Intelligent machine tool: perspective and themes for future development

The machine tool is the key manufacturing facility for modern advanced manufacturing systems, and it has been playing the most important role in mechanical manufacturing of industrial goods. Extensive R&D efforts have been devoted to improve the performances of the machine tools in the past from various viewpoints, such as accuracy, reliability, productivity, efficiency and flexibility.

Some of the key issues in the recent development of machine tool technology are summarized as follows:

(1) High accuracy or ultraprecision machine tool: The accuracy is most important for the machine tool so as to guarantee the accuracy and performance of the products. The efforts have been devoted to improve the accuracy of machine tool by increasing the geometrical accuracy, the thermal stability, the static and dynamic rigidity, and also the controllability of machine. The ultraprecision machine tool contributed much to manufacture the key components of the precision devices including various opto-mechatronic devices.

(2) High productivity and efficiency: The cutting and the feeding speeds of machine tool have been continuously increased recently so that the productivity and efficiency are much increased. The development of the cutting technology and the tools for high speed machining is becoming much more important.

(3) Adaptation to manufacturing systems: Various machine tools with new configurations, functions and peripherals have been developed which fit to specific purposes of various manufacturing systems to improve their productivity and flexibility.

(4) Low cost: The cost of manufacturing and hence the investment to manufacturing facilities are always considered to be critical in the competitive manufacturing world. Low cost machine tools with reduced options and limited capabilities are attracting current machine tool market.

(5) Advanced control: Recent advances in the advanced controltechnology, the computer technology and the high performance actuators made it possible to implement new advanced control to machine tools.

The present paper focuses to the new innovative control technology of machine tool, namely intelligent control which is now emerging as the next generation control of machine tools. The outline of intelligent control is presented here based on the review of the historical background of machine tool control.

 

1. Выпишите из текста инфинитивы в функции обстоятельства цели и переведите их вместе с относящимися к ним словами.

2. Выпишите из текста все сказуемые в страдательном залоге и переведите их вместе с подлежащими.

3. Найдите в тексте предложение с конструкцией "сложное подлежащее с инфинитивом" и переведите его.

4. Выпишите из текста все герундии, определите их функции и переведите их вместе с относящимися к ним словами.

5. Найдите в тексте сложносочиненное предложение, укажите подлежащее и сказуемое в каждом из предложений, переведите все предложение.

6. Проанализируйте второе предложение пункта (3), определите вид придаточного предложения, укажите, относится оно к глаголу или существительному. Переведите все предложение.

7. Выпишите из последнего предложения текста причастия II, определите их функцию и переведите все предложение.

8. Переведите текст с учетом выполненных заданий.

 

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Intelligent machine tool: perspective and themes for future development (continued)

The machine tool has twice experienced revolutionary development in its modern history. Figure 1 summarizes brief history of machine tool development and related key technologies introduced.

The first revolution for machine tool is the powered machine tool which was introduced in the era of the industrial revolution late in the 18th Century. The primary driving force of the machine tool, which was the natural one, such as man power, animal power or water power, was replaced by the artificial power source such as steam power or later electric power. Various types of machine tools were invented in those days, which are regarded as the originals of the modern machine tools, such as drilling machine, milling machine etc.

The productivity of the machine tool in terms of efficiency and speed and also the accuracy of machining have been much improved by introducing the powered machine tools. Most of the machine tools were controlled mechanically with use of sophisticated built-in mechanisms, such as lead screws, cams and links, which are typical for analog control.

The second revolution for machine tool was caused by introduction of numerical control (NC) invented by J T. Parsons in 1952. The information and signal processing portion of the machine tool control was separated from the actuators actually driving the machine tool hardware. The separation of the two accelerated, on one hand, advancement of the sophisticated control of machine owing to the development in the information processing technology or typically the computer technology, while it enhanced simplification and new development of the actuators.

Various sophisticated computer NC (CNC) machine tools have been developed and put into practical use, which include 5-axis milling machine, machining center equipped with automatic tool changer (ATC) and automatic pallet changer (APC), turning center etc.

