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Metal Casting Technologies : March 2007
www.metals.rala.com.au 14 TECHNICAL FEATURE Cad and Cam -- keep them together T By Steve Thomas, CIM Solutions he only thing that will never change is change itself. This has never been so true than in the manufacturing industry. The technology of manufacture has become so advanced that process's that used to take weeks can now be done in hours and components that used to need 2, 3 or sometimes more machine tools to complete them are now fully machined from start to finish on a single machine with only one setup required. Cad/Cam software has also had a significant effect on the casting and foundry industries although not all of it has been positive. Thanks to complex modelers, design engineers can now present ever more complex shapes to the tool and patternmakers to produce. However the very same software can be used to solve these problems almost as easily. It has become clear that the existing model of using separate cad and cam products from separate suppliers and expecting them to work together "seamlessly" together causes numerous technical and operational problems. Integration is the only way forward. Obviously a completely integrated package from one developer means that the part (design), the tool, the drawings and the machining are all linked to each other, all of the time, so changes and improvements are handled automatically. And of course you only need to learn how to use one package not 2 or 3 separate ones. Moreover, in 5-axis work it is essential to have every aspect of the machine tool and work holding environment accurately modeled if you are to avoid collisions and of course in a true 3D modeler this is a relatively simple process and once again as the user is in a single integrated environment these items are visible at all times and the system can warn the user of any impending problems. The benefits of integration are reflected in the bottom line. For instance, using the latest integrated cad/cam software 5- axis machine tool users can reduce or eliminate the use of long cutting tools. A major feature to look out for is the capability to automatically convert 3-axis toolpaths into 5-axis toolpaths. This makes the whole process of working in 5-axis extremely simple because the software will calculate how far over it can tilt the spindle without causing a collision. This means faster cutting speeds, less tool wear and better surface finish resulting in minimal polishing times. Using this technology reports indicate a reduction from a required tool length of 105mm being reduced to 35mm. If you currently do not have 5-axis machines then look for the ability to automatically split a tool path dependent on tool length. This will allow you to use more suitable machining methods for the longer tools. Constant 3D stock monitoring is essential if you want to minimize "air cutting". The appropriate software always knows exactly what the stock looks like and so makes intelligent decisions when roughing and finishing ensuring that it only cuts where its needed. Finally consider the quality of the support you can expect after the sale. Sad to say that in far too many cases CAM support is done by CAD specialists most of whom have never set foot on a shop floor let alone operated or programmed any form of CNC machine tool. ● Steve has been in the manufacturing industry for over 30 years and almost all of that time he has been involved with CNC machining and Cad/Cam software. He now runs CIM Solutions a cad/cam company with an emphasis on integration of cad and cam for manufacturing companies. Contact Phone (02) 8824 9095 or 0417 175 928 www.cimsolutions.com.au.