Lathe machine: Main Parts, Operation and Working

Lathe machine: Main Parts, Operation and Working 

 Lathe machine is a basic machine which is used in every metal forming industries. It is combination of many parts which works together to perform a desire function. A lathe machine is used to machine cylindrical work piece which is 360 degree symmetrical form the axis of rotation. It used to perform turning, chamfering, boring, facing, internal threading, shaping, slot cutting etc. on cylindrical work piece.

There are many types of lathe machine but each machine consist some basic part which are essential for its proper working. These parts are bed, tool post, Chuck, head stock, tell stock, legs, Gear chain, lead screw, carriage, cross slide, split nut, apron, chip pan, guide ways etc. These parts work together to obtain desire motion of tool and work piece so it can be machined. 

The lathe machine works on basic principle that when the work piece rotate at a constant speed and a tool is introduce between its rotation, it cut the metal. This is basic fundamental of it. The working of lathe machine is explained in later section of this article.

Lathe machine: Main Parts, Operation and Working

We have briefly discussed about parts and working of lathe machine in upper section of this article. Now we will describe it.

Parts of Lathe Machine:

The lathe consist following parts.

1. Bed

It is the main body of the machine. All main components are bolted on it. It is usually made by cast iron due to its high compressive strength and high lubrication quality. It is made by casting process and bolted on floor space.  

2. Tool post

It is bolted on the carriage. It is used to hold the tool at correct position. Tool holder mounted on it.

3. Chuck

Chuck is used to hold the workspace. It is bolted on the spindle which rotates the chuck and work piece. It is four jaw and three jaw according to the requirement of machine.

4. Head stock

Head stock is the main body parts which are placed at left side of bed. It is serve as holding device for the gear chain, spindle, driving pulley etc. It is also made by cast iron.

5. Tell stock

Tell stock situated on bed. It is placed at right hand side of the bed. The main function of tell stock to support the job when required. It is also used to perform drilling operation.

6. Lead screw

Lead screw is situated at the bottom side of bed which is used to move the carriage automatically during thread cutting.

7. Legs

Legs are used to carry all the loads of the machine. They are bolted on the floor which prevents vibration.

8. Carriage

It is situated between the head stock and tell stock. It is used to hold and move the tool post on the bed vertically and horizontally. It slides on the guide ways. Carriage is made by cast iron.

9. Apron

It is situated on the carriage. It consist all controlling and moving mechanism of carriage.

10. Chips pan

Chips pan is placed lower side of bed. The main function of it to carries all chips removed by the work piece.

11. Guide ways

Guide ways take care of movement of tell stock and carriage on bed.

12. Speed controller

Speed controller switch is situated on head stock which controls the speed of spindle.

13. Spindle

It is the main part of lathe which holds and rotates the chuck.

Lathe Machine Operation & Working:

Lathe machine is used to cut the metal from cylindrical work piece, and convert it into desire shape. It turns the cylindrical work piece, and during turning a sharp edge cutting tool introduce, which cuts the metal. Its working can be described as follow. 

Lathe Machine Operation

1. A cylindrical work piece fixed to the chuck. A chuck may have three jaw or for jaw according to the requirement. The work piece is at the center or some eccentric according to the process perform.

2. The spindle starts to rotate and set it at desire speed. The spindle speed plays a huge role during cutting. The spindle rotates the chuck and work piece.

3. Now check the work piece is turning properly. If it not set the work piece using dial gauge.

4. Now set the tool at desire feed by moving the tool post and carriage. The feed also play main role during cutting. Large feed may cause unwanted temperature increase.

5. After it tool is introduce between moving work piece at desire feed rate. It cut the metal from work piece. The feed rate is set at the cutting condition.

6. Now all unwanted metal is removed by moving the carriage form horizontally and vertically as desire according to the job requirement. After complete all process we got a well finished job.

7. Lathe can perform turning, boring, chamfering, shaping, facing, drilling knurling, grooving as shown in figure.

Synchromesh Gearbox

Synchromesh Gearbox 

Difference Between ASS & ORS

American Standard Association (ASA)

The ASA system consists of seven elements to denote a single point cutting tool. They are always written in the following order. Back rake angle Side rake angle, End relief angle, Side relief angle, End cutting edge angle, Side cutting edge angle, and nose radius.

For example, tool signature 0, 10, 6, 6, 10, 12, 1 means
Back rake angle = 0°
Side rake angle = 10°
End relief angle = 6°
Side relief angle = 6°
End cutting edge angle = 10°
Side cutting edge angle = 12°
Nose radius = 1mm

Orthogonal Rake system (ORS) or International system

The ORS system comprises seven parameters to describe a tool. The main elements of ORS designated in the following order Angle of inclination, Normal rake angle, Side relief angle, End relief angle, End cutting edge angle, Approach angle and Nose radius.
Example: Tool signature 5, 10, 6, 6, 5, 90, 1
Angle of inclination = 5°
Normal rake angle = 10°
Side relief angle = 6°
End relief angle = 6°
End cutting edge angle = 5°
Approach angle = 90°
Nose radius =1mm

Chip thickness ratio

Difference Between Project Management and General Management

• Project management is usually employed in projects that are temporary and time constrained. General management is employed for ongoing procedures or functions of certain organizations, businesses etc.

