The starting point of a screw machine design is usually to generate a suitable profile for its rotors, since this is one of the major factors governing its efficient operation. Preliminary performance is then determined based on the assumption of one-dimensional heat and fluid flow within the machine. The rotor profile and other geometric characteristics of a machine are then optimised to meet customer requirements, while several alternative configurations are explored. Detailed design of the compressor components is then performed for a finally selected and optimised design by use of a CAD package.  Depending on the manufacturing methods available, forming tools then have to be designed for producing the rotors. Finally, the design can be verified and its performance determined more accurately by the use of Computational Continuum Mechanics (CCM) to estimate full three-dimensional heat and fluid flow and fluid–solid interaction within the compressor.  A number of factors have, however, inhibited the adoption of this procedure, which, if it is to be carried out rapidly and reliably, requires interoperability among the digital tools used.

The Design Integration for Screw COmpressors – DISCO software integrates the screw machine design components in a user friendly environment suitable for industrial use. It manages both geometric and non geometric information transfer between the software components used. These are related to the heat and fluid flow, optimisation parameters, boundary conditions and operational parameters that are organised so that the function, behaviour and structure interoperation is embedded in the code. The interface basically consists of five modules named SCORPATH, SCORG, SCOCAD, SCOCFD and SCONOISE. The organisational scheme of DISCO is given in the following figure. The interface is written in Visual basic suitable for any Windows based operating system. Other in-house components such as SCORPATH and SCORG are written in Fortran and are available for most operating systems including UNIX and LINUX. CAD systems are also available for all operating systems while CCM software typically runs on UNIX and LINUX machines but is in some cases available for Windows as well. The interface requires only shared input parameters to describe the geometric and operating conditions of a screw machine. It allows full control over each step of the design process, providing that all changes in the final model are communicated back to the previous design phases and vice versa. The emphasis is therefore on the central parametric control and the reduction in number of data.

This relaxes the computer resource requirements, as well as reducing the required time to conduct the full mechanical design of screw machines, when compared to traditional design processes.

SCORPATH generates rotor profiles by the use of curves given for one rotor being applied to the other or from a common rack using the envelope gearing method. The result is given in the form of 2-D output coordinates later used by the CAD system to generate the 3-D geometry. Additionally, SCORPATH utilises the forces on the compressor rotors, derived from thermodynamic calculations, for the further mechanical design of the machine. The results are stored as standard ASCII files.
In addition, SCORPATH also calculates the tool profile stored as an ASCII file with coordinate points. This is used later as a basis for Computer Aided Manufacturing.

SCOCAD organises output data from SCORPATH into a standardised database, with unique structure for all screw machine designs available, to be implemented to an arbitrary CAD system. These data are provided as the coordinate points for rotors, ports and the manufacturing tool. Since these are automatically transferred to the CAD system, the 3D solid model can be built in a short time. Additionally, parametric organisation of the data interchange through the external data base enables the design to be easily modified not only from the CAD system itself but also from both the external database and the SCOCAD environment. Being incorporated in DISCO, SCOCAD then enables the design changes to be introduced to other applications also integrated in DISCO. In addition, it permits the calculation and/or the selection of the machine elements from a database independent of the CAD system. The 3-D solid model obtained from the CAD system serves as a basis for rapid prototyping, while drawings are automatically provided to support more conventional manufacturing methods.

SCORG prepares a numerical mesh of the domains in the vicinity of the rotors for 3-D flow and structure analysis. This is done by integrating the data of rotor and rack profiles from the SCORPATH input. At the same time, SCOCCM uses the integration of CAD and CCM software to generate polyhedral numerical meshes of the stationary parts of the numerical mesh. It then integrates the compressor geometry and working parameters generated by the SCORG and CAD systems with the commercial CCM, software. The computational grid of the screw compressor rotors generated by SCORG and the numerical grid of other parts of the compressor, including the suction or the discharge chambers, which may be generated from either the SCORG or the CAD system, are imported into the CCM software through the pre-processor script file. That file also contains working parameters, information of the differencing scheme and other required solver information. Finally, the results obtained from the CCM calculations are evaluated so that the design of the machine can be reviewed and changed if required.