How to Run CNC Machines

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By starting the machine properly and allowing the moving parts of a CNC machine to lubricate, you can make precision parts in an accurate, consistent manner. Running a CNC machine requires a good eye and attention to detail, and by observing the machine while cutting and diligently measuring parts, you can make the adjustments and tool changes necessary to reduce waste.

Set the machine positioning according to the manufacturer's specifications. When a machine is first turned on, it does not know where the spindle is located in relation to the chuck jaw or the work table, respectively.

Start the spindle in a mill or the lathe in which you are using. These need to spin for a few minutes to warm them up and lubricate them before accurate cuts can be made. Start them using the manual speed knob or button and slowly increase the speed to about 50 percent of the maximum. Leave them spinning for up to 10 minutes to ensure that the lubrication has reached all parts of the spindle.

Insert tools into the tool turret. You can either insert them directly into the tool turret or call the tool up on the control and insert them manually into the spindle. Then, call up the next tool; the machine will place the existing tool into the tool turret, and you can then insert the next tool into the spindle.

Teach each individual tool so that the machine control knows the depth. Since the tool will enter offsets for each tool, you must teach them individually so that the machine is aware of the location of the tip of the tool. The machine should have a tool offset screen and an automatic tool teach routine that will teach each tool you have placed automatically using a tool eye or laser to register the tool's tip location.

Call up the program to be used, or write one at the machine. Most CNC controls have hard drive space where programs can be stored. You can also create a new program directly at the control and run a simulation to make sure there are no problems.

Start your program at a slow feed rate to make sure that things look right and that each individual tool is doing what it should based on the program movements. Once you get through the first piece, you can raise the speed of the feed rate, but just keep an eye on your tooling. Look for wear of breakage, and make the necessary offset adjustment or tool changes.