An important extension of CNC is the adaptive control (AC). The machining process is included in the feed back control loop of the machine by introducing the adaptive control, while only the motions of the tool and thework table are controlled by the conventional CNC. Various types of sensors have been developed and utilized to detect the state of machining and to feed back its information.

The machine tools developed up to now are all driven and controlled according to the predetermined commands, which are either prepared manually or automatically by the computer with the aid of CAM software and the data base.

One of the possible control systems for the next generation machine tool will be the intelligent control.

1. Найдите в тексте слово-заместитель ранее употребленного существительного и переведите его, определив заменяемое им слово.

2. Выпишите из текста все сказуемые в страдательном залоге и переведите их вместе с подлежащими.

3. Выпишите из текста сложные предложения, в которых придаточное определительное предложение, относящееся к подлежащему главного предложения, стоит за сказуемым. Переведите эти предложения.

4. Выпишите из четвертого абзаца последнее предложение, определите вид придаточного предложения, укажите подлежащее и сказуемое главного предложения. Переведите все предложение.

5. Выпишите из пятого и шестого абзацев все именные группы и переведите их.

6. Выпишите из пятого и шестого абзацев слова с окончанием –ing, укажите, какой глагольной формой они являются, определите их функции и переведите их вместе с относящимися к ним словами.

7. Переведите текст с учетом выполненных заданий.

 

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Intelligent machine tool: perspective and themes for future development (continued)

As it was mentioned earlier, the machine tool is the primary constituent element of today's manufacturing systems and therefore it is worth reviewing the history of manufacturing systems and discuss the role of machine tool in the next generation manufacturing systems.

Figure 2 briefly summarizes the process of technology development in the manufacturing systems. The history of modern integrated manufacturing systems goes back to well-known Ford System for mass production of automobiles, while the automation of mid-volume, mid-variety production was launched by invention of the NC machine tool. The innovation in NC machine tool technology and the computer technology created a new manufacturing system named direct NC (DNC) system, where plural number of NC machine tools are controlled by a central computer. The DNC system is identified as a typical outcome of integration of information flow for machining in the manufacturing system.

The integrated control of the information flow and the material flow in the manufacturing system was realized by Flexible Manufacturing System (FMS), where the work materials and the tools are transported between the automated warehouse and the machines by AGV's and handled by industrial robots etc. Sophisticated machine tools, suchas machining centers and turning centers have played the essential role in FMS.

Although FMS was introduced intentionally to enhance the flexibility in the automated manufacturing capability of mid-volume, mid-variety production, it was soon found that FMS is not necessarily flexible enough, and it is risky to invest a large capital to FMS. For such reasons, FMC was known to become much popular and has been installed world wide, which is smaller in size but equipped with the minimum functions of the manufacturing systems, which include the control computer, the CNC machine tools, the automated work handling system for storage, transport, loading and unloading, and sometimes the automatic inspection machine for the work. FMC is less costly as compared with FMS, easier to operate and more flexible to cope with changes of the customer order.

 

1. Выпишите из текста союзы, присоединяющие придаточные предложения к главным, и переведите эти союзы.

2. Выпишите из текста безличные предложения и переведите их.

3. Выпишите из текста сказуемые в страдательном залоге с последующим косвенным дополнением с предлогом by и переведите их вместе с подлежащими двумя способами.

4. Выпишите из второго абзаца сложноподчиненное предложение, в котором придаточное предложение вводится союзным словом (наречием). Определите вид придаточного предложения и укажите возможные переводы наречия. Найдите в тексте еще одно такое же предложение.

5. Найдите в тексте конструкцию "сложное подлежащее с инфинитивом" и переведите ее.

6. Выпишите из текста сложное предложение, в котором придаточное определительное предложение, относящееся к подлежащему главного предложения, стоит за сказуемым. Переведите это предложение.

7. Переведите текст с учетом выполненных заданий.

