Machining (or Shaping)

Once measuring and laying out are completed, the machining of materials can begin.

During machining, different tools and techniques are used to shape parts according to the manufacturing drawings presented in the manufacturing process sheet.

Machining generally takes place as follows.

1. Roughing

2. Choosing tools and techniques

3. Shaping the material

First, roughing, as the name suggests, involves cutting the material to a rough approximation of the finished part, removing excess material, and keeping only the portion necessary for manufacturing.

Next, the techniques, instruments, and tools are chosen according to the type of material. For example, since metals are generally harder than wood, specific types of drill bits and saw blades are used to work with them.

Finally, shaping the part involves turning the materials into the desired shape.

Many techniques are used to shape material. Here are the ones used most frequently.

Materials most susceptible to bending are metals and thermoplastics, because they have good malleability. Cambering causes a plastic deformation of the machined material, because the bend is permanent.

There are several tools for cutting parts. Tool selection is based on the nature of the material to be cut and its thickness.

When building an electrical circuit, conductive wires must be connected. For the conductive materials to make contact, the insulating sheath at the end of the wires must be removed first. This technique can be performed using wire strippers.

When building an electrical circuit, it is sometimes necessary to join conductive wires. Once the insulating sheath is removed from the ends of the wires, it is important to ensure that the conductive materials are joined. It is done by splicing—twisting the strands of the two wires together to form a helix. It ensures that the two wires stay attached.

Computer-aided design (CAD) software enables a file to be created where the technical object is modelled. The three-dimensional model is then read by the 3D printer which in turn deposits thin layers of plastic to manufacture the desired object.

Threading is a complementary technique to tapping. Threading creates a helical thread around a cylindrical part. A screw is a common example of an object shaped by threading. The die used must be chosen according to the nature of the material, the size of the bar to be threaded, and the type of thread desired.

Just like bending, rolling causes plastic deformation of the machined material. In addition, the technique is often used before cambering, because it can produce materials in sheets, making them more malleable for bending.

Moulding occurs when a liquid material is poured into a hollow mould and after solidifying, it is removed. Plastics, glass, and aluminum are materials that are frequently shaped by moulding to produce an object.

Drilling is performed with a drill bit inserted into a drill. It is important to choose a drill suitable for the hole to be drilled. The choice is made according to the diameter of the hole, but also the nature of the material to be drilled. The rotation speed of the drill must also be adjusted according to the two parameters. For example, the greater the hardness and the larger the diameter, the lower the rotational speed of the drill.

To make a permanent bond between two metal parts, such as between the copper strands of two conductive wires, tin is melted onto the two parts in contact. Once the tin has solidified, the link between the two pieces is rigid and permanent.

A tap is fixed to a tap holder (also called a tap wrench) and is screwed inside the material to be tapped. It can also be done by attaching a tap to a drill chuck. The tap used must be chosen according to the type of thread required and the nature of the material to be tapped.