3D Printing – Cutting Edge Revolutionary Manufacturing Process
Published on : Wednesday 07-10-2020
Jasbir Singh enumerates the advantages additive manufacturing provides over conventional manufacturing processes.
Additive Manufacturing, which is commonly known as 3D printing, is a process of producing real objects/items of any shape and sizes using computer aided cloned design by way of building layer by layer. It is different from commonly available conventional manufacturing processes. 3D printing process is free from any form of traditional fabrication, like:
1. Unlike extrusion and injection process where mould of base material is produced into required size or cut piece used from a block of same material.
2. Using subtractive manufacturing process where drilling, cutting, milling, machining, welding, threading processes are used.
3D printing is the modern alternative to conventional manufacturing processes. It has attributes like high efficiency, cost effective, better accuracy with no tolerance product output, superior quality, and high flexibility besides being a less time consuming process. It can produce high quality, industrial grade products of complex design. The products are built and assembled without bolted or welded joints, which is inconceivable by conventional techniques of manufacturing. 3D printing can build items with gradient material at user’s place by cloning/copying the similar sample or producing from digitally stored 3D or CAD design.
There are seven major additive manufacturing processes as per ASTM F42:
1. Photopolymerisation.
2. Material jetting.
3. Binder jetting.
4. Material extrusion.
5. Powder Bed Fusion.
6. Sheet Lamination.
7. Direct Energy Deposition.
Type of 3D Printing techniques
1. Fused Deposition Modeling (FDM)
-Fused Filament Fabrication (FFF)
-Melted Extrusion Modeling (MEM)
2. Stereolithography (SLA) or SL
3. Digital Light Processing (DLP)
4. Selective Laser Sintering (SLS) or Melting (SLM)
-Direct Metal Laser Sintering (DMLS)
-Selective Heat Sintering (SHS)
5. Electron Beam Melting (EBM)
6. Powder Bed and Inkjet Head 3D Printing (PP), and
7. Laminated Object Manufacturing (LOM).
3D printers using almost similar techniques are available in market that use ‘material extrusion’ to print 3D objects. By material extrusion technique it builds up a 3D product created layer by layer, by melting of a material (thermoplastics) using computer controlled nozzle. FDM, PJP, FFM, MEM or FFF techniques are all basically the same thing. The SLS, SLM, DMLS, DMP, EBM, SHS acronyms are similar but use slightly different type of 3D printing technology. However, they all share a common bonding process. These are similar techniques but using different names to distinguish design and the name of developer.
A large number of plastic filaments are applied in 3D printers using ‘material extrusion’ to print 3D objects. The two most common forms of plastic are ABS and PLA. ABS is Acrylonitrile Butadiene Styrene, a petroleum (oil) based thermoplastic for producing the components in industry using injection moulded parts. PLA is Polylactic acid. It is a bio-degradable form of plastic that is manufactured from extract of plants such as corn starch or sugar cane. It is polyester generated by synthetic alteration of naturally occurring lactic acid. ABS plastic requires much higher temperature to reach its melting point as compared to PLA, and their 3D objects are stronger, harder and have a long lifespan. Both ABS and PLA have their own advantages and so the user selects the process based on application. The requirement of multi?material parts in additive manufacturing has steadily increased for the past few years. Materials like polymers, metals, ceramics and biomaterials are aggressively being used in various 3D techniques to obtain multi?material products.
3D printing in flying machines
Aircraft industries are exploring lighter and more durable materials for its parts. This reduces overall weight of aircraft, which in turn reduces the fuel consumption. 3D printer developers/manufacturers are closely monitoring the requirement of the aircraft industry to provide high end printing solutions to meet the growing needs. 3D printing supports reliable production because it permits rapid manufacturing of machine components, spare parts and non-critical components of any shape without loss of material. Components made using 3D printer techniques are much lighter than those produced with traditional process. Lighter means less material or lighter material and so it will be economical. This allows the reduction of bulk material consumption for manufacturing.
