Development of the Factory System

Today the term “factory’ refers to a large establishment where people cooperate in mass production of industrial or consumer goods (1). The factory system is known from ancient times. Pottery works have been uncovered in ancient Greece and Rome. In various parts of the Roman Empire factories manufactured glassware and bronze ware for export as well as for domestic consumption. In the Middle Ages, large silk factories were operated in Syria; and in Europe textile factories were established in England, France, and Italy.

During the 16^th and 17^th centuries, the advance of science and the development of new trade routes to the Far East stimulated commercial activity and the demand for manufactured goods promoted industrialization. The factory system, which replaced the domestic system and became the characteristic method of production in modern economies, began to develop in the late 18^th century. A series of inventions transformed the British textile industry and marked the beginning of the Industrial Revolution. Cotton goods were the major factory – made products during the early 19^th century. Meanwhile, new machinery and techniques were being invented that made it possible to extend the factory system to other industries.

As the 20^th century began, the factory system of production prevailed throughout the United States and most of Western Europe. In 1913 Henry Ford, the pioneer automobile manufacturer, made a great contribution to the expansion of the factory system in the U.S. when he introduced assembly line techniques to automobile production in the Ford Motor plant.

By the mid – 20^th century, the development and use of increasingly sophisticated (2) equipment in modern factory operation and the rise to leadership positions of professional managers had led to the introduction of automation in the industrial process.

In the engineering workshop machining is only one part of the overall production process. There are two more basic operations: design and administration. In the engineering industry of the future, all three of these operations will be done with the help of computers, which will greatly reduce the need for labour. The few places where people will be involved with the factory’s processes will be in the design room and in a control area where the factory’s administrators sit. At the heart of the factory will be a complex communications network that links all the machines in the plant. The mechanisms in the plant will be linked by wires and will talk to each other in a binary code (3). Due to the rapid rate of technical progress over the nearest twenty years, such plants may become our reality very soon.

The Lathe

The lathe is one of the most useful and versatile (1) machines in industry, and is capable of carrying out many machining operations. The main components of the lathe are the headstock (2) and tailstock (3) at opposite ends of a bed, and a tool-holder (4) between them which holds the cutting tool (5). The toolholder stands on a cross slide (6) which enables it to move across the saddle or carriage as well as along it, depending on the kind of job it is doing. The ordinary centre lathe can accomodate only tool at a time on the toolholder, but a turret lathe is capable of holding five or more tools on the revolving turret. The lathe bed must be very solid to avoid vibrations.

The head-stock incorporates the driving gear (7) and a spindle which holds the workpiece and causes it to rotate. The cutting speed of the tool is an important factor. Tapered centres in the hollow nose of the spindle and of the tailstock hold the work firmly between them. A feed shaft from the headstock drives the toolholder along the saddle, either forwards or backwards, at a fixed and uniform speed. This enables the operator to make accurate cuts and to give the work a good finish (8). Gears between the spindle and the feed shaft control the speed of rotation of the shaft, and the forward or backward movement of the toolholder.

The gear which the operator will select depends on the type of metal which he is cutting and the amount of metal he has to cut off. For a deep or roughing cut (9) the forward movement of the tool should be less than for a finishing cut. Centres are not suitable for every job on the lathe. The operator can replace them by various types of chucks (10), which hold the work between jaws (11), depending on the shape of the work and the particular cutting operation. He will use a chuck, for example, to hold a short piece of work for drilling, boring or screw-cutting (12).

A transverse (13) movement of the tool post across the saddle enables the tool to cut across the face (14) of the workpiece and gives it a flat surface. For screw-cutting, the operator engages the lead screw, a long screwed shaft which runs along in front of the bed and which rotates with the spindle. The lead screw drives the toolholder forwards along the correct speed, and this ensures that the threads on the screw are of exactly the right pitch. The operator can select different gear speeds, or reverse the movement of the carriage and so bring the tool back to its original position.

Lathes are now made with numerical control (for short NC) and with computer. They work automatically according to programs. The unit is called a machining centre.

The Engine

The engine is the source of power that makes the car move. It is usually called an internal combustion engine because gasoline is burned within its cylinders or combustion chambers (1). Most automobile engines have six or eight cylinders.

The engine produces power by burning air and fuel. The fuel is stored in a fuel tank. The fuel tank is connected to a fuel pipe. The fuel pipe carries the fuel to a fuel pump. The fuel pump is connected to the carburettor. The fuel pump pumps the fuel into the carburettor. In the carburettor the fuel is mixed with air. The fuel and air are drawn into the engine cylinder by the piston. Then the fuel and air are compressed by the piston and ignited by the spark plug. They burn and expand very quickly and push the piston down. Thus the power is produced. The burned fuel and air are expelled from the cylinder by the piston.

The flow of gases into and out of the cylinder is controlled by two valves. There is an inlet valve allowing fresh fuel mixture into the cylinder and an exhaust valve which allows the burnt gases to escape.

There are two basic engine operating cycles:

a) the four-stroke cycle (2);

b) the two-stroke cycle.

The greatest number of cars use piston engines. The four-cycle piston engine requires four strokes of the piston per cycle.

The complete four-stroke cycle comprises:

1. the induction intake stroke (3) (the piston moves downwards);

2. the compression stroke (the piston moves upwards);

3. the power stroke (4) (the piston moves downwards);

4. the exhaust (5) stroke (the piston moves upwards).

The upper limit of the piston movement is called the top dead centre (6) (t.d.c.). The lower limit of piston movement is called the bottom dead centre (b.d.c.). A stroke is the piston movement from the top dead centre to the bottom dead centre or from the bottom dead centre to the top dead centre. In other words, the piston completes a stroke each time it changes the direction of its motion.

