The shape of prints to come

3D printing will turn manufacturing on its head

By Morand Fachot

Since the mid-18th century, manufacturing has been affected by technical innovations that have led to the gradual replacement of many craft-based activities by mechanized and automated processes. From weaving to the mass production of automobiles and consumer goods and the introduction of information technology (IT) in manufacturing, these processes have had an influence on all areas of life. The emergence of 3D printing is the latest in a long line of disruptive technologies to make its mark on manufacturing. 

AM metal hinge for aircraft engine covers AM metal hinge for aircraft engine covers: 50 % lighter than the conventional model (Photo: EADS)

Various names, common features

3D printing relies on computer aided design (CAD) data and files – which could come from scans of objects – to make various products by adding layers of material. When used to make prototypes to test concepts or products, 3D printing is usually described as rapid prototyping. Increasingly it is also used to manufacture complex parts such as automotive or aerospace components, in varying quantities, in a process known as additive manufacturing (AM).

3D printing is not only deployed in industrial environments but is now also being used in the home environment by hobbyists and in small businesses, by users whose customers have small- or medium-size desktop printers, to test concepts and to produce items in very limited numbers.

This completely new and very flexible AM production process is in complete contrast – and presents many benefits – to more traditional capital-intensive ones that need moulding, casting, milling or machining processes, which require heavy and costly machinery.

A completely different variety of materials, machines and processes is used in 3D printing. 

Wide range of materials

3D-printed products can be made in a variety of materials. They include:

  • many types of thermoplastics, polymers, resins and even silicones, which can be used for different applications and products such as tooling (rapid tooling for low volume or hard tooling for higher volume manufacture), prototypes and goods
  • ceramic pastes, used for biomedical applications (bone substitute, bone implants), aerospace parts, energy applications (fuel cells) and luxury goods
  • metals, including alloys, to print intricate aerospace and other mechanical parts
  • nanoparticle inks to print electronic components such as printed circuit boards and flexible electronics
  • bioartificial tissues to print implants 
  • glass
  • concrete, used to print buildings 

Materials dictate processes and equipment

3D printing processes and equipment differ according to the type of material used in the additive process and to the end use/product. Some AM uses different types of material, e.g. plastics and metals, but often the methods are similar. Generally speaking, the materials are placed on a surface (bed) or a tank that is gradually lowered (or raised) as layers are formed and solidified.

Thermoplastics / polymers are the most common 3D printing materials. They can be:

  • filaments melted and deposited layer after layer through fused deposition modelling (FDM) or fused filament fabrication (FFF). These are used by most desktop printers. Another method is direct energy deposition (DEP) where heat is applied with a laser or electron beam
  • plastic powders sintered (compacted) using a laser beam (Sintratec) or another heat source (HP)

Photopolymer resins are another type of synthetic material used in AM. They are contained in a tank and hardened by an ultraviolet (UV) light source directed at them by a laser beam or a digital light processing (DLP) source using a projector, as with DLP TV sets.

Ceramic pastes (produced by mixing different ceramic powders with photosensitive resins) are used to print objects onto a support, layer after layer. Different shapes can be printed at the same time. In the ceramic AM process, printing is followed by debinding (removing the binding additives, e.g. resins), separating objects from their support, sintering them using a laser beam or other heat source and then cleaning and finishing them manually or automatically.

Metals are treated using different AM processes, using atomized powders placed on a bed or filaments which are then fused to form layers by sintering / melting using laser or electron beams. 

Equipment meets small and large industry needs

3D printing equipment using thermoplastics/polymers ranges from home desktop printers for filaments and costing a few hundred dollars, to intermediate 3D printers like the Sintratec SLS 3D polymer sintering printer at around USD 5 700, all the way up to more advanced machines for industry, like HP Jet Fusion 3D printers, which use plastic powders and cost in excess of USD 120 000. Machines similar to the HP Jet Fusion 3D, but faster, sell for anything between USD 140 000 and USD 1 000 000.

AM machines for metal powders are generally much more expensive, but they are used mainly in advanced industrial environments to produce complex high-performance products such as jet engine nozzles, brackets or airfoils for aircraft.

