, ensuring accuracy and precision engineering. For our clients this means we can meet their exacting specifications using the technology at our disposal.

To achieve the critical surface finish needed, 3 cuts were required. The initial cut removed the waste piece as can be seen in one of the photographs. As a result of the required fit between the male and female parts secondary and tertiary cuts were then made in order to improve the accuracy of both the cut and surface finish.

The same process can be repeated as many times as is needed by the machines that we use. With this project it meant that an impeller could be created numerous times so there was very good repeatability in size etc.

Our clients were very happy with the results and if in the future an impeller is needed again, the whole process can be redone easily and effectively.