On the intake (induction) stroke the intake valve is opened. The mixture of air and vaporized gasoline is delivered into the cylinder through the inlet valve.

On the compression stroke the inlet valve is closed so that the mixture can be compressed. On the power stroke both valves (inlet and exhaust) are closed in order to rise pressure during the mixture combustion.

On the exhaust stroke the exhaust valve is opened to exhaust the residual gas. In the two-cycle engines the entire cycle of events is completed in two strokes or one revolution of the crankshaft.

Automation

Automation is a word coined in the 1940s to describe processes by which machines do tasks previously performed by people. The word was new but the idea was not. Automation is the third phase in the development of technology that began with the industrialization of the 18^th century. First came mechanization which created the factory system and separated labour and management in production.

Mass production came next. It was a technology based on principles of production and organization.

Mass production refers to manufacturing processes in which an assembly line (1), usually a conveyer belt, moves the product to stations where each worker performs a limited number of operations until the product is assembled.

In the automobile assembly plant such systems have reached a highly-developed form. A complex system of conveyer belts and chain drives (2) moves car parts to workers who perform the thousands of necessary assembling tasks.

Automation is a technology based on communication, computation and control.

Automation was first applied to industry in continuous – process manufacturing such as refining petroleum, making petrochemicals, and refining steel. A later development was computer-controlled automation of assembly line manufacturing, especially those in which quality control was an important factor.

The truly automated devices must possess one or more of the following elements: system approach, programmability, feedback (3).

With a system approach, an automated production line consists of a series of workstations connected by a transfer system to move parts between the stations. People are not required.

Thus, transfer lines (4) are different from assembly lines where people are very much in evidence.

With programmability, modern automated lines are controlled by programmable logic controllers, which are special computers that can perform timing and sequencing functions required to operate such equipment.

Finally, feedback makes an automatic device vary its routine (5) according to changes that take place around it. Using feedback devices (sensors), machines can start, stop, speed up, slow down, count, inspect, test, compare, and measure. These operations are commonly applied to a wide variety of production operations.

Computers have greatly facilitated (6) the use of feedback in manufacturing processes. Computers gave rise to the development of numerically controlled machines.

More recently, the introduction of microprocessors and computers have made possible the development of computer – aided design and computer – aided manufacture (CAD and CAM) technologies (7).

When using these systems a designer draws a part and indicates its dimensions with the help of a mouse, light pen, or other input device. After the drawing has been completed the computer automatically gives the instructions that direct a machining centre to machine the part.

Another development using automation are the flexible manufacturing systems (FMS) (8). A computer in FMS can be used to monitor and control the operation of the whole factory.

The automation technology has a great influence on all areas of the economy. Nevertheless each industry has its own concept of automation that answers its particular production needs.

Robot Technology

The term “robot” is derived from the Czech word “robota”, meaning “compulsory labour”. It was first used by Czech playwright Karel Čapek, who in 1920 wrote a drama about machines that could move like human beings – and do their work. Robot is a computer – controlled machine that is programmed to move, manipulate objects, and accomplish work while interacting with its environment. Robots are able to perform repetitive tasks more quickly, cheaply, and accurately than humans.

An industrial robot is a unit which has movement functions with a high degree of freedom similar to human arms and hands and is able to move autonomously on the basis of sense and perception.

Today practically all sectors of the economy and industry are looking forward to introducing industrial robots. But robot building is not simple and certainly not cheap. If every sector begins to build its own robots, it will be impossible to avoid unnecessary duplication of research and development, and large sums will be wasted. Therefore the need is to concentrate all efforts in robot technology in one pair of hands, in a powerful inter-sectoral scientific and technical organization. Only in this way it is possible to ensure the maximum standardization of production of industrial robots and multipurpose automatic manipulators.

There are two rational ways in the field of robotics. The first one is to build standardized modules – unified elements on the basis of which it will be easy to assemble, in different combinations, robots for the most varied of purposes. The second way is to create an inter-sectoral exchange fund of robots so that research and development of designers in different technical fields should be within the reach of all interested organizations and enterprises.

The robots are divided into three generations: programmed, adaptive and intellectual. Characteristic of the first generation – the programmed robots – is that their control system acts according to a rigid oft-repeated programme all the time. But the programmed robots are easily returned to various action programmes.

The adaptive robots, robots of the second generation, have been already worked out and will be widely applied in production at the close of this and the beginning of the next decade. Their fundamental difference from the first robot generation is the appearance of artificial sensors, which give the adaptive robots the ability to see, to hear and feel. The possibilities of them are immeasurably (1) greater than the robots of the first generation.

The third generation – intellectual robots – will be able to perform intricate (2) selective operations, and carry out practically autonomous work, not depending on the operator. Robots with artificial intelligence will be able to identify objects in a pile, select the objects in the appropriate sequence and assemble them into a unit. And then we shall be able to speak about a robot revolution in the economy, about a many-fold (3) increase of labour productivity, and the advent of a new age of industrial production – the age of fully automated enterprises and maybe, whole branches of industry. Robot technology as seen from the text above refers to the art and science of creation and use of robots.

Today robots play a major role in welding, press-forming, coating and other operations, particularly in the automotive industry. Robots are used in a lot of manufacturing operations. The applications of robots can be divided into three categories:

1. material handling; 2. processing operations; 3. assembly and inspection.

The commercial use of robots is spreading, with the increasing automation of factories, and they have become essential to many laboratory procedures. Japan is the most advanced nation exploring robot technology. Nowadays robots continue to expand their applications.