In this article we will discuss about:- 1. Introduction to Computer Integrated Manufacturing 2. Meaning of Computer Integrated Manufacturing 3. Features 4. Business Integration 5. Advantages.
Introduction to Computer Integrated Manufacturing (CIM):
Computer Integrated Manufacturing (CIM) encompasses the entire range of product development and manufacturing activities with all the functions being carried out with the help of dedicated software packages. CIM is considered a natural evolution of the technology of CAD/CAM. The product data is created during design and this data is transferred from the modeling software to manufacturing software without any loss of data.
This methodological approach is applied to all activities from the design of the product to customer support in an integrated way, using various methods, means and techniques in order to achieve production improvement, cost reduction, fulfilment of scheduled delivery dates, quality improvement and total flexibility in the manufacturing system.
CIM uses a common database wherever feasible and communication technologies to integrate design, manufacturing and associated business functions that combine the automated segments of a factory or a manufacturing facility.
ADVERTISEMENTS:
CIM reduces the human component of manufacturing. CIM stands for a holistic and methodological approach to the activities of the manufacturing enterprise in order to achieve vast improvement in its performance.
CIM also encompasses the whole lot of enabling technologies including total quality management, business process reengineering, concurrent engineering, workflow automation, enterprise resource planning and flexible manufacturing.
Manufacturing industries strive to reduce the cost of the product continuously, achieve reduction in inventory, reduce waste to remain competitive in the face of global competition. In addition, there is the need to improve the quality and performance levels on a continuing basis. Another important requirement is on time delivery.
In the context of global outsourcing and long supply chains cutting across several international borders, the task of continuously reducing delivery times is really an arduous task. CIM has several software tools to address the above need and to increase flexibility in manufacturing to achieve immediate and rapid response to: product changes, production changes, process changes, equipment changes, change of personnel, etc.
ADVERTISEMENTS:
Fig. 41.2 shows a typical control loop of a manufacturing system.
Meaning of Computer Integrated Manufacturing:
CIM is a recent technology being tried in advanced countries and it comprises a combination of software and hardware for product design, production planning, production control, production equipment and production processes.
ADVERTISEMENTS:
It is an attempt to integrate the many diverse elements of discrete parts manufacturing into one continuous process like stream. It would result in increased manufacturing productivity and quality and reduced manufacturing costs.
It employs flexible machining system (FMS) which saves a manufacturer from replacing equipment each time a new part has to be fabricated. The current equipment can be adopted to produce new part (as long it is in the same produce family), with programmable software and some retooling. Thus, this system has the ability to switch from the machining of one component to different one with no down-time for change over.
This system requires NC lathes, machining centres, punch presses etc. which have ability to be readily incorporated into multi-machine cell or a fully integrated manufacturing system. Colour graphics display systems having facility of on line interactive generation of geometry form the human-machine interface.
This new technology attempts to exploit all the three methods of increasing productivity, viz. increasing the rate of metal removal, keeping the tool working for a greater proportion of time, and run them longer. Obviously multi-spindle machines with greater horsepower, stiffness and longer speed ranges are the choice for such system.
ADVERTISEMENTS:
Automatic tool changers (which change the type of tool in the spindle and also provide means of renewing dulled edges) are must. Lathes employ automatically swappable magazines of tool- racks to supply fresh cutting edges for automatic insertion into turrets.
Tool holders employed are of two-piece concept in which little more than the insert pocket is separable from the shank. This light element—little more than the tool holder nose is stored, transported, swapped and accurately repositioned by the automatic system.
Robot for handling workpieces automatically is another important machine tool peripheral essential for CIM system.
Manufacturing by CIM technique could be separated into four blocks viz. (Refer Fig. 41.1):
ADVERTISEMENTS:
(i) Product Design:
Product design for which interactive computer aided design (CAD) system allows the drawing and analysis tasks to be performed. These computer graphics systems are very useful to get the data out of the designer’s mind into a presentable form and enable analysis in fraction of time required otherwise and with greater accuracy. Design process is speeded up considerably.
(ii) Manufacturing Planning:
Computer aided process planning helps to establish optimum manufacture routines and processing steps, sequences and schedules so that the process is optimum.
(iii) Manufacturing:
Computer aided manufacturing (CAM) helps identify manufacturing problems and opportunities. Distributed intelligence in the form of microprocessors could be used to control machines and material handling and collect the data on current shop conditions.
(iv) Computer-Aided Inspection and Reporting:
Computer-aided inspection and reporting provides a feedback loop.
Computer integration of all these four activities provides the most current and accurate information about all the departments, thereby permitting better tighter control and enhances the overall quality and efficiency of the entire system. Improved communication among departments results in betterment of product by influencing the designer to consider limitations of manufacturing problems and vice versa.
The availability of most current data permits instantaneous updating of production-control data which in turn permits better planning and more effective scheduling. All machines are fully utilised, handling time reduced, parts move more efficiently through production. Product quality and design are improved. Workers become more productive and have not to waste time in coordination and searching of previous data.
In order that computer really performs its function for a given product line, a data base has to be built up which would provide computer with necessary information based on the in- depth understanding of the manufacturing process and entire system.
Normally the entire flexible manufacturing system (FMS) is managed by a computer through a distributed-logic architecture operating at several levels. A machine may have dedicated program for its own functioning. At the same time it has to obtain commands from many computers and provide necessary information desired for functioning of complete system. All such activities have to be properly coordinated.
Intermediate level of controls could be provided, such as to take care of material handling. Parts in such a system will be loaded according to instructions from supervisory computer. The computer also dispatches tooling according to the expected tool life for each tool and take desired action at appropriate time. It also generates a variety of pertinent reports like tool life data, production data, etc.
