THE METALS MOST USED IN PRECISION MECHANICS

A metal can be machined in precision mechanics to the desired end product. But what are the metals most used in precision mechanics? Let’s find out together.

What factors should be taken into account before selecting metals?

The choice of materials for a given application requires careful evaluation of their ability to be cut, carved and finished in the most appropriate manner.
When assessing the machinability of a metal, factors such as hardness, thermal and electrical conductivity and malleability must also be considered.
Although many types of metal are compatible with precision machining, each has its own specific advantages in relation to the product to be obtained.
Companies specializing in precision engineering create a wide variety of parts and finished products by using metal alloys.
The most commonly used metals for machining are:
• Aluminium
• Copper
• Brass
• Stainless steel
Each metal has its own advantages for the machining process. We discover the characteristics of the metals most used in precision mechanics.

Characteristics of metals used in precision engineering

Following the peculiar characteristics of the metals most used in precision mechanics.
Aluminium
Aluminium has an excellent response during cutting, drilling, punching and milling.
It is also very durable and aesthetically pleasing. Its processing requires less effort than that required by other metals. It requires special tools that differ from those used for the processing of other materials.
Aluminium, thanks to its high degree of workability, is used in the production of:
• Pipe studs
• Machine parts
• Mobile phones
• Filters

Brass
Brass is an alloy made of zinc and copper and is known for its golden appearance and good workability. It is used for the production of products such as:
• Bushing
• Handles
• Lamp parts
• Marine components
• Electrical devices
• Valves
• Bearings
The following properties make brass an excellent material for use in a variety of fields:
• Low melting point
• Low magnetism
• Resistance to corrosion and oxidation
• Excellent malleability
• No need for surface finishing
• Low friction

Copper
Copper is a natural metal with excellent conductive properties. It is used to build products such as:
• Hand tools
• Radiators
• Generators
• Connectors
• Pots and pans
• Heat exchangers
• Engines
It is the metal which offers the best electrical conductivity among all metals to be worked. It also conducts heat well, is rust-resistant and easily mouldable.

Stainless steel
Stainless steel is an ideal metal in many applications because it has a higher resistance to rust and corrosion than other types of steel.
It is made of an alloy formed by iron and chromium, which binds to oxygen particles forming solid chromium oxide on the steel surface. This means, however, that stainless steel has a limited ability to resist scratches and abrasion.
Stainless steel is used to produce a large number of objects, including:
• Industrial equipment
• Medical devices
• Aerospace and automotive components
• Military hardware
Stainless steel owes many of its valuable properties to passivation, a chemical process in which acids remove excess iron from the surface of the material, creating an inert oxide protective and anti-corrosive layer. The latter protects steel from rust.

Fundamentals of metal working

The first and most important step in metal working is to identify the type of material that will be processed. The more accurate the assessment you are able to make of the type of metal, the more effective the work.
Some metals are considered "soft". Examples include aluminium, brass and copper, often referred to as non-ferrous metals or alloys. They are easily machined and can be cut at high speeds without significant tool wear. Softer metals can therefore be milled using higher feed rates and speeds. Under suitable conditions, soft metals will give a high quality surface finish and can be machined with extremely tight tolerances. Due to their malleable nature, they can be subject to scratches. For this reason, when working with them, it is essential to pay attention in order to minimize the abrasion on the surface.
There are several types of harder metals. Steel falls into this category and includes different types, including carbon steel, special steels, tool steel, stainless steel.
Additional hard metals may include materials such as chromium, iron, manganese and titanium. These metals all react differently during production and can also be difficult to work with, so it is important to adjust the tools and feed rates. Harder metals need to be cut with slower feed rates and will have a major impact on tool life.
When working with a metal you are not familiar with, it is always best to start cautiously with speed and advances. This will help to limit scrap and tool wear, allowing more room for manoeuvre when it is necessary to fine-tune cutting speeds.

Heat and metal in precision mechanics

Heat can play a significant role when working metals in precision mechanics. Excess heat can cause the starting material to deform or expand. Softer metals can start to melt if high temperatures are reached.
Harder metals may undergo work hardening, where the heated area actually becomes harder as the temperature increases.
While some metals have a higher heat resistance than others, it is best to limit excessive heat where possible to avoid problems during machining.