石家庄铁道大学毕业设计
附录A 外文资料翻译
A.1：英文
The Role of Electricity in Quality and Reliability
L.ANDON GOODMAN, BSc(Eng) ,
ARTCS, CEng , MIMechE, FIEE, MIProdE , MBIM ,
MIMH, FRSA
It would be difficult today to find any manufacturing unit which does not rely on electricity at some stage of a production cycle . Electricity is a versatile energy source and has consequently found widespread use, so much so that its part in modern production methods is not always fully appreciated. Correctly applied electricity is a tool which can contribute immensely in achieving high quality and reliability in industrial production. In describing the role of electricity in quality and reliability this. Paper deals with the services provided by the electricity supply industry and how the utilization of electricity can help in achieving the desired standard of product quality and reliability.
the electricity supply industry
In the year ending 31st March, 1966, 65,672,000,00 0 units of electricity were sold to industry out of a total of 154,124,000,00 0 units. Much of the work of the electricity supply industry has been directed at ensuring reliability of supply for its customers coupled with an efficient generation, transmission and distribution system. Work is in progress on a 400,000 volt super grid to be completed in 1970 and a direct current trans mission link, the first of its kind in the world,will be commissioned in the London area in 1970.
Reliability of supply
The supply industry's record of reliability for the year ending March 1966 was
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石家庄铁道大学毕业设计
good.Preliminary figures from the National Fault Reporting scheme indicate that the overall average continuity of supply was 99.98%.The predominating causes of interruptions were such hazards as gales,lightning,heavy snowfalls and accidental damage caused.
For example,by mechanical equipment and workmen' s picks,High reliability can
only be achieved by intensive effort and the above record is the result of many years of intensive research and development on a number of fronts. For example, careful analysis is made of the reliability records of plant and equipment. This ensures that purchases are guide d towards that plant and equipment with the best record of reliability.
Live line working a means of carrying out maintenance and other work on high
voltage over-head lines without interrupting the supply is now routine procedure in many electricity board areas and its wider use is being planned.The technique relies on the use of insulated, long reach tools capable of withstanding 100,000 volts per foot. To the customer the advantage of live line working is reliability of supply. One electricity board has estimated that 1,200,000 customer hours were saved between September 1963 and March 1966 through their use of this technique. Expenditure on research in 1965 - 196 6 amounted to ￡9.43 million and is likely to reach ￡11.8 million in 1966 - 1967,such i s the investment in the future development of electricity supply. Much of this research is directed at improving the efficiency, the reliability and the quality of the supply of electricity and the service offered t o the customer.
industrial use of electricity for quality an d reliability
Over the past few years the study of quality control and reliability has developed
into a major manage ment technique.Quality control is no longer defined simply as an inspection function but is an inherent part of the whole production process. It must be planned and worked for,using whatever means are appropriate.
Industry is asked to make its approach to the review of methods of working during
Q & R Year as ambitious and original as possible.It would be a great pity if the opportunity were not taken to re-examine the techniques now in use in the light of the technological changes which have taken place in recent years . Even the most conscientious worker can only maintain a high standard of product quality when supported by plant and equipment capable of consistently meeting these standards.
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石家庄铁道大学毕业设计
influence on product Q & R
With its many uses in industry it would be impossible to define any particular field of
application in which electricity make s its major contribution to Q & R.Th e high degree of process control available and the cleanliness of application are,however,two features which make the use of electricity very suitable and sometimes essential in the manufacture of products of high quality and reliability. Every function within a factory can be said to have some influence on the saleability of the final product. Some of these function s are often regarded as an indirect overhead without rearising the important part they play in achieving a high quality product.Lighting and air-conditioning, which can effect the efficiency of work people, are two possible examples.Nevertheless a great deal depends upon the product design and the production methods adopted, and both must be kept unde r constant review.
Q & R problems trace d t o production plant are not necessarily best solved by replacing worn out equipment with its modern counterpart. Examination of the whole process cycle ma y well suggest that a more modern technique should be introduced. Some examples of new approaches to new and old problems are given below.
improved Q & R with better lighting
As mentioned previously,the contribution made by good lighting to the quality of a product is not always appreciated.