Computer integrated manufacturing has the advantage of possessing intelligence to maximise the process, provided process is well understood and all parameters can be measured in real time. It has been established that in metal cutting, virtually every parameter related to process can be determined if the shear angle is known.
It is possible to feed into the computer all the data to compute strain, strain rate, flow stress, sliding coefficient of friction at the chip tool interface, unit h.p., and the total power being consumed, cutting temperatures etc. It is also possible to determine how these parameters change with changes in material condition, feed, speed, depth of cut, tool geometry, etc.
Features of a Computer Integrated Manufacturing:
The manufacturing company is a complex, dynamic, and stochastic entity consisting of a number of semi- independent subsystems interacting and intercommunicating in an attempt to make the overall system function profitably. The complexity comes from the heterogeneous environment (both hardware and software), huge quantity of data, and the uncertainty of external environment.
The complex structure of the system and the complex relationships between the interacting semi-autonomous subsystems are also responsible to make the system more complicated. The general manufacturing systems can be decomposed into seven levels of decision hierarchies.
Decisions at the business levels are made at less frequent intervals (but have implications for longer periods into the future) and are made on the basis of more abstract (and slower to change) information on the state of the system. Decisions at the lower levels are made more frequently using much more detailed information on the state of the system.
Three kinds of decisions should be made for any manufacturing company:
(i) What kinds of products will be made,
(ii) What resource is needed to make the products, and
(iii) How to control the manufacturing systems.
However, these decisions cannot be made separately. If the company wants to make a decision at any level, it should get access to the information at other levels also. In the whole processes of decision making, the core concept is integration.
Computer Integrated Manufacturing (CIM) is considered as a totally automated factory in which all manufacturing processes are integrated and controlled by a CAD/CAM system. CIM enables production planners and schedulers, shop floor foremen, and accountants to use the same database as product designers and engineers.
It provides the right information to the right place at the right time, which enables the achievement of its product, process and business goals. It also aims at greater efficiency across the whole cycle of product design, manufacturing, and marketing, thereby improving quality, productivity, and competitiveness.
Further it provides for integration of the total manufacturing enterprise through the use of integrated systems and data communications coupled with new managerial philosophies that improve organizational and personnel efficiency. Human plays a very important role in CIM design, implementation, and operation.
The entire CIM operates at three levels, viz.:
(i) General management, and human resources management,
(ii) Three process segments: product and process definition, manufacturing planning and control, and factory automation. These process segments represent all the activities in the design and manufacturing phases of a product life cycle making the product from a concept to its assembly,
(iii) Information resources management and the common database.
The information system plays a vitally important role in the operation of CIM. Although there are many kinds of activities in managing a manufacturing company, each activity has different function in business management and production control, the associated function unit for the information system of CIM normally can be classified into three kinds of tasks: information collection, information processing, and information transfer.
Information collection task is the basic function of an information system, the collected information forms the basis of decision making at different levels from business management to device control. There are many methods of information collection depending on the information sources and technologies used.
Device sensors may provide data regarding device status, barcode scanner may provide data about the production status of the on line products, form scanner and database table view interfaces may provide data about order, raw material purchasing, and user requirements. Some data may also come from e-mail systems. The data collected can be stored in different data formats and in different repositories.
The second task of information systems is information processing, which is closely related with the business functions of a company. The business functions vary from strategy planning, process planning, product design, warehouse management, material supply, to production management and control. The upper-stream process data is processed by algorithms or human interference, the produced instructions are used for the down-stream process. In the data processing process, different decisions will be made.
The decisions made can be used in optimizing the production processes or satisfying some user requirements, such as delivery time and quality requirements. The third task of information system is data transfer between different function units.
It has three main functions, i.e., data output from application software in certain data format to one kind of data repository, data format transformation, and data transfer from one application to another application within the same computer or in a network environment.
Business Integration in Computer Integrated Manufacturing (CIM):
System view (including man, business, and technology) is important view in CIM concepts. In order to form a coordinated system, the man, business, and technology in a company must be integrated. Another aim of the integration is the integration of material flow, information flow, and capital flow.
Enterprise integration is an ongoing process since enterprise will evolve over time according to both internal needs and external challenges and opportunities. The level of integration should remain a managerial decision and should be open to change over a period of time.
Hence, one could find in some parts of a CIM enterprise, a set of tightly coupled systems and elsewhere, a set of loosely coupled systems according to choices made by this particular enterprise. The need to implement multi-vendor systems both in terms of hardware, software and an easy re-configuration requires the provision of standard interfaces. Usually there are three levels of integration covering physical systems, application, and business integration.
Business integration is concerned with the integration of those functions that manage, control and monitor business processes. It provides supervisory control of the operational processes and coordinates the day-to-day execution of activities at the application level. Application integration is concerned with the control and integration of applications.
Integration at this level means providing a sufficient information technology infrastructure to permit the system wide access to all relevant information regardless of where the data reside. The physical system integration is concerned with the interconnection of manufacturing automation and data processing facilities to permit interchange of information between the islands of automation.
Advantages of Computer Integrated Manufacturing (CIM):
CIM technology offers following unique advantages:
(i) Remarkable flexibility for manufacturing diverse components in the same setup by easy and quick manipulation of software.
(ii) High rates of production with consistent high quality.
(iii) Uninterrupted production with negligible supervision or hands-on work.
(iv) Economical production even where product demand is only moderate in volume.
(v) Drastic reduction of lead times, where drastic changes in design are called for.
(vi) Integrating and fine tuning of all factory functions such as raw and semi-finished materials flow, tooling, metal cutting, inspection, etc.