Computer Integrated Manufacturing

An Overview of Computer Integrated Manufacturing (CIM)

Graphics courtesy of BPIOpens in new window The acronym CIM stands for computer integrated manufacturing, a manufacturing process supported by computers. CIM involves the total integration of Computer Aided Design (CAD)Opens in new window/Computer Aided Manufacturing (CAM)Opens in new window and also other business operations and databases.

Besides CAD/CAM, the other components of CIM are CAP (Computer Aided Planning) and CAQ (Computer Aided Quality Assurance).

Since about 1970, there has been a growing trend in manufacturing firms toward the use of computers to perform many of the functions related to design and production. The technology associated with the trend is called CAD/CAM, or Computer Aided Design (CAD)Opens in new window and Computer Aided Manufacturing (CAM)Opens in new window.

Today, it is widely recognized that the scope of computer applications must extend beyond design and production to include the business functions of the firm. The name given to this more comprehensive use of computers is Computer Integrated Manufacturing (CIM).

An attempt to define CIM reminds us about the story of a group of blind persons trying to describe an elephant by touching it. Each has a different description depending upon which part of the elephant’s body was touched.

In the case of CIM, several definitions have been attempted. However, the one coined by Shrensker (1990) for the Computer and Automated Systems Association of the Society of Manufacturing Engineers (CASA/SME) is perhaps the most appropriate. According to him,

Other relevant definitions include:

• One needs to think of CIM as a computer system in which the peripherals, instead of being printers, plotters, terminals, and memory disks, are robots, machine tools, and other processing equipment. It is a little noisier and a little messier, but it’s basically a computer system.
  — Joel Goldhar, Dean, Illinois Institute of Technology



• CIM is a management philosophy, not a turnkey computer product. It is a philosophy crucial to the survival of most manufacturers because it provides the levels of product design and production control and shopfloor flexibility to compete in future domestic and international markets.
  — Dan Appleton, President, Dacom, Inc.



• CIM is an opportunity for realigning your two most fundamental resources: people and technology. CIM is a lot more than the integration of mechanical, electrical, and even informational systems. It’s an understanding of the new way to manage.
  — Charles Savage, President, Savage Associates

Computer integrated manufacturing includes all the engineering functions of CAD/CAM and the business functions of the firm as well. These business functions include order entry, cost accounting, employee time records and payroll, and customer billing.

CAD/CAM is based on the capability of a computer system to process, store, and display large amounts of data representing part and product specifications. For mechanical products, the data represents graphic models of the components; for electrical products, they represent circuit information, and so forth. CAD/CAM technology has been applied in many industries, including machined components, electronic products, equipment design, and fabrication for chemical processing. CAD/CAM involves not only the automation of the manufacturing operations, but also the automation of elements in the entire design-and-manufacturing procedure.

Computer-aided design makes us of computer system to assist in the creation, modification, analysis, and optimization of a design. The designer, working with the CAD system rather than the traditional drafting board, creates the lines and surfaces that form the object (product, part, structure, etc.) and stores this model in the computer database. By invoking the appropriate CAD software, the designer can perform various analyses on the object, such as heat transfer calculations. The final object design is developed as adjustments are made on the basis of these analyses. Once the design procedure has been completed, the computer-aided design system can generate the detailed drawings required to make the obect.

Computer-aided manufacturing involves the use of computer systems to assist in the planning, control, and management of production operations. This is accomplished by either direct or indirect connections between the computer and production operations. In the case of direct connection, the computer is used to monitor or control the processes in the factory. Computer process monitoring involves the collection of data from the factory, the analysis of the data, and the communication of process-performance results to plant management. These measures increase the efficiency of plant operations. Computer process control entails the use of the computer system to execute control actions to operate the plant automatically, as described above. Indirect connections between the computer system and the process involve applications in which the computer supports the production operations without actually monitoring or controlling them. These applications include planning and management functions that can be performed by the computer (or by humans working with the computer) more efficiently than by humans alone. Examples of these functions are planning the step-by-step processes for the product, part programming in numerical control, and scheduling the production operations in the factory.

In an ideal CIM system, computer technology is applied to all the operational and information-processing functions of the company, from customer orders through design and production (CAD/CAM) to product shipment and customer service. The scope of the computer system includes all activities that are concerned with manufacturing. In many ways, CIM represents the highest level of automation in manufacturing.

