3D PRINTING TECHNIQUES AND RAPID PROTOTYPING. Distributed in Australia by: Document Solutions

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1 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING Distributed in Australia by: Document Solutions

2 CONTENTS INTRODUCTION 3 3D PRINTING PROCESS 4 3D PRINTING TECHNOLOGIES 6 FUSED FILAMENT FABRICATION 7 STEREO-LITHOGRAPHY AND DIGITAL 10 LIGHT PROCESSING SELECTIVE LASER SINTERING (SLS) 12 APPLICATIONS OF 3D PRINTERS 14 IN INDUSTRY RAPID PROTOTYPING 14 WHAT ARE THE OTHER OPTIONS? 15 WHAT ARE THE QUALITY REQUIRE- 15 MENTS FOR PROTOTYPING AND WHICH 3D PRINTING TECHNIQUE TO USE? WHAT ARE THE RESOURCES THAT 16 THE TEAM IS WILLING TO INVEST INTO RAPID PROTOTYPING? SAFETY AND RISK 18 Leapfrog 3D Printers H. Kamerlingh Onnesweg 2, 2408 AW, Alphen aan den Rijn, The Netherlands

3 INTRODUCTION The primary driving factor for the adoption of 3D printing techniques in the development of products is that 3D printing is an additive manufacturing process. Traditionally, products are constructed using a subtractive process that involves removing material from an object until it creates the desired part. Products that are manufactured with this method are most mass produced items. Although accurate to the needed requirements, these methods produce waste and many components require multiple machining runs to reach the desired specifications. Additionally, for producing prototypes and proof of concepts, the costs associated can be high due to the nature of reiterations during the design process and expensive tooling machines used. 3D printing instead works through building millimetre thick layers using a variety of different materials such as carbon, nylon, metal and different plastics. Many more materials are continuing to be developed to meet manufacturing needs. The promise of producing full products at home is not yet realized, nevertheless, rapid developments are happening in other areas, namely all the major engineering fields such as the automotive field, aerospace, mechanical engineering and civil engineering. The aim of this white-paper is to highlight the most utilized 3D printing techniques and explore the qualities that each technique has. This paper will highlight material choices and both the strength and weakness of each printing technique in the context of rapid prototyping within an organization.

4 4 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING 3D PRINTING PROCESS The 3D printing process involves steps that need to be taken before the creation of a prototype or end-use product. CAD software has been one of the biggest contributors to the advancement of 3D printing technologies. It is used in nearly all product development processes in some form or another. It is a crucial tool that creates 3D objects that can help product development teams test and adjust key elements in a product before shipping. The 3D printing process has become easier due to the advancement of software that can make use of the technology Designing the component in CAD software The first step in creating a 3D printed object is designing the product or component using computer software. There are 3 main design tools: CAD tools, free-form modelling software and sculpting software. Each category differs in the method that is used to create a 3D object. Converting the Design to an STL file format and transferring it to the 3D printer In order to convert the 3D design to a printable object, it must first be converted to an STL file. This is a special file format that is used to allow the communication between a computer and the 3D printer. After conversion, the user needs to use slicer software to create layers. The printer will use these layers to create the object. The STL format is the standard file format for 3D printing and all major CAD software packages support it. Setting up the 3D printer Before printing, the printer needs to be set up to accurately construct a 3D object. The setup process involves entering the correct parameters such as the material to be used, speed, temperature, and power sources. The setup process is different with each 3D printing technique. Computer Aided Design (CAD) is software that allows for the construction of objects in a virtual environment. Examples include Auto desk, Solidworks and many others. The STL file format is the most widely used file format for 3D printers. It converts 3D models into a readable format for the printer. If your STL model is rough, so will be your printed object.

5 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING Construction of the object Removing and cleaning Post-processing The building process is automated and only requires occasional monitoring to ensure accurate quality. After the completion, the object needs to be removed. Depending on the 3D printing method used, the object may still not be set or hardened. Therefore, careful handling is required. The final step is postprocessing, this includes painting and removal of support structures which are used in certain 3D printing techniques. Support structures are used to keep the 3D model s geometry intact since a heated polymer may deform. An example of this is an arch for a model building where a support is needed below the crown. Post-processing can also include aesthetic modifications of the object, such as painting, sanding and polishing. There are variations in support material options. Some are soluble in water and others require careful removal from the printed objects.

