Industrial engineering is the engineering discipline that concerns the design, development, improvement, implementation and evaluation of integrated systems of people, knowledge, equipment, energy, and material. Industrial engineering draws upon the principles and methods of engineering analysis and synthesis, as well as mathematics, physical and social sciences together with the principles and methods of engineering analysis and design to specify, predict and evaluate the results to be obtained from such systems. Industrial engineers work to eliminate wastes of time, money, materials, energy and other resources.
Industrial Engineering is also known as Production Engineering, Manufacturing Engineering or Manufacturing Systems Engineering; a distinction that seems to depend on the viewpoint or motives of the user. Recruiters or Educational establishments use the names to differentiate themselves from others.
Whereas most engineering disciplines apply skills to very specific areas, industrial engineering is applied in virtually every industry. Examples of where industrial engineering might be used include shortening lines (or queues) at a theme park, streamlining an operating room, distributing products worldwide, and manufacturing cheaper and more reliable automobiles.
The name "industrial engineer" can be misleading. While the term originally applied to manufacturing, it has grown to encompass services and other industries as well. Similar fields include operations research, systems engineering, ergonomics and quality engineering.
There are a number of things industrial engineers do in their work to make processes more efficient, to make products more manufacturable and consistent in their quality, and to increase productivity.
Areas of Expertise
The expertise required by an Industrial Engineer will include some or all of the following elements. People with limited education qualifications, or limited experience may specialise in only a few.
- On demand
- Investigate problems relating to component quality or difficulties in meeting design and method constraints.
- Investigate problems with the performance of processes or machines.
- Implement design changes at the appropriate times.
- Specifically per Product (short term)
- Analysis of the complete product design to determine the way the whole process should be split into steps, or operations, and whether to produce sub-assemblies at certain points in the whole process. This requires knowledge of the facilities available in-house or at sub-contractors.
- Specification of the method to be used to manufacture or assemble the product(s) at each operation. This includes the machines, tooling, jigs and fixtures and safety equipment, which may have to be designed and built. Notice may need to be taken of any quality procedures and constraints, such as ISO9000. This requires knowledge of Health and Safety responsibilities and Quality policies. This may also involve the creation of programs for any automated machinery.
- Measurement or calculation of the time required to perform the specified method, taking account of the skills of the operator. This is used to cost the operation performed, to allow balancing of assembly or machining flow lines or the assessment of the manufacturing capacity required. This technique is known as Work Study. These times are also used in Value Analysis.
- Specification of the storage, handling and transportation methods and equipment required for components and finished product, and at any intermediate stages throughout the whole process. This should eliminate the possibility for damage and minimise the space required.
- Specifically per Process (medium term)
- Determine the maintenance plan for that process.
- Assess the range of Products passing through the process, then investigate the opportunities for process improvement through a reconfiguration of the existing facilities or through the purchase of more efficient equipment. This may also include the out-sourcing of that process. This requires knowledge of design techniques and of investment analysis.
- Review the individual Products passing through the Process to identify improvements that can be made by redesign of the Product, to reduce (or eliminate) the cost that process adds, or to standardise the components, tooling or methods used.
- Generically (long term)
- Analyse the flow of Products through the facilities of the factory to assess the overall efficiency, and whether the most important Products have priority for the most efficient process or machine. This means maximising throughput for the most profitable products. This requires knowledge of statistical analysis and queuing theory, and of facilities positional layout.
- Training of new workers in the techniques required to operate the machines or assembly processes.
- Project Planning to achieve timely introduction of new products and processes or changes to them.
- Generally, a good understanding of the structure and operation of the wider elements of the Company, such as sales, purchasing, planning, design and finance; including good communication skills. Modern practice also requires good skills in participation in multi-disciplinary teams.
Value engineering is based on the proposition that in any complex product, 80% of the customers need 20% of the features. By focusing on product development, one can produce a superior product at a lower cost for the major part of a market. When a customer needs more features, sell them as options. This approach is valuable in complex electromechanical products such as computer printers, in which the engineering is a major product cost.
To reduce a project's engineering and design costs, it is frequently factored into subassemblies that are designed and developed once and reused in many slightly different products. For example, a typical tape-player has a precision injection-molded tape-deck produced, assembled and tested by a small factory, and sold to numerous larger companies as a subassembly. The tooling and design expense for the tape deck is shared over many products that can look quite different. All that the other products need are the necessary mounting holes and electrical interface.
Quality Assurance/Quality Control
Quality control is a set of measures taken to ensure that defective products or services are not produced, and that the design meets performance requirements. Quality Assurance covers all activities from design, development, production, installation, servicing and documentation. This field introduced the rules “fit for purpose” and “do it right the first time”.