The conceptual goal of modern factories is computer integrated manufacturing. CIM denotes data-driven automation that affects all components of the manufacturing enterprise: design and development engineering, manufacturing, marketing and sales, and field support and service.

Computer-aided design systems were first applied in the electronics industry. Today, they feature three-dimensional modeling techniques for drafting and manipulating solid objects on the screen and for deriving specifications for programs to drive numerical-control machines. Once a product is designed, its production process can be outlined using computer-aided process planning systems that help select sequences of operations and machining conditions. Models of the manufacturing system can be simulated by computers before they are built. The basic manufacturing functions—machining, forming, joining, assembly, and inspection—are supported by computer-aided manufacturing systems and automated materials-handling systems. Inventory control systems seek to maintain an optimal stock of parts and materials by tracking inventory movement, forecasting requirements, and initiating procurement orders.

The technological sophistication of manufacturing information systems is impressive, and it increasingly includes applications of robotics, computer vision, and expert systems—a part of Artificial Intelligence (AI)—which comes under computer science. The core of the CIM concept is an integrated database that supports the manufacturing enterprise and is linked with other administrative databases.

In a sense, CAD/CAM allows the mass production system to manufacture customized, handmade articles. The machinery can be adapted to a particular product through computer programming, enabling work on small batches to achieve many of the economies, previously available only through mass production of identical objects. Computer aided design itself makes possible the testing of production methods and the design of the product by running tests (of such factors as ability to withstand stress, for example) through the computer. If necessary, the product design or the process can be modified without going to the expense and time required for building actual prototype models.

CIM is recognized as the islands of automation; these ‘islands’ have been created in many enterprises and can be categorized into four groups. These groups are listed below along with typical islands of automation found in these groups.

1. CAD/CAM

• Group technology
• Computer aided engineering
• Computer aided design
• Computer aided manufacturing

1. Manufacturing planning and control

• Inventory control
• Shop loading
• Capacity planning
• Master scheduling
• Purchasing

1. Factory automation

• Computer-aided manufacturing
• Robotics
• NC/DNC/CNC
• Flexible manufacturing systems
• Automated materials handling systems
• Automated test equipment
• Process controllers

1. General business management

• General and cost accounting
• Marketing
• Order entry
• Decision support
• Labor collection
• Payroll

Issues Confronting CIM

One of the key issues regarding CIM is equipment incompatibility and difficulty of integration of protocols. Integrating different brand equipment controllers with robots, conveyors and supervisory controllers is a time-consuming job which has a lot of shortening. Quite often, the large investment and time required for software, hardware, communications, and integration cannot be financially justified easily.

Another key issue is data integrity. Machines react clumsily to bad data, and the costs of data upkeep as well as general information systems departmental costs are higher than those involved in a non-CIM facility.

Yet another issue is the attempt to program extensive logic to produce schedules and optimize part sequence. There is no substitute for the human mind in reacting to a dynamic day-to-day manufacturing schedule and changing priorities.

Computer integrated is no panacea, nor should it be done with religious fervor. It is an operational tool that, if implemented properly, for all manufacturing problems, will provide a new dimension to competing: quickly introducing new customized high quality products and delivering them with unprecedented lead times, swift decisions, and manufacturing products with high velocity.

Developing an accurate database for each piece of equipment’s maintenance history is also the responsibility of the maintenance department. This history will allow the maintenance department to provide accurate data for decisions related to the plant or facility equipment.

For example, the maintenance department can provide input to equipment design and purchase decisions, assuring that equipment standardization is considered.

This aspect alone can contribute significant financial savings to the company. Standardization reduces inventory levels, training requirements, and start-up times. Accurate equipment histories also helps stores and purchasing not only reduce downtime, but also avoid carrying too much inventory.

3.    Early Equipment Management and Maintenance Prevention

The purpose of this goal is to reduce the amount of maintenance required by the equipment. The analogy that can be used here is the difference in the maintenance requirements for a car built in 1970 compared to a car built in 2000.

The 1970 car was tuned up every 30-40,000 miles. The 2000 car is guaranteed for the first 100,000 miles. This change was not brought about by accident. The design engineers carefully studied the maintenance and engineering data, allowing changes to be made in the automobile that reduce the amount of maintenance. The same can be true of equipment in a plant or facility.

