الفهرس 
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Abstract
Over the last 50 years CNC machine tools were programmed using G&M
code (ISO 6983). G & M code has several problems such as information loss
since it delivers only limited information to the CNC excluding valuable
information such as part geometry and the process plan used to generate the
NC code. G&M code (ISO 6983), also, lacks the interoperability between the
different controllers of CNC machines because its code schema depends on
the machine tool controller. The basis for development of the next generation
of CNC controllers is based on ISO 14649. This new standard is known as
STEP-NC, which is being developed worldwide to replace G&M codes.
Researches in STEP-NC are categorized based on the researcher’s main
focus in terms of manufacturing technology and processes such as; milling
processes, turning and turn-mill processes, EDM, process plan, etc. Limited
researchers studied the problems faced by the current CNC systems when
STEP-NC becomes widely available. The current CNC machine tools will be
widely affected because each machine tool is dependent on its own machine
tool controller. The research work documented in this thesis introduces a
conversion system with an aim to solve the problems faced by the current
CNC systems.
The converting system takes the STEP-NC file and converts it to the required
G-codes that are ready to be loaded to the targeted CNC controller. This
system consists of:-
• pre-processor module which reads the STEP-NC file and extracts the required information needed for the conversion process.
• tool-path generator module which calculates the approach and machining tool paths since STEP-NC files do not contain exact tool-paths needed for the cutter location in G&M codes file.
• execution module which generate the G&M codes file according to the targeted CNC controller using the extracted and calculated information from the previous modules.
In order to apply this methodology, user interface software has been developed using Microsoft Visual C# language that enables the user to convert automatically from STEP-NC file into G&M code file which saves time and effort. Several examples from ISO 14649-11 have been applied on the developed software as case studies. The generated G&M code file have been verified using graphical simulation software to examine the cutter movements and locations. The generated G&M code file showed correspondence between the two final shapes. This thesis consists of five chapters and two appendices. Each includes the following. Chapter 1: Introduction This chapter describes the evolution of CNC machines and its programming techniques showing limitations of the currently used technique (G&M code) and the emergence of the new technique (STEP-NC) showing its advantages. Chapter 2: Literature review This chapter covers a brief description of the most important researches related to STEP-NC and focusing on shortcomings that is concerned in this research. Chapter 3: Methodology of conversion
This chapter describes the conversion system showing its input and output
and the components of the converting system.
Chapter 4: Case studies
This chapter includes several examples from the standard ISO 14649-11
taken as case studies.
Chapter 5: Conclusion and future work
This chapter presents conclusion about the conversion system with
suggestion of possible future work.
Appendix A: Description of STEP-NC file
This appendix consists of description of the STEP-NC file according to ISO
14649-11.
Appendix B: STEP-NC Files
This appendix contains STEP-NC files which are taken as case studies.