In the manufacture of ornamental tiles,flaws such as deformation, chips cracks etc are inevitable however carefully the process is controlled.By detecting these faults in tiles at an early stage further expensive and wasteful processing is avoided and the final product quality is improved. The result so f an investigation by one wellknown company revealed that 20% of the faulty tiles escaped detection during manufacture, even the at the final inspection stage only 2￡% were rejected . Thus , 17￡% of the faulty tiles found their way on to the market. This obviously would not do. The lighting level was generally proved tot-give 60lumens/sq.ft.instead of 10-15 lumens/sq.ft.For early production processes and 140 lumens/sq.ft.
For final inspection.The clour quality of the light was also improved. The result is that only 4% of all faulty tiles reach final inspection and 2% are rejected there. Moreover, clour vision in the final stage is now so good that some tiles rejected for off-clour can be
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石家庄铁道大学毕业设计
accurately regraded according to their shade and sold as \see clearly that quality goods are being made and its aid to inspection are not the only gain from good lighting. Many companies also list reduced safety hazards and improved working conditions which create good relations between management and workpeople. This, in turn is reflected in a more efficient working unit.
improved Q & R with electric heating
Process heating is a field in which electricity excels in achieving high product quality due to its cleanliness and controllability.
Pottery firing ——When their old tunnel kiln was reaching the end of it s useful life,a nationally known pottery manufacturing company, based in Dorset, in consultation with the Southern Electricity Board decided to replace it with three \each rated at 220kW. Each kiln has two heated bases which are used alternately and enable work to be unloaded from one base and reloaded while heating is carried out using the other base. The firing cycle is automatically controlled by a specially cut cam which determines the rate of rise, and takes between 10 hours and 11 hours to bring the kiln up to a temperature of 1050 deg. C. A further seven hours is required for cooling. A very even firing has been achieve d with these kilns making it possible to improve the quality of the ware and reduce the quantity of \
Induction billet heating—In the highly competitive market of extruded aluminum for the architectural and motor industries quality of extrusion and finish are of prime importance. To ensure high quality, one leading aluminum extrusion company use all electric methods to process the raw aluminum through to the finished product.
These methods, it is claimed, allow flexibility of operation and accurate quality control while at the same time offer savings in floor space, labor costs and reduced scrap.
One important feature of the production process is the initial heating of the aluminum billets prior to extrusion. Ajax Magnetosphere induction heaters are used to heat 26 in. X7 India. billets to between 850 deg. F and 1000deg . F in three minutes, representing a vast improvement in speed compared with batch furnaces where a large batch of billets is heated in a cycle of about five hours. In addition, induction heaters allow greater temperature control and flexibility of operation.
Paint drying on plastic—One company who were seeking to expand their business in
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石家庄铁道大学毕业设计
the plastic container market were finding difficulties in drying the print on the plastic sufficiently quickly . Temperature control had to be accurate to avoid over-heating the plastic and melting it.
Initial tests using hot air revealed a problem in the static electric charge of the bottles which was found to attract a layer o f fine dust, even in a few hours.
A further problem was the space required by an air drying installation.
By employing electric infra-re d heating , drying was speeled up and bottles could be packed straight off to the dryer.This system affected a significant saving in time and eliminated both the space and dust problem s simultaneously .
Metal melting—An important feature of induction melting is undoubtedly the high quality of the metal it produces. This has been borne out by the experience in one foundry where two conventional cupola s were replaced with a three-ton mains-frequency induction tilting furnace.Previously the cupolas had been used to produce only Whiteheart iron . Now, due to the new furnace , the company i s able to extend its malleable field t o include Blackheart iron .
Since its installation the furnace has increased the company's production potential. Metallurgically it is more flexible than the cupolas it replaces and is producing a superior analysis resulting in less scrap .
It is worthy of note that as a result of tests, carried out in co-operation between the company and engineers of the North Western Electricity Board, the Electricity Board were able to recommend a satisfactory method of working which would take advantage of the industrial tariff structure and reduce the company' s costs.
control and inspection
Process control systems are now universally accepted a spart of the production pattern. There are of course many different levels of control and the system adopted can have a profound effect on the quality of the product.
One system, which probably goes further than most in production quality control is that installed in the tinplate factories of a company in South Wales. This system is based on the Arch digital computer of Elliott Automation Ltd., and devised entirely by the tinplate companys' own engineers after a comprehensive investigation into the many problems involved .
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