THE TOOL AND MACHINE SHOP

Machining

Conventional machining, one of the most important material removal methods, is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machines, and drill presses, are used with a sharp cutting tool to mechanically cut the material to achieve the desired geometry. Machining is a part of the manufacture of almost all metal products, and it is common for other materials, such as wood and plastic, to be machined. A person who specializes in machining is called a machinist. A room, building, or company where machining is done is called a machine shop. Much of modern day machining is controlled by computers using computer numerical control (CNC) machining. Machining is not just one process; it is a group of processes. The common feature is the use of a cutting tool to form a chip that is removed from the workpart, called swarf . To perform the operation, relative motion is required between the tool and work. This relative motion is achieved in most machining operation by means of a primary motion, called "cutting speed" and a secondary motion called "feed'". The shape of the tool and its penetration into the work surface, combined with these motions, produce the desired shape of the resulting work surface.

Machine shopA workshop where power-driven tools are used for making, finishing, or repairing machines or machine parts.

Machine tool

A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by machining, which is the selective removal of metal. The term machine tool is usually reserved for tools that used a power source other than human movement, but they can be powered by people if appropriately set up. Many historians of technology consider that the true machine tools were born when direct human involvement was removed from the shaping or stamping process of the different kinds of tools.

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The History Of The Machine Shop

Machine shops are the places in which many of today’s inventions were first born. From the machine shop idea appeared places such as the laboratory and the workshop. A machine shop will be home to pretty much every piece of kit you might possibly think of. Here are a few good examples: nuts and bolts, screws, and other metal pieces, measurement tools, work benches, welding equipment, tools used for fabricating various items.

1200 - 1299 Horizontal bench lathe appears, using foot treadle to rotate object. 1569 THEATRE DES INSTRUMENTS ET MACHINES written: includes modified

center lathe and other guides. (Jacques Besson, France) 1700 Earliest accurate metal-working lathes in use. 1760 First metal-cylinder blowing engine built at Carron Ironworks: use of cast iron

in machines led end of wooden construction in power machinery. (John Smeaton, Scotland)

1783 Grinder for tools and cutters invented. (Samuel Rehe, France) 1808 ca. Power compressor used to drive workshop tools: apparently for the first

time. (Wm Murdock, Britain) 1820 - 1849 Lathes, drilling, boring machines and planers -- most primary machine

tools -- refined. 1902 Hydraulic drives and controls introduced for machine tools. (Brown and Sharpe, US)

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Pakistan Railways Carriage Factory, Islamabad

The pakiatan railway carriage factory may be called a Plant / Factory / Workshop / Warehouse or business in Islamabad is a very very equipped place with thousands of skill persons the following is the list of latest month orders in the machine shop of the factory.

Major Machining Operations There

In the factory machine shop the whole shop is sub divided into various sections as: Cnc ,section, Milling section, Lathe section, Drilling section .

And various machines as;

Shapers Lathes Grinders Drill machines Planers Milling machines Cnc etc…

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General types of machining operations

The three principal machining processes are classified as turning, drilling and milling. Other operations falling into miscellaneous categories include shaping, planing, boring, broaching and sawing.

Turning operations are operations that rotate the workpiece as the primary method of moving metal against the cutting tool. Lathes are the principal machine tool used in turning.

Milling operations are operations in which the cutting tool rotates to bring cutting edges to bear against the workpiece. Milling machines are the principal machine tool used in milling.

Drilling operations are operations in which holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the workpiece. Drilling operations are done primarily in drill presses but sometimes on lathes or mills.

Miscellaneous operations are operations that strictly speaking may not be machining operations in that they may not be swarf producing operations but these operations are performed at a typical machine tool. Burnishing is an example of a miscellaneous operation. Burnishing produces no swarf but can be performed at a lathe, mill, or drill press.