It is a truism that "quality is free." Very often, it costs no more to produce a product that always works, every time it comes off the assembly line. While this requires a conscious effort during engineering, it can considerably reduce the cost of waste and rework.
Commercial quality efforts have two foci. First, to reduce the mechanical precision needed to obtain good performance. The second is to control all manufacturing operations to ensure that every part and assembly are within a specified tolerance.
Statistical process control in manufacturing usually proceeds by randomly sampling and testing a fraction of the output. Testing every output is generally avoided due to time or cost constraints, or because it may destroy the object being tested (such as lighting matches). The variances of critical tolerances are continuously tracked, and manufacturing processes are corrected before bad parts can be produced.
A valuable process to perform on a whole consumer product is called the "shake and bake." Every so often, a whole product is mounted on a shake table in an environmental oven, and operated under increasing vibration, temperatures and humidity until it fails. This finds many unanticipated weaknesses in a product. Another related technique is to operate samples of products until they fail. Generally the data is used to drive engineering and manufacturing process improvements. Often quite simple changes can dramatically improve product service, such as changing to mold-resistant paint, or adding lock-washed placement to the training for new assembly personnel.
Many organizations use statistical process control to bring the organization to Six Sigma levels of quality. In a six sigma organization, every item that creates customer value or dissatisfaction is controlled to assure that the total number of failures are beyond the sixth sigma of likelihood in a normal distribution of customers - setting a standard for failure of fewer than four parts in one million. Items controlled often include clerical tasks such as order-entry, as well as conventional manufacturing processes.
Quite frequently, manufactured products have unnecessary precision, production operations or parts. Simple redesign can eliminate these, lowering costs and increasing manufacturability, reliability and profits.
For example, Russian liquid-fuel rocket motors are intentionally designed to permit ugly (though leak-free) welding, to eliminate grinding and finishing operations that do not help the motor function better.
Some Japanese disc brakes have parts toleranced to three millimeters, an easy-to-meet precision. When combined with crude statistical process controls, this assures that less than one in a million parts will fail to fit.
Many vehicle manufacturers have active programs to reduce the numbers and types of fasteners in their product, to reduce inventory, tooling and assembly costs.
Another producibility technique is near net shape forming. Often a premium forming process can eliminate hundreds of low-precision machining or drilling steps. Precision transfer stamping can quickly produce hundreds of high quality parts from generic rolls of steel and aluminum. Die casting is used to produce metal parts from aluminum or sturdy tin alloys (they are often about as strong as mild steels). Plastic injection molding is a powerful technique, especially if the special properties of the part are supplemented with inserts of brass or steel.
When a product incorporates a computer, it replaces many parts with software that fits into a single light-weight, low-power memory part or micro-controller. As computers grow faster, digital signal processing software is beginning to replace many analog electronic circuits for audio and sometimes radio frequency processing.
On some printed circuit boards (itself a producibility technique), the conductors are intentionally sized to act as delay lines, resistors and inductors to reduce the parts count. An important recent innovation was to eliminate the leads of "surface mounted" components. At one stroke, this eliminated the need to drill most holes in a printed cricuit board, as well as clip off the leads after soldering.
In Japan, it is a standard process to design printed circuit boards of inexpensive phenolic resin and paper, and reduce the number of copper layers to one or two to lower costs without harming specifications.
It is becoming increasingly common to consider producibility in the initial stages of product design, a process referred to as design for manufacturability. It is much cheaper to consider these changes during the initial stages of design rather than redesign products after their initial design is complete.
Industrial engineers study how workers perform their jobs, such as how workers or operators pick up electronic components to be placed in a circuit board or in which order the components are placed on the board. The goal is to reduce the time it takes to perform a certain job and redistribute work so as to require fewer workers for a given task.
Fredrick Taylor and Frank and Lillian Gilbreth did much of the pioneering work in motion economy. Taylor's work sought to study and understand what caused workers in a coal mine to become fatigued, as well as ways to obtain greater productivity from the workers without additional man hours. The Gilbreths devised a system to categorize all movements into subgroups known as therbligs (Gilbreths spelled backwards). Examples of therbligs include hold, position, and search. Their contributions to industrial engineering and motion economy are documented in the children's book Cheaper by the Dozen.
Industrial engineers frequently conduct time studies or work sampling to understand the typical role of a worker. Systems such as MOST have also been developed to understand the work content of a job.
Other areas of expertise
- Solid modelling
- Quantum mechanics
- Industrial engineers
- Institute of Industrial Engineers
- Systems engineering
- Operations research
- Quality control
- Statistical process control
- Value engineering
- Reverse engineering
- Production topics
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