 

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Intelligent machine tool: perspective and themes for future development (continued)

On the other hand, rapid progress in the recent software technology and information processing technology combined with the development in the manufacturing hardware mentioned above made it possible to totally integrate the industrial activities from the marketing and the R&D activity to the final manufacturing process of the products and their delivery, which is well known as CIM, or Computer Integrated Manufacturing. The hierarchical control of information in FMS or CIM through the information network is quite effective, as it was expected, to control the total manufacturing activities for fixed or well-scheduled production.

It was found, however. that such a hierarchical structure of control for the totally integrated manufacturing system is not flexible enough to cope with the drastic changes in the user needs, the unscheduled changes in production, the express jobs and the unexpected malfunction of manufacturing facilities etc. The distributed control rather than the hierarchical control is expected to be more flexible to cope with such changes in production.

It is thus expected recently that new type of highly flexible manufacturing systems with distributed autonomous manufacturing agents and their distributed control will be the key for the mechanical manufacturing industries in the future which are to produce a large variety of new products according to the changeable demands of the customers. The machine tools required for such autonomous distributed manufacturing systems, or sometimes referred to as holonic manufacturing systems, will be the ones which are autonomously operated and yet cooperative with other machines and manufacturing facilities. Such autonomous and cooperative machine tools must be highly intelligent.

Itis thus concluded that the intelligent machine tool is the key to the next generation manufacturing systems.

The concept of intelligent machine tool is new and there is not yet clear definition for it, however the intelligent machine tool is characterized typically by the following specific features:

(1) Intelligence; to acquire, systematize and utilize the manufacturing knowledge,

(2) Autonomy; to make decisions based on its own criteria, and physically support and maintain itself if possible,

(3) Flexibility; to cope with various changes in requirements, available resources, constrains etc.,

(4) Cooperation; to find mutually agreeable solutions with other machines or agents through communication, exchange information and negotiation.

 

1. Проанализируйте первое предложение первого абзаца, определите тип предложения, найдите подлежащее и сказуемое, проанализируйте глагольные формы с окончанием –ed. Переведите это предложение.

2. Найдите в тексте инфинитив в функции обстоятельства следствия и переведите его вместе с относящимися к нему словами.

3. Выпишите из текста оборот "сложное подлежащее с инфинитивом" и переведите его.

4. Найдите в тексте сказуемое с глаголом to be в качестве модального глагола и переведите его вместе с подлежащим.

5. Выпишите из второго предложения третьего абзаца глагольные формы с окончанием –ed, определите их функции и переведите вместе с относящимися к ним словами.

6. Найдите в тексте слово-заместитель ранее употребленного существительного и переведите его, определив заменяемое слово.

7. Найдите в тексте предложение с конструкцией There+be и переведите его.

8. Переведите текст с учетом выполненных заданий.

 

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Turning Centers Update

Turning centers are modern lathes or turning machines equipped with computer numerical control (CNC), multiple tooling, and flexible automation equipment. With rotary tooling now available, milling, drilling, tapping, and other operations can be performed in the same setup. This can sometimes eliminate the need for a machining center or other machine tools to perform secondary operations.

Many turning centers are of modular design that permits expansion to higher automation levels when required. Turning centers are most frequently used as flexible stand-alone machines. However, they are also being integrated as components of flexible manufacturing cells (FMCs) consisting of two or more machines, a material handling system, and a cell controller.

Advantages of modern turning centers include improved quality workpieces, increased productivity, greater flexibility, and cost savings. Improved quality results from the improved accuracy and reliability of the machines and controls and the integration of in-process or post-process gaging. Increased productivity is attained from faster setups, reduced manual toolchanging requirements, more rapid metal removal rates, and shorter cycles. The capability of producing a wide variety of parts increases their flexibility. Optional equipment is available for maximizing automation with minimum changeover time.