Major aircraft and helicopter companies have started using 3D printed parts for lighter and efficient engines and turbines. The use of 3D technology for making aircraft spare parts is still limited to non-critical components, which are not subjected to high overloads. Brackets and supports of aircraft parts are commonly manufactured by 3D printer. Bigger structures, e.g., parts of wings and cabin parts are now being tried/implemented by major giants. Safety plays a very important role in aerospace as the material selection and its printing counts critically while producing those components. In aircraft, the selection of material plays very important role where elements selected should have low flammability and toxicity and in addition are required to have high mechanical and thermal resistance. Important factors are flammability class V0 according to UL94 standard and good FST (Flame, Smoke, Toxicity) properties that the 3D printing designers are exploring.
Innovation and adaptation
The aircraft industry is gradually replacing non critical metal components with high strength, light weight, durable filaments/resins, meeting all standards by using 3D printing technology. The aviation sector requires components that are mainly made of aluminium, stainless steel and super alloys based on nickel and titanium, which have to be highly accurate. Metals such as inconel, titanium, stainless steel and spherical stainless steel among others, are now used in 3D printing thanks to the innovative technology of laser metal deposition (LMD). Each of these materials has its own distinct advantages. Many such components are under advanced stage of development for mass production by 3D printing technology having same accuracy and better life span.
The manufacturing of complex parts for aircrafts in series production becomes very expensive. Due to the small lot sizes, 3D printing techniques are optimum for various such applications. 3D printing is best suited for products that are highly complex and need periodic customisation, and the requirement is in small volumes. This also brings in the advantage of zero inventories and makes the parts available for long periods, even after discontinuation of the production line of that aircraft model. Aerospace industries require highly complex parts that are manufactured in small quantities and have high unit production costs. This makes aerospace industry highly suitable for the implementing 3D printing techniques for its
manufacturing. The current limitation in build speed and maximum part size are also one of the challenges. However, the process will get cheaper and faster along with the improvement in technology and wide-scale adoption, with large capacity printers being developed.
Airlines operators are always on the lookout to improve the flying experience of their passengers for which cabin design plays a major role. Creating custom interiors for cabin, seats, baggage holds, toilets, sliding seating cum tilting night relaxing chairs, for specific airline needs and functions is a growing trend and a perfect task for 3D printing. This has paved the way for new possibilities of more customisation of parts of aircraft cabin as it
doesn’t require much tooling changes based on one produced specifications. The manufacturing of custom components/parts becomes, faster and cost-effective. The target is to produce at lower cost, low inventory, low production and delivery time. 3D printing is beneficial for complex product prototyping to small batch production in cost-effective and efficient manner.
Futuristic 3D printing
3D printing technology has been evolving for more than 30 years by now mainly to build models, smaller prototypes and industrial parts. This has brought manufacturing out of factories to homes and offices, for more complex parts at affordable cost for applications in space research, rockets and satellites. Major companies like Boeing, Airbus and GE have created internal and integrated departments to develop prototypes using 3D printing to build various functional products required for aircraft and are investing heavily in research and development for newer applications.
In spite of certain limitations in requirement of large scale mass production, additive manufacturing provides numerous other advantages such as weight reduction, optimum use of raw materials, minimal wastage of expensive materials, ease in manufacturing of complex components, etc. The on-going path is to meet the demand for low-cost, high accuracy and durable products using rugged material selection by design and development through new 3D printing technologies. Lots of work is focused on the performances of using different materials in critical applications, and on development of new methods and techniques in 3D printing for reliable output. Newer printing methods focus mainly on the flexibility of the present frequently used materials, processing parameters and the production factors, which influence the quality and mechanical performances of the printed objects that are considered significant while development in pilot phase. The development includes complex shapes, structures and optimisation technique to improve reliable products for increased material strength and other physical properties.
Security & Safety
Safety and security of intellectual property is also an important aspect. In today’s competitive market, the additive manufacturing technology also helps protect the designs and product development information. AS now it is possible to manufacture or print the product in-house, 3D printing technologies help to a large extent to prevent design leak and lost opportunity. By using in-house 3D printing technology, the company can produce the required product prototype internally which prevents the leakage of concepts and designs.
Jasbir Singh is an Automation Expert with experience in Factory Automation and Line Automation in a large production house. He is an Implementation Strategist, Business Coach and a regular writer on automation, AI, robotics, digital technology, network communication, IIoT, wireless communication, blockchain and use of advance digital technology. Jasbir has a long association with industry to improve factory automation in production lines for productivity improvement in India and overseas by advising and also transforming into digital platform by use of AI. He may be reached by mail at: [email protected]