Additive production denotes all production methods, in which the part to be produced is built up layer by layer out of a raw material, available as a powder or as a wire. Today the selective laser melting (SLM) is the main method on high-precision parts. Here metal powder is applied in typical 20–100 µm layers and then completely molten by means of a laser beam selective at those areas which shall become the component. With the solidification of those areas to a compact metal structure with the physical properties of the original material, and after removing the remaining, not molten metal powder at the end of the production process, the final component is built up.
One of the main features of all additive production methods is, that almost each inside contour or cavity can be produced without problems; and this by directly using given CAD-data. With this, there are no additional costs for patterns or special tools — the additive production method is the ideal method for batch size “1”.
Based on these parameters, a systems engineering for the design of multistage throttling cartridges used in Arca Ecotrol control valves was developed, which generates ready to use CAD-data directly out of the control valves sizing. These throttling cartridges can be conducted either with given (constant) number of single throttling stages, but also with a variable number of stages (as a function of the valve opening).
The design with variable number of throttling stages is suitable for applications, where there is a significant dependency between flow and differential pressure. This means at low flow (small valve opening) there is a high differential pressure across the control valve (with susceptibility for cavitation) whereas at full valve opening the pressure drop is quite small, requiring a rather high flow coefficient.
