What Is Additive Manufacturing (+ Pros and Cons)

Additive manufacturing (AM) is the process of adding substances to manufacture or create an object. While many believe that AM is a relatively new technology, it has been around since the late 1980s.

Additive manufacturing takes a transformative approach to assembly and industrial fabrication. AM uses computer-aided design (CAD) software to guide digital hardware that accurately produces detailed geometric shapes.

Through the meticulous deposit of layer upon layer of material, AM enables the creation of lighter, stronger parts and systems that bring digital flexibility and efficiency to manufacturing operations.

Commonly known as 3D printing and rapid prototyping, the terms refer to two of the independent processes that are subsets of additive manufacturing.

There are seven different categories of additive manufacturing, these are:

1. Binder jetting

Also referred to as 3D printing or powder bed and inkjet. Binder jetting uses liquid materials printed onto thin layers of powder.
Building layer by layer and, effectively glueing the particles together.

Metals, foundry sand, and ceramics in the granular form are commonly used in binder jetting. Used in a variety of applications, such as the construction of large sand-casting moulds and the fabrication of low-cost 3D printed metal parts.

2. Directed energy deposition

Directed energy deposition uses thermal energy to fuse metal and metal-based materials by melting the material as it is deposited.

Also referred to as laser metal deposition, plasma arc melting and direct metal deposition, it is used for low volume part fabrication, rapid prototyping, and repair.

3. Material extrusion

Otherwise referred to as fused layer modelling or fused filament fabrication, material extrusion uses continuous filament of polymer or composite material to construct 3D parts.

The material is pushed through an extruding nozzle, where it is heated and then deposited, layer by layer, onto the build platform.

4. Material jetting

In material jetting, droplets of material are selectively deposited, continuously, or on-demand, onto the build platform.

The deposit is then cured by a heat source or ultraviolet light to form a 3D object. Material jetting is also known as direct ink writing and multi-jet modelling and uses a similar process to that of a two-dimensional ink jet printer.

Material used in this method include polymers, waxes, composites, and biological materials.

5. Powder bed fusion

The powder bed or multi-jet fusion process includes the various printing techniques of selective laser sintering and melting, direct metal laser sintering, electron beam melting, and selective heat sintering.

High-power thermal energy via a laser or electron beam, is used to melt and selectively fuse material powder together.

6. Sheet lamination

Sheet lamination is an additive manufacturing process that bonds together thin sheets of material.

Also referred to as selective deposition lamination and laminated object manufacture, sheets are usually feed via a system of rollers.

They are then bonded together, layer-by-layer, to form a single sheet.

7. Vat photo polymerisation

The earliest method of 3D printing, vat photo polymerisation creates 3D objects using special resins called photopolymers.

The liquid photopolymer is selectively cured by targeted, ultraviolet, light-activated polymerisation.

Metal additive manufacturing or metal 3D printing is a type of additive manufacturing that uses a heat source – such as a laser or electron beam – to heat metal in powder or wire form so that it consolidates to form an object.

This manufacturing process offers unsurpassed design freedom and the ability to manufacture parts from a variety of metal-based materials, and has a number of benefits.

Metal additive manufacturing is an important part of manufacturing industry growth. It helps manufacturers improve efficiencies, reduce waste, lower emissions, and increase the speed to market of stronger and lighter parts.

How does additive manufacturing work?

Additive manufacturing technology relies on a digital data file being transmitted to a machine that then produces a three-dimensional object.

The machine builds the object layer by layer. First the raw material in powder form is spread in a thin layer where the part is to be built, and this is then treated so that it forms a solid shape. Subsequent layers are then produced the same way until the whole object is completed.

Understanding metal additive manufacturing processes

There are three primary methods leading the metal additive manufacturing trend:

• Powder bed methods spread a thin layer of powder over the powder bed surface. Once this layer is spread, high-powered thermal energy – a laser or electron beam – is used to selectively meld and sometimes melt the powder together. We’ll focus on this type of additive manufacturing method below.
  
• Directed energy deposition is where the raw material is deposited using a nozzle at the same time as it is melted with a heat source. This process is performed over several layers to produce a solid object.
  
