Cutting strategy

To continue calculating and obtaining data for the parameters of this machine I need to define a method for tool paths (The paths the cutter will pass along)

The machine will need to be capable of high speeds and high feeds to machine MDF. These characteristics can be used to machine aluminum providing the correct tooling is selected.

Traditional CNC cutting strategies generally cut in small depths across the whole area when cutting a pocket or profile and then finish the outside or inside profile with a small cut width. They also incorporate what is known as a step over value where each cut is a given value of thickness. An example of this is a slot will be cut 10mm wide with a 10mm cutter the cutter will then move over 5mm and cut the slot width to 15mm this would be a 50% cross over or 5mm.

HSM (High speed machining) strategies are generally very different. Cutting a pocket will start with a circular pocket that then cuts in an axial pattern towards full depth. When at full depth it will then machine outwards with a step over value and finish the profile in the same manner as traditional CNC would. There are other aspects of variations within HSM that improve things further such as Waveform from EDGECAM.

The advantage of high speed machining is that it can dramatically increase MRR values. Heat produced within the cutting process is mostly ejected with the chip. Tool life increases as the tool is generally not cutting on just the end section of the tool and is cutting on the full flute length of the cutting flutes.

However there are some drawbacks to HSM. It increases the volume of each chip resulting in more aggressive chip clearance methods such as high pressure coolant being directed at the cutter. It also increases cutting force dramatically. This is something that needs to be avoided.

The cutting strategy that will be employed within this machine is a more traditional approach. However using tooling designed for HSM. This will allow shallow cuts with high spindle speed and high feed speed whilst steel keeping a suitable MRR value. It will also mean that less force is applied to the cutter and machine. Resulting in less deflection affecting accuracy and less magnitude of resonance.