Broad Coverage

…converting ideas into useful products...

Manufacturing encompasses all the activities of making discrete engineering products from raw material by various processes and operations following a well-organized plan for all the aspects involved. Advanced manufacturing refers to the application of enabling technologies in manufacturing. It is important to realize that the advanced manufacturing systems also require input from the traditional manufacturing, many times with stricter control of dimensions and other technological properties. Therefore, it becomes important to select proper manufacturing processes and strategies to deliver the products with right quality at the right time to the customers at a competitive price in a sustainable manner. The challenges faced by the manufacturing engineers differ from sector to sector depending on the variety and quantity required. Typical manufacturing intensive sectors are automobile, space, health care, energy, textile and defence. It is a well-known fact that manufacturing is a wealth-creating activity. Besides encouraging large scale industries, efforts must be focused on setting up small and micro scale industries. Under the right conditions, young professionals will be able to setup their manufacturing enterprise anywhere in the country. Manufacturing has a distinct advantage of engaging people with different skills, as the activities vary from traditional to advanced levels.

Sub-themes along with topics and names of the researchers working in the sub-themes are given under different themes (A-E) in the following sections. The contents will be updated from time to time.

Manufacturing Processes

… bringing about changes in shape and property…

Processes For Shape Changes: Processes such as casting, molding, forming and powder metallurgy processes produce net-shape parts. The parts can also be produced by additive methods either by traditional joining processes and advanced processes like laser beam welding, electron beam welding, friction stir welding, or incremental processes such as layered fusion deposition, 3-D printing and laser sintering. To enhance the productivity and to maintain stricter control of dimension and property, continuous improvements and innovations are necessary in the net-shape manufacturing processes. It is possible only through a fundamental understanding of process mechanics and influence of different variables on the process outcome.

Subtractive processes involve removal of excess material to produce parts with required shape, size and finish. For realization of quality parts, the parts made by net-shape or additive processes also require the application of subtractive processes on selected areas. Shearing action by sharp edges on a cutting tool or abrasive grains on a grinding wheel removes material in the form of chip or swarf in traditional processes. When it becomes difficult to shear the material, non-traditional processes based on other sources of energy such as chemical, electrical, laser, plasma and high velocity jet, and different hybrids are used. Further improvement in finish is achieved by honing and super-finishing processes that use abrasive sticks and also by lapping, extrude honing, abrasive flow finishing and magneto-rheological abrasive finishing processes that use abrasives in different carrier medium. In certain applications, chemical, electro-chemical and hybrid processes are used to improve the surface finish. The basic mechanics involved in the subtractive processes are also to be understood thoroughly to improve the productivity and part quality.

Net-Shape Processes:

(i) Casting processes: Die-casting, Investment casting, Squeeze casting; Stir casting

(ii) Processes for polymeric materials: Moulding processes, Fibre reinforced composites fabrication

(iii) Forming processes: Bulk deformation, Sheet metal forming

(iv) Powder metallurgy processes: Metallic parts, carbides and ceramics parts

Additive Processes:

(i) Joining processes: Arc welding, resistance welding, laser welding, electron beam welding, explosive joining; friction stir welding; Brazing and soldering

(ii) Incremental process: Layered fusion deposition, 3-D printing, Laser sintering

Subtractive Processes:

(i) Traditional material removal processes: Turning, drilling, milling, high speed machining, grinding. Mechanical micro-machining

(ii) Non-traditional material removal processes: Electro-discharge, Electro-chemical; Laser beam; Electron beam, Abrasive Water jet; Electro-chemical grinding; Hybrid methods; Micro-/nano-fabrication methods

(iii) Finishing processes: Honing, Lapping, super-finishing, Extrude honing, Abrasive flow finishing, Magneto-rheological abrasive finishing, hybrid methods

Processes for Property Change: Certain parts require changes in bulk material properties at different stages of manufacturing and the material is therefore subjected to suitable heat treatment cycle. For example, molds and dies are easily machined in annealed condition, while through-hardening is done before the final grinding or die-sinking. Changes in the properties of surface layer alone can be achieved by burnishing, peening, surface hardening, laser treatment, coatings, plating, and protective painting. Selection of appropriate method depends on the service requirements.