• Metal binder jetting is the most common method used for high-volume applications. Liquid binder is imprinted onto thin layers of powder and an object is created layer by layer by essentially gluing the particles together. The object is then treated – either sintered or infiltrated – to harden it.

These methods take a transformative approach to assembly and industrial fabrication. By using computer-aided design software to guide digital hardware, metal additive manufacturing can accurately produce detailed geometric shapes. Through the meticulous deposit of layer upon layer of metal powders, lighter, stronger parts can be produced,  offering manufacturing operations more flexibility and greater efficiency.

These methods take a transformative approach to assembly and industrial fabrication. By using computer-aided design software to guide digital hardware, metal additive manufacturing can accurately produce detailed geometric shapes. Through the meticulous deposit of layer upon layer of metal powders, lighter, stronger parts can be produced,  offering manufacturing operations more flexibility and greater efficiency.

Additive manufacturing: a mini case study

Three engineers and cycling enthusiasts from Melbourne recognised an opportunity to capitalise on additive manufacturing technologies and materials to develop a premium bike frame built locally in Australia.

Their challenge was to create a super-light bicycle frame strong enough, and with enough visual appeal, to sell at a price the market would accept. So they produced  titanium components and carbon fibre tubing produced by using additive manufacturing techniques.

By doing so Bastion Cycles became the first in the world to design, develop, test and market a commercially viable, high performance road bike using additive manufacturing.

Initially the company focussed on design and outsourced the additive manufacturing of its components before a decision was made to bring the additive manufacturing process in-house.
Metal prototypes were designed to explore the technology and tested to pass ISO impact tests. The advantage of modular design capability through additive manufacturing meant prototypes could be redesigned very quickly.

Additive manufacturing provides the business with new opportunities unattainable through traditional bicycle manufacturing. It means that Bastion can produce frame walls as thin as 0.25 to 1.5mm, and that they're able to vary the geometry for total customisation.

Bastion Cycles' website offers an online tool that allows customers to design and customise their bike frame – and they can then also follow the production process from start to finish.

There are many advantages of additive manufacturing – and each of these individual advantages have in common a certain degree of waste reduction and/or energy savings.

The following are just some of the many advantages of additive manufacturing:

1. Accelerated prototyping

AM expedites product development by enabling the creation of many varying prototypes that can be produced faster and cheaper in comparison to lengthy traditional methods. Several prototypes can be printed before committing to a production run, leaving less room for error in the whole process.

In AM, any changes to the original specification are made digitally, reducing the modification costs to achieve the desired result. Traditional design modifications are generally more expensive to undertake.

2. Customisation

AM manufacturing offers design innovation and creative freedom without the cost and time constraints of traditional manufacturing.

The ability to easily alter original specifications means that AM offers greater opportunity for businesses to provide customised designs to their clients. With the ease to digitally adjust design, product customisation becomes a simple proposition.

Short production runs are then easily tailored to specific needs.

3. Energy savings

In conventional manufacturing, machinery and equipment often require auxiliary tools that have greater energy needs. AM uses fewer resources, having less need for ancillary equipment, and thereby reducing manufacturing waste material.

AM reduces the number of raw materials needed to manufacture a product. As such, there is lower energy consumption associated with raw material extraction, and AM has fewer energy needs overall.

4. Environment benefits

The environmental benefits of additive manufacturing are an advantage to businesses seeking to improve manufacturing sustainability.

AM offers many positive environmental benefits in comparison to traditional manufacturing. The most notable of which are waste reduction and energy savings.

The processes of additive manufacturing, compared to traditional manufacturing, are more efficient and significantly reduce the environmental impact of waste products.

AM offers greater material efficiency because it only uses what is needed to create a product.

5. Inventory stock reduction

AM can reduce inventory, eliminating the need to hold surplus inventory stock and associated carrying costs.

With additive manufacturing, components are printed on demand, meaning there is no over-production, no unsold finished goods, and a reduction in inventory stock.

6. Legacy parts

AM has gifted companies the ability to recreate impossible-to-find, no longer manufactured, legacy parts.