6 6 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING 3D PRINTING TECHNOLOGIES The current state of 3D printing is dominated by a number of techniques, each having a different procedure, materials, and performance and end product properties. The method chosen is dependent on the requirements by the user. The three most used are *Fused Filament Fabrication (FFF), Stereolithography (SLA) and Selective Laser Sintering (SLS). These 3 types differ mainly with the state of the raw materials before the printing process. FFF uses melted plastics, known as a filament, SLA uses a liquid resin as a starting base while SLS begins with a powder composite that is melted to form the model. 3D printing can be used for 3 main applications: 1. Rapid Prototyping 2. Tooling and moulds 3. Direct Manufacturing Many organizations use rapid prototyping to test concepts, form and fit for products. It allows a company to verify the product and test its viability. Tooling and moulding is the process of creating a custom designed final products. This is often the case for complex products that require special machinery in production. Moulds are used to cast tools and can also be manufactured to create more prototypes. Direct manufacturing is the creation of a product using 3D printers. As 3D printers improve and more materials become available, more companies are using direct manufacturing as part of their production process. The added advantage of 3D printing is it allows an organization to build custom parts for customers without having to restructure their complete production process. 3D PRINTING METHOD 8% 4% 3% According to the Smithers Pira report, the market share distribution of 3D Printing techniques is mainly dominated by FFF 3D printers. This is mainly due to the availability of lowcost printers which are sold globally with recently many printers being manufactured in China. One key distinction, however, is the majority being hobbyist printers. Brothers, R. C. (2017). The Future of 3D Printing to Surrey, UK: Smithers Pira. 85% (Brothers, 2017, p. 25) FDM SLA SLS Others *FFF is also known as Fused deposition modelling (FDM). FDM is a trademark of Stratasys but is also used to describe the same printing process.

7 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING 7 FUSED FILAMENT FABRICATION 1 2 FILAMENT DUEL EXTRUDERS BUILD BED FFF is the most commonly used additive manufacturing method. It utilizes a filament (coiled plastic) that is melted through a heated nozzle and the desired part is built layer by layer. The printer consists of two nozzles able to move along the X and Y axis. Additionally, it includes a build tray that moves down as each layer is constructed. FFF is mainly used for rapid prototyping. The layer height range is between millimetres. This method is the most accessible since materials are affordable and so are the printers. Additionally, the wide range of materials is constantly being developed meaning more versatility will be possible in the future at a lower cost. Melted filament based Multiple materials possible Requires support material for complex models Materials and printers are inexpensive

8 8 3D P R I NT I N G TEC HNIQ UES AND RAPID PROTOT Y P IN G POPULAR FUSED FILAMENT FABRICATION MATERIALS ABS PLA PVA ABS Acrylonitrile Butadiene Styrene PLA Polylactic acid PVA Polyvinyl alcohol ABS is a popular durable and flexible plastic. It is lightweight and is easy to work with and is already widely used in other mainstream products. PLA is a material derived from biodegradable compounds and is widely used in additive manufacturing. Being derived from natural sources means it is safer to use than ABS. Another great feature is PLA can be used with food which opens it up to the food industry and the medical industry. PVA is a water-soluble plastic used in 3D printing primary as a support structure material in the construction of complex structures. Applications ABS is used for architectural models, concept product models, manufacturing, fixtures and general DIY projects. Prototyping low-cost models and functional models. Used as a support material. PLA is not as heat resistant as ABS and has a rough texture that can degrade over long periods of time. PVA is an expensive material compared to the other plastics and can also release toxic fumes if the temperature settings are too high. Limitations ABS has a high-temperature requirement and this can create fumes. This can be mitigated if the 3D printer comes with an air purification system.

9 3D P R I NT I NG T ECHNIQUES AND RAPID PROTOT Y PING HIPS PETG 9 Nylon HIPS High Impact Polystyrene PETG polyethylene terephthalate (glycol) Nylon Poly-amide HIPS is a filament that is very similar to ABS but unlike ABS, it is soluble in d-limonene. It also has the advantage of being lighter than ABS making it a useful filament for various applications. PETG is a very durable material that is used in 3D printing. It has high strength and high heat resistance. Furthermore, it is safer than ABS when using it alongside food products or medical instruments. Nylon is utilized heavily due to its industrial strength, flexibility and durability. It is stronger than both ABS and PLA and additionally has the added advantage of being affordable. PETG is used for prototyping models, functional prototypes and end-use products. It is also used for mechanical parts since it is not affected by shrinkage, warping and it is fairly flexible. Nylon is used for many applications due to its versatility. It is used for both prototyping, manufacturing, tooling and machine parts. Although highly durable, the disadvantage of using PETG is that it requires careful calibration to achieve highquality prints. Nylon requires proper storage because it absorbs moisture easily and can also produce fumes if exposed to high temperatures. Applications HIPS is used both to build prototypes but has the additional benefit of being able to be a support material for complex prints. Limitations HIPS requires that your printer has both a heated bed and is capable of reaching high temperatures for effective printing.

