Metal Parts Manufacturing: Types Of Process and Materials
As the global demand for custom metal parts and sheet metal fabrication services increases, manufacturers have a great opportunity for improved metal parts manufacturing business. The covid-19 may have slowed down the markets since 2020, but there is a boom in rapid prototyping, 3D printing, and other manufacturing processes.
CNC turning, forging, and die casting are only some of the many metal manufacturing methods in the market. The types of materials to use can also vary a lot, not forgetting that you need to identify a reliable provider.
In this article, we will explore a few prominent metal fabrication processes and materials. This information will offer deep insight into the existing technologies and metals, their pros and cons, and the points to remember when choosing from among the metal parts manufacturing options.
What’s Metal Fabrication?
Metal fabrication is a blend of different processes focused on a metal material and resulting in a product or end part. It is systematic and starts with a design followed by a series of activities that end with a metal part or component that meets preset requirements.
The metal fabrication process comprises popular techniques such as joining, bending, cutting, and finishing. The expert use of these techniques results in a wide range of products, from ornamental pieces to structural parts.
In a metal fabrication project, particularly if it is a custom type, a few steps are critical. These are product design, metal material selection, metal cutting/shaping, joining/welding, and finishing.
Types of Metal Materials
There are limits to the different types of metal raw materials that can be used in metal parts fabrication. Although the pool of choices is wide, you will realize that some metals are more commonly used than others. This is because they present favorable characteristics and properties.
Manufacturers are guided by many factors when settling on any particular metal material. It could be hardness, ductility, impact strength, corrosion resistance, and so on. Every metal material presents some, all, or none of the characteristics that a manufacturer desires.
Let us now look at a few categories of materials used in metal parts manufacturing:
Hard Metal
This is one of the two major taxonomies of metals used in metal parts fabrication. This category of metals is renowned for wear resistance and hardness. Due to their packed atomic structure, hard metals can overcome deformation and heavy loads.
When shaped for tasks such as drilling and cutting, hard metals can maintain that shape. Below are a few examples of hard metals:
Steel
Steel is an alloy of different elements including manganese, silicon, and carbon. The presence of carbon as iron-carbide (Fe3C) makes steel significantly strong and hard.
Depending on the amount of carbon present, steel can be categorized as low carbon-steel, medium-carbon steel, or high-carbon steel. Low-carbon steels such as mild steel have a carbon content of up to 0.25 %. For medium-carbon steel, the carbon content can reach 0.55%. High-carbon steel has a carbon content of up to 2.1%, which makes them relatively harder and stronger.
Steel may also be categorized based on the method of manufacture, properties of the metal, and the alloying elements present. For instance, cold rolled steel and hot rolled steel are differentiated by the temperature levels during processing.
Stainless Steel
Stainless steel is different from steel in the sense that steel is based on iron while stainless steel contains chromium. Stainless steel has a characteristic silver mirror coating.
It is easy to use, a reason why many fabricators use it for CNC machined metal parts. Stainless steel is also easy to weld and bend. Due to its chromium content, the metal does not corrode easily, hence its relevance in projects that require corrosion resistance.
Inconel
Inconel is one of the strongest metals available for metal parts manufacturing. It is particularly popular for its ability to operate in high-temperature environments. For a better perspective of the strength of this metal, consider that stainless steel is only 73.2 Kilo pounds per square inch (KSI) in tensile strength compared to Inconel’s 160 KSI.
Consider this metal for parts in jet engines, oil & gas equipment, and heat treatment equipment. It holds well in rapid temperature changes, corrosive environments, and fatigue associated with aerospace industry and comparable industries.
Chrome
Chromium is a hard and brittle transition metal that is greyish. It is remarkably corrosion resistant, instead reacting with the environment to create a chromium oxide layer on stainless steel.
The Moh’s hardness scale gives this metal a scale of 8.5, which is easily higher than even the rating of titanium. Given its strength and corrosion resistance, chromium finds widespread application in areas where aesthetics and durability are essential. A good example is in chrome plating.
