Novel Additive Manufacturing Processes and Techniques in Industry 4.0

1. Introduction

Industry 4.0, emerging fourth industrial revolution which has integrated the concept of intelligence acquired production system and futuristic automation. In this era, industry 4.0 has changed world by adding IoT (internet of things), data analytics, cloud computing, robotics and automation, additive manufacturing etc. But before introduction of this cyber world in production systems, there were no concept gathering information, exchanging and analysing it and converting the physical industries into smart factories. Nearly two decades ago, in 1990’s two evolving technologies were warmly embraced by the manufacturing industry; they were 3D printing and rapid prototyping which come under the category of additive manufacturing. Both rapid prototyping and 3D printing uses Computer aided designing (CAD) software to create any mechanical part. As per Wohler’s report 2018, additive manufacturing term was first coined in the year 1960; subsequently few patents were filed on this technology in the year 1980, although commercially it was made available in 1987. Additive manufacturing technology was first commercially exploited by Charles Hull after the discovery of stereolithography (SLA). Later many methods were proposed namely: Fused deposition modelling (FDM), inkjet printing, powder bed fusion, 3D Printer etc. The basic building block of every method was same but they were different in terms of material usage andequipment used.New technologies are emerging at very fast rate because of its ease of accessibility in public domain since their filed patents got expired and this drove the manufacturers to fabricate new additive manufacturing based printing machines. The idea of rapid prototyping was first conceived and developed in 1980’s (Wu et al., 2016). Rapid prototyping technology helps in product development where variety of products can be fabricated with reduction in material and time consumption. In 3D printing technique we can create any part or shape with any level of complexity in its structure as many modern machines posses. In 3D printing, material is deposited layer by layer lying at the top of each other with the help of computer controls (Berman, 2012). Since, both rapid prototyping and 3D printing are using similar computer interface hence they are placed under the category of additive manufacturing (Ivanova et al., 2013) Merits of additive manufacturing are many like increased precision, repeatability of geometric specification, customization of product and variation in quality. In additive manufacturing the information is processed through CAD file to stereolithography compatible file which is also known as standard tessellation language (STL). Generally, three dimensional part product is modelled using CAD software, imported on any computer numeric controlled machine (CNC) which further decode the imported information such as geometric configuration, thickness etc by slicing each layer and then print according to the desired specification. This technology is a great boon to many industries which are now heavily dependent on it. One such industry is aerospace industry which could utilize light weight material to reduce length to weight ratio. Additive manufacturing has revolutionized medical industry by implanting replica of CT-imaged tissues, production of 3D printed drugs and civil industries by creating 3D printed houses (Vaezi et al., 2013). In 2004, society of manufacturing engineers classified various emerging technologies in manufacturing sector and integrated it to additive manufacturing. In 2012, the list was further updated and more techniques were added to the additive manufacturing category. In the past few decades, market of 3D printer has extensively increased due to its ability to adapt and ease to produce customise end product as per user specification at relatively low cost. It has been forecasted that by 2022, additive manufacturing will have the highest chunk of the market share. But still comprehensive research is needed in order to integrate additive manufacturing with advance manufacturing technologies (Stansbury & Idacavage, 2016). Additive manufacturing is officially designated as manufacturing technique by American Society for Testing and Materials (ASTM) by ASTM F2792. It defines additive manufacturing as a material joining process in which material layers are fused on top of each. Generally, simple engineering materials such as metals, ceramics, polymers, concrete, poly-lactic acid (PLA) and acrylonitrile butadiene styrene (ABS) are used in this technology. Some special materials for specific applications are used, such materials are advance metals and alloys, thermoplastics, fibre reinforced composite, biodegradable metal based and polymer based alloys etc. Mechanically properties can be improvised and product can be made less defective by controlling the anisotropic behaviour of materials. CAD software provide user friendly environment which enables product designers and researchers with easy customization of product as well as advanced simulation and optimization capabilities. Mechanical properties can be changed from one point to another and simultaneous changes are made in the design by CAD software (Stansbury & Idacavage, 2016). Although, additive manufacturing has many advantages but it also has few drawbacks like high energy consumption, limited engineering material, high cost if micro 3D printers are considered, illegal weaponry production, lack of skill personnel etc.