Machining is not just one process; it is a group of processes. The common feature is the use of a cutting tool to form a chip that is removed from the workpart, called swarf . To perform the operation, relative motion is required between the tool and work. This relative motion is achieved in most machining operation by means of a primary motion, called "cutting speed" and a secondary motion called "feed'". The shape of the tool and its penetration into the work surface, combined with these motions, produce the desired shape of the resulting work surface.

Now I will represent the report in detail:

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LATHE

In the centre lathe section I have saw at least 20 lathes machines of different types and sizes and the main part were

.

Lathe machines possess accessories which are use for different purposes the main accessories I have seen were:

faceplate, three- or four-jaw chuck, mandrel , collet , spur drive, dead center, live center, lathe dog etc.

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The lathe may be used for:

boring, drilling, tapping, turning, facing, threading, polishing, grooving, knurling, trepanning

As the machining operations of lathe are concerned I have seen;

lathe machines that perform various operations such as

Knurling

Knurling is a manufacturing process, typically conducted on a lathe, whereby a visually-attractive diamond-shaped (criss-cross) pattern is cut or rolled into metal. This pattern allows hands or fingers to get a better grip on the knurled object than would be provided by the originally-smooth metal surface.

Threading

Threading is a lathe operation used for creating internal / external precision machined threads with a single point tool. Uses a special cutting tool that reflects the thread form.

Turning

Turning is a lathe operation in which the cutting tool removes metal from the outside diameter of a workpiece. A single point tool is used for turning. A workpiece may be held in a 3, 4, or 6 jaw chuck, collets or may also be held between centers.

Facing

Facing is a lathe operation in which the cutting tool removes metal from the end of the workpiece or a shoulder. A workpiece may be held in a 3, 4, or 6 jaw chuck, collets or a faceplate. Facing is a machine operation where the work is rotated against a single point tool.

Tapping

Tapping is the process of cutting a thread inside a hole so that a cap screw or bolt can be threaded into the hole. Also, it is used to make threads on nuts. Tapping is done with a tool called a tap.

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The different types of lathes I saw there are:

Turret LatheTurret lathes are used in production machine shops where several sequential operations are needed on single workpiece. The turret lathe has a rotating turret mounted to the carriage so that as soon as an operation with one tool is completed, the turret is indexed to bring another tool into working position. The part is then machined again without having to remove it from the chuck or collet. Eight (or more) different operations can be performed on a workpiece using this type of machine.

Centre lathe

The Centre Lathe is used to manufacture cylindrical shapes from a range of materials including; steels and plastics. It is a machine tool which spins the workpiece to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.

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SHAPERS

A shaper is a type of machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical. A shaper is analogous to a planer, but smaller, and with the cutter riding a ram that moves above a stationary workpiece, rather than the entire workpiece moving beneath the cutter.

The type of shapers are

- Horizontal / plain or universal- Vertical - Special

And those I have saw was Horizontal / plain or universal shaper

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A shaper operates by moving a hardened cutting tool backwards and forwards across the workpiece. On the return stroke of the ram the tool is lifted clear of the workpiece, reducing the cutting action to one direction only.The workpiece mounts on a rigid, box-shaped table in front of the machine.

Shaping machines are used to produce mainly fiat surfaces, shoulders, grooves and similar shapes.

They belong to the basic equipment of every mechanical workshop and are required both in the repair sector and in the construction of means of production.I had seen only the cutting action of shaper machine.

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GRINDING MACHINE

A grinding machine is a machine tool used for grinding, which is a type of machining using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the workpiece by shear deformation.

Types of grinding machines include the:

- Plain Surface grinders- Rotary Surface grinders- Tool & Cutter grinders- Universal grinders- Internal grinders

And the type of grinders I had seen were Plain Surface grinders and Tool & Cutter grinders.another type of grinders called as non-precision grinders are used for rough usage.

