Post on 29-May-2017
A grinding machine, often shortened to grinder, 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.
Grinding is used to finish workpieces that must show high surface quality (low
surface roughness) and high accuracy of shape and dimension. As the accuracy in
dimensions in grinding is on the order of 0.000025 mm, in most applications it tends to
be a finishing operation and removes comparatively little metal, about 0.25 to 0.50 mm
depth. However, there are some roughing applications in which grinding removes high
volumes of metal quite rapidly. Thus, grinding is a diverse field.
These machines include the:
Belt grinder, which is usually used as a machining method to process metals and other
materials, with the aid of coated abrasives. Sanding is the machining of wood; grinding
is the common name for machining metals. Belt grinding is a versatile process suitable
for all kind of applications like finishing, deburring, and stock removal.
Bench grinder, which usually has two wheels of different grain sizes for roughing and
finishing operations and is secured to a workbench or floor stand. Its uses include
shaping tool bits or various tools that need to be made or repaired. Bench grinders are
manually operated.
Cylindrical grinder, which includes both the types that use centers and the centerless
types. A cylindrical grinder may have multiple grinding wheels. The workpiece is rotated
and fed past the wheel(s) to form a cylinder. It is used to make precision rods, tubes,
bearing races, bushings, and many other parts.
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Cylindrical grinder
Tool and cutter grinder and the D-bit grinder. These usually can perform the minor
function of the drill bit grinder, or other specialist toolroom grinding operations.
Jig grinder, which as the name implies, has a variety of uses when finishing jigs, dies,
and fixtures. Its primary function is in the realm of grinding holes and pins. It can also be
used for complex surface grinding to finish work started on a mill.
Gear grinder, which is usually employed as the final machining process when
manufacturing a high-precision gear. The primary function of these machines is to
remove the remaining few thousandths of an inch of material left by other manufacturing
methods (such as gashing or hobbing).
Surface grinder which includes the wash grinder. A surface grinder has a "head" which
is lowered, and the workpiece is moved back and forth past the grinding wheel on a
table that has a permanent magnet for use with magnetic stock. Surface grinders can
be manually operated or have CNC controls. Rotary surface grinders or commonly
known as "Blanchard" style grinders, the grinding head rotates and the table usually
magnetic but can be vacuum or fixture, rotates in the opposite direction, this type
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machine removes large amounts of material and grinds flat surfaces with noted spiral
grind marks. Used to make and sharpen; burn-outs, metal stamping die sets, flat shear
blades, fixture bases or any flat and parallel surfaces.
Surface grinder
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Lathe machine is the only one of the most versatile machine in the engineering
workshop. While many soma to types lathe machine was used before the 18th century,
first nanun lathes that can cut threads are only created in 1797 by an Englishman
named Henry Maudslay mechanics. His invention was a machine used in the
construction of railroad steam engine James Watt invention in the early 19th century at
the time of the industrial revolution England.sejak of time this machine has been
improved and added with some additional equipment in order to manufacture the
components correctly and precision. In Malaysia, the machine is very popular that every
engineering workshops have at least one machine.
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Function of Lathe Machine
The main parts lathe machine consists of a platform , tools front , rear tool , quick
change gear box and a car.
Base
a) (a ) The track is the backbone of a lathe machine . The accuracy depends on the
rigidity of lathe machines , precision alignment and on track.
b) ( b ) The top of the track can be V-shaped or flat and lie on top of other
equipment such as front equipment , front of cars and equipment .
c) ( c ) The track is made of high quality cast iron . Heat treatment of violence
committed against him so as to be resistant to wear .
Front Tools
a) (a ) This section is located to the left of the track machine .
b) ( b ) the main spindle shaped a hollow shaft which is supported by several
bearings are located in this section . Hujunjg spindle or tool nose to drop out
before the form of a tapered , threaded type or types of key cam ( kam lock)
c) ( c ) At the end of the spindle is some peraltan like chuck , lathe and tetengah live
dish can be installed and used discretion to hold a workpiece or component to be
indiameter .
d) ( d ) To turn the main spindle , a tool for future tools tackle or a series of
networking gear . Front Tools Geared have a wider range of rotation speeds and
more accurate when compared with devices that bertakal front . After the pulley
can slip when exposed to oil and this run resulted in an uneven or slippery .
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Back Equipment
a) (a ) This section is located on the right track. It can be activated throughout the
track and can also be locked in any desired position . Tools back consists of two
main parts, the body and the base.
b) ( b ) In the body there is a spindle with a Morse penirusan standards . Morse
taper clipper handle , such as drilling and reaming can be mounted on the
spindle .
c) ( c ) Sites with precision machined tools back to be seated on the right track . On
site there are two screws that are used coordinator to align the parallelism
between tetengah dead or alive tetengah tool offset turning back so kaedh tuirus
with this .