10 10 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING STEREO-LITHOGRAPHY AND DIGITAL LIGHT PROCESSING 1 2 PRINT BED LIQUID RESIN GLASS RESIN TRAY LASER REFLECTOR UV LASER The SLA technique uses a photosensitive liquid resin that is hardened by using a light source. In contrast to FFF, an object is created through a build platform being lowered into the resin and a light source above or underneath hardening the material. The objects created are usually more accurate and smoother than FFF, however this method is mainly used for intricate small objects and has issues with larger objects. There are industrial options available, but these are mainly used for businesses that need custom parts for clients or custom tooling. Liquid resin based Multiple materials possible Requires support material for complex models Printers are expensive

11 3D P R I NT I NG T ECHNIQUES AND RAPID PROTOT Y PING 11 POPULAR STEREO-LITHOGRAPHY AND DIGITAL LIGHT MATERIAL TYPES GENERAL RESINS ENGINEERING RESINS General purpose resins Engineering resins Unlike FFF, SLA uses liquid resins that can be categorized by use and not specific material types. This is due to the variety of companies that produce their own variants and resin combinations. Engineering resins can come with a number of attributes that are dependent on the development requirements. Some are similar to ABS (Tough), others have high-temperature resistance or overall durability. These type of resins are used for both rapid prototyping and also direct manufacturing. General purpose resins have similar finishes to standard plastic and colour choices are limited. Although these resins have various properties that aim to reproduce the durability of injection moulded parts, they can be expensive. Applications General purpose resins have a number of standard uses. The main advantage they bring is they allow for high fidelity prototypes to be built. However, SLA has issues with building larger models. General purpose resins are used to produce, jewellery, functional prototypes and art models. Limitations SLA uses a variety of chemical solvents, and UV light which require safety precautions to be strictly followed. Tough Resins: Prototypes and visual prototypes. These resins are designed for heavy use cases and case where the structure will be subjugated to high stress. High-temperature resistant resins: Tooling or moulds that require heat-resistant properties. Overall durable resins: Rapid prototyping and visual prototypes. Tough Resin: Low heat resistance High-temperature resistant resin: Low strength. All resins require careful storage solutions.

12 12 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING SELECTIVE LASER SINTERING (SLS) 1 2 LASER POWDER ROLLER LASER REFLECTOR POWDER STORAGE BUILD BED Selective Laser Sintering (SLS) is a method that uses a laser to solidify a powder material. It works by having a build area that is filled with a powder composite and storage compartment. The small amount of powder in the build area is heated to just below its melting point by a laser. As the laser melts the first layer, the build platform moves down as the powder store area moves up. This action adds a new layer that can be melted by the laser. The other powder that remains in the build area also acts as a support for the object. This method is suitable for functional components and end products. Generally, SLS is used with different polymer materials while metallic components are produced using DMLS (Direct metal laser sintering). This process is similar but has different power requirements and slightly different processes due to the metal. Traditionally SLS is a method that has been strictly used by large institutions due to the high price of an SLS printer. Powder resin based Multiple materials composites available No need of support structures Printers are very expensive

13 3D P R I NT I NG T ECHNIQUES AND RAPID PROTOT Y PING 13 POPULAR SELECTIVE LASER SINTERING MATERIALS PLASTIC POWDERS METALLIC COMPOSITES Plastics Metal composites SLS printers can print using a variety of plastics to produce desired parts. There are metal composites like Alumide which is a composite of nylon and aluminium particles. The most commonly used polymer is nylon, however, there are equivalent composites that have the properties of ABS, PLA and other standard printing plastics. Often glass or other materials are added in SLS powders to induce specific material requirements. Like plastics, everything in terms of characteristics is dependent on end-user requirements. So long as the metal can be melted, then it is viable for DMLS. Applications The applications for plastic powders for SLS are to produce a wide variety of standard prototypes, visual concepts and functional prototypes. These prototypes can have heat resistant properties or be flexible. One example is printing shoe components. Functional prototypes and tooling for aerospace, medicine, electronics and rapid manufacturing. The usage of these parts is for highly customizable situations that require unique engineering solutions that are not easily found in standard industry. Limitations SLS standard plastics have different properties and deficiencies. Depending on the composite, the deficiencies are similar in nature to standard polymers. The variety of materials are limited however for SLS printing. Better materials are expensive depending on the composite. SLS can be risky due to possible combustion due to the metals and powder inhalation.

