What is industrial engineering?
The field of industrial engineering has had many definitions given to it. Most of the definitions include all of the same elements stated in slightly different ways. For example the Accreditation Board for Engineering and Technology (ABET) defines industrial engineering as
The American Institute of Industrial Engineers (AIIE) defines industrial engineering as
Both definitions describe industrial engineering as a broad field concerned with integrating all the different aspects in a service or production environment. Part of being an industrial engineer is learning how to balance changes.
The origins of industrial engineering can be traced back to many different sources. Fredrick Winslow Taylor is most often considered as the father of industrial engineering even though all his ideas where not original. Some of the preceding influences may have been Adam Smith's treatise The Wealth of Nations, published in 1776, Thomas Malthusís Essay on Population, published in 1798, David Ricardoís Principles of Political Economy and Taxation, published in 1817, and John Stuart Millís Principles of Political Economy, published in 1848.  All of these works provided Classical Liberal explanations for the successes and limitations of the Industrial Revolution. Adam Smith was an economist as were most of his contemporaries at the time. "Economic Science" is the phrase to describe this field in England prior to American industrialization. The amount of influence this literature had on Taylor is unknown.
Another major contributor to the field and precursor to Taylor was Charles W. Babbage. Babbage was mathematics professor at Cambridge University. One of his major contributions to the field was his book On the Economy of Machinery and Manufacturers in 1832. In this book he discusses many different topics dealing with manufacturing, a few of which will be extremely familiar to an IE. Babbage discusses the idea of the learning curve, the division of task and how learning is affected, and the effect of learning on the generation of waste. He also was very interested in different methods of wage administration and even suggested profit sharing as a viable approach. Charles Babbage was the first person to suggest building a mechanical computer, "analytical calculating machine" as he called it, for the purpose of solving complex mathematical problems. An idea that is far beyond the technology of his time but later proves to be a valuable concept to the modern IE.
In the United States during the later part of the nineteenth century more developments where being made that would lead to the formalization of industrial engineering. Henry R. Towne stressed the economic aspect of an engineerís job. How was the engineer going to improve the bottom line for the company? Towne belonged to the American Society of Mechanical Engineers (ASME) as did many other early American pioneers in this new field. It was to the ASME that Towne expressed the need to develop a field focused on manufacturing systems. The IE handbook says the, "ASME was the breeding ground for industrial engineering." Towne along with Fredrick A. Halsey worked on developing and presenting wage incentive plans to the ASME. It was out of these meetings that the Halsey premium plan of wage payment developed. The purpose of his plan was to increase the productivity of workers without negatively affecting the cost of production. The plan also suggested that some of the gains be shared with the employees as an incentive to keep it going. This is one early example of one profit sharing plan.
Henry L. Gantt also belonged to the ASME and was interested in selection of workers and their training. He, like Towne and Halsey, would present papers to the ASME on topics such as cost, selection of workers, training, good incentive plans, and scheduling of work. He is the originator of the Gantt chart, currently the most popular chart used in scheduling of work. Today however, the Gantt chart is coupled with statistics to make more accurate predictions. Other types of charts that have developed out of the early scheduling efforts are the Program Evaluation and Review Technique (PERT) and Critical Path Mapping (CPM).
No history of industrial engineering would be complete without mentioning Fredrick Winslow Taylor. Taylor is probably the best known of the pioneers in industrial engineering. He used the ASME as present his ideas on the organization of work by management. He coined the term "scientific management" to describe the methods he developed through empirical studies. His work, like others, covered topics such as the organization of work by management, worker selection, training, and additional compensation for those individuals that could meet the standard as developed by the company through his methods. The Taylor method of Scientific Management had far reaching effects on the industrial revolution, in America, and abroad.
