Review of Current Trend of Advanced Manufacturing Technology and Process: 3D Printing in Manufacturing

Amir Afiz Bin Mohamed Nizan (GS40910)1, Khairuddin Bin Haji Osman (GS40244)2

1,2Faculty of Engineering, Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia

Keywords: 3D printing, Additive manufacturing, Applications

Abstract. The advancement of modern manufacturing technology has allowed the development of 3D printing or additive manufacturing (AM) process to become more apparent as it continues to be practice widely across all industrial, manufacturers and consumer sectors. In this modern era, the high demand for the fabrication of complex components can now be successfully be delivered through creating objects directly, by adding material layer by layer in a variety of ways hence the term additive manufacturing (AM). This article aims to provide an introduction to 3D printing technology and its applications that helps revolutionize the today’s manufacturing processes. Through the understanding of the basic concept of 3D printing, the article will then review the current and emerging 3D printing technologies as well as briefly discussing the future potential and impact it brings to the development of the manufacturing applications.

Introduction

The term 3D printing is categorized under additive manufacturing process where the build-up of an object is obtained from a three-dimensional digital model. From the complete digital model, instead of removing material to create the object, the process adds material in successive patterns to create the desired shape. In 1981, the first published article about 3D printing technology was introduced by Hideo Kodama of Nagoya Municipal Industrial Research Institute where later in 1984 the first functioning 3D printer was introduced by Charles Hull through the invention of Stereolithography Apparatus (SLA) [1]. Through the years, the technology has developed rapidly to the point where different arrays of systems are being used to fabricate products ranging from sporting equipment, jewellery and fashion items to aerospace components, automotive tooling and medical implants. 3D printing itself has capture a lot of attention of people nowadays for example the news of a plastic handgun that was produced using a 3D printer [2]. This plastic gun can escape the detection of airport security system as the plastic gun comprises of 15 printable plastic components and a single metal part which acts as the firing pin and appears to be too small to trigger metal detection systems. Despite 3D printing technology is not the answer to every type of production method, however its advancement is helping accelerate design and engineering faster and more efficient. In more advance countries such as the United States, it is found that that 75 per cent of large manufacturers are currently implementing 3D printing in some form while 59 per cent of small manufacturers are implementing 3D printing [3]. This number shows that adaptation of 3D printing in the industry is blooming despite most of the manufactures uses the technology for prototyping purposes and small quantity product releases. The article will further be reviewing on the various 3D printing technologies available and the applications use specifically.

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3D Printing Technologies

The main principle of understanding 3D printing is that the technology is an additive manufacturing process. The 3D printing technology requires the use of software that slices the 3D digital (CAD) model into layers at sub mm scale. Each layer is then traced onto the build plate by the printer, once the pattern is completed, the build plate is lowered and the next layer is added on top of the previous one. This is fundamentally different from the known existing manufacturing process which is the Subtractive Manufacturing (SM) where the process requires removing of material from a preformed block. The known processes are mostly referred to processes such as Milling and Cutting which are subtractive manufacturing techniques. This type of process creates a lot of waste as the material that is removed generally cannot be reused and later simply sent out as scrap. The idea of that 3D printing can produce parts directly; it can negate the need of assembly hence producing products that are potentially to be fully functioning. However, many steps are still required prior to the delivering the of a part that includes the preparation of the actual 3D design, file conversion and also consideration of producing complicated parts that demands supports during the build process. Additional finishing process for produced parts also is important where skilled and technical finishing touches are required to obtain desired surface roughness of parts. Despite the process notably being complicated and time consuming, today’s advancement in research and development has allowed the upgrades and continual updates of the software and printing technique to become more mobile and user friendly.

The first 3D printing technique to be commercialised was Stereolithography (SL) (Fig. 1) which was mentioned developed in 1984. This technique of 3D printing is equipped with perforated platform located beneath a container of a liquid Ultraviolet (UV) curable polymer resins (photopolymer resins), together with an UV laser moving in all X-, Y- and Z- directions. A beam of laser light is used to trace the first slice of an object on the surface of the liquid, causing a very thin layer to harden. The platform is then slowly lowered and another slice is traced and hardened and this process is repeated until the complete object has been printed [2]. Despite having additional requirements such as support structures for some parts and also extensive curing process to harden the polymer, SL is generally accepted as one of the most accurate 3D printing processes with good surface finish [4].

