生产自动化专业英文译文

Production Automation

Introduction to production Automation

Automation is a widely used term in manufacturing. In this context ,automation can be defined as technology concerned with the application of mechanical, electronic, and computer-based systems to operate and control production. Examples of this technology include:

·Automatic machine tools to process parts.

·Automated transfer lines and similar sequential production systems

·Automatic assembly machines

·Industrial robots

·Automatic material handing and storage systems

·Automated inspection systems for quality control.

·Feedback control and computer process control.

·Computer systems that automate procedures for planning, data collection, and decision making to support manufacturing activities.

Automated production systems can be classified into two basic categories: fixed automation and programmable automation.

Fixed Automation

Fixed automation is what Harder was referring to when he coined the word automation. Fixed automation refers to production systems in which the sequence of processing or assembly operations is fixed by the equipment configuration and cannot be readily changed without altering the equipment. Although each operation in the sequence is usually simple, the integration and complex. Typical features of fixed automation include 1.high initial investment for custom-engineered equipment, 2.high production rates,3.application to products in which high quantities are to be produced ,and 4.relative inflexibility in accommodating product changes.

Fixed automation is economically justifiable for products with high demand rates. The high initial investment in the equipment can be divided over a large number of units, perhaps millions, thus making the unit cost low compared with alternative methods of production. Examples of fixed automation include transfer lines for machining, dial indexing machines, and automated assembly machines. Much of the

technology in fixed automation was developed in the automobile industry; the transfer line (dating to about 1920 ) is an example.

Programmable Automation

For programmable automation, the equipment is designed in such a way that the sequence of production operations is controlled by a program, i.e., a set of coded instructions that can be read and interpreted by the system. Thus the operation sequence can be readily changed to permit different product configurations to be produced on the same equipment. Some of the features that characterize programmable automation include 1. high investment in general-purpose programmable equipment, 2. lower production rates than fixed automation, 3. flexibility to deal with changes in product configuration, and 4. suited to low and / or medium production of similar products or parts (e.g. part families). Examples of programmable automation include numerically controlled machine tools, industrial robots, and programmable logic controllers.

Programmable production systems are often used to produce parts or products in batches. They are especially appropriate when repeat orders for batches of the same product are expected. To produce each batch of a new product, the system must be programmed with the set of machine instructions that correspond to that product. The physical setup of the equipment must also be changed; special fixtures must be attached to the machine, and the appropriate tools must be loaded. This changeover procedure can be time-consuming. As a result, the usual production cycle for a given batch includes 1. a period during which the setup and reprogramming is accomplished and 2. a period in which the batch is processed. The setup-reprogramming period constitutes nonproductive time of the automated system.

The economics of programmable automation require that as the setup-reprogramming time increase, the production batch size must be made larger so as to spread the cost of lost production time over a larger number of units. Conversely , if setup and reprogramming time can be reduced to zero, the batch size can be reduced to one. This is the theoretical basis for flexible automation, an extension of programmable automation. A flexible automated system is one that is capable of producing a variety of products ( or parts) with minimal lost time for changeovers from one product to the next. The time to reprogram the system and alter the physical setup is minimal and results in virtually no lost production time . Consequently, the system is capable of producing various combinations and schedules