Apron
a) The apron is installed in front of the bolt gap . Aprons have some gear and
equipment used to control movement and kekesot latitude intervals . A hand
lever mounted to the pinion mesh with the rack is located under the runway. The
lever arm is rotated when to move the car manually. Overall the car and kekesot
Lintan can be moved automatically or manually
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Milling machines are tools designed to machine metal, wood, and other solid materials.
Often automated, milling machines can be positioned in either vertical or horizontal
orientation to carve out materials based on a pre-existing design. These designs are
often CAD directed, and many milling machines are CNC-operated, although manually
and traditionally-automated milling devices are also common. Milling machines are
capable of dynamic movement, both of the tool and the workpiece, and many milling
machines can perform multi-axis machining. Because of variations in orientation,
operation and application, milling machines have varying functions and different
operating principles.
Tooling
Milling machines can be outfitted with a number of tool heads to accomplish different
machining needs. Some of these tool heads include cutters, rounding mills, fluted mills
and ball end mills. Some milling machines have rotating tool ends that can change
depending on the needed task—computer programming communicates with the
machine when to change its tooling.
The different tooling used in milling machines is based on material and desired shape.
Because materials like wood and steel have different physical properties, different tool
bits are needed to properly machine the materials. If a milling machine uses a tool bit
that is not strong enough to machine steel, the tooling and even the machine itself can
be damaged. Tooling that is too strong for softer materials can damage the workpiece.
The basic tooling bit on a milling machine is called the cutter. A cutter is a shaped bar
that has saw teeth. The cutter rotates rapidly to cut down and shape materials. The
cutter is attached to an arbor, which is sometimes called a mandrel or mandril, a shaped
bar that varies in size, length and ending, and is used to hold the cutter firmly.
A milling cutter’s saw ending can be spaced, sized and oriented in many ways.
Generally, the teeth are either positioned in a straight up-and-down orientation, or
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angled in a helical orientation. Straight teeth are preferable in operations on denser
materials, while helical teeth can create very smooth cuts on softer materials. There are
a variety of cutters within these categories, including dense end cutters, t-slot cutters,
and angle cutters. Cutters are subject to different standardized sizes, with CAT sizes as
the most commonly-used standardization category in the United States.
Types of Milling Machines
Milling machines are categorized by their orientation to their workpiece and their degree
of motion.
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Die Sinking EDM
Electric discharge machining (EDM), sometimes colloquially also referred to as spark
machining, spark eroding, burning, die sinking or wire erosion, is a manufacturing
process whereby a desired shape is obtained using electrical discharges (sparks).[1]
Material is removed from the workpiece by a series of rapidly recurring current
discharges between two electrodes, separated by a dielectric liquid and subject to an
electric voltage. One of the electrodes is called the tool-electrode, or simply the ‘tool’ or
‘electrode’, while the other is called the workpiece-electrode, or ‘workpiece’.
When the distance between the two electrodes is reduced, the intensity of the electric
field in the volume between the electrodes becomes greater than the strength of the
dielectric (at least in some point(s)), which breaks, allowing current to flow between the
two electrodes. This phenomenon is the same as the breakdown of a capacitor
(condenser) (see also breakdown voltage). As a result, material is removed from both
the electrodes. Once the current flow stops (or it is stopped – depending on the type of
generator), new liquid dielectric is usually conveyed into the inter-electrode volume
enabling the solid particles (debris) to be carried away and the insulating properties of
the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is
commonly referred to as flushing. Also, after a current flow, a difference of potential
between the two electrodes is restored to what it was before the breakdown, so that a
new liquid dielectric breakdown can occur.
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Wire-cut EDM
The wire-cut type of machine arose in the 1960s for the purpose of making tools (dies)
from hardened steel. The tool electrode in wire EDM is simply a wire. To avoid the
erosion of material from the wire causing it to break, the wire is wound between two
spools so that the active part of the wire is constantly changing. The earliest numerical
controlled (NC) machines were conversions of punched-tape vertical milling machines.
The first commercially available NC machine built as a wire-cut EDM machine was
manufactured in the USSR in 1967. Machines that could optically follow lines on a
master drawing were developed by David H. Dulebohn's group in the 1960s at Andrew
Engineering Company for milling and grinding machines. Master drawings were later
produced by computer numerical controlled (CNC) plotters for greater accuracy. A wire-
cut EDM machine using the CNC drawing plotter and optical line follower techniques
was produced in 1974. Dulebohn later used the same plotter CNC program to directly
control the EDM machine, and the first CNC EDM machine was produced in 1976
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