Titanium
As one of the most abundant materials and with perfect mechanical properties, titanium is also popular in the metal parts fabrication industry. Here are some properties of this metal, whose atomic number is 22:
High strength-to-density ratio
Relatively high elasticity
Corrosion resistance
low thermal expansion coefficient
As one of the most abundant materials and with perfect mechanical properties, titanium is also popular in the metal parts fabrication industry. Here are some properties of this metal, whose atomic number is 22:
Soft Metal
Metals that have low melting points and can be effortlessly shaped or molded into different shapes belong to a category called soft metals. The malleability property emanates from the loosely arranged atomic structure.
The atoms are easy to manipulate, unlike the hard metals that have a tightly packed atomic structure.
Aluminum
When a metal parts fabrication project requires a combination of low weight and strength, lightweight aluminum becomes a good choice. Industries that look for the high strength-to-weight ratio of aluminum materials include aerospace and automotive industries. When you add to the mix the versatility, workability, and thermal qualities of some of the aluminum alloys, it is easy to understand why aluminum is one of the most popular metals for sheet metal parts, structural components, metal sheets, and so on.
Magnesium
If there is a metal that is closely associated with low weight and fire risk, it is magnesium. But there is more to this metal that makes it more usable than most die-castable metals in terms of strength-to-weight ratio. It is available in many alloys and has a long die-cast tool life. Magnesium is also versatile, fitting in both large and small casting projects.
Owing to its low weight, magnesium suits many metal parts manufacturing projects where aluminum would work. This is because the two share many characteristics. The metal is popular in the automotive industry where it is used in making components such as:
Steering wheels
Pedals
Panels
Support brackets
Magnesium alloys are found in the aerospace industry too, for instance, in helicopter gearboxes. The corrosion resistance and superior strength of the metal are evident in this area. Other areas of application are beverage cans, machinery parts, desulpherizer in steel manufacture, and cathodic protection in pipelines.
Brass
This metal is largely made up of copper and zinc. The result of this combination is a malleable metal that melts at a low temperature. The characteristic reddish-yellow hue of brass makes the metal a popular choice for decoration projects.
In connection to the antibacterial properties, brass is found in medical components that are often exposed to germs and diseases. Like many other metals, it is possible to subject brass to processes that improve its chemical and physical properties including corrosion resistance and strength.
Copper
The naturally-occurring metal is renowned for its usability for metal parts manufacturing even in the raw state. You don’t have to take copper through subsequent steps to use it. It has some of the most important features of a metal – softness, malleability, and thermal conductivity.
For these properties, the metal is a common feature in electrical wirings. Copper is also prominent in industrial machinery manufacture. The alloys brass and bronze contain copper as one of their components.
How to Manufacture Metal Parts?
Do you ever wonder how various metal components and parts are manufactured? Several metal fabrication techniques exist, each with different capabilities, metal requirements, working principles, pros, and cons.
Popular metal part manufacturing techniques include the following:
CNC milling and turning
Die casting
Forging
Metal injection molding
Sheet metal and stamping
Metal 3D printing
CNC Machining - Milling and Turning
CNC milling and turning are metal parts manufacturing processes that use the CNC machine or CNC machining technology to remove material from a piece of metal. Apart from milling and turning, the other popular machining procedure is drilling.
The removal of the extra material from the parent metal material using the milling method is enabled by a setup comprising multi-point cutting tools in a CNC machining setup. CNC milling and turning are relatively new approaches. The older methods were manual but the concept is the same. Typically, milling is a secondary metal manufacturing process.
Turning produces cylindrical metal parts and is accomplished on a lathe machine. The lathe machine carries a single-point cutting tool that removes material from the rotating metal. The CNC turning machine is a recent development, but the manual turning process is still an option. Turning using the CNC machining method is preferable for many things including higher accuracy of the results.
CNC milling and turning is preferable for manufacturing metal parts with high dimensional tolerances and speed of operation. The versatility of CNC machining and the fact that the operations can continue for 24 hours are notable advantages.
Unfortunately, CNC machining through milling and turning has size limitations and the high cost is this technology can be a deterrent in metal parts fabrication.