14 14 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING APPLICATIONS OF 3D PRINTERS IN INDUSTRY RAPID PROTOTYPING Rapid prototyping is a method of quickly manufacturing prototypes of products or creating tooling quickly and cost-effectively. The goal for many product development teams is to reduce the lead time in the development process. Many companies face bottlenecks due to the need to ensure quality for the end product. Both designers and engineers need to create prototypes to ensure that there are no design flaws in the product. Prototyping allows the development team to demonstrate products to stakeholders, create debate on design choices and quickly redesign faulty prototypes. The advent of 3D printing has meant the process has evolved and allowed for a number of advantages over the standard methods. Before the decision to start rapid prototyping with 3D printers, there are a number of questions that a product team needs to answer. 1. What are the other options? 2. What are the quality requirements for prototyping and which 3D printing technique to use? 3. What are the resources that the team is willing to invest into rapid prototyping? 4. Is 3D printing safe? Rapid Prototyping Process Research and Planning Design/Reiterations Review Build and Evaluation 1. The research and planning stage involves information gathering and accurately defining the goals, the problem that the product will solve and objectives before the design phase. 2. The design phase involves creating product mock-ups and using CAD software to create a 3D object. Reiterations are carried out after the evaluation stage if problems are discovered. 3. Before the product can be built, a design review is carried out to better reach product goals and requirements. 4. After approval of the design, the build stage involves printing the design and then evaluating the object to see if it meets desired specifications. If issues are discovered, the process begins again before production.

15 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING 15 WHAT ARE THE OTHER OPTIONS? Before 3D printing s technological advances, two of the most popular standard prototyping methods have been injection moulding and CNC machining. These methods are all subtractive and have some limitations. They are usually expensive considering the material wastage and requirements of complex expensive machines to create an object. CNC machining involves creating a CAD model, with a precise machining plan which is created to instruct the CNC machine on how to cut, mill or drill the raw material into the desired object. This process is time-consuming and many complex objects require multiple runs in order to meet the product specifications. Considering this process, if a reiteration for a product is needed, the process needs to be restarted. This method is extremely expensive and requires careful planning. The advantages are only felt when it comes to mass production but are limited during the product development stage. Injection moulding is the process of creating parts using melted material by inserting it into a mould and then allowing it to harden. The process is widely used in manufacturing and has its own advantages and disadvantages. However, issues arise when it comes to prototyping since it is a large industrial process that requires special tools and is mainly used in the production of metal parts and plastics. The costs to benefit is limited during the product development stage and this method is slow when changes are required. A small or medium sized business cannot justify the cost in relation to benefit during the development of a product. Additionally, the handling of the molten material is a safety concern for many businesses. Safety precautions are implemented but accidents can still occur. 3D printing, unlike the previous methods, is the fastest technique for rapid prototyping. Lead times are significantly lower irrespective of product complexity and the costs are minimal. WHAT ARE THE QUALITY REQUIREMENTS FOR PROTOTYPING AND WHICH TECHNIQUE TO USE? The second step in the rapid prototyping decision process is to make decisions regarding what kind of 3D printer to use depending on your fidelity requirements. In terms of complexity, all 3D printers can achieve complex geometries, unlike subtractive methods. For low fidelity concepts that involve more visual prototyping and basic functional prototypes with no specific requirements then the best choice would be FFF. FFF recently has made strides in quality and can create high-quality prints. Higher fidelity requirements can be achieved with SLA, however, the higher fidelity requirements mean more costs, both in materials and general operational costs. SLS can achieve medium fidelity models, mainly intricate small models and has the added bonus of metallic materials, but the investment requirements are the highest with printers being the main cost.

