Metalwork machines are those machines that are used to perform various processes for making metal products;the processes include:cutting,bending,forming and joining.
TYPES OF METALWORK MACHINES
The power hacksaw is a metal cutting machine which is used for cutting various sizes of metals to be used for the production of items. The power hacksaw is electrically driven or operated and also can cut metal rod of big diameters or thickness with ease compared to the hand hacksaw.
This metalwork machine can cut circular,rectangular,triangular and hexagonal shapes of metal rods or bars.
Grinders are used for sharpening tools and grinding surfaces;they are also used to cut off excess metal or unwanted metal to bring the component to the desired shape.There are different types of grinders.They are:
The bench grinder is a very small machine,which is always mounted on a bench in the workshop. It has its grinding wheels(abrasive) mounted at each end of a shaft protruding from an electric motor. Bench grinder is mostly used for general purposes of light grinding and sharpening of tools. The grinding operation of a bench grinder is referred to as ”off hand”. This is because the work piece is brought into contact with the abrasive wheel by a free hand.
The pedestal grinder is similar to the bench grinder and it is usually bigger than the bench because of its length. It is always mounted on a base of its own which is bolted to the floor. The pedestal grinder is used for the sharpening of tools and also for other general grinding operations.
The surface grinder is for grinding flat and parallel surfaces. It is used to obtain a high quality surface finish of metal,coupled with a high degree of accuracy.
Grinding means the removal of metal surplus or oversize from the work piece surface. It is also used for other purposes like obtaining a very high degree of accuracy and a good smooth finish. Cutting off and sharpening of tools are other benefits of grinding operation.
Off-hand grinding operation is a type of grinding machine which is held firmly in the tool rest and brought in contact with the wheel surface. During the off-hand grinding process,the tool often becomes hot. It is advisable to cool the tool by intermittent dipping in a recommended coolant. Note that water should not be used in cooling because it causes cracks to occur on the surface of the tool which may lead to breakage;and again the tool should not be held too long against the wheel to avoid overheated.
The centre lathe is a power-operated machine designed to produce a geometrical surface to a high level of accuracy.The tool is rigidly fixed on a tool post and moved along a parallel path to the centre axis of the revolving work piece in order to generate a cylindrical surface.Note that to generate means to produce the required surface by the intersection of two opposing conditions that are:
- Rotation of the work piece
- Movement of the tool
The following are the types of lathes;they are: centre lathe,capstan-lathe,turret-lathe. The centre-lathe consists of an accurately machined bed upon which the headstock that provides a means of rotation of the workpiece is mounted. The tailstock providing a means of support for the workpiece;the tailstock is movable along the bed when necessary. Then the saddle unit is accurately located upon the bed and can also be moved along it with the single point cutting tools mounted for carrying out the necessary operations.
PARTS OF THE CENTRE-LATHE AND THEIR FUNCTION
This the foundation of the machine and its basic structure; it is important that the bed is robust and rigid in construction . The lathe bed is made of cast iron,having rigid legs and accurately machined. The bed provides the framework on which the other parts are mounted;the parts like the headstock,tailstock,the carriage and tool post.
The headstock is the casting fastened to the left end of the bed and it is used to rotate the workpiece;and also it houses the chuck in its front as well as the backgear which provides the drive to the hollow spindle passing through it.
The tailstock is the component that is located at the right side of the bed of the machine.The tailstock can be moved along the bed’s length such that it can be locked in position at any desired point along the bed of the machine. The tailstock carries various tools and fittings like the lathe-centre,drill chuck,taper shank drills and reamers. It is also used for supporting one end of the workpiece when turning between centres.
The carriage of the lathe carries various functioning parts performing different functions.These includes: the saddle,cross slide,compound rest,top slide and apron.