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As the function and the working of grinder are concerned

Grinding machines remove material from the workpiece by abrasion, which can generate substantial amounts of heat; they therefore incorporate a coolant to cool the workpiece so that it does not overheat and go outside its tolerance. The coolant also benefits the machinist as the heat generated may cause burns in some cases.

Grinding is an operation in which the cutting is done by the use of abrasive particles. Grinding processes remove very small chips in very large numbers by cutting the action of many small individual abrasive grains. The abrasive grains are formed into a grinding wheel.Very smooth surfaces can be accomplished by the use of the proper grinding wheel.

MILLING MACHINE

The milling machine removes metal with a revolving cutting tool called a milling cutter. With various attachments, milling machines can be used for boring, slotting, circular milling dividing, and drilling. This machine can also be used for cutting keyways, racks and gears and for fluting taps and reamers.And the main parts are:

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I had observed the horizontal and vertical milling machines with different cutting tools.

Milling operations may be classified under four general headings as follows:

Face milling. Machining flat surfaces which are at right angles to the axis of the cutter

Plain or slab milling. Machining flat surfaces which are parallel to the axis of the cutter.

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Angular milling. Machining flat surfaces which are at an inclination to the axis of the cutter.

Form milling. Machining surfaces having an irregular outline.

And using the operations we can do boring , slotting, dividing etc

Types of milling machines include: KNEE-TYPE MILLING MACHINE UNIVERSAL HORIZONTAL MILLING MACHINE RAM-TYPE MILLING MACHINE UNIVERSAL RAM-TYPE MILLING MACHINE SWIVEL CUTTER HEAD RAM-TYPE MILLING MACHINE

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PLANERS

A planer is a type of metalworking machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath .A planer is analogous to a shaper, but larger, and with the entire workpiece moving on a table beneath the cutter, instead of the cutter riding a ram that moves above a stationary workpiece.

The principle parts of the planer are

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Planers are generalley divided into 5 types:

Double Housing Planer Open Side Planer Edge Type Planer Divide Table Planer Pit Type Planer

The planer I have seen was one sided planer

The common operations performed in a planer are generraly same as of shaper but it is far better in big size handling the operation I had seen were:

Planning flat horizontal surfaces. Planning curved surfaces. Planning slots and grooves.

DRILL MACHINES

A machine designed to hold drill bits which will produce cylindrical holes is a drill press and used for producing cylindrical holes, as well as reaming, boring, counter-boring, counter-sinking, honing, lapping and tapping.

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There are three major types:

- Sensitive drill (light drilling)- Upright drill (heavy duty drilling)- Radial arm drill press (large, heavy workpieces)

And main parts are seen:

Drilling is an economical way of removing large amounts of metal to create semi-precision round hole or cavity. Drilling allows a person to make holes through boards, metals, and other materials. Used for last removal of stock on preparation for other operations like boring, reaming, or tapping.

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Some major drilling operations are:

Spot drilling

Center drilling

Deep hole drilling

Gun drilling

Trepanning

Microdrilling

And the type I had observed were spot drilling and center drilling.

COMPUTERIZED NUMERICAL CONTROL MACHINES (CNC)

Numerical control (NC) refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to manually controlled via handwheels or levers, or mechanically automated via cams alone. modern computer numerical controlled (CNC) machine tools that have revolutionized the manufacturing process. Modern CNC mills differ little in concept from the original model built at MIT in 1952. Mills typically consist of a table that moves in the X and Y axes, and a tool spindle that moves in the Z (depth). The position of the tool is driven by motors through a series of step-down gears in order to provide highly accurate movements, or in modern designs, direct-drive stepper motors.

NC-like systems are now used for any process that can be described as a series of movements and operations. These include laser cutting, welding, friction stir welding, ultrasonic welding, flame and plasma cutting, bending, spinning, pinning, gluing, fabric cutting, sewing, tape and fiber placement, routing, picking and placing (PnP), and sawing.

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The cnc I had seen there was a planer cnc .

Proof of I being there

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