CNC and Waterjet

Dr. Ruff (MANE)- CNC Machining and Waterjet Cutting - September 18, 2015

            Dr. Ruff, of the Manufacturing Innovation Learning Lab at RPI, taught us a lot about the different methods of CNC machining they use in manufacturing at RPI. The main two methods he showed us were using a CNC mill with metal tools, and using a water jet with garnet as an abrasive to cut different materials. These processes used in manufacturing contribute to the entire process described by Mr. Chiappone last week.

            They first use a CAD program such as AutoCAD to design a drawing to be cut. They then import it into a CAM program such as MasterCAM to generate the code that the CNC machine requires to create the part. This method is used for both actual parts and molds for things like injection molding. After going through the CAM process, the code is sent to the CNC mill, where thousands of different tools can be used by the machine to mill the design into the part. Sometimes as a test, they use machinable wax to further verify the code is correct, beyond the virtual verification of the CAM software or the machine itself. Parts up to about 12”x18”x12” can be milled by the CNC mill they have. Water-soluble oil is used as a coolant to prevent excess heat from being created by the milling process. After the part is done being milled, it can be milled again on a different face, be protected with something like powder coating, or immediately be taken to be joined with something else to move along the manufacturing process.

            The process is similar with water jet cutting, but that process uses a completely different machine to move water with 50,000 psi through a tube to cut metal and other materials. The water is combined with an abrasive garnet in order to cut such strong, thick metals. The water also goes through a small hole in ruby in order to increase the velocity of the high pressure water. The water can move through the hole at as fast as mach 2. Unfortunately, the water jet cutter can only machine 2D parts, as the depth of the cut can’t really be varied as the cut is being made. (Size, thickness, materials used?)

            There are incredible benefits of being able to machine parts using code generated by a computer. Multiple parts can be made from the same template much faster, saving time and money. There are also fewer mistakes in the computerized milling process than with manual control. Making products faster with less liability increases production and drives prices down. The use of CNC machining is incredibly important in this day and age.