A wide variety of turning center types and sizes is available. While some have single or multiple vertical spindles, most are of the horizontal spindle design. These are of three basic forms: center-type (shaft), chucking-type, and universal (combination shaft-chucker), barfeed attachments being available for most chucking and universal machines. The Titan series of turning machines built by the Warner & Swasey Turning Div., Cross & Trecker Corp. (Solon, OH), is a modular system having many common components that permits the making of more than 100 basic machine configurations, including vertical and horizontal models with one or two spindles and two or four-axis control.

 

1. Выпишите из первого абзаца сказуемое в страдательном залоге, имеющее в своем составе модальный глагол, и переведите его вместе с подлежащим.

2. Найдите в тексте глагол to be в составных именных сказуемых и переведите их вместе с подлежащими.

3. Выпишите из первого предложения второго абзаца причастие II, определите его функцию и переведите вместе с относящимися к нему словами.

4. Выпишите из последнего предложения второго абзаца и последнего предложения текста слова с окончанием –ing, определите, какой глагольной формой они являются, а также их функции и переведите их вместе с относящимися к ним словами.

5. Найдите в тексте случаи употребления as, определите его функции и переведите их вместе с относящимися к ним словами.

6. Выпишите из текста независимый причастный оборот и переведите его.

7. Выпишите из текста именные группы и переведите их.

8. Переведите текст с учетом выполненных заданий.

 

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Turning Centers Update (continued)

Selection of the number of axes to be controlled on a turning center depends on production requirements. Some two-axis, point-to-point positioning control systems are satisfactory if no taper or contour cutting is required. Most two-axis systems, however, are available with simultaneous linear and circular interpolation. Three and four-axis, continuous-path control systems permit machining radii, tapers, and contours. Such systems generally provide increased productivity when internal and external surfaces can be machined simultaneously. A spindle-positioning C axis is provided for machines using rotary tooling for cross and end-working operations.

Some machines are provided with a fifth axis by using a second workholding chuck on a sliding-head spindle or tail-stock subspindle. This permits simultaneous secondary operations to be performed on the rear ends of parts cut from bar stock. The second chuck grips the workpiece during cutoff; after cutoff, the gripped part is retracted to perform the secondary operations. When the secondary operations have been completed, the chuck releases the workpiece, and a parts catcher is generally employed to prevent the part from falling.

A nine-axis Millturn machine made by Voest-Alpine (Linz, Austria) combines a four-axis, two-turret turning center with a five-axis machining center. The machine actually has eight axes mechanically, but has nine axes electrically, with the Z axis being shared by the top turret and the milling unit. Turning, boring, milling, drilling, tapping, contouring, and other operations can all be completed with a single clamping of the workpiece. The milling head (including a toolchanger), arranged on a separate cross-slide, can be pivoted and has an additional axis vertical to the machine bed for angular and off-center, intricate milling and drilling operations.

The design and construction of modern turning centers have been substantially improved to increase rigidity for reduced vibration and to increase stiffness for minimum deflection. Most of these machines now have slant beds instead of the flat horizontal beds that were common for lathes.

The beds of CNC turning centers are completely made of reinforced concrete having six times the damping capability of cast iron, thus providing high dynamic stiffness for improved surface quality and long tool life. Also, more thermal energy is required to raise the temperature of the concrete beds, contributing to highly consistent,accurate machining.

 

1. Выпишите из первого предложения текста инфинитив, определите его функцию и переведите вместе с относящимися к нему словами.

2. Выпишите из второго предложения текста придаточное предложение и переведите его, используя обратный порядок слов.

3. Выпишите из второго абзаца герундий в функции обстоятельства и переведите его вместе с относящимися к нему словами.

4. Найдите во втором абзаце инфинитивный оборот, определите его тип и переведите его.

5. Выпишите из текста все инфинитивы в функции обстоятельства и переведите вместе с относящимися к ним словами.

6. Выпишите из текста независимый причастный оборот и переведите его.

7. Выпишите из последнего абзаца причастия I в функции обстоятельства и переведите их вместе с относящимися к ним словами.

8. Переведите текст с учетом выполненных заданий.

 

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