Three Law of ROBOTICS

Law of Robotics

There are three law of Robotics developed by Mr. Issak asimove also called Asimove's law are.

1st law

A robot may not injure a human being or, through inaction, allow a human being to come to harm.

2nd law

A robot must obey orders given it by human beings except where such orders would conflict with the First Law.

3rd law

A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

Ultrasonic Machining

Ultrasonic Machining

Introduction

         Ultrasonic machining, is a manufacturing process that removes material from the surface of a part through high frequency and low amplitude vibrations of a tool against the material surface in the presence of fine abrasive particles.

The fine abrasive grains are mixed with water to form a slurry that is distributed across the part and the tip of the tool.

Important parameters

•Frequency :  about 20000 to 30000 Hz

•Amplitude :  0.05 to 0.125 mm 

•Tool material :  Steel, stainless steel etc.

•Abrasive material : Silicon carbide, aluminum oxide, boron carbide

•Material of operation : Brittle and hard material

•Transducer material : Nickel or Nickel alloys 

Schematic diagram

Part Introduction

• Power Source: 

High frequency high voltage power supply require for this process. This unit

converts low frequency electric voltage (60 Hz) into high frequency electric

voltage (20 kHz).

•Transducer: 

Transducer is a device which converts electric single into mechanical vibration.

•Booster: 

The mechanical vibration generated by transducer is passes through booster

which amplify it and supply to the horn.

Tool holder/Horn: 

As the name implies this unit connects the tool to the transducer. It transfers amplified vibration from booster to the tool. It should have high endurance limit.

Working Principle 

        First the low frequency electric current passes through electric supply. This

low frequency current converts into high frequency current through some

electrical equipment.

This high frequency current passes through transducer. The transducer converts

this high frequency electric single into high frequency mechanical vibration.

This mechanical vibration passes through booster. The booster amplify this high

frequency vibration and send to horn.

Horn which is also known as tool holder, transfer this amplified vibration to tool

which makes tool vibrate at ultrasonic frequency.

As the tool vibrates, it makes abrasive particle to vibrate at this high frequency.

This abrasive particle strikes to the work piece and remove metal form it.

Advantages of USM

•Hard material can be easily machined by this method.

•No heat generated in work so there is no problem of work hardening or change in structure of workpiece.

•Non-conductive metals or non-metals, which cannot be machined by ECM

of EDM can be machined by it.

Disadvantages of USM

•It is quite slower than other mechanical process.

•Tool wear is high because abrasive particle affect both work-piece and

tool.

•It can machine only hard material, Ductile metal cannot be machine

by this method.

•It cannot used to drill deep hole.

Applications of USM

•This machining is used to machine hard and brittle material like

carbide, ceramic, glass etc.

•This is used in machining of die and tool of drill, wire drawing

machine etc.

•Used in fabrication of silicon nitrite turbine blade.

•It is used to cut diamond in desire shape.

Water Jet Machining

Water Jet Machining

Introduction

            Water jet machining is process of removing unwanted material from workpiece by means of high pressure fluid with or without abrasive material.

In water jet machining, high velocity water jet is allowed to strike a given workpiece. During this process, its kinetic energy is converted to pressure energy. This induces a stress on the workpiece. When this induced stress is high enough, unwanted particles of the workpiece are removed.

Block Diagram

Part Introduction

•Reservoir: Storing water that is to be used in the machining operation.

•Pump: It pressurize  the water from the reservoir.

•Intensifier: Connected to the pump. It intensifies the water to a desired level.

•Accumulator: Temporarily store the pressurized water. It is connected to the

flow regulator through a control valve.

•Control Valve: It controls the direction and pressure of pressurized water that

is to be supplied to the nozzle.

•Flow regulator: It is used to regulate the flow of water.

•Nozzle:  Discharge water to the workpiece at high velocity.

Working principle

•Water from the reservoir is pumped to the intensifier using a hydraulic pump.

•The intensifier increases the pressure of the water to the required level.

Usually, the water is pressurized to 200 to 400 MPa.

•Pressurized water is then sent to the accumulator. The accumulator

temporarily stores the pressurized water.

•Pressurized water then enters the nozzle by passing through the control valve

and flow regulator.

•Control valve controls the direction of water and limits the pressure of water

under permissible limits.

•Flow regulator regulates and controls the flow rate of water

•Pressurized water finally enters the nozzle.