Figure 1: Schematic of Stereolithography Technique

Fused Deposition Modelling (FDM), is another additive manufacturing technology commonly used for modelling, prototyping, and production applications. The process uses the principal of laying down material layer by layer to produce the desired part. Employing the extrusion methodology, the process starts by melting plastic filament that is deposited, via a heated extruder, a layer at a time, onto a build platform according to the 3D data supplied to the printer. Each layer

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hardens as it is deposited and bonds to the previous layer in the end producing a fairly robust objects to a high degree of accuracy [5]. This technology can be used with different materials such as polymers, foodstuffs and even synthetic stone [2]. Figure 2 shows an FDM schematic process using the extrusion methodology.

Figure 2: Schematic of Fused Deposition Modelling Technique

Another broad of technology that is applied in the 3D printing process is the Selective Laser Sintering (SLS) that works with fine powdered materials. Also an additive manufacturing, here the process uses heat projected through a high power laser (for example, a carbon dioxide laser) to bind small particles of plastic, metal ceramic, or glass powders into [6]. As each layer of the material is completed the powder bed drops incrementally and a roller levels the powder over the surface of the bed prior to the next pass of the laser for the subsequent layer to be formed and fused with the previous layer. The process is repeated until a desired three-dimensional part is fabricated. SLS technology is widely used in manufacturing industry as its ability to easily produce complex geometries directly from digital CAD data. Depending on the material, advantages of SLS is that up to 100% density can be achieved with material properties comparable conventional manufacturing methods hence large numbers of parts can be packed within the powder bed, allowing very high productivity [6]. Figure 3 represents the schematic process of SLS in every SLS 3D printing used.

Figure 3: Schematic of Selective Laser Sintering Technique

Similar to the method of building up objects from successive layers of powder, a 3D printing technology known as Multi-Jet Modelling (MJM) is available where object layers are created by emitting liquid photopolymer from a print head (like inkjet printers) as per shown in figure 4. The

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layer later is cured using UV light to harden the object. Material jetting is a very precise 3D printing method, producing accurate parts with a very smooth finish [4]. An advantage of this technique compared to others is that it is able to simultaneous deposit a number range of materials, which means that a single part can be produced from multiple materials with different characteristics and properties.

Figure 4: Schematic of Multi-Jet Modelling Technique

There are other 3D printing technologies that can be found available depending on the intended use of the user, either it to be production of a large scale product or for personal use. The variation selection of 3D printing available also must suit with the material selection in order to obtain a solid and functioning product. Table 1 shows mentioned and all other available 3D printing technologies and the material used for the product fabrication [6].

Type Technologies MaterialExtrusion Fused deposition modelling (FDM) Thermoplastics, eutectic

metals, edible materialsGranular Direct metal laser sintering (DMLS) Almost any metal alloy

Electron beam melting (EBM) Titanium alloys

Selective heat sintering (SHS) Thermoplastic powder

Selective laser sintering (SLS) Thermoplastics, metal powders, ceramic powders

Powder bed and inkjet head printing, Plaster-based 3D printing (PP)

Plaster

Laminated Laminated object manufacturing (LOM) Paper, metal foil, plastic film

Light Polymerized

Stereolithography (SLA) Photopolymer

Digital light processing (DLP) Liquid resin

Table 1: Types of 3D Printers

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Effects of 3D Printing in Manufacturing Industry

Along with the increase of 3D printing technology nowadays, the response to this technology is growing in all industry especially in healthcare, automotive, aerospace and manufacturing industries. The output from 3D printing can be used as a prototype in some industries to determine the effectiveness of the product before it is released to the open market.

Prototype is an early model or sample of a product built and it is used to test a concept or process of a new product before it is launched to the consumer use. It is the largest application for 3D printing today [7]. Prototyping gives the designers and customers to touch and test the products in the early stage of design cycle. The idea producing prototypes is to avoid waste of time and money due to changes later in real product.

By printing prototypes, manufacturers can shorten the development of product that agreed by the customer. For example, using the 3D printing prototypes, the Japanese manufacturer of correctional and massage devices known as Akashi can reduce the time of a new product by 90 percent compared using previous outsource prototyping service [7].

In some industries, 3D printing was used to produce direct part as their final product known as direct digital manufacturing [7]. It is used to shorten production time and enable the final product enter to the consumer market more quickly. Nowadays 3D printing has been used in many areas for prototyping and direct digital manufacturing. The example of the industries that using 3D printing technology in their production will be discussed in chapter applications of 3D printing below.

Applications of 3D Printing

Medical and Dental Industries

The 3D printing technology has been used broadly in healthcare industry especially in orthodontic and prosthetic devices unit. The 3D printing has potential to save lives and solve the problem in future. Early development 3D printing in healthcare is to create tissue, organs, bones and as well as prosthetic devices.