• Usually, in project management, resources are limited. In contrast, general management is also responsible for resourcing whatever necessary ingredients as deemed necessary for the continuation of functions.

• Management is an academic discipline taught in schools and universities all over the world. Project management often falls under this broad discipline of management.

• Therefore, one can say that the difference between project management and general management does not lie in leadership or other qualities required, but in the scope of responsibilities that lie within each role.

Project management

Project management:

       Project management is the application of processes, methods, knowledge, skills and experience to achieve the project objectives. General. A project is unique,transient endeavor  undertaken to achieve planned objectives, which could be defined in terms of outputs, outcomes or benefits.

Compression ratio

Compression ratio-
It is the ratio of total volume by clearance volume

Mathematically-
r=Vt/Vc
   =[Vc+Vs]/Vc
Or , r=1+(Vs/Vc)

Mean effective pressure

Mean effective pressure-
It is defined as the pressure which is thought to be acting on the piston through out power stroke
  If it is related to indicated power then it is known as Imep
  It is related to B.P then it is known as Bmep


significance-
The actual performance of various engine are compaired on the basis of mean effective pressure

1st Internal Questions.

Failure of knuckle joint

The most common mode of failure is overloading. Operating forces of the application produce loads that exceed the clamp load and the joint works itself loose, or fails catastrophically. It occur due to shear forces and twisting moment.

we know the knuckle pin is used in knuckle joint to join the two shafts together and mode of failure of knuckle joint is failure due to crushing and failure due to shearing.when we exceed the designed load at the ends of the shafts then failure occurs.

Failure due to shearing:-

P= 2X shearing stress 

X shearing area

Failure due to crushing:-
P= crushing stress 

X crushing area

A knuckle joint has nine possible modes of failure. They are:

1. Failure of rod end by tension
2. Failure of rod end by double shear
3. Failure of rod end by crushing
4. Failure of forked ends by tension
5. Failure of forked ends by double shear
6. Failure of forked ends by crushing
7. Failure of knuckle pin by tension
8. Failure of knuckle pin by double shear
9. Failure of knuckle pin by bending

What is scope???

Scope is a project management term for the combined objectives and requirements necessary to complete a project. Properly defining the scope of a project allows a manager to estimate costs and the time required to finish the project. A project's scope includes all of the information and deliverables that are expected as the project progresses toward completion

5 BASIC PHASES OF PM

5 Basic Phases of Project Management
Project Management Institute, Inc. (PMI) defines project management as "the application of knowledge, skills, tools and techniques to a broad range of activities in order to meet the requirements of a particular project." The process of directing and controlling a project from start to finish may be further divided into 5 basic phases:

1. Project conception and initiation
An idea for a project will be carefully examined to determine whether or not it benefits the organization. During this phase, a decision making team will identify if the project can realistically be completed.

2. Project definition and planning
A project plan, project charter and/or project scope may be put in writing, outlining the work to be performed. During this phase, a team should prioritize the project, calculate a budget and schedule, and determine what resources are needed.

3. Project launch or execution
Resources' tasks are distributed and teams are informed of responsibilities. This is a good time to bring up important project related information.

4. Project performance and control
Project managers will compare project status and progress to the actual plan, as resources perform the scheduled work. During this phase, project managers may need to adjust schedules or do what is necessary to keep the project on track.

5. Project close
After project tasks are completed and the client has approved the outcome, an evaluation is necessary to highlight project success and/or learn from project history.

HYDRAULIC BRAKING SYSTEM

It is one of the most uses full braking system.it is called hydraulic braking system because the force is applied by the liquid pressure.

 SYTEM IS USED DUHYDRAULIC BRAKINGE TO

1. .For equal braking effort hydraulic braking system we us
2. .Easy to construct due to absence of brake rod
3. .The rate of wear is less

CONSTRUCTION

The main component of hydraulic braking system is

1. .master cylinder
2. . wheel cylinder

         Master cylinder is a cylinder  which contains reservoir for brake fluid ,. Master cylinder is operated by brake pedal  and connected to wheel cylinder of each wheel through the steel pipe lines.

The system is filled with the liquid  under low pressure when brakes are not applied .the liquid is known as brake fluid  and usually mixture of glycerin ,alcohol and some additives.

  Each wheel brake consist a cylinder brake i.e drum or disc which is mounted inside the wheel.

WORKING PRINCIPLE

Hydraulic  braking system works on principle of friction. master cylinder basically piston cylinder  device contains brake fluid  .

 When brake pedal is applied push rod moves the inside the cylinder which build up a pressure .

Due to this pressure  hydraulic fluid is  forced  inside the pipe lines  under pressure.

Then this fluid enters to the wheel where as a  small piston cylinder arrangement called caliper. this high pressure oil push the  piston pads towards the drum /disk .three by brake is applied.

MACHINABILITY AND TOOL LIFE

Machinability 

Machinability is a term indicating how the work material responds to the cutting process. In the most general case good machinability  means that material is cut with good surface finish, long tool life, low force and power requirements, and low cost.

It depends upon

The condition of the work material includes eight factors: microstructure, grain size, heat treatment, chemical composition, fabrication, hardness, yield strength, and tensile strength..

Tool life 

The tool life is the duration of actual cutting time after which the tool is no longer usable.