Machining

Machining is a production process that remove material. This type of process contrast with additive manufacturing.

Machining is a manufacturing process that involves removing material. This is known as subtractive production technology, as opposed to additive manufacturing. It involves working a block to give it the desired shape and size. After machining, the part is unfinished and may require surface treatment.
The term machining covers several material removal processes: milling, turning, drilling, mortising, grinding, reaming, etc. are some of the techniques included under the term machining.
Machining is used to work metals as well as hard and soft plastics. When it comes to woodworking, this is often specified as "wood machining".
To remove material, depending on the process, movement (often rotation) is given either to the workpiece (turning) or to the tool (milling). Removing large quantities of material requires several passes with depths that can vary with each pass. The greater the depth of the pass, corresponding to the thickness of material removed, the greater the force applied to the tool and the less smooth and precise the result. The precision expected of machined parts is often very high, to the nearest micron. The speed of rotation parameter influences the quality of the surface finish of the part at the end of the machining process.
This is known as high-speed machining. There are many parameters to consider when choosing the equipment and tools used for each project.
Increasingly, the general engineering and precision engineering industries are being transformed by the technology used. There are traditional machining centres and numerically controlled machining centres known by the abbreviation "NC". The NC machining centre is computer-controlled using computer-aided design and manufacturing (CAD/CAM) software. It is by far the most widely used machine in workshops today.
CAM software controls the production tools by monitoring the tools used, the order of operations and the position of the part and the tool in space to remove the material needed to machine the required part. Machining centres can also be fitted with loading robots to automate the loading and unloading of material for machining. NC equipment has made it possible to increase production rates by reducing manual handling time. It has also reduced the number of errors, thanks to computer simulation of the machining process, which anticipates problems such as tool choice and the sequence of material removal stages.

When the machine is capable of working autonomously for long periods of time, it is referred to as masked time, meaning that the operator can work on several machining centres at the same time, loading and unloading the machines while the others are running. Working in masked time on numerically controlled machines with loading robots means that reduced teams can work at night or even at weekends. These technological advances are speeding up the reduction in production costs, but are resulting in a loss of flexibility for machining single parts or small production runs.
When we talk about machining centres, we often refer to the number of working axes on the machine. The simplest machines work on 3 axes, X, Y and Z, i.e. length, width and thickness. When the number of axes increases to 4 or 5, this refers to the possibility of moving the part and the tool, as well as the axis of the tool arm. Machining machines specify the axis in which the electro-spindle, which rotates the tool, is located. This is either vertical or horizontal. Sometimes it is the workpiece that can be moved, in which case we talk about a cradle. In the case of the most advanced machines, the electro-spindle is placed on a mobile arm that can be at an angle between horizontal and vertical. In the latter case, the workpiece does not necessarily move; it is the arm carrying the electro-spindle and the cutting tool that moves around the workpiece.

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