The Wake Forest Institute for Regenerative Medicine has developed a 3D printing using patient’s own cultured cells or stem cells [7]. This was done due to shortage of donated organs for transplant. The designed printer is to print organ or tissue structures that can retrieve data from CT or MRI scanner. The basic idea is to print living cells and biomaterials that hold cells together into a 3D shape and then it will be implanted into the body. For example, the Nicklaus Children’s Hospital in Miami has successfully made a surgical operation on aortic heart defect on a 4-years old girl, Mia Gonzales [11, 12]. Doctor has diagnosed Mia's problem and it is caused by double aortic arch that was putting pressure on her windpipe, making it difficult for her to breathe and to cough up phlegm when she had a cold [11, 12]. The 3D model of aortic heart has been created and printed using data taken directly from her CT scan using PolyJet Technology printers and Object Studio software which is developed by Stratasys [12].

The 3D printing technology also useful in designing of prosthetic devices because uses of lightweight materials. As example, for 2-years old girl, Emma has received her 3D-printed new arm (Fig. 5). She was born with a rare disease called arthrogryposis multiplex congenita which is can cause joints to become permanently fixed in a single position [13]. Therefore, it was impossible for her to lift her own arms on her own in order to do something as simple as picking up a toy or even

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giving her mom or dad a big hug [13]. This arm are light enough to her whose has weight 25-pounds to operate it. The 'magic arms' owned by Emma has been designed using SOLIDWORKS 3D CAD and a 3D printer, Wilmington Robotic Exoskeleton (WREX) device by non-profit organization called Magic Arms [13].

Figure 5: Emma with her ‘magic arm’ (left) [13] and Mia’s surgeon used a 3D model of her heart to reveal the best method of repair for her double aortic arch (right) [12]

With the advancement of 3D printing technology, it has open a new chapter in the orthodontic fields where the accuracy of printing and fast production times has enable patients to enjoy a beautiful smile. This can be proved by APEX Dental Milling Centre was one of the early adopters of CAD/CAM technology for producing dental parts straight from CAD design imagery [15]. The company was switched from using outsource to produce their product using CNC machines to in-house 3D printing. Therefore, it can offers lower price and faster delivery times to their customer while maintaining its high quality standards.

Figure 6: Apex uses an Objet Eden 3D printer to make crowns, bridges, inlays, etc. [15]

Automotive Industry

Major automotive manufacturers have been using 3D printing for prototyping. Take for example, Honda was switched from CNC machines for develop their product to 3D printing [8]. Honda Group was introduced 3D printing in 2006. They realized that 3D printing would be advantageous to their production. Therefore, Honda has purchased an Object® Eden500VTM 3D printer for its accuracy, speed, build size, easy support material removal and its ability to create fine details [8].

Previously, Honda Access used CNC machines to prototype parts (in-house or outsourced), which required full-time operators onsite to ensure safety from the machines’ noisy rotating blades. Outsourcing the project often increased delays due to slower communications between Honda Access and the service bureaus, leading to potential delay of time to market [8]. Therefore with adopting 3D printing technology, the problems using CNC machines has been eliminated. Figure 7 shows one of product example by Honda made using 3D printing i.e. fog light.

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Figure 7: Fog light production using 3D printing [8]

Lightweight components are the main key in fast supercar industry. Lamborghini well known as one of the supercar manufacturer in the world has adopting 3D printing in their lab which is run on FDM technology to produce a prototype car (fig. 8). These was done for determining fit and improve load paths their supercar which is printed in 1/6 scale [9]. By adopting this technology, Lamborghini has claimed that the time and cost has been reduced compare to traditional process.

Figure 8: The 1/6 scale FDM prototypes helped Lamborghini Lab determine fit and improve load paths [9]

Aerospace Industry

As others industries, aerospace industry also make an investment on 3D printing to improve the performance of assets, reducing maintenance requirements, saving fuel costs with lighter parts and consolidating components. The aerospace industry is a key growth market for 3D printing. Typically 3D printing in aerospace was used to develop engine and turbine parts as well as cabin interior components.

As example Boeing is the earliest adopters of 3D printing technology in aerospace industry. They has printed 22,000 components that are used in military and commercial planes [10]. Using 3D printing, Boeing has printed more than 30 parts including air ducts and hinges for 787 Dreamliner aircraft. The 3D printing for air ducts has been printed in one piece compare to traditional techniques which is one by one up to 20 parts due to its complex internal structure [10]. With this new technology, it reduces inventory and does not require assembly and improves inspection and maintenance times. Another benefit is reducing shipping time, reduces friction in the supply chain and reduces inventory level at the factory because all of the components was produced on site instead of ordered from other manufacturers which is take weeks to arrive at an assembly factory [7].

