Criterion in the choice of cut machine
Chip production - a turning operation and cutting tool can affect chip production which is often quite difficult to handle which means that a cut machine must be selected that will break chips before they get too long since smaller chips are easier to be removed and collected. Long stringy chips are more difficult to control and they can snarl and cause damage on the workpiece.
Hardness of workpiece – the choice for the cut machine is also affected by tougher and harder metal alloy workpieces that are being turned. Alloys and steel with hardness of up to 45 Rockwell ‘C’ can be turned with standard carbide or carbide-coated cutting tool. On the other hand, hardened steel, stainless steel and nickel super alloys may require alternative cutting tool insert materials like ceramic, poly-crystalline diamond or cubic boron nitride. If turning is done using these cutting inserts, it will eliminate the need for grinding and other secondary processes. The problem though is the expensive price of these cut machines but they can be expected to last longer.
Geometry of cutting tool – or the shape of the cutting tool plays an important role in determining its speed and surface finish. For difficult turning operations, the ‘wiper’ and multi-corner geometries are becoming quite popular.
Cutting fluid – is important for the cut machine because it cools the cutting tools, flushes away chips from the workpiece and lubricates the point where the cutting tool and chips meet. However, there are instances when cutting fluid is not recommended like in the turning of cast iron and other hard materials that are better performed ‘dry’.
When does the cut machine excel?
- Reduce time in the cut – meaning certain features can be combined in one form and produced in one pass when surface finish is not a critical factor.
- Reduce non-cutting time – when two or more tools are combined, this can reduce the number of cutting tool changes that eat up on non-productive time.
- Improve overall tool life – coolant ports that do require adjustment can be optimized to reduce operator error and ensure that the flow of coolant is always directed into the cutting zone.
- Improve efficiency – inserts are allowed to work to their fullest potential if they are cut with edge preparation and coating specific to the material being machined.
- Reduce cost per part – is almost always the final goal
- Increase process reliability – may require customization of the cutting tool with multiple types of inserts that will exactly fit the cut machine