Die Casting
This metal parts manufacturing method involves using pressure to fill a mold cavity with molten metal and allowing the molten metal to cool inside the cavity for the production of a metal part. It is very effective in the manufacture of precise and identical metal parts because the same die is used multiple times. It is often used in mass production of metal parts.
Die casting is comparable to the typical molding and casting process, but some details are different. A hydraulic press applies pressure on the cavity parts to ensure a complete seal. Unlike in sand casting and other casting methods, the cavity in die casting remains undamaged after the part has been manufactured.
Die casting is suitable for repeatable manufacture of lightweight metal components at a low cost. The resulting parts are precise and typically strong.
However, die casting is a relatively expensive casting process. The cost and maintenance requirements of the casting machine are typically high.
Forging
This is another popular metal fabrication process. It is characterized by the hammering of metal with a die or hammer until it acquires the desired shape and size. Another name for forging is “applying compressive force.”
Forging comes in several variations including cold forging, which is performed at room temperature. When the temperature is warmer but lower than the recrystallization temperature, the process is called warm forging. At the recrystallization temperature of the metal, this process is referred to as hot forging.
The resulting metal parts have high hardness and strength. They find applications in ball joints, gears, shafts, and landing gears. Other applications are flanges, axle beams, drill bits, and missiles among others. As you would expect, forging is popular in the automotive, aerospace, and power generation industries.
Proponents of the technique cite low skill requirements, low cost, and the possibility of manufacturing a variety of shapes easily. However, there are several challenges including size limitations, unattainability of close tolerances, safety concerns, and the need for secondary finishing.
Metal injection molding
The application of the plastic injection molding method for metal parts manufacturing is called metal injection molding (MIM). This technique brings the automation and ease of plastic manufacturing to metal manufacturing. It enables the production of metal parts with tight tolerances and complex shapes.
Sheet metal and stamping
Sheet metal stamping is characterized by the use of a stamping press comprising of a die and tool to apply pressure on a metal sheet to get the desired shape. The result is the formation of a new shape or the removal of a piece of metal from the sheet. This sheet metal fabrication technology fits where there is a need for smaller parts, higher volumes, repeatable dimensions, and complex shapes.
Sheet metal stamping is common in the manufacture of appliances, electrical components, fastenings, and construction devices. You will find such components in automotive engines, aircraft parts, telecom products, and electronics.
Regarding custom sheet metal stamping, the cost challenges can be a hindrance, especially in preparing the mold for sheet metal parts.
Metal 3D printing
In case you are wondering, yes, metal 3D printing for metal parts manufacturing exists. It is an additive manufacturing process whereby metal is deposited in a precise format to create metal parts. Some metals that can be turned into powder and used in 3d printing technology are tungsten, aluminum, copper, and cobalt chrome. Others are nickel-based alloys, steel, and stainless steel.
The media and methods used in the varieties of metal 3D printing may be diverse, but two elements are common: Metal in powder form and a printing process based on high energy.
Techniques under this category of metal parts manufacturing include EBM (Electron Beam Melting), Direct Metal Laser Sintering (DMLS), and (Selective Laser Melting). Lesser used methods are Binder Jetting, Metal Injection Moulding, and Laser Metal Deposition (LMD).
Manufacturers looking for the most complex metal parts should consider metal 3D printing. For instance, cooling channels and other complex internal shapes come out perfect with this metal parts manufacturing technique. This method rarely produces waste and is highly reliable.
Note that the risk of dangerous substances being produced in the course of metal 3D printing is rife. Metal powders could enter wounds or eyes and cause serious health issues. Carbon monoxide and other harmful gases are produced. Fire from the metal powder is also a danger.
Custom metal parts manufacturing from Aria
Many factors come into play when deciding which metal parts manufacturing process to use – the budget, type of metal, final product, and so forth. We have covered several metal part manufacturing techniques and popular metals used in fabrication.
By comparing and contrasting CNC machining, die casting, and all the other metal manufacturing methods, it is easy to make an informed choice and get the best metal parts manufacturing results.
Sometimes you just want to have an expert handle the manufacturing process for you. Whether you need general metal fabrication components or intricate aerospace quality parts, Aria Manufacturing Limited is here to handle all your orders with impeccable manufacturing services results.