•Here, it expands with a tremendous increase in its kinetic energy.

•High velocity water jet is produced by the nozzle.

•When this water jet strikes the workpiece, stresses are induced. These stresses

are used to remove material from the workpiece.

Advantages of WJM

1) Water jet machining is a relatively fast process.

2) It prevents the formation of heat affected zones on the workpiece.

3) It automatically cleans the surface of the workpiece.

4) WJM has excellent precision.

5) It does not produce any hazardous gas.

6) It is eco-friendly

Disadvantages of WJM

1) Only soft materials can be machined.

2) Very thick materials cannot be easily machined.

3) Initial investment is high.

Applications of WJM

1) Water jet machining is used to cut thin non-metallic sheets.

2) It is used to cut rubber, wood, ceramics and many other soft materials

.

3) It is used for machining circuit boards.

 4) It is used in food industry.

Abrasive Jet Machining

Abrasive Jet Machining

Introduction

         Abrasive jet machining (AJM) is an abrasive  blasting machining process that uses abrasives propelled by a high velocity gas to erode material from the workpiece. Common uses include cutting heat-sensitive, brittle, thin, or hard materials. Specifically it is used to cut intricate shapes or form specific edge shapes.

Important parameters

•Abrasive particle size : 0.025mm

•Pressure of gas : 4 bar

•Speed : 1000 Km/h

•Grit material : Aluminum oxide, silicon carbide, glass beads

Block Diagram

Part Introduction

Mixing chamber: 

It is used to mix the gas and abrasive particles

.

Filter: 

It filters the gas before entering the compressor and mixing chamber.

Hopper: 

Hopper is used for feeding the abrasive powder.

Pressure gauges and flow regulators: 

They are used to control the pressure and regulate the flow rate of abrasive jet.

Vibrator: 

It is provided below the mixing chamber. It controls the abrasive powder feed

rate in the mixing chamber.

Nozzle:

It forces the abrasive jet over the work piece. Nozzle is made of hard and

resistant material like tungsten carbide

Working Principle

• Dry air or gas is filtered and compressed by passing it through the filter and

compressor.

• A pressure gauge and a flow regulator are used to control the pressure and

regulate the flow rate of the compressed air.

• Compressed air is then passed into the mixing chamber. In the mixing

chamber, abrasive powder is fed.

• A vibrator is used to control the feed of the abrasive powder. The abrasive

powder and the compressed air are thoroughly mixed in the chamber. The

pressure of this mixture is regulated and sent to nozzle.

The nozzle increases the velocity of the mixture at the expense of its pressure.

A fine abrasive jet is rendered by the nozzle. This jet is used to remove

unwanted material from the workpiece.

Advantages of AJM

1) Surface of the work piece is cleaned automatically.

2) Smooth surface finish can be obtained.

3) Equipment cost is low.

4) Hard, brittle and materials high strength can be easily machined.

Disadvantages of AJM

1) Metal removal rate is low.

2) Nozzle life is less. Nozzle should be maintained periodically.

•tungsten carbide nozzles : About 12 to 30 hours,

•sapphire nozzles : About 400 hours

3) Abrasive Jet Machining cannot be used to machine soft materials.

M-codes used in CNC

M-Codes

List of Miscellaneous codes used in CNC Milling and Turning

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 off; 
(Lathe and Mill)

M06 - Automatic Tool change; 
(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)

G-codes used in CNC Milling and Turning machine

G-Codes

List of G-codes used in CNC Milling and Turning

G00 - Positioning at rapid speed; 

(Mill and Lathe)

G01 - Linear interpolation; (Machining in straight line)

(Mill and Lathe)

G02 - Circular interpolation clockwise (machining arcs);

(Mill and Lathe)

G03 - Circular interpolation, counter clockwise; 

(Mill and Lathe)

G04 - Dwell

(Mill and Lathe)

G09 -  Exact stop

(Mill and Lathe,)

G10 - Setting offsets in the program; 

(Mill and Lathe)

G12 - Circular pocket milling, clockwise; 

(Mill)

G13 - Circular pocket milling, counterclockwise; 

(Mill)

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)

G31 - Skip function; 

(Mill and Lathe)

G32 - Thread cutting; 

(Lathe)

G33 - Thread cutting; 

(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)

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 - Thread cutting cycle; 

(Lathe)

G94 - Per minute feed; 

(Mill)

G95 - 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)