The Gilbreth family is accredited with the development of time and motion studies. Frank Bunker Gilbreth and his wife Dr. Lillian M. Gilbreth worked on understanding fatigue, skill development, motion studies, as well as time studies. Lillian Gilbreth had a Ph.D. in psychology which helped in understanding the many people issues. The Gilbreth family was interested in the "one best way" to do work. One of the most significant things the Gilbreth family did was to classify the basic human motions into seventeen types, some effective and some non-effective. They labeled the table of classification therbligs (Gilbreth spelled backwards). Effective therbligs are useful in accomplishing work and non-effective therbligs are not. Gilbreth concluded that the time to complete an effective therblig can be shortened but will be very hard to eliminate. On the other hand non-effective therbligs should be completely eliminated if possible. Gilbreth claims that any form of work can be broken down into these simple types of work.
When the United States entered World War II the government enlisted scientist to study there war plans, production methods, and logistics. These scientists developed a number of techniques for modeling and predicting optimal solutions. Later when this information was declassified the field of Operation Research was born. Much of the work was still highly theoretical and a good understanding of how to apply it in the real world did not exist. Engineers tended to ignore the developments in this field because of this. This intern caused the gap between the Operation Research (OR) group and the engineering profession to widen. Only a few companies where quick to develop Operation Research departments and capitalize on the benefits afforded by this new type of analytical modeling.
In 1948 a new society, the American Institute for Industrial Engineers (AIIE), was opened for the first time and began to give a more professional authenticity for the practicing engineers. Up to this time industrial engineers really had no specific place in the hierarchy of a company. Depending on the primary focus of the industrial engineering department the IE may end up in engineering, manufacturing, or personnel. The ASME was the only other society that required its members to have an engineering degree prior to the development of the AIIE.
During the 1960s, and after, Universities began to adopt operation research techniques and add them to the curriculum for the Industrial Engineering Degree. Now for the first time the methods of industrial engineering could rest on an analytical foundation, instead of the old method of empiricism. New developments in mathematics for optimization as well as new methods of advanced statistical analysis helped to fill in the holes once left by the purely theoretical approach. However, problems where extremely large and complex to and until the digital computer was developed processing this kind of information was almost impossible.
With Digital Computer and mass storage capabilities the industrial engineer had a brand new tool for calculating massive problems quickly. Prior to the computer computations on a system would take weeks or months if possible at all, but with the computer and the development of sub-routines, calculations could be done in minutes and easily repeated with new problem criteria. With the storage capabilities of the modern digital computer, results from previous systems could be saved and compared with new information. This data gave industrial engineers a powerful way of studying production systems and their reaction to change.
What are some of the topics the industrial engineer studies?People
This area is what sets industrial engineering apart from the other engineering disciplines. The IE undergoes several courses in psychology and social science to help them understand some of the work place dynamics involved in managing people. It also helps them develop effective methods of dealing with these problems. Other areas of concern for the IE are how many people are required, is the job designed correctly for a human operator (Ergonomics), is the operation safe, what level of pay should be offered for the work, does the job require the employee to get more training, and is there good communication between management and their employers.
To understand the manpower requirement a great deal of time study and motion study activity will need to occur. Depending on the companyís policies for setting work standards one of several methods will be chosen.
Performing a motion study. Every job can be broken down into itsí fundamental work elements. The Gilbreth family found that there are seventeen of these motions. The time to complete each motion does not change. This is the important part. Jobs can be studied visually or through the assistance of a camera for micro-motion studies.
Whether the study is visual or micro the IE will be applying the same rules of motion economy to the person, environment and tools. The rules that are applied to the person, intend to help the person move in a more balanced and synchronized manner. For example, both hands should begin and end moving at around the same time. Foot pedal devices should only be used when the operator can sit down.
The environment for the workers also needs to be set up to promote efficiency of work. Tools should be placed in fixed locations to eliminate the search and selection therbligs. Work surfaces and chairs should be adjusted to the correct working heights to eliminate stress. Whenever possible, gravity feeders should be used to deliver parts to the correct location. The worker's tools should be designed to eliminate multiple cuts. Adjustment handles should be designed to maximize the operatorís mechanical advantage.
The process above is a continuous process. To stay competitive companies must continue to increase the production capacity of their facilities while reducing their cost. The IE will be expected to come up with additional improvements each year.
