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During the last 25 years or so, the use of computer aided design (CAD) and computer aided manufacture (CAM) have revolutionised the way product design and manufacture takes place. All designing used to take place on a drawing board and all making was limited to mainly manually operated machine tools.

From 2D and 3D drawings parts can be drawn and specified, rotated and tumbled, detail added and operation and use simulated on screen long before the part is made. This uses powerful 3D maths programming language that allows designers to create 3D wire frame and parametric drawings. 3D visualisation helps the designers and engineers agree more readily and optimise design.  On screen modelling saves time creating models and prototypes too. Testing virtual parts is far less costly or time consuming. Loads and stresses in parts can be plotted using finite element analysis (FEA).

CAD derived drawings can be rapidly interpreted across multinational and global business and parts made from them worldwide.  Sending working files between design studio and a factory takes a few seconds. This utilises data exchange formats (DXF).

Importantly CAD can also be used to plan and simulate process and production too so that each stage of manufacture planned and evaluated more easily. This is often part of a more integrated approach to manufacturing called; computer integrated manufacture (CIM).

Using a CIM approach helps manufacturers store designs and interact with  data, production records, metrology data, production rates, stock levels, wastage and calculate the unit cost too! Such systems rely heavily on data acquisition systems (DAS).

Drawings convert into surface paths for parts that are then more easily calculated as tool paths for computer numerically controlled (CNC) machine tools. Tool changes and routines can be calculated and simulated and production time estimated. When tools are moving and not cutting that is wasted production time, so computer software is used to minimise ‘air time’ for tools.
On machine tools all the motors, encoders and limit switches are linked to the computer to continually update the software of the tool and workpiece positions.  The computer can even calculate and compensate for tool wear and vibration to optimise the process. Tool path and movements are specified using G and M codes (and other codes too). These are often generic defined movements or operations. The international standard for CNC codes is ISO 6983.