How to cut aluminum with a mini mill cnc router
Set the tool in the holder or directly in the spindle if your mini mill is a single tool CNC. Teach the tool position according to manufacturer's directions, which vary by machine company. Teaching allows the computer to know where the tip is at all times, and by inputting the diameter of the tool, the machine can compensate its cutting based on the program instructions.
Place a precision vise on the table. Small precision vises are perfect for mini mills when your standard 8-inch vise is too big and heavy. Make sure that the table is clean from metal chips and debris. Use an indicator on the spindle and move it in the X axis, left to right, to make sure the vise is straight so that the raw material is cut accurately.
Place your raw aluminum in the vise to be cut. Tap it lightly in place after tightening the vise by hand. Try to wiggle the aluminum to make sure it is in tightly. Loose material can cause damage to the tool and the inside of the machine. Remove the vise handle after you have tightened the raw material.
Set the zero, or starting point, for the program. Many programs will start on the right side of the raw material. Set your zero based on how the machining process was programmed. If they used the center and the raw material is 5 inches, you may want to start at 2.6 inches, to the right of center. In that case. you will use an indicator or edge finder to get the zero and then set your starting point 2.6 inches from that point, which will bring the tool within .1 inch from the edge, which is enough clearance.
Start the machining process, but set the rapids very low. The rapids dictate the speed at which the tool is brought to the raw material. If you run your rapids slowly at first, you can be sure that the program and starting point are set properly. If not, quick rapids can result in the tool smashing into the table, vise or raw material, resulting in damage.
Watch the load meters on the CNC control and increase or decrease the feed rates on the override to make the program more efficient. Many programmers under-utilize a machine when they first start, but the program can be adjusted to maximize the cutting power of a mini mill.