**5. CAM systems (Computer Aided Manufacturing)**

In the milling of complex forms, due to complexity of the paths of tool, the generation of the programs for CNC machines should be deeds with aid of software, the CAM (Computer Aided Manufacturing). Although the acronym CAM expresses a generic system for support a chain of manufacture, the term CAM is commonly employed for the generation of programs for CNC machines.

The CAM calculates the paths of the tool for carry out milling, besides simulating the movement of the machine for certification, and generates the CNC programs for the manufacturing of the piece.

At present, the biggest application of CAM software is for the programming of machining by milling, in special 3 to 5 simultaneous axes. CAM software can also generates CNC commands for EDM machines, lathes, and laser or water pressure cutting machines, among other applications carried out by equipment controlled by a CNC.

The CAM systems can be independent software that works in assembly with any application CAD, in general 3D, needing this, the importing of geometries in formatstandard, such as, IGES, STL, VDA-FS, etc.

A CAM system can be used to develop three main activities: i) calculate the tool paths for the machining the CNC machine; ii) carry out the simulation of the machining calculated;

Advanced Free Form Manufacturing by Computer Aided Systems – Cax 567

after roughing Tool path for

semi-finishing

Fig. 10. A methodology to define the block of raw material for the semi-finishing

Raw material

than the tools utilized in roughing.

**5.3 Programming finishing operations** 

Fig. 11. Finishing depth of cut

finishing. The main principles are:

previous operations and finalize the operations of milling.

The tool parameter of geometrical cut itself maintains the same concept.

Therefore, in the corners relief operation should be employ tools with diameters smaller

The more modern CAM software presents a tool for identifying these regions automatically. The algorithm identifies the corners of the geometry of the piece where it has a radius less than the ray of the tool of thins. In the finishing of this algorithm the software requests the information of the diameter of the tool that was employed in roughing, identifies the areas and calculates the machine paths of these regions, employing a tool of smaller diameter.

This is an operation of three-dimensional milling, utilizing 3, 4, or 5 free axes, according to arrangement of the machine-tool. This operation is going to remove all excess material of the

In the finish, the axial cut depth parameter passes the tolerance value and depending on the position of the tool-piece, this depth will not be necessarily axial, as illustrated the Figure 11.

The CAM systems present offer different algorithms to calculate machine paths for

a. **Parallel passes horizontally constant.** Probably this is one of the first algorithms for finish path calculation to be developed, and is widely employed. Known as

iii) generate programs for specific CNC machines. Doubtless the first function is more important and can represent the main difference between the diverse CAM systems available in the present market.

The operations of milling, focusing on the making of complex forms, can be classified as: roughing, semi-finishing, relief of corners and finishing. For each one of these operations exist different techniques and peculiarities of programming with CAM.