The manufacturing engineer is expected to know the material properties and the changes that can be brought about by suitable treatments. It is essential to know the charaterization  of treated surface and the functional requirements.

Bulk Properties:

(i) Heat-treatment processes:: Annealing, normalizing, homogenization, hardening

(ii) Severe plastic deformation processes:: Equal Channel Angular Pressing, Accumulative Roll Bonding, Friction Stir Processing

Surface properties:

(i) Surface deformation: Burnishing, peening

(ii) Thermal treatment: surface hardening, laser treatment

(iii) Protective coatings: plating, painting

Verification of Manufactured Parts

…checking conformance to specification…

Different characteristics of the manufactured parts are measured by metrology instruments to verify their conformance to specification. It is mandatory that the results are quoted along with the uncertainty in the measurement. For many critical characteristics, 100% inspection is necessary. For non-critical characteristics, sampling inspection is good enough as it reduces the inspection time and cost. It is prudent to introduce verification at intermediate stages and make the operator responsible to produce quality parts.

Systematically carried out measurements are also useful to ascertain the process capability from time to time. A good background in statistics is necessary for the people involved in the measurement and analysis. A suitable training is necessary for people involved in the metrology and inspection tasks. The skill level required is one order higher than that of the process people.

Geometrical Characteristics:

(i) Dimension: Linear, angular

(ii) Form: Straightness, flatness, circularity, cylindricity, free-form profile/surfaces

(iii) Surface finish: surface texture, waviness, roughness

(iv) Relationship: Parallelism, perpendicularity, concentricity, co-axiality, runt-out

Technological Characteristics:

(i) Surface hardness

(ii) Residual stresses

(iii) Functional test: strength, fatigue, corrosion

Manufacturing Equipment and Tooling

…making machines and accessories to facilitate manufacturing…

The equipment necessary for different processes such as casting, forming, machining and other non-traditional processes are designed and developed by the respective equipment manufacturer. Standard tools and accessories are also available to meet the manufacturing requirements of simple parts. However, industries buying these machines for production of parts with complex geometry have to develop required production tools, namely dies, moulds, special cutting tools and work-holding devices for each part. Sometimes, dedicated machines are needed to enhance the quality and productivity. Manufacturing engineer faces the challenges in developing not only the dedicated machines, but also a number of production tools for the parts. All the machines and tooling are subjected to rigorous inspection by appropriate metrology equipment for qualifying them.

It is seen that many courses on manufacturing have been removed from the curriculum to make way for latest topics that are more descriptive. With the available resources, one can learn them on their own. However, certain core-courses require rigorous classroom teaching and practical training. For example, a course on machine-building must be revived with more emphasis on machine tools development. Also a course on tool design and engineering must be made as a core-course.

Machines:

(i) Foundry equipments: Sand filling machines, shakers, die-casting machines, squeeze casting machines, stir casting machines

(ii) Forming machines: Forging machines, presses, special purpose forming machines

(iii) Machine tools & other machines: Metal cutting: General purpose machine tools, High speed machines, Special Purpose Machines: Gear cutting machines, deep-hole drilling machines, Non-traditional: EDM, ECM, AWJM

Tooling:

(i) Patterns, Dies and Moulds: Patterns, molds and dies for casting; molds for plastic parts, forging and press working dies

(ii) Cutting tools: Single point tool, multi-point tools, form cutting tools, generation cutting tools

Enabling Technologies:

…making machines sense and act intelligently…

The metrology which has remained mostly as a post-manufacturing activity can now be moved closer to manufacturing process as a result of technological advancement. Measurement, automation and information technologies are required to take the manufacturing to the advanced level. Measurement technology must be built into the system with metrology and sensing devices for online monitoring of the process. The process automation is then achieved by signal processing and appropriate feedback control. Automation of tool path movement is done using CNC technology and part or tool changes are handled by robotic arms and such devices. Information technology is useful in CAD-CAM integration and process simulation, and to take manufacturing to web-based and virtual reality environment.

