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Friday, 25 January 2019

Electrification of a Body (or) Electrification processes of bodies

          A body can be charged or electrified in many ways; the methods are discussed below:
a. Charging by friction
b. Charging by conduction or contact
c. Charging by induction
d. Electrification byh heating
e. Electrification by pressure

a. Charging by friction: When two nutral bodies are rubbed against each other, due to friction one of them losses electrons and hence gets positively charged and the body that ains electrons gets negetively charged.
Experiment: Take a small piece of uncharged plastic rod and cloth, rub against each other this will result both of them get charged. Same thing will happen between rubber rod and fur, Glass rod and silk cloth.

b. Charging by conduction: When a charged body is brought in direct contact with an uncharged body (or nutral body), it shares its charge with it. Thus the uncharged body becomes charged.

c. Charging by Induction: The process of temporary electrification of an initially neutral conductiong body (induced) by bringing a charged body (inducer) close to it without making any actual contact between the bodies is known as charging by induction.

d. Electrification by heating: Certain bodies, when heated, is electrified by presenting contrary electricities names in two diametrically opposite points. The phenomenon is called pyroelectric phenomenon. It is more common in crystalls, such as Tourmaline.

e. Electrification by pressure: Certain bodies, when compressed, is electrified, displaying electricities names against the ends. The phenomenon is called piezoelecttric phenomenon. It is also ore common in crystals, such as Tourmaline, Calcite, and Quartz. 

Thursday, 24 January 2019

Static Electricity

          Electricity is the phenomenon of flow of electric charges. The study related to the charges, when they are at rest is called as "Static electricity". Static electricity generates through friction.
          Greeks found that amber when rubbed with fur attracts small objects. The substances which on rubbing acquire the nature to attract lite objects are called as charged or electrified. The charged bodies possess electric charges by virtue of which they interact with each other. This force of interaction is called as "Electric force".

Some examples of static electricty are:

1) When we brush Dry hair with a plastic comb static electricity is produced. If we done it in a dark room we can also notice sparkles.
2) Similarly when we pass a comb through the dry hair, the hair will starts moving or stand.
3) We rub a plastic pen or a comb and placed near small pieces of paper they will get attracted.
4) Lightining is the best example of static electricity. Lighting causes due to the positive and negetive charges in the cloud.
5) We even can bend a stream of water using static electricity.


Uses:
There are several practical uses of static electricity, they are

1) Spray painting for car parts
          The spray nozzle is connected to a negetive electrode by this we can charge each droplet of paint. The car body parts is given a positive charge. When the paint is sprayed from a paint gun, the sprayed particles of paint will attracted by the car body parts. There are several more advantages by this method painting they are : (a) Paint goes to the charged body part not to the uncharged or nutral flor,  (b) Paint only attracted by body parts so less wastage, (c) there is no need of skilled labour for painting (d) the paint will distibuteded evenly so job will look neater.

2) Pollution control
          Static electricity is used in pollution control. Static charge is given to the dirt particles in the air and opposite charge is given to the collector. By this the dirt particles which are present in the air are attraced by the collector and pollution is controlled. These devices are called as "Electro static precepitators". Factories and thermal power plants use this kind of technique to reduce pollution coming from their smoke chimnies.

3) In photo copier








Basic Electricity

          The flow of electrons from one place to another is called as Electricity. Electrons can flow through any material, However electron flow is easy in some than in others. How simply it flows is termed as "Resistance". The resistance of material is measured in Ohm's

Basically the mater can be devided into

Conductors: The substances in which the electrons can flow easily. They offer low resistance.
Ex: Copper, Aluminium, Gold , Silver, Mercury, Sea water, Concrete, Steel, Iron.
Semi-conductors: A substance, usually a solid chemical compound, which can conduct electricity under certain circumstances.
Ex: Silicon, Germanium, Antimony, Arsenic, Boron, Carbon, Selenium, Sulfur, and Tellurium. 
Insulators: The substances in which electrons flow with great difficulty. They offer high resistance.
Ex: Pure water, Glass, Air, Dry Wool, Dry Wood, Plastic, Rubber, Diamond,  Asphalt, Oil, Ceramics, Quartz.


