Originally Posted by
HimyKabibble
BTW - Depth of cut is determined mostly by the rigidly and spindle power of your machine. Generally, if your goal is removing material quickly, you want to go as deep as the machine will allow. On most benchtop machines, that won't be very deep. At some point, you may have to back off, if you either can't keep the chips clear, or can't get enough coolant in to prevent burnign or welding. But other than that, DOC is pretty much independant of RPM and chipload. Pick your RPM, based on SFPM (80-100 for mild steel, 300-400 for aluminum, if using HSS tools). Then pick your chipload, based on the tool makers recommendations. If you get poor surface finish, or the machine shakes and "complains", reduce RPM, but maintain the chipload, until the machine is happy. A reasonable "rule of thumb" for chip load is figure 0.002" for a 1/2" tool, and scale by tool size for larger or smaller tools. So, for example, a 1" tool would give 0.004" chipload, while a 1/4" tool would give a 0.001" chipload. Below about 1/8", you need to get more conservative, or you'll break a lot of tools. Once you have the RPM and chipload happy, then see how deep you can go. Again, when you see surface finish deteriorate, or get shaking or the spindle slowing down, back off.
Regards,
Ray L.