For example, the restoration of classic cars has greatly benefited from additive manufacturing technology.

Where legacy parts were once difficult and expensive to find, they can now be produced through the scanning and X-ray analysis of original material and parts.

In combination with the use of CAD software, this process facilitates fast and easy reverse engineering to create legacy parts.

7. Manufacturing and assembly

A significant benefit of additive manufacturing is the ability to combine existing multi-part assemblies into a single part.

Instead of creating individual parts and assembling them at a later point, additive manufacturing can combine manufacturing and assembly into a single process.

Effectively consolidating manufacture and assembly into one.

8. Material waste reduction

In conventional manufacturing processes, material is typically removed from a larger piece of work; think timber milling or cutting shapes from sheets of steel.

In contrast AM starts from scratch, adding material to create a component or part.

By using only the substance necessary to create that part, AM ensures minimal waste. AM also reduces the need for tooling, therefore limiting the amount of material needed to produce components.

9. Part flexibility

Additive manufacturing is appealing to companies that need to create unusual or complex components that are difficult to manufacture using traditional processes.

AM enables the design and creation of nearly any geometric form, ones that reduce the weight of an object while still maintaining stability.

Part flexibility is another major waste reduction aspect of AM. The ability to develop products on-demand, inherently reduces inventory and other waste.

10. Part reliability

Small components and those with intricate parts, or small moving pieces typically require strict manufacturing tolerances and very controlled assembly processes.

Additive manufacturing methods help to reduce the number of component defects and improve part reliability.

Additive manufacturing technology allows manufacturers to print entire components with precise tolerances. Thereby, improving part reliability and product quality.

11. Production flexibility

A key benefit of additive manufacturing is the ability of producers to quickly switch between different products.

Allowing a more streamlined supply chain and economical production batches, minus costly and/or time-consuming setup.

This inherent made-to-order technology with the flexibility to create small batch orders, means producers end up with fewer unsold products and less inventory waste.

12. Supply chain improvements

The benefits of additive manufacturing on supply chains takes many forms.

It reduces material waste, simplifies production processes, and the on-demand production offered by additive manufacturing improves supply chain flexibility because the finished product can be manufactured in proximity to the end-user.

AM improves process flexibility that enables supply chains to quickly react to demand, lowers supply chain risk by providing a contingency plan and helps to reduce supply-related costs.

1. Cost of entry

With additive manufacturing, the cost of entry is still prohibitive to many organisations and, in particular, smaller businesses.

The capital costs to purchase necessary equipment can be substantial and many manufacturers have already invested significant capital into the plant and equipment for their traditional operations.

Making the switch is not necessarily an easy proposition and certainly not an inexpensive one.

2. Production costs

Production costs are high. Materials for AM are frequently required in the form of exceptionally fine or small particles that can considerably increase the raw material cost of a project.

Additionally, the inferior surface quality often associated with AM means there is an added cost to undertake any surface finishes and the post-processing required to meet quality specifications and standards.

3. Additional materials

Currently there is a limit to the types of materials that can be processed within AM specifications and these are typically pre-alloy materials in a base powder.

The mechanical properties of a finished product are entirely dependent upon the characteristics of the powder used in the process. All the materials and traits required in an AM component have to be included early in the mix.

It is, therefore, impossible to successfully introduce additional materials and properties later in the process.

4. It’s slow

As mentioned, additive manufacturing technology has been around since the eighties, yet even in 2021, AM is still considered a niche process.

That is largely because AM still has slow build rates and doesn’t provide an efficient way to scale operations to produce a high volume of parts. Depending on the final product sought, additive manufacturing may take up to 3 hours to produce a shape that a traditional process could create in seconds.

It is virtually impossible to realise economies of scale.

5. Post-processing

A certain level of post-processing is required in additive manufacturing because surface finishes and dimensional accuracy can be of a lower quality compared to other manufacturing methods.

The layering and multiple interfaces of additive manufacturing can cause defects in the product, whereby post-processing is needed to rectify any quality issues.