Unfortunately, most companies do not keep the data necessary to make these changes, either internally or through the equipment vendor. As a result, unnecessary maintenance is performed on the equipment, raising the overall maintenance cost.

4.    Training to Improve the Skills of All People Involved

Employees must have the skills and knowledge necessary to contribute in a TPM environment. This requirement involves not only the maintenance department personnel, but also the operations personnel. Providing the proper level of training insures that the overall equipment effectiveness is not negatively impacted by any employee who did not have the knowledge or skill necessary to perform job duties.

Once employees have the appropriate skills and knowledge, their input on equipment improvement needs to be solicited by senior management. In most companies, this step only takes the form of a suggestion program. However, it needs to go well beyond that; it should also include a management with an open doors policy. Such a policy indicates that managers from the front line to the top are open and available to listen to and give consideration to employee suggestions.

A step further is the response that should be given to each discussion. It is no longer sufficient to say “That won’t work” or “We are not considering that now.” In order to keep communication flowing freely, reasons must be given.

Therefore, managers must develop and utilize good communication and management skills. Otherwise, employee input will be destroyed and the ability to capitalize on the greatest savings generator in the company will be lost.

5.    Involving Operators (Occupants) in Routine Maintenance

This goal finds maintenance tasks related to the equipment that the operators can take ownership of and perform. These tasks may amount to anywhere from 10-40% of the routine maintenance tasks performed on the equipment.

Maintenance resources that were formerly engaged in these activities can then be redeployed in more advanced maintenance activities such as predictive maintenance or reliability focused maintenance activities.

Cost-Benefit of These Goals

The questions now raised are: Are these goals all worth it? These questions are answered positively and quickly because results are as follows:

Productivity

• 100-200% increases
• 50-100% increase in rates of operation
• 500% decrease in breakdowns

Quality

• 100% decrease in defects
• 50% decrease in client claims

Costs

• 50% decrease in labor costs
• 30% decrease in maintenance costs
• 30% decrease in energy costs

Inventory

• 50% reduction on inventory levels
• 100% increase in inventory turns

Safety

• Elimination of environmental and safety violations

Morale

• 200% increase in suggestions
• Increased participation of employees in small group meetings

With all of these benefits, it is important for all companies to recognize the importance and value that productive maintenance can bring to the company.

Any company trying to achieve World Class status through other programs such as Computer Integrated Manufacturing (CIM)Opens in new window, Just in Time (JIT)Opens in new window, Total Quality Control (TQC)Opens in new window, Total Employee Involvement (TEI)Opens in new window, or Lean ManufacturingOpens in new window, will soon find that these programs will not work without total reliability of the company’s assets, which is the primary responsibility of the maintenance organization. In particular, Just in Time, Total Quality Control, and Total Productive Maintenance are all essential.

Without full utilization of these three programs, the goal of being globally competitive will never be reached.

History of TPM

From where did TPM evolve? What spurred its development? TPM originated in Japan and was an equipment management strategy designed to support the Total Quality Management strategy. The Japanese realized that companies cannot produce a consistent quality product with poorly-maintained equipment.

TPM thus began in the 1950s and focused primarily on the preventive maintenance. As new equipment was installed, the focus was on implementing the preventive maintenance recommendations by the equipment manufacturer. A high value was placed on equipment that operated at designed specifications with no break-downs. During these same years, a research group was formed which later became the Japanese Institute of Plant Management (JIPM)Opens in new window.

During the 1960s, TPM focused on productive maintenance, recognizing the importance of reliability, maintenance, and economic efficiency in plant design. This focus took much of the data collected about equipment during the 1950s and fed it back into the design, procurement, and construction phases of equipment management. By the end of the 1960s, JIPM had established and awarded a PM prize to companies that excelled in maintenance activities.

Then in the 1970s, TPM evolved to a strategy focused on achieving PM efficiency through a comprehensive system based on respect for individuals and total employee participation. It was at this time that “Total” was added to productive maintenance. By the mid-1970s, the Japanese began to teach TPM strategies internationally and were recognized for their results.

This process was an evolutionary one that took time, not because it was technically difficult to produce the results, but because of the efforts to change the organizational culture so that it valued the “Total” concept.