Metal Fabrication Methods

Metalworking Processes and Techniques

Casting Process

Casting consists of introducing molten metal into a container with an internal cavity called a mold. Molds can be manufactured from steel or foundry sand.

1. The metal is heated in an oven until it melts.
2. The liquid metal is poured inside the mold.
3. It is cooled until the metal solidifies.
4. The solidified part is removed from the mold.

Material Handling

These techniques are carried out with tools and machine tools using prefabricated materials such as bars, rods, plates, etc.

Marking Tools

• Punch
• Scriber
• Dividers

Cutting Techniques and Tools

• Sheet metal shears or snips
• Guillotine
• Press and die cut
• Hacksaw

Circular Saw

A machine tool mainly used for cutting large boards or plates. It can make straight and oblique cuts.

Grinder

This is a very versatile tool that consists of a removable circular grinding wheel. Based on the type of grinding material, it can be used for cutting, stripping, sanding, polishing, etc.

Punching and Drilling

• Punching
• Drilling

Carving and Trimming

Techniques using tools such as:

• Chisel
• Burin

Shaping and Finishing

File

Consists of a wooden or plastic handle and a grooved metal body. Files may have different sections (round, flat, square, etc.) and are used to remove excess material from a workpiece.

Sander

An electric machine that uses sandpaper to smooth a surface. It achieves surface smoothing through alternative or orbital movement.

Joining Techniques

Fixed Joining Techniques

In these unions, the parts cannot be separated without deterioration or breakage of the joining element. This type of union is used when there is no provision for the separation or removal of parts.

Examples include:

• Rivet
• Press fit
• Adhesives
• Welding

Welding

Welding is the union of materials applied through heat and pressure on their surfaces. It often requires the provision of filler materials, which can be of a different or the same nature as the pieces being joined.

• If filler material is used and is of a different nature, it is heterogeneous welding (e.g., soldering).
• If no filler material is used, or if the filler material is of the same nature as the parts being joined, it is homogeneous welding.

Soft Welding Type

• Nature: Heterogeneous
• Instrument: Electric welder
• Temperature: ~400°C
• Filler Material: Tin-lead alloy
• Applications: Tin plates, brass pieces, etc.

Removable Joining Techniques

Unlike fixed joints, these allow the union and separation of parts without causing rupture or damage to the components.

Bolt and Nut Union

The bolt passes through the pieces to be joined. The nut is screwed onto the bolt protruding from the other side. Washers are often placed between the bolt/nut and the workpiece material to prevent breakage or loosening of the union.