1. Eric Berlin Jason Sarkozi Brandon Tsuge Matthew Woo 05/14/10

2.  Introduction  Steps for CNC  Computer Modeling and Programming  Machine Preparation  Machining  Finish Product  Conclusion Bridgeport CNC Machine

3.  A CNC machine is a computer numerically controlled machine  It is used to mill and drill work pieces in need of tight tolerances.  The CNC used was a Bridgeport made in 1995 with 3 axes. Calibration and tool changing needed to be done manually. Current machines utilize up to 5 axes with automatic tool changers.

4. Sample Solidworks Model Sample Featurecam Model Parts are first modeled in a CAD program like Solidworks Models can then be imported into a CAM program, where various parameters and tools are chosen. A text file is exported and is then used by the CNC machine.

5. Tools for CNC Machine The tools are lined up neatly in a rack in the order they will be used in the CNC machine. Lubricant is used for the countersink drill bits to remove heat Safety goggles should be worn at all times during the CNC process

6. Alignment Process Setting the Z-Axis Process for Each Tool Use a vice and spacers to hold the part elevated Make sure that the sides of the part are parallel to the axis of the path Use a test indicator to run parallel with the part to test for any displacements on the probe Use a spring loaded edge finder to align the part with the tool. When the tip of the tool spins flush with the tool itself, then the edge of the part is at the center of the edge finder

7. A dial is used to make sure the distance from the tool to the part is two inches. Record the Z position offset of two inches to the memory Repeat the process for each tool used in the CNC process Dial Used to Accurately Line the Tool with the Part A lubricant and Air Tube is Used to Cool the Part Lubricant is used to lubricate and remove the heat from the part If no lubricant is used, you can lose the temper of the tool meaning that the tool will become softer

8. Center Hole Milled OutAll Holes Drilled and Tapped or Countersinked Holes are spot drilled, the drilled then finished with a tap or countersink. The center hole is milled out. During the process the air pump continuously blows away debris.

10. Cleaned, Finished Product  The part is removed from the milling machine  The burrs are removed with either a “deburring tool” or a hand file  The part is rinsed off with water and simple green to remove any metal chips that may be hanging on to the part  The end result is a clean, finished product

11.  Standard CNC machines generally can machine accurately to.001 -.0005 in.  Cutting speeds depend on many factors (material being machined, lubricants being used, type of cutting tool, etc.) but are generally in the.003 -.012 in. chip per tooth range  Pros: relatively accurate, cheap and fast for mass production, high removal rates, programmable  Cons: set up time, initial capital outlay, expensive for prototyping