Performing a time study. Without a standard the company will find it hard to estimate lead-time on their products. Times very greatly when the employee does not know what the expectation of company is. In order to correct this problem the IE will develop a fair standard expectation for each operation. It has been estimated that 12% of a company's total cost comes from direct labor. Another 43% of cost comes from the material cost. The other 45% is spent in overhead. So the idea that the largest productivity gains can be felt on the floor does not hold up in this light. Standards will be set for all parts of the company not just the operations performed by the direct laborers. The IE will be involved in analyzing and standardizing office work as well.
A good time study will take into account the unavoidable delays, fatigue, and to an extent, outside interferences. Time for wasteful steps, such as searching for tools, will not be included in the final standard. The expectation is that the workplace will be designed to accommodate the work and will be free from this type of waste.
By setting a performance standard the company can look at the schedule for the next year and determine if they have the proper amount of manpower. Prior to establishing standards the company would have to go on their gut feelings about the current capacity and need for additional help.
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The idea of mass production is to take a complex job and break it down into simple and repeatable task that can be performed with a high level of precision by the same set of operators. If the workstation, task, and environment are not designed properly the worker will be subjected to safety and health risk. Companies sometimes choose to ignore violations do to cost; however, with the current health care prices, the company could easily find itself paying triple the original cost. The IE should be aware of these issues and work with management to resolve them as quickly as possible.
From the company's point of view they want to minimize the amount of money they have to pay to the employees. This goal often goes against the other goal of management and that is productivity. The productivity of the employee is directly linked to the monetary rewards for the employee. There are several plans that have been developed over time with the intent of balancing the cost with productivity.
An IE will help the company analyze their current situation and will often be responsible for suggesting an appropriate plan. After a plan has been decided upon the IE can be instrumental in its success. Some examples of plans are: piece rates and standard labor hour plans, gain-sharing plans, employee stock ownership plans, and profit-sharing plans.
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The operators must be appropriately trained. Standards are set using people that are familiar with the job and people who have mastered the skills required to perform the job. If other individuals are going to be expected to perform at this level then they will need to be trained.
In a competitive market the employees become even more valuable, but if their training is not kept up to par then the company's most valuable asset is losing value. As new processes and methods are developed it is the responsibility of the IE to help make sure the proper level of training is administered.
Where the mechanical engineer and manufacturing engineer will be concerned with the specific machine abilities and tooling requirements, the IE will be looking at the amount of time it will take to set-up the machine, the cycle time of the machine, the number of operators required, the foot-print size, the power requirements, as well as the ergonomic design.
While the mechanical and manufacturing engineer will also be interested in the above information they will not be making their selection based on these criteria. However, the IE needs to integrate the equipment in a predefined production environment. If the machine is too large it may not fit into the area allocated for it. If the machine runs too fast then the company is buying excess capacity that may not be able to be used. If the machine runs to slow then the company is injecting a bottleneck into the system. The bottleneck will regulate the output of that part of the system. These are the types of considerations that the IE goes through during the selection of a machine.
The size of the machine and the energy requirements are very important if the equipment is going into a cellular environment. If the machine requires a separate foundation then it becomes a monument in the plant and the flow of parts must be compensated. Unless it is unavoidable, smaller less expensive equipment should be purchased, even if minor enhancements are required. This is usually a better practice then buying a more expensive machine and only using 20-40% of itsí functionality. This will also help the company to remain competitive by reducing the amount of invested capital. A group of specialized people can be developed in house for the purpose of machine modification. By buying less expensive machines and then modifying them the employer will have specialized equipment not available to their competitors and this will help give them an added edge.
Set up time is the amount of time it takes to begin producing different parts on a machine. For example, this time would be calculated from the last good part, type A, to the first good part, type B. It is extremely important that this time be minimized so the economic lot size can be shrunk. If set-up times remain large the company will operate with high levels of work in progress and finished goods tying up the companies valuable capital. Companies that fail to reduce their set-up times have a tendency to look sluggish in regards to their customers.
