Manufacturing processes are the steps through which raw materials are transformed into a desired final shape and size by a controlled material-removal process (subtractive manufacturing).
The term machinability refers to the case in which a metal can be machined to an
acceptable surface finish. The three main machining processes are classified as turning, drilling, and milling. Other operations falling into miscellaneous categories include shaping, planing, boring, broaching and sawing.
Material removal processes can be broadly divided into two groups:
Conventional Manufacturing process:
In conventional machining processes, machine tools composed of harder materials – such as lathes, milling machines, and drill presses – are used to cut and shape a workpiece through direct contact. The three chief conventional machining operations are turning, milling and drilling, although there is a miscellany of other operations:
- Turning operations rotate the workpiece against a cutting tool, typically a lathe.
- Milling operations rotate a cutting tool, or milling machine, against the workpiece.
- Drilling operations produce holes in the workpiece with a rotating cutter.
Pros:
- Effective when materials are neither too hard nor too brittle.
- The pervasiveness of CNC machining allows for the execution of conventional machining processes with incredible precision and consistency.
In several industries, hard and brittle materials like tungsten carbide are used for making cutting tools while high-speed steel is used for making gear cutters, drills, taps, milling cutters etc. If such materials are machined with the help of conventional machining processes, either the tool undergoes extreme wear (while machining hard workpiece) or the workpiece material is damaged (while machining brittle workpiece) because of the necessity of the direct contact in the former process. This gave rise to the need for UCMP.
Unconventional Machining
In unconventional machining processes, technologies are used so that there is no direct contact between the tool and the workpiece. Instead, other forms of energy are used to shape materials: electrical, thermal, chemical, mechanical. There are many different unconventional machining methods. Because unconventional machining avoids direct contact between the tool and the workpiece, that wear and damage are nonexistent. Additionally, unconventional machining can be helpful when performing delicate work with the brittle material, again preventing damage to the workpiece. Because unconventional machining can reduce tool wear-and-tear, as well as demands of time and energy for repairs, these methods can reduce overall costs.
| CONVENTIONAL PROCESS | UN-CONVENTIONAL PROCESS |
| Macroscopic chip formation | Chip may or may not be formed |
| Requirement of a physical tool | No such compulsion |
| Cutting tool is harder at all temperatures | This is not the necessary case |
| Tool wearing (direct contact) | No tool wearing (no direct contact) |
| Cutting forces act | Different energy domains |
| Lower accuracy and surface finish | Higher |
| Spare parts are easily available | Spare parts are not easily available as they are much costly than the conventional ones |
| Noise pollution | No |
| Higher material wastage | Lower |
| Low capital cost | High capital cost |
Mech Webster 