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Figure 9: Boeing has printed more than 20,000 parts using 3D printing technology [10]

Current Technology in 3D Printing

Additive manufacturing technology known as direct digital manufacturing (DDM) has been developed and applied to manufacturing today. It is one of the unique alternative for the production of end-user items. DDM has been designed to expand 3D printing technology from producing prototype to a real product directly from CAD files. The main objective of designing DDM is to remove constraints in traditional manufacturing processes, such as injection molding or die casting. It is being applied in a diverse range of industries such as in aerospace, automotive, consumer products, electronics and defence especially in medical and dental industries [16]. The advantages of DDM are [17]:

i) Rapid Deployment – After finish the designing of component, it can be manufactured immediately and delivered to customer faster.

ii) Low Capital Expenditure - With DDM there is no need for tooling, therefore, the initial cash outlay to ramp up manufacturing is dramatically reduced and companies can protect their cash flows, fund more new products and justify products for markets with low annual demand.

iii) Unlimited Complexity – DDM constructs parts with an additive fabrication process like FDM, thus, the design complexity is unlimited and it is free where there is no additional cost to manufacture sophisticated, intricate and complex designs.

iv) Part Consolidation – Since unlimited complexity is possible by using DDM technology, multiple components can be consolidated into a single item and it will impact on time, cost and quality are significant.

Conclusion

The 3D printing technology has been used rapidly in all industry in worldwide especially in manufacturing industries. From developing of the prototyping to produce a real product using direct digital manufacturing based on the customer requirements. Its process has been reduced the time it takes for designers and engineers to conceptualize, create, and test prototypes. With the application of 3D printing, most of the industry agreed that it can reduce the time of production time by 50 to 70 percent as well as labour costs up to 80 percent.

The 3D manufacturers also trying to develop and realize the cheapest and user-friendly 3D printer for home consumer markets. Nowadays, all the 3D printers in market is not suitable for home users because of cost factor and software used limited to the particular manufacturers, means that the software used with 3D printer is dedicated not from other open software in the markets. With the creation of 3D printers for home users, the cost factor and the software will not be a constraint anymore.

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References

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[2] Robert Bogue. 3D Printing: The Dawn of a New Era in Manufacturing? Assembly Automation, Vol. 33 Iss 4 pp. 307 – 3011. (2013).

[3] Brett P. Conner Guha P. Manogharan Kerry L. Meyers. "An assessment of implementation of entry-level 3D printers from the perspective of small businesses", Rapid Prototyping Journal, Vol. 21 Iss 5 pp. 582 – 597. (2015).

[4] Information on http://www.3Dprinintingidustry.com.

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[6] European Social Fund. Domain Group 3D Printing Workshop Notes. (2007-2013).

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[8] “Case study: Honda Access shifts its customization options into high gear with 3D printing”. Information on http://www.stratasys.com/resources/case-studies/automotive/honda-access

[9] “Case study: Lightweight Components Are Key to Fast Supercar”. Information on http://www.stratasys.com/resources/case-studies/automotive/lamborghini

[10] “3-D printing could remake U.S manufacturing,” USA Today, 10 July 2012. Information on http://www.usatoday.com/money/industries/manufacturing/story/2012-07-10/digital-manufacturing/56135298/1

[11] “Case study: Shaping your heart”. Information on http://www.stratasys.com/resources/case-studies/medical/nicklaus-childrens-hospital

[12] “Surgeons used a 3D printed heart to practice complicated surgery on a 4 year old girl”. Information on http://www.digitaltrends.com/cool-tech/3d-printed-heart-surgery/

[13] “3D printer builds ‘Magic Arms’ for two-year-old girl with joint disease”. Information on http://www.digitaltrends.com/cool-tech/3d-printer-builds-magic-arms-for-two-year-old-girl-with-joint-disease/

[14] “GE Aviation gets FAA Certification for First 3D Printed Jet Engine Part”. Information on http://3dprinting.com/news/ge-aviation-gets-faa-certification-for-first-3d-printed-jet-engine-part/

[15] “Case study: APEX Achieves Complete Digital Workflow With 3D Printing”. Information on http://www.stratasys.com/resources/case-studies/dental/apex-dental-milling-center

[16] “White paper: Direct Digital Manufacturing: Industries and Applications”. Information on http://usglobalimages.stratasys.com/Main/Secure/White%20Papers/Rebranded/SSYS_WP_direct_digital_manufacturing_part_four_industries_and_applications.pdf?v=635011144452370076

[17] “White paper: Direct Digital Manufacturing: Advantages and Consideration”. Information on http://usglobalimages.stratasys.com/Main/Secure/White%20Papers/Rebranded/SSYS_WP_direct_digital_manufacturing_part_two_advantages.pdf?v=635011144326894902

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