Tuesday, 20 November 2018

G AND M-CODES FOR CNC MACHINES

CNC G codes
G00 - Rapid traverse; Mill and Lathe
G01 - Linear interpolation (machining a straight line); Mill and Lathe
G02 - Circular interpolation clockwise (machining arcs); Mill and Lathe
G03 - Circular interpolation, CCW Polar co-ordinates; Mill and Lathe
G04 - Dwell time; Mill and Lathe
G09 - Mill and Lathe, Exact stop
G10 - Polar co-ordinates linear interpolation; Mill and Lathe
G12 - Circular pocket milling, clockwise; Mill
G13 - Circular pocket milling, counterclockwise; Mill
G14 - Exact spindle stop
G17 - X-Y plane for arc machining; Mill and Lathe with live tooling
G18 - Z-X plane for arc machining; Mill and Lathe with live tooling
G19 - Z-Y plane for arc machining; Mill and Lathe with live tooling
G20 - Inch units; Mill and Lathe
G21 - Metric units; Mill and Lathe
G27 - Reference return check; Mill and Lathe
G28 - Automatic return through reference point; Mill and Lathe
G29 - Move to location through reference point; Mill and Lathe (slightly different for each machine)
G31 - Skip function; Mill and Lathe
G32 - Thread cutting; Lathe
G33 - Thread cutting lead constant; Mill
G34 - Thread cutting lead increasing; Mill
G35 - Thread cutting lead decreasing; Mill
G40 - Cancel diameter offset; Mill. Cancel tool nose offset; Lathe
G41 - Cutter compensation left; Mill. Tool nose radius compensation left; Lathe
G42 - Cutter compensation right; Mill. Tool nose radius compensation right; Lathe
G43 - Tool length compensation; Mill
G44 - Tool length compensation cancel; Mill (sometimes G49)
G50 - Set coordinate system and maximum RPM; Lathe
G52 - Local coordinate system setting; Mill and Lathe
G53 - Machine coordinate system setting; Mill and Lathe
G54~G59 - Workpiece coordinate system settings #1 t0 #6; Mill and Lathe
G61 - Exact stop check; Mill and Lathe
G65 - Custom macro call; Mill and Lathe
G70 - Finish cycle; Lathe
G71 - Rough turning cycle; Lathe
G72 - Rough facing cycle; Lathe
G73 - Irregular rough turning cycle; Lathe
G73 - Chip break drilling cycle; Mill
G74 - Left hand tapping; Mill
G74 - Face grooving or chip break drilling; Lathe
G75 - OD groove pecking; Lathe
G76 - Fine boring cycle; Mill
G76 - Threading cycle; Lathe
G80 - Cancel cycles; Mill and Lathe
G81 - Drill cycle; Mill and Lathe
G82 - Drill cycle with dwell; Mill
G83 - Peck drilling cycle; Mill
G84 - Tapping cycle; Mill and Lathe
G85 - Bore in, bore out; Mill and Lathe
G86 - Bore in, rapid out; Mill and Lathe
G87 - Back boring cycle; Mill
G90 - Absolute programming
G91 - Incremental programming
G92 - Reposition origin point; Mill
G92 - spindle speed limit, Thread cutting cycle; Lathe
G94 - Feed rate, Per minute feed; Mill
G95 - Feed rate, Per revolution feed; Mill
G96 - Constant surface speed control; Lathe
G97 - Constant surface speed cancel
G98 - Per minute feed; Lathe
G99 - Per revolution feed; Lathe

CNC M Codes
M00 - Program stop; Mill and Lathe
M01 - Optional program stop; Lathe and Mill
M02 - Program end; Lathe and Mill
M03 - Spindle on clockwise; Lathe and Mill
M04 - Spindle on counterclockwise; Lathe and Mill
M05 - Spindle stop; Lathe and Mill
M06 - Tool change; Mill
M07 - Flood Coolant on; Lathe and Mill
M08 - Coolant on; Lathe and Mill
M09 - Coolant off; Lathe and Mill
M10 - Chuck or rotary table clamp; Lathe and Mill
M11 - Chuck or rotary table clamp off; Lathe and Mill
M19 - Orient spindle; Lathe and Mill
M30 - Program end, return to start; Lathe and Mill
M97 - Local sub-routine call; Lathe and Mill
M98 - Sub-program call; Lathe and Mill
M99 - End of sub program; Lathe and Mill

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