To maximise the benefits of AM and minimise its disadvantages, manufacturers must adapt their design approach. Here’s a practical checklist:

• Minimise support structures: Design parts to reduce overhangs and unnecessary supports, as these increase material use and post-processing time. Consider self-supporting angles and integrate features that eliminate the need for external bracing during printing.
• Optimise lattice infills: Use lattice structures for strength while reducing weight and material use. Experiment with different lattice geometries to balance rigidity and flexibility and ensure the design supports load-bearing requirements without compromising efficiency.
• Wall thickness requirements: Ensure walls are thick enough for strength but thin enough for efficiency. Overly thick walls can lead to excess material consumption and longer build times, while thin walls may compromise durability. Validate thickness against the chosen material’s mechanical properties.
• Build orientation: Position parts to minimise stress and improve surface finish. Proper orientation can reduce the need for supports, improve dimensional accuracy, and shorten production time. Analyse how orientation affects thermal gradients and residual stresses during printing.
• Material selection: Choose materials suited to performance needs and cost constraints. Consider factors such as corrosion resistance, thermal conductivity, and weight. For metal AM, evaluate powder quality and particle size distribution to ensure consistent results and avoid defects.

Additive manufacturing has been advancing in technology since the late 1980s and has experienced widespread use in the past decade.

While the applications of additive manufacturing will continue to grow, the benefits of additive manufacturing have already vastly transformed the following five industries:

Aerospace

With some of the most demanding industry standards in terms of performance, the aerospace industry was one of the first to adopt additive manufacturing. The commercial and military aerospace domain needs flight-worthy components that are made from high-performance materials.

Common AM applications in the aerospace space, include environmental control system ducting, custom cosmetic aircraft interior components, rocket engines components and combustor liners.

Additive manufacturing helps deliver complex, consolidated parts with the enhanced strength that is a requisite in the industry. With consolidated designs that require less material and overall weight reduction, which is a crucial factor for the aerospace industry.

Consumer products

Marketing teams, designers, and graphic artists function to form ideas and deliver products to market as quickly as possible while adapting to fluctuating trends and consumer demand. Part of this process is spent simulating the look and feel of the final product.

AM has proven beneficial to the product development of many consumer goods such as sporting goods and consumer electronics.

Quickly delivering detailed iterations early in the product development life cycle, with fine details, functionality, and realistic aesthetics.

As AM technology advances in speed and build volume, it is likely that more consumer products will look to additive manufacturing for larger volume demands.

Energy

Additive manufacturing’s innovation in producing efficient, on-demand, lightweight components has driven success in the energy sector.

Centring on AM’s capability to quickly create tailored components and environmentally friendly materials that can withstand extreme conditions.

Key AM applications that have developed in the gas, oil and energy industries include various control-valve components, pressure gauge pieces, turbine nozzles, rotors, flow meter parts, and pump manifolds.

With the capability to develop corrosion resistant metal materials AM has the potential to create customised parts for use under-water or other harsh environments, associated with the industry.

Medical

The rapidly innovating medical industry utilises AM solutions to deliver breakthroughs in functional prototypes, surgical grade components, and true to life anatomical models.

AM in the medical field is producing advancements in the areas of orthopaedic implant and dental devices, as well as tools and instrumentation such as seamless medical carts, anatomical models, custom saw and drill guides, and custom surgical tools.

Material development in the medical industry is critical with the certified biocompatible materials potentially revolutionising areas of customised implants, and the life-saving devices and pre-surgical tools to increase patient results.

Transportation

The transportation industry requires parts that withstand extreme speeds and heat, while still being lightweight enough to avoid preventable drag. The benefit of additive manufacturing’s ability to develop lightweight components has led to more efficient vehicles.

Additive manufacturing – and particularly metal AM – is shaping the future of production. While costs remain a challenge, technology is becoming increasingly accessible, offering SMEs opportunities to innovate and compete.

Additive manufacturing thrives on precision and efficiency. Without accurate stock management, production can stall. Unleashed inventory management software gives you real-time visibility of raw materials, ensuring you don’t face delays or overstocking issues. 

With real-time reports and seamless integration, you can align your additive manufacturing processes with lean inventory practices for maximum profitability.

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