The importance that attaches to metal AM for high-tech sectors was highlighted by the 2016 USD 1 300 million majority stakes taken by General Electric (GE) in Sweden’s 3D printer maker Arcam and in Germany’s 3D printing firm Concept Laser.

Wide range of applications points to bright prospects across domains

The interest in AM shown by high-value/high-tech engineering sectors such as the aerospace industry and the possibility of producing complex parts more quickly and cheaply point to a positive outlook for 3D printing.

Leading aircraft makers like Airbus and Boeing, and their suppliers, such as engine manufacturers GE and Rolls-Royce, are increasingly investing in AM, which they anticipate will help cut production time and costs as well as the operating costs of their products, a significant marketing argument.

Boeing, for instance, cuts production time to nine hours by having Arconic make airfoils for its aircraft, using AM. Previously the process took 14 weeks. These parts are also lighter and less of the costly material involved is wasted during production. Arconic’s R&D VP, Don Larsen, told CNBC that the AM market was doubling each year for his company.

GE has started printing fuel nozzles for its jet engines. These are 25% lighter than nozzles of the previous generation, are produced as single units rather than being assembled from 20 different parts, and are more than five times as durable. GE plans to print 22 000 fuel nozzles a year for its LEAP engine in a new plant in Alabama, USA.

As Mohammad Ehteshami, who runs GE Additive, which produces engine parts using AM, said: “In the design of jet engines, complexity used to be expensive. But additive [manufacturing] allows you to get sophisticated and reduces costs at the same time. This is an engineer’s dream. I never imagined that this would be possible”.

Another possible interesting application of AM is in making individual parts when spares or drawings are no longer available. Old parts can be scanned in 3D and printed from the 3D format file.

Prototypes can be produced much faster and cheaper than through traditional methods, while custom-made items can be made at a fraction of the cost of producing a single model. For instance, 3D printer manufacturer Formlabs was able to print 500 fully-customized wristbands at a cost of USD 3,75 per piece in two days, as against USD 9 using traditional injection moulding to produce the same number of pieces but in only one type of design.

Germany’s Berker switch manufacturer says that it needs 28 days using traditional tooling to try a design compared with three days using 3D printing. The cost using traditional tooling is USD 22 300 rather than USD 3 800 with an AM process. 

IEC standardization work is essential to 3D printing

3D printing uses equipment that is complex and relies for many of its components and processes on International Standards developed by IEC technical committees (TCs) and subcommittees, as well as by SCs of the Joint TC created by the IEC and the International Organization for Standardization (ISO), ISO/IEC JTC 1.

AM equipment contains a very wide range of electronic components, including circuit boards, laser equipment, motors for moving parts, cables, switches and sensors.

For instance, documentation for the HP Multi Jet Fusion 3D printer states clearly that the printer is “IEC 60950-1” compliant. IEC 60950-1:2013, Information technology equipment – Safety – Part 1: General requirements, was prepared by IEC TC 108: Safety of electronic equipment within the field of audio/video, information technology and communication technology.

For its part, ISO/IEC JTC 1/ SC 28: Office equipment, develops International Standards for “basic characteristics, test methods and other related items of products such as 2D and 3D printers/scanners, copiers, projectors, fax and systems composed of their combinations, excluding such interfaces as user system interfaces, communication interfaces and protocols”.

3D printing may be an emerging and disruptive technology, but its future relies significantly on the adoption of a wide range of IEC and ISO/IEC International Standards.

Gallery
3D-printed fuel nozzle This 3D-printed high-temperature fuel nozzle is 25% lighter, five times more durable, runs cooler than current nozzles made from 20 different parts (Photo: GE)
AM metal hinge for aircraft engine covers AM metal hinge for aircraft engine covers: 50% lighter than the conventional model (Photo: EADS)
Team Owl Morpheus 3D printer Team Owl Morpheus 3D printer uses a DLP projector to cure liquid resins to form objects (Photo: EnvisionTEC)
EnvisionTEC 3D printing equipment EnvisionTEC 3D printing equipment (Photo: EnvisionTEC)
EnvisionTEC 3D printed glass object EnvisionTEC 3D printed glass object (Photo: EnvisionTEC)