Still more tips for operating a CNC mill

Continuing the theme of the past two columns, here are additional tips for enhancing the operation of a CNC milling machine. Because speed and momentum reduce costs when applied to part processing, you should use every tool, trick and option at your disposal to get jobs out the door as quickly as possible.

All images courtesy of T. Lipton

Drill-point endmills enable you to drill, mill and chamfer.

■ If you are planning or rearranging your CNC shop, be sure to include a water hose bib near the machines. Machines that operate all day long lose a significant amount of coolant to evaporation. This can be made up by adding water or a makeup solution of your water-based coolant to maintain the correct concentration.

■ Plumb a quick disconnect in line with your coolant line. If you make a short hose with a spray nozzle, it can be used to wash the inside of a machine after a job. This also makes it easier to steal some coolant from another machine in a pinch.

■ Apply cutting tools as long as possible to reduce cycle times. You can drill, mill and chamfer, for example, with a drill-point endmill. Sometimes a subtle change in tool selection will allow a tool to be used for several operations, eliminating the need for tool changes and noncutting time. This tip is valid even for rapid tool changes. Vertical machining centers typically have less-than-stellar spindle utilization, so anything you can do to keep the tool in the cut is a good thing.

■ A trick for separating multiple ganged parts involves applying a 90° chamfer mill or drill-point endmill to follow a contour that will be the parting line between the parts. Leave 0.001 ” to 0.003 ” of material at the bottom for an easy break line on the back of the ganged parts. Then, you can easily snap off the parts and insert them in pocketed soft jaws for second-side operations.