16 16 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING WHAT ARE THE RESOURCES THAT THE TEAM IS WILLING TO INVEST INTO RAPID PROTOTYPING? Resource decisions for 3D printing depending on: Technique choice Volume of printing parts Sizes of intended parts, Material choice Post-Processing requirements starting around US $50, while the more expensive filaments, especially for engineering purposes can cost around US $100. This cost-benefit means a higher volume of printing can be achieved at a lower cost than the other printing technologies. FFF printers also come in a variety of sizes and have the largest advantage in printing larger models. The largest printers can build models over a meter long and post-processing is minimal with less waste than other printing technologies. In terms of choice in printing techniques, FFF, as mentioned, is the most affordable. Printers start at US $1500 and prices go upwards for higher-end models. The higher-end models have features and capabilities to improve the quality of prints and better print quality. In terms of printing volume, FFF also has the largest capacity possibilities. The material costs also are relatively low with filaments TECHNIQUE COMPARISON TABLE Attribute FFF SLA SLS Raw Material Used Solid Liquid Powder Raw Material Handling Easy Medium Hard Resolution Low High Medium Machine Costs Low Medium High Operation Costs Low High Medium Material Options Many Few Few Surface Medium Very Smooth Smooth Build Volume Large Small Medium Use Easy Intermediate Intermediate Print Complexity High, with soluble support High, with support High Support Structures Can be removed by hand Have to be remove None or by dissolving in water by plier/cutter Post Processing Low to none Medium, curing Medium, removing powder Time-to-market After Printing Instant Curing, 15 minutes Removing powder, 10 minutes Machine Preparation Low, 5 minutes avg. Very low, 1 minute avg. Low, long heat up? Machine After-care Medium, 10 minutes avg. Medium, 10 minutes avg. Low, 15 minutes avg. Recommended Protection None Gloves Gloves, mask Deformation Gradually Sudden Gradually

17 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING 17 SLA printers are relatively expensive with prices ranging from US $3000 to over US $ Material costs, however, begin at around $150 for resins and as stated, prices increase as you purchase for higher fidelity requirements. The volume capabilities of SLA are lower than the other printing techniques due to the need to cure the liquid resin. Additionally, the part sizes that can be printed are smaller than other printing technologies. This is due to the nature of the printing setup where many machines lift the object from the resin, therefore larger objects can be challenging to print. There are reverse setup options where the laser is above and this allows the volume capacity to increase but at a cost. These printers incur large investment costs and management of the liquid resin in a large printer is difficult during the post-processing step. SLS printers are the priciest, but they offer medium print quality. They are mainly for large organizations and pricing starts at US $10000 and can reach above US $ for industrial configuration printers. Material costs are also pricey, starting at US $100 and the metallic powder being the priciest. SLS printed parts can be larger than standard SLA, but smaller than FFF s capacity. Select Laser Sintering is suitable for more high-fidelity oriented printing and is effective in the higher end production requirements for engineering companies. These requirements are for end-use products, functional prototypes at the end of the product development process before full-scale production can begin.

18 18 3D PRINTING TECHNIQUES AND RAPID PROTOTYPING SAFETY AND RISK Before making a purchase of a 3D printers, the issue of safety is a major factor depending on intended use. Having machines that use heat, lasers and a multitude of different materials that can be mishandled is a risk that needs to be considered at every step of the prototyping process. Each development team needs to assess the usage frequency, the location of the printer, how well trained are the users and the safety features of the printer before making a purchase. Each printer has its safety concerns when it comes to usage and some need more safety training than others. The following table highlights key areas of concern: SAFETY COMPARISON TABLE Hazards FFF SLA SLS Material Handling Low: Most filaments come in a solid coil and pose no immediate danger to the user. Medium: SLA uses liquid resin with many mixtures that can cause irritation to eyes and skin. High: Powder polymers can easily be inhaled and dropped leading to safety concerns for users. Flammability Low: Heated nozzles can reach high temperatures and should not be Low: Liquid resins are low risk to flammability depending on handling. High: Metallic powders do have a risk with combustion. touched during operation. Toxicity Low: ABS can produce fumes but many printers have air filters. Medium: Mishandling of liquid resins is a danger and ingestion Medium: Powder can get into sensitive areas and cause health concerns. is hazardous. Inhalation Low: Inhalation main arise from possible material fumes, but Low: Resins need to be stored carefully and enclosed. High: Powders can be inhaled before or after printing. printers can be purchased with HEPA air filters. UV Radiation None High: UV radiation is a health risk. Low: SLS mainly uses lasers to melt powder polymers. Training requirements Minimum Medium High

19 Leapfrog 3D Printers H. Kamerlingh Onnesweg 2, 2408 AW, Alphen aan den Rijn, The Netherlands Distributed in Australia by: Kyocera Document Solutions Australia Copyright 2018 Leapfrog 3D Printers. All rights reserved.