An IE will generally be responsible for coming up with a cost analysis on the equipment purchase. There are a several ways of coming up with this. The IE or the upper levels of management will decide upon the specific method.
The IE will also take into account how long the machine is expected to last when developing the cost analysis. A straight-line depreciation may be decided upon over the machines life. The salvage value, or the value of the machine at the end of itsí useful life, is also taken into account.
The traditional way of looking at efficiency was to keep the machine running at a 100% whether the products can be used or not. The idea was that the cost of the machine could be spread out over the amount of time it was kept running. Therefore the higher the machines efficiency, time running / time available, the better the accounting numbers looked in regards to machine cost. This tended to increase the work in progress as well as build finished goods inventories, which is undesirable.
The amount of maintenance that the machine is going to require is a variable that must be considered by the IE before the machine is put into the system. All machines are going to require some amount of maintenance, but care should be taken when selecting machines so maintenance time is minimized.
Another issue about maintenance is whether or not the staff on hand will need to be retrained. The OEM may require that a third party perform the maintenance on the machine, if so the cost of this service should be included in the overall cost analysis.
The IE is concerned with the delivery and flow of material throughout the plant. It is nice if the plant has been planned with material flow in mind, but often the plant has evolved as the company has. This can lead to a poorly outfitted facility that could be hindering higher levels of production.
Many IE are employed to evaluate the needs of a company and then design a facility that can accommodate these needs. Planning starts with the geographical selection and location. Research must be done into the local compliance codes. The planner will need to determine if there will be adequate access to suppliers and the local transportation industry.
Based on the head count in the facility the IE will need to ensure that there is enough water, adequate restrooms, and cafeteria or local food service available. If the employees will be driving cars to work then an appropriate parking lot will need to be set up.
Beyond that the IE will also be responsible of laying out the equipment and material storage locations for the plant. The key part of this analysis is how things will flow through the plant. You donít want the parts to travel any further then they must. Traveling is a form of waste that needs to be minimized.
To allow the manufacturer to stay flexible the production lot sizes should be minimalized. This will only be economical after the reduction of machine set-ups have been achieved. An IE can look at the lot size of a company as an indicator of flexibility of a company.
Economic Order Quantity
This is one of the calculations that can be used to determine the quantity of material that should be ordered to minimalize the shipping and additional cost of raw material. This is a one form of a linear equation, an example of using methods development by the operations research scientist.
Since inventory is capital that cannot be converted until finished and purchased by a consumer, it should be kept to a minimal. Inventories not only tie up capital but they reduce the flexibility of the supplier. If the customer requests a change then the inventory runs the risk of becoming obsolete. The cost of this outdated inventory will, more then likely, have to be written off by the host company.
The quality of the material can affect all parts of the system. Poor quality material often introduces excessive amounts of rework into each of the processes. If the company accepts poor material then their product will possibly end up shoddy and may or may not cause the company to loose business. A typical job for an IE would be to work with the quality department to set up a Total Quality Management system TQM.
Where is the future for Industrial Engineers?
Since about 1970 industrial engineering curriculum has integrated the methods of operation research scientists. With these analytical methods and the advancing technologies for the computer, modeling complex production and service systems will become more feasible. All the other fields of engineering have had the opportunity to set up experiments to develop the science behind the physical phenomenon. The industrial engineering field now has the same ability to talk analytically about systems.
In the future the IE will be using more of the OR techniques coupled with advanced PC based modeling packages to analyze production and service problems. Companies will expect the IE to develop a representative model of their systems and give accurate predictions about future performance. While modeling is used by many of the larger companies it has failed to penetrate the market as a viable and required tool.
With the advent of E-Business the companies will need more advanced and accurate techniques of predicting outcomes. These techniques will come from computer simulation. The ability to run the business 24x7 will force the company to be more flexible in their approaches. These 24x7 systems will be database and technology driven. The modern IE will need to be aware of and able to use the tools available in IT as well as the methods of the OR scientist to be successful in this new age.