An advantage of producing something additively is that material is deposited only where needed, so there is little waste
by Jayashree Mendes
Of the many people who have under gone any kind of dental maintenance, few would know that they have inside their mouths some of the first products of a new industrial revolution. Over the last few years, several thousands of dental crowns, bridges and braces are being made with the help of additive manufacturing (AM) or 3D printing. Certainly, industrial 3D printers are changing manufacturing.
What do you think would be the reaction of a manufacturer if given the choice of getting a product to market with almost no capital risk, no inventory, and no re-tooling production equipment? Additive manufacturing certainly offers some great advantages and one of them is the ability to escape the constraints of traditional production processes, and to make things with unique shapes. Such kind of printing uses powerful CAD programmes and algorithms calculate the most efficient structure required to achieve the lightest weight and yet still handle all the loads and stresses that will be placed upon the object. Gary Kittle, business development executive, UTS Aerospace Systems, says, “We recently opened our state-of-the-art Materials and Process Engineering (MPE) laboratory in Connecticut. The capabilities of the lab include additive manufacturing and will build metal and plastic engineering development parts, and also high temperature composites to develop carbon-carbon and silicon carbide-based composites. These composites will be used in aircraft brakes and nano materials to develop light-weight metal matrix and polymer composites for a variety of applications across UTC Aerospace Systems.”
New ways to produce
One reason why 3D printers are becoming mainstream is that the “inks” they use are getting better thanks to advances in materials science. For instance, Stratasys, an Israeli-American company that makes 3D printers, uses a method called PolyJet, which is similar to inkjet printing: cartridges deposit layers of a liquid polymer which are cured with ultraviolet light. The company has just unveiled a new PolyJet model called the J750. It uses multiple cartridges to print items in 360,000 different colours and any combination of six different materials, which can be rigid or flexible, opaque or transparent.
Speaking about the benefits of additive manufacturing, Dr Robert N Yancey, vice-president, additive manufacturing, Altair, says, “Some of the typical benefits that AM offers are no manufacturing constraints needed in design of parts, part consolidation (reducing part count in an assembly and hence additional manufacturing processes), light-weighting, capability to handle complex geometries, ability to build parts on demand, reduced design-manufacturing times due to reduced iterations and no cost or time penalties for design modifications.”
The adoption of rapid prototyping by industry had been a slow but steady process until about a decade back. In the early 90s, it was only SLA technology that delivered results of practical use to the industry. However, SLS and LOM lacked quality. With time, SLS has begun offering better quality and resolution. Another technology from the 1990’s was FDM by Stratasys. Their so-called easy-to-use 3D office printers have taken additive manufacturing to the masses. Nishant Shah, director, engineering services, Imaginarium, says, “It is only in the last decade that India has realised the importance of AM and its potential. Huge corporations are now spinning out companies, which focus only on AM and the ways it will help them to reduce time and cost, and increase efficiency. Here it is mainly aviation and defence companies that use AM as a mainstream manufacturing process. But AM can effectively be deployed in automobile to architecture to medical to jewellery to FMCG. Some are using it to its full potential. But, yes, there still remains the task of creating awareness of the technology.”
Currently, the industrial range of 3D printers used in part production have envelope volumes ranging from – 200mm3, 300mm3, 400mm3 up to 1000mm3 and some are going beyond that as well.
Then there’s the cost factor. Brigadier SM Sharma (Retd), CEO, Continental Defence Solutions, says, “Additive manufacturing will take time to mature in India; in its present form it can be applied to limited components. The advantages of relatively defect-free components and the fact that it can used to make critical parts is a good option. But the whole aspect of cost is so huge that its adoption will take time.”
For instance, the parts that Bharat Electronics Ltd (BEL) prototype are manufactured up to a volume of 600x500x600mm3. Most of its housings are manufactured using AM and all the product elements are assembled, tested and offered to customers for their review. Parts like Ballot Unit and VVPAT was completely manufactured and offered to ECI for design approval. With advancements in AM, it is obvious that future mass manufacturing of crucial parts in the aerospace industry will be taken over by AM. A good example would be the engine fuel nozzle reconfiguration. The result is a single part that completely replicates all of the twists, turns and interior chambers that the old fuel nozzle needed. It was fabricated using multiple parts (20 individual parts), welded and assembled. The new fuel nozzle was manufactured using AM, which is not only a single part, but also 25% lighter and remarkably five times stronger.
What customers can expect
Indian manufacturing companies need not worry that they might have to cast off their current facilities and install a new one — at least for some years to come. It is not about to replace mass manufacturing. Even though the technology is improving, the finish and durability of some printed items can still fall short of what producers require. And nor can 3D printers crank out zillions of identical parts at low cost, as mass-production lines can. Nevertheless, 3D printers have their virtues, which are why they are starting to be used by some of the world’s biggest manufacturers, such as Airbus, Boeing, GE, Ford and Siemens.
Quizzed about the maturity of AM in the aerospace industry in India, SM Vaidya, executive VP & business head, Godrej Aerospace, says, “Additive manufacturing has just been introduced to the aerospace industry. To the best of my knowledge, there is no commercial or military dying object with AM yet. Qualifying these parts will require specifications to be laid down and approved which is currently not ready. Most of the specifications are at a draft stage. India has few machines imported or built but there is no powder or wire manufacturing setup yet. Alongside AM one needs to consider other facilities like HIP, NDT, etc.”
He believes that AM is the same as composite manufacturing where process control plays an important part in certification as every part is new. It can be close to a foundry or casting but there remains much to be done such as knowing the major process variables that will control the quality. As standards and specifications are yet to mature, designers need to be careful in selecting properties.
Altair’s Dr Yancey prefers to consider the bright side of AM. He says, “Increased adoption of 3D printing in aerospace will disrupt traditional supply chains, MRO companies would be able to get a aircraft serviced in much lesser time than
today, fuel consumption will reduce as there will be light-weighting, concept design to product launch cycle times will drastically come down, space vehicles could carry more payload, satellites will have more applications on board, and integrated electronics on aerospace structures will make the parts smarter.”
However, Renishaw is positive that introducing AM solutions in India can lower the entry barrier by providing cost-effective access to machinery, facilities and AM expertise. Nayan Patel, AMSC – India manager, Renishaw says, “The Centres will provide a confidential development environment in which firms can explore the benefits that AM can bring to their products, and quickly build their knowledge and confidence in AM as a production technology. Renishaw will offer a full range of training module to help customer from design for manufacturing to material development and this forms part of our global strategy.”
Some factory bosses have said that 3D printing will never replace mass manufacturing. Perhaps, but it does not have to in order to transform production processes. AM systems are being mashed together with traditional production methods, which themselves are improving with digital technologies.