The manufacturing engineer is expected to be familiar with sensor technology, automation and information technology. Unfortunately, even the existing mechatronics courses do not meet the growing demands in the manufacturing sector. Tailor-made programs need to be floated and skill upgradation is done depending on the type of industry.

Measurement Technology:

(i) Metrology: Dimensional, form and surface finish measurements

(ii) Sensors: Force, temperature, vibration, acoustic emission

Automation Technology:

(i) Process automation: CNC technology, adaptive control, AI

(ii) Handling automation: Conveyors; manipulators, robotics

Information Technology:

(i) CAD- CAM: Process simulation; virtual manufacturing, Web-based manufacturing

Manufacturing Strategies

…deciding system configuration and practices…

Based on the product design, data analysis and life cycle analysis, configuration of manufacturing system must be arrived using system simulation and intelligent decision support system. Among the approaches like best practices, world-class manufacturing, lean manufacturing, agile manufacturing and other hybrid methods, appropriate practices have to be identified for small, medium and large scale manufacturing. Proper mix of manufacturing and managerial aspects must be ensured for healthy manufacturing environment.

Manufacturing System:

(i) System configuration: Product design, Data analysis, Life cycle analysis, Layout, system simulation, Intelligent decision system

Practices:

(i) Small, medium and large scale manufacturing: World-class manufacturing, Lean Manufacturing, Agile Manufacturing

Application in Different Sectors

…facing challenges posed by other sectors…

Manufacturing covers almost all the sectors; typical ones being automobile, space, electrical and electronics, energy, health care, textile and defence. Since newer and advanced materials are used in these sectors and the product sizes vary from several meters to few millimeters with feature sizes ranging from millimeter to micrometer, the challenges have to be met only with innovations in processes and practices. In the present context, life cycle cost will be deciding factor in global competiveness. Therefore, it is necessary for a manufacturing engineer to have an in-depth knowledge of cost estimation and control.

The product performance must be monitored throughout its life and this is possible through appropriate sensor technology and data analytics. To cater to these challenges, research and development must be encouraged within the organization. Strong tie-ups with leading research and academic institutions in the country are necessary to promote development of newer products and processes.

Typical Manufacturing sectors:

(i) Transport: Automobile, Space,

(ii) Energy:

(iii) Health care:

(iv) Textile machines:

(v) Electrical and Electronics:

(vi) Defence:

Education Policy in Manufacturing

…catch them young...

The education and training policy must be evolved to achieve excellence in manufacturing in all sectors. The best approach will be to “Catch Them Young”. Abundant curiosity inherent in the children, as evident from the way they build sand-castles in beach and temporary shelters using discarded material, must be nurtured in the school level. To start with, the children can be asked to make demonstration models using easy-to-cut materials. As they grow, they can make functional parts using locally available materials. In senior level, they can make parts by 3-D printing. School curriculum must have a provision for this practical work.

School-level competition on make-your-part can be held as an annual event. Like popular “science” books on different topics, popular “engineering” books on manufacturing must be brought out. In college/university level, existing completely descriptive or highly theoretical courses on manufacturing must be replaced by courses that include practical aspects in addition to the basic concepts. Even manufacture of a device can be considered as a free-elective and given appropriate credit. At the post-graduate level, a course on manufacturing planning and cost estimation must be introduced.

Special training programs can be offered to students to inculcate entrepreneurship skills and prepare their minds right from the senior school level. Government must encourage young graduates to get into entrepreneurship by removing procedural bottlenecks and offering incentives. Working professionals in manufacturing also require continuous skill upgradation and they may be given certificate on completion of each program.