As we mentioned in our previous article, machining is one of the main processes in steel fabrication. In this article, we will take a closer look at what is machining, its processes, and the main utilized technologies.
Machining Overview
Machining is a term that describes a wide range of manufacturing processes and techniques, where the material is removed from a workpiece to match a final design using a tool. This process can be used in the manufacturing of metal, wood, plastic, ceramic, and composites products. The traditional machining processes evolved in the middle of the 19th century. These include turning, drilling, milling, boring, grinding, etc. They utilized equipment such as lathes, drilling presses, milling machines, and many others. As technology progresses, new technologies were developed such as Computer Numerical Control (CNC), Electrical Discharge Machining (EDM), Electro-chemical Machining (EDM) and others.
Machining Operations:
The main machining operations are categorized into turning, drilling, and milling. However, many other operations like grinding, planing, sawing, and broaching can fall into miscellaneous categories. Let us have a look at the main operations.
Turning: it is the operation where the workpiece is rotated against the stationary cutting tool to remove the material. Due to the nature of turning, it can be done on either the exterior or interior -which is called “boring"- of the workpiece. Boring usually follows drilling in order to polish the dimensions and accuracy of the holes. Lathes are the main machines for turning and they can be found as manually operated or computer-aided in CNC types.
Drilling: as the name implies, drilling is about making cylindrical holes into the workpiece using drill bits. It is one of the preliminary stages in making finished holes. Since drill bits are prone to follow the path of least resistance, their holes are subsequently tapped, reamed -improve surface roughness- or bored by another machining process to bring its dimensions within the acceptable tolerance.
Milling: contrasting turning operations, the cutting machines rotate around the workpiece to remove material. This provides a higher degree of freedom and flexibility. Milling machines can fall into four main categories, hand, plain, universal, and omniversal milling machines.
Machining Technologies
Computer Numerical Control (CNC): CNC is one of the most common technologies used in large machining, where computers control the movements of the machines following the input code. This leads to an increase in efficiency, accuracy, and cost-saving. An advanced technique using CNC is precision machining in which the material removal is done through close tolerances. We will explore it further in a future article.
Electrical Discharge Machining (EDM): EDM is a non-mechanical process utilizing either chemicals or erosive sparks. It is used in machining very detailed features of the design. A downside for EDM is that it requires the material to be conductive, thus, limiting its usage.
Electro-chemical Erosion (ECM): ECM is a cold machining process that does not stress the material thermally. It is usually used in working on extremely hard materials such as titanium aluminides, Inconel, and high nickel. Similar to EDM, ECM requires the material to be conductive.
Laster Cutting: a high beam energy light is used to melt, vaporize, or burn into the material. This provides an extreme precision which can be used in high-quality surface finishes as well as patterns etching.
Water Jet Cutting: a high-pressurized stream is used to cut into the workpiece either as pure water or with an addition of an abrasive. It can be applied in materials that can suffer from induced heat processes.
Summary
In this article, we explored machining operations and technologies. For more information on related products and services visit our website. Also, you can check our other articles here.