Running a CNC machine relies heavily on assuring coolant flow to prevent thermal breakdown of tooling and the proper setup to assure that parts are cut correctly. Whether it is a mill or a lathe, these two basic concepts must be followed for accurate parts and maximum tool life. By following a few routines, you can cut parts with accuracy and speed.

CNC Mill

Set up the tooling for the machine. CNC mills are capable of using many tools for one specific job and these tools are kept in the tool turret. You must "teach" each tool so that the machine is aware of its location to accurately cut the raw material. Teaching the tool allows the machine to know where the tip is located to use the dimensions dictated in the program to cut the material accurately. You can enter a command on the main CNC computer that will automatically pull each tool from the turret and "teach" it with a probe, which measures the distance from the spindle head to the tip as tooling is never exactly one length and can vary depending on the holder used and the tool clearance needed for the part. Tram the vise or work-holding fixture to assure that the cuts are straight. Place a dial indicator on the spindle and run it along the front and sides of the vise to make sure it is perfectly straight. If the vise is off by even a small amount, the cuts will not be straight. Tighten the raw material in the vise securely. Using maximum hand pressure, close the vise or fixture so that it is held securely. Rough cuts can cause vibration, so the material must be in very tightly to keep it from coming loose during machining. Adjust coolant so that it hits the tips of each tool. The coolant acts as a cooling agent and lubricant for the cutting process. Keep the table and vise free of metal chips and debris. If you have metal chips under the raw material before cutting, you piece may be cut inaccurately. By diligently clearing and cleaning your work surfaces, you may prevent waste due to any raw material that may be sitting incorrectly in the fixture or vise.

CNC Lathe

Run the simulator to make sure that the tools do not encroach upon the spinning jaws. This will cause a crash and will pull your machine out of alignment. Preventing a crash is the best way to run a CNC lathe without incident. Check the coolant flow often. As the coolant evaporates, the flow becomes weaker and the stream may miss the tool tip, causing thermal breakdown and damage to the tool. If the next tool comes in and starts to cut and the previous tool has been damaged, the new tool may crash and cause damage to the tool holder or tool turret. Make sure the cycle is finished before attempting to open the CNC door. There are flying chips and coolant spray that may get in your eye or cause damage to the skin. It is best to watch the cycle carefully through the window of